(04) 2035 LQ GP - CERTIFIED EIR - Section III (2013)Terra Nova/La Quinta General Plan EIR
Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
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LA QUINTA GENERAL PLAN
ENVIRONMENTAL IMPACT REPORT
III. EXISTING ENVIRONMENTAL CONCERNS, PROJECT IMPACTS AND
MITIGATION MEASURES
Aesthetics A.
Introduction and Background
The La Quinta General Plan Update Planning Area is located in the eastern portion of the
Coachella Valley, along the base of the Santa Rosa Mountains. The desert setting and
surrounding mountains provides picturesque backdrop and aesthetically pleasing environment
for the community. This section describes the existing aesthetic qualities of the La Quinta
Planning Area for the 2035 General Plan Update, which includes the incorporated portions of the
City and the two Sphere of Influence areas. It also discusses the potential impacts that may occur
from implementation of the General Plan Update and provides mitigation measures to reduce
impacts to visual resources.
Thresholds of Significance/Criteria for Determining Significance
Article 5, Section 15064 of the CEQA Guidelines provides guidance for determining the
significance of the environmental effects caused by a project. Appendix G of the CEQA
Guidelines provides a list of environmental factors that potentially may be affected by
completion of a project. The La Quinta 2035 General Plan Update would have a significant
effect on aesthetics if it is determined the project:
a) Has a substantial adverse effect on scenic vista.
b) Substantially damages scenic resources, including, but not limited to, trees, rock
outcroppings, and historic buildings within a state scenic highway.
c) Substantially degrades the existing visual character or quality of the site and its
surroundings.
d) Creates a new source of substantial light or glare, which would adversely affect day
or nighttime views in the area.
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1. Existing Conditions
Regional Setting
The Planning Area for the City of La Quinta 2035 General Plan Update is situated in the eastern
portion of the Coachella Valley in central Riverside County. The region is in an area known as
the Salton Trough, which is a fault controlled basin caused by the complex system of faults
crossing the region, including the San Andreas Fault. The Salton Trough is an expansive basin
that runs in a northwest to southeast direction, and includes varying topography and wildlife
habitats. Within the General Plan Update Planning Area, elevations range from 190 feet below
sea level in the southeastern portion of the Planning Area to 1,600 feet above sea level along the
peaks of the Coral Reef Mountains in the southwestern portion of the Planning Area. Other
topographic features in the region include the Indio Hills, located northeast of the Planning Area,
and the Santa Rosa Mountains, located west of the Planning Area.
The City of La Quinta is part of a larger community of local jurisdictions that make up the
Coachella Valley. To the north of La Quinta are the cities of Palm Desert, Indian Wells, Indio,
and a small portion of unincorporated Riverside County. These communities are primarily made
up of low-density residential neighborhoods, commercial centers, and resort and entertainment
facilities. Jurisdictions to the east of La Quinta include Indio, Coachella, the communities of
Vista Santa Rosa and Thermal. Land uses in these areas are predominantly low-density
residential and commercial, but also include agricultural lands, polo fields, rural residential, and
a regional airport. To the south of La Quinta are lands within the jurisdiction of the County of
Riverside, and areas subject to Native American Tribal jurisdiction. These areas are
predominantly agricultural lands, rural residential uses, and vacant desert lands. To the southwest
and west of La Quinta is public open space that is conserved as part of the Santa Rosa and San
Jacinto Mountains National Monument.
Existing Scenic Conditions
The La Quinta General Plan Update Planning Area is comprised of many land uses, including
residential, commercial, resort facilities, office parks, agricultural facilities, golf courses, open
spaces, and vacant land. These land uses are built primarily on the Valley floor and within the
Cove. Development within the City Limits is generally built at lower densities, and buildings
throughout the Planning Area tend to be low-rise structures. Views of local mountains and scenic
vistas throughout the incorporated portions of the City are generally good, however suburban
development, including buildings, walls, and mature landscaping can limit views in certain
places.
The eastern Sphere of Influence is rural and sparsely developed. Land uses in the Sphere include
single family residential, agricultural production and equestrian uses. There is also a considerable
amount of fallow vacant land once used for agriculture. Views of local mountains and scenic
vistas throughout this portion of the Sphere are preserved and unobstructed due to sparse
development. As a result of this rural character, the aesthetic quality is more open and views of
surrounding mountains are less restricted when compared to the more developed portions of the
region.
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Visual Character
The existing visual character of the Planning Area can be characterized as both suburban and
rural. The incorporated portion of La Quinta exemplifies suburban character. La Quinta’s
suburban character is influenced by typical suburban land uses, including residential
neighborhoods, commercial shopping centers, office parks, golf courses, parks, and community
facilities. These land uses are built along landscaped boulevards with curb, gutter and sidewalks.
Large retail centers are located along Highway 111, while community scale commercial
development occurs on Washington Street and Jefferson Street.
The eastern Sphere can be characterized as more rural, and lack many of the suburban features
found throughout the incorporated portions of La Quinta. Development is sparse, and land uses
are predominantly associated with agricultural production, ranches, or nurseries. Existing
residential uses within these areas are predominantly on larger lots. An exception is a single-
family neighborhood near Jackson Street and Avenue 55, which is more typical of a suburban
style subdivision. Roads throughout the eastern Sphere of Influence tend to be two-lane rural
roads built without sidewalks, curbs and gutters, or landscaping.
Architectural Styles
La Quinta includes a mixture of building types built over various time periods, and with a variety
of architectural styles. Development includes structures built in the early twentieth century, and
new master-planned communities built within the last decade. Architectural styles include those
typical of Spanish Colonial, Mediterranean, Tuscan, and Modern styles. Spanish Colonial
architecture is the most prevalent style used in La Quinta, and examples include the La Quinta
Resort & Spa and the more recent Old Towne development in the Village.
Architectural styles throughout the Sphere of Influence Areas are limited and are associated with
rural lifestyle. Large equestrian facilities and ranch style homes on large lots are scattered
throughout the area.
Light and Glare
Existing sources of light and glare in the Planning Area are found mostly within the city limits.
Large commercial centers along Highway 111 produce light and glare from parking lots, signs,
and street lighting for security purposes. There are also various car dealerships along Highway
111 that produce light and glare for security purposes. Existing school playfields and recreational
facilities, such as La Quinta Park and La Quinta Community Park, also produce light and glare
from overhead field lights. Major arterials throughout the City produce light and glare from
street lamps, signalized intersections, and vehicle headlights.
Light and glare within the Sphere of Influence is minimized by the lower intensity of existing
development. The eastern Sphere is dominated by vacant desert, agricultural fields and very low
density residential, which produce lower levels of light than the urbanized areas of the City. The
lack of street lights and traffic signals in the area also limit the amount of light and glare.
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2. Project Impacts
The 2035 General Plan Update will facilitate new development throughout the Planning Area
through the adoption of its Land Use Map, and policies promoting development. Therefore, the
General Plan Update has the potential to impact the existing aesthetic quality of the Planning
Area. The General Plan Update does not, however, propose any significant changes to the land
use pattern in the City.
The General Plan Update designates the Sphere for low density residential, commercial,
industrial, and community facilities. The General Plan Update also requires the master planning
of the eastern Sphere. This master plan could change the character of the eastern Sphere in the
long term, should these lands be annexed into the City.
The following discussion highlights the potential impacts on aesthetic resources, including scenic
vistas, scenic resources, visual character, and light and glare from implementation of the 2035
General Plan Update.
Scenic Vista Impacts
Within the Planning Area, scenic vistas include views of natural features, including the Santa
Rosa, San Jacinto, and Little San Bernardino Mountains.
The General Plan Update will facilitate new development in areas that are currently vacant, and
encourage redevelopment in existing urbanized areas within the City. The development of new
manmade structures, including buildings, streets, signage, walls, and landscaping, has the
potential to replace or disrupt views of the surrounding natural landscape. Redevelopment
projects in existing urbanized areas may also potentially affect the scenic vista if they increase
the intensity of the built environment. Conversion of empty lots or parking lots into new compact
developments or structures increase the potential to block views of the surrounding desert and
mountains from existing development.
Within the eastern Sphere, the General Plan Update will allow new residential, commercial and
industrial uses upon annexation, on lands that are currently used for agriculture. The conversion
of agricultural land has the potential to change the rural character of the area, and diminish the
openness and views of nearby mountains. As described above, however, the General Plan Update
includes master planning of the Vista Santa Rosa area prior to annexation or development in the
City. The stated purpose of this master planning effort is the preservation of the neighborhoods
character. In addition, the Sphere area will be subject to the policies and programs of the Land
Use and Sustainable Community Elements if annexed.
The General Plan Update provides policies and programs to protect existing views and maintain
existing scenic vistas. These include policies relating to the preservation of existing
neighborhoods, and the implementation of development standards to reduce impacts from new or
redeveloped projects on adjacent lands. Further, the City will continue to implement its Zoning
standards, which limit building height, and control mass and scale. Finally, the Sustainable
Community Element contains policies geared to high quality design in harmony with the natural
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environment, as well as the preservation of natural resources. The policies and programs
contained in that Element will also limit the potential impacts on scenic vistas resulting from
implementation of the General Plan Update. As a result, impacts on scenic vistas caused by
implementation of the General Plan Update, will be less than significant.
Scenic Resources Impacts
Scenic Resources includes trees, rock outcroppings, and historic buildings that are visible from a
state scenic highway. Currently, there are no state scenic highways that run through La Quinta or
the Sphere of Influence. Therefore, impacts to scenic resources along a state scenic highway will
be less than significant.
As discussed in more detail in the Cultural Resources Section, there are a number of recorded
historic-period buildings in the Planning Area. New development has the potential to impact
these structures. The General Plan includes policies protecting historic structures, and assuring
that these structures are assessed and protected, where necessary, if development is proposed. In
addition, impacts and mitigation measures associated with cultural resources are discussed
further in Section III-E of this document. The policies of the General Plan, and mitigation
measures included in Section III-E will assure that impacts associated with historic buildings will
be less than significant.
Visual Character Impacts
The existing visual character of the Planning Area includes the existing look, feel, and quality of
urbanized and natural areas. As described above, the Planning Area is currently characterized as
both urban and rural. The incorporated portions of the Planning Area are predominantly urban,
while the Sphere of Influence is predominantly rural. The General Plan Update has the potential
to cause significant impacts on the existing visual character of the area, especially in the Sphere
of Influence.
Existing development within the City consists of small scale and lower density residential,
commercial, office, public facilities, golf courses, parks and open space. Buildings tend to be
low-rise structures, which preserves views of the surrounding mountains from private and public
lands. An interconnected street system provides accessibility throughout the City limits. For the
most part, streets are developed with sidewalks, curbs, and gutters. Landscaping along public
right-of-ways provides visual relief from the built environment and enhances the visual character
of the community.
The General Plan Update does not propose changes in land use intensities or densities, insofar as
no new land use designations are being considered. Policies and programs in the General Plan
Update are consistent with the existing character of development in the City, and do not propose
intensification or densification of the City or Sphere. Streets will continue to be developed with
curb, gutter, and landscaping to improve visual character along public right-of-ways. Visual
character impacts within the City, therefore, are expected to be less than significant.
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The visual character of the Sphere is currently more rural than that within the City’s limits, with
very low-density ranch homes, small subdivisions, farms, polo fields, and vacant land. The
General Plan Update does not change the land use designations within this area, and includes a
requirement for master planning of the area prior to annexation. New development in the area
will be governed by this master plan if these lands are annexed to the City. As stated in the
General Plan Update, the master plan is to reflect the character of the area. This requirement will
result in development consistent with this character, which will serve to preserve the visual
character of the area.
As development occurs, new and expanded streets will also develop throughout the Sphere of
Influence, and existing rural roads will be widened and developed with new sidewalks, curbs,
and gutters. The development standards for these streets will include parkway landscaping, trails
and sidewalks, as is required throughout the City, if these lands are annexed. The development
standards will be set in the proposed master plan, which must be developed to reflect community
character. The General Plan Update will therefore have less than significant impacts on the
visual character of the Sphere of Influence.
Light and Glare Impacts
Light and glare impacts are associated with increased urbanization. Within the City limits, the
majority of lands are developed, and daytime and nighttime skies are already affected to a
limited extent by light and glare. The adoption of the General Plan Update will facilitate similar
development patterns in the City to those that exist today. Further, the General Plan Update
maintains policies and programs currently in effect that limit lighting, and the City’s Municipal
Code prohibits light spillage onto neighboring properties. Therefore, implementation of the
General Plan Update will have a less than significant impact on light and glare impacts within
the City.
Build out of land uses proposed for the Sphere will increase the light and glare in this area. Dark
skies will diminish with more traffic, buildings, street lights and indoor illumination. The City
Outdoor Lighting Ordinance (Section 9.100.150 of the Municipal Code) provides regulations for
reducing light and glare caused by new development. The General Plan Update maintains
policies and programs to preserve low lighting levels and the Outdoor Lighting Ordinance, and
requires all future development to develop according to these regulations.
Therefore, implementation of the General Plan Update will have a less than significant impact on
light and glare.
3. Mitigation Measures
The La Quinta 2035 General Plan Update will facilitate continued urbanization in areas that are
undeveloped, but also provides goals, policies and programs to reduce aesthetic impacts
associated with new development. The City’s land use pattern will not change due to the Update,
and the Land Use and Sustainable Community Elements will control the mass, scale and bulk of
new projects and redeveloped sites. Impacts associated with aesthetics are expected to be less
than significant, and no mitigation measures are required.
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Agricultural Resources B.
Introduction and Background
The General Plan Planning Area has soils and topography suitable for agricultural production.
The Riverside County Important Farmland Map of 2008 has designated areas within the
Planning Area as being important farmland, particularly within the eastern Sphere. Currently,
however, farming in the eastern Sphere is scattered, and much of the lands remain vacant or
fallow. This section assesses impacts on agricultural resources from future growth and
development resulting from the General Plan Update.
Thresholds of Significance/Criteria for Determining Significance
Article 5, Section 15064 of the CEQA Guidelines provides guidance for determining the
significance of the environmental effects caused by a project. Appendix G of the CEQA
Guidelines provides a list of environmental factors that potentially may be affected by
completion of a project. The La Quinta General Plan Update would have a significant effect on
Agricultural Resources if it is determined the General Plan Update would:
a) Convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance, as
shown on the maps pursuant to the Farmland Mapping and Monitoring Program of
the California Resources Agency, to non-agricultural use.
b) Conflict with existing zoning for agricultural use, or a Williamson Act Contract.
c) Involve other changes in the existing environment, which, due to their location or
nature, could result in conversion of Farmland, to non-agricultural use.
1. Existing Conditions
Agriculture has been a major source of economic activity in the Coachella Valley since the turn
of the 20th century. The Valley provides excellent soils, flat topography, abundant sunshine, and
available water resources, making it a contributor to the State’s agricultural production. The date
palm was introduced to the Valley, and has historically been a staple crop for the region. Other
crops, such as grapes, citrus, vegetables, turf production and ornamentals have also been farmed
in the region. Land available for agricultural production continues to be threatened by increased
urbanization. Since World War II, the Coachella Valley has increased in popularity as a resort
destination, and become home for permanent residents, winter visitors, and the associated
commercial development required to support these households.
La Quinta has experienced the same growth patterns experienced by other nearby cities in the
Coachella Valley. The Sphere of Influence is more rural, with scattered farms, nurseries, and
very low density development. Much of the farming in this area, however, has ceased and the
area remains vacant land. Future development on these vacant lands will be more suburban in
nature.
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Existing Agricultural Land Uses in the Planning Area
Agricultural uses in the General Plan Update Planning Area are located primarily within the
Sphere of Influence, however a few small citrus groves are located within City limits.
Undeveloped portions of incorporated La Quinta and the Sphere are located in areas designated
as Prime Farmland, Farmland of Statewide Importance, Unique Farmland or Lands of Statewide
Importance, according to the Riverside County Important Farmland Map of 2008. The map was
compiled by the Farmland Mapping and Monitoring Program, under the California Department
of Conservation. 1 In 2008, there were approximately 1,700 acres of important agricultural land
located in the City, and 7,391 acres in the Sphere of Influence, for a total of 9,091 acres. A
description of each classification is found below.
Prime Farmland
Prime Farmland is defined as land with quality soil and moisture supply that allows for
production of high yield crops when managed by modern farming methods. These lands are best
suited for producing food crops, feed, forage, fiber, and oilseed crops. The best use of the land is
for cropland, pastureland, rangeland, and forestland, however urban uses are not recommended.2
Prime Farmland is the largest category of farmland found within the Planning Area. According
to the Important Farmland Map of 2008, approximately 5,424 acres, or 66% of total land in the
Sphere of Influence are designated Prime Farmland. Within the City Limits, 457 acres are
designated as Prime Farmland.3
Farmland of Local Importance
Farmland of Local Importance represents the second largest share of farmland within the
Planning Area. These lands have the soil quality and characteristics of Prime Farmland or
Statewide Important Farmlands, but lack available irrigation water. These lands may produce
crops important to Riverside County, but are not listed as Unique Farmland Crops.4
The Sphere has approximately 1,832 acres of land under this category, which represents
approximately 22% of total land within the Sphere of Influence. Within the City Limit,
approximately 1,214 acres are designated as Farmlands of Local Importance.5
1 “Riverside County Important Farmland 2008”, prepared by California Department of Conservation, Division of
Land Resource Protection, prepared September 2009. 2 Ibid. 3 As provided by City of La Quinta Planning Department through Riverside County Important Farmland GIS
Data, http://redirect.conservation.ca.gov/DLRP/fmmp/county_info_results.asp. 4 “Riverside County Important Farmland 2008”, prepared by California Department of Conservation, Division of
Land Resource Protection, prepared September 2009. 5 As provided by City of La Quinta Planning Department through Riverside County Important Farmland GIS
Data, http://redirect.conservation.ca.gov/DLRP/fmmp/county_info_results.asp.
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Unique Farmlands
Unique Farmlands represents the third largest type of farmland in the General Plan Update
Planning Area. This type of farmland has reduced soil quality or characteristics from Prime
Farmland or Statewide Important Farmlands, but can still be used for high value food and fiber
crops. These lands are capable of producing crops such as citrus, olives, and avocados.6
The Sphere of Influence has approximately 133 acres designated as Unique Farmlands, which
includes the nurseries in the northern Sphere of Influence. The City Limits has 29 acres
designated as Unique Farmland.
Statewide Important Farmlands
Statewide Important Farmlands represent the smallest share of farmland in the La Quinta
General Plan Update Planning Area. These lands are similar to Prime Farmlands, however do not
exhibit as good soil as Prime Farmland. Statewide Important Farmland still has a good
combination of physical and biological characteristics for producing similar crops as Prime
Farmlands, and is available for cropland, pastureland, rangeland, or forestland.7
There are minimal amounts of land considered Statewide Important Farmlands. The Sphere of
Influence has only 1.98 acres of Statewide Important Farmlands, and the City Limit has no
acreage designated as Statewide Important Farmlands.8
Williamson Act Lands
Lands under the Williamson Act, or California Land Conservation Act, are agricultural lands that
allow special tax assessment. These lands are taxed on the basis of agricultural production rather
than market value. The goal of the Williamson Act is to protect agricultural land from being sold
for development. 582 acres of land with Williamson Act contracts are located within the Sphere
of Influence. Based on 2008 Riverside County data, approximately 218.9 acres were in renewal,
and 363 acres were in non-renewal.9 Non-renewal means the farmland reverts back to market
conditions and can be sold at fair market value. Farmland in non-renewal status generally
indicates agricultural land will be developed to non-agricultural land uses.
6 “Riverside County Important Farmland 2008”, prepared by California Department of Conservation, Division of
Land Resource Protection, prepared September 2009. 7 “Riverside County Important Farmland 2008”, prepared by California Department of Conservation, Division of
Land Resource Protection, prepared September 2009. 8 As provided by City of La Quinta Planning Department through Riverside County Important Farmland GIS
Data, http://redirect.conservation.ca.gov/DLRP/fmmp/county_info_results.asp.
9 As provided by City of La Quinta Planning Department through Riverside County Important Farmland GIS
Data, http://redirect.conservation.ca.gov/DLRP/fmmp/county_info_results.asp.
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2. Project Impacts
Conversion of Designated Farmland Types
Implementation of the La Quinta 2035 General Plan will facilitate urban development on lands
designated as Prime Farmland, Farmland of Statewide Importance, Unique Farmland, and
Farmlands of Local Importance. The designation is based on soil types, climatic conditions and
access to irrigation, and does not consider the urban environment in which these lands may
occur. As mentioned above, approximately 9,091 acres, or 29% of the General Plan Update
Planning Area, is designated agricultural lands of statewide or local importance according to the
Riverside County Important Farmland Map of 2008. There were approximately 1,700 acres of
important agricultural land located in the City, and 7,391 acres in the Sphere of Influence. The
1,700 acres located within the City limits are not in agricultural production, and have been
designated for urban uses for some time. Because these lands are located within the City limits,
their loss has generally already occurred, and no significant impact will result.
Implementation of the General Plan Update does not require landowners to immediately convert
farmland to new land uses. However, new development proposed will be required to develop
according to new land use designations. As a result, agricultural lands will be affected by new
growth and development. There are currently over 545,000 acres of important farmland in
Riverside County10. The 7,391 acres of land designated as important farmland represents 1.3% of
the total important farmland in the County. The eventual loss of these lands will not significantly
impact agriculture in the region.
Land uses within the eastern Sphere of Influence are currently governed by the County’s Vista
Santa Rosa Community Plan, which allows for both residential and agriculture related uses.
These lands will continue under the jurisdiction of the County of Riverside until the completion
of master planning for the area. The General Plan Update requires that the master planning
consider the area’s character. This is likely to include very low intensity development, and
agricultural or ranching uses. Further, the City’s Zoning Ordinance includes an
Agricultural/Equestrian Overlay which applies to all lands in the Sphere. This overlay was
specifically designed to allow for the preservation of agricultural and ranching uses in the Sphere
area. No change to this Overlay is proposed, and the standards and land uses permitted in the
Overlay would continue to apply to projects if they were annexed to the City.
Conflicts with Agriculture Zoning
Current zoning standards in the City provide for Very Low Density residential, which allows
equestrian and ancillary agricultural uses on large residential properties. The Very Low Density
Residential zone was established as a transition zone between urban uses within the City Limits
and the agricultural lands within the Sphere of Influence. These uses allowed in the Very Low
Density Residential zone, however are generally not associated with large commercial
agricultural production. The Zoning Ordinance also includes an Agricultural/Equestrian Overlay
10 California Department of Conservation, Division of Land Resource Protection. 2008-2010 Land Use Conversion
inventory.
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which applies to all lands in the Sphere. This overlay was specifically designed to allow for the
preservation of agricultural and ranching uses in the Sphere area. The zoning designations will
remain, and the General Plan Update will have less than significant impacts on agricultural
zoning in the City.
The eastern Sphere of Influence is currently under Riverside County jurisdiction, and will
continue to abide by the County’s zoning standards. City standards will apply only if these lands
are annexed into the City of La Quinta. The County’s Vista Santa Rosa Community Plan assigns
a variety of land uses within four planning areas. One of these planning areas includes a
proposed Village Center, and includes land uses such as Mixed-Use, High Density Residential,
Medium Density, and Medium High Density Residential. The majority of lands in the Vista
Santa Rosa Community, however, are designated Low Density Residential, Very Low Density
Residential and Estate Density Residential. Small agriculture uses and equestrian related uses are
permitted to continue in these low-density land use designations.11
The La Quinta General Plan Update designates the eastern Sphere of Influence primarily as Low
Density Residential, and requires the preparation of a master plan prior to annexation. The
master plan is further required to reflect the character of the area. Annexation to the City cannot
occur without the completion of this master plan. Based on the character of the area, it can be
expected that the master plan will contain provisions for equestrian and agricultural facilities,
and that agricultural uses would remain within the land use mix of the area. Further, the
Agricultural/Equestrian Overlay currently in effect under the City’s Zoning Ordinance will
remain upon adoption of the General Plan. The Overlay allows and protects agricultural and
equestrian activities in the Sphere, should any portion of these lands be annexed in the future. As
a result, impacts associated with agricultural zoning would be expected to be less than
significant.
Williamson Act Lands
In 2008, there was approximately 582 acres of land under Williamson Act Contract in the eastern
Sphere of Influence, of which approximately 218.9 acres were in renewal, and 363 acres were in
non-renewal. The program is voluntary, and landowners enter contracts with initial term of up to
ten years. Based on the acreage currently in non-renewal, the general trend in the region has been
to remove lands from Williamson Act contracts. The adoption of the General Plan Update will
have no impact on these contracts, insofar as they are entirely controlled by the land owners.
Since all contracts currently occur within the Sphere, which is not currently within the City’s
jurisdiction, the General Plan Update will have no immediate impact on these contracts. In the
long term, however, if the Sphere were to be annexed, the land owners would have the ability to
cancel their contracts and develop their land in more suburban land uses, if the master plan were
to so designate these lands. Conversely, nothing in the General Plan Update requires or mandates
the termination of these contracts, and impacts associated with Williamson Act contracts will be
less than significant.
11 “Vista Santa Rosa Community Land Use Concept Plan”, County of Riverside Planning Department, June 17,
2008.
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Conversion of Farmland to Non-agriculture Uses
The implementation of the General Plan Update will facilitate development on lands currently
used for agriculture in the Sphere of Influence. The General Plan Update does not mandate that
landowners terminate agricultural production, but provides regulations when development does
occur on these lands. As previously stated, the General Plan Update includes the master planning
of the Sphere, where agricultural activities occur. The master plan is required to consider and
include community character, and may include agriculture as an allowed land use. Finally, none
of the policies, programs or land use designations of the General Plan Update will apply to any
of these lands if they are not annexed to the City. As a result, adoption of the General Plan
Update will have a less than significant impact on the conversion of farmland to non-agricultural
uses.
3. Mitigation Measures
The General Plan Update will facilitate continued urbanization in areas that are undeveloped and
used for agriculture. The General Plan Update will not directly require conversion of farmland to
non-agricultural uses, however indirect pressures may encourage agricultural landowners to sell
or develop the land. The following mitigation measures will reduce impacts associated with the
conversion of agriculture land to nonagricultural uses.
1. Prior to lands under Williamson Act contract being annexed into the City of La Quinta,
the City shall coordinate with property owners, County of Riverside, and appropriate
state agencies to assure transfer of Williamson Act contracts to the City.
2. The master plan for the Vista Santa Rosa area will incorporate the area’s agricultural
character.
3. New development will be required to provide buffers adjacent to existing agricultural
lands.
4. Incorporate date palms, citrus trees, or other important crops into landscape plans for
open space, right-of-way landscaping, and parks to the greatest extent possible.
Mitigation Monitoring and Reporting
A. New development proposals shall be reviewed by the Planning Department to assure that
master planning and development proposals provide buffering between agricultural lands and
urban land uses.
Responsible Parties: Planning Department, developers, affected landowners.
B. Work with the Department of Conservation and the Farmland Mapping and Monitoring
Program to update the Riverside County Important Farmlands Map to reflect new urban
development and available farmland with General Plan Update Planning Area.
Responsible Parties: Planning Department, Department of Conservation, County of
Riverside
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Air Quality and Greenhouse Gases C.
Introduction
This section of the EIR addresses potential impacts associated with air quality and greenhouse
gas emissions that may arise from implementation of the General Plan Update. The existing air
quality and greenhouse gas conditions, forecast emission projections within City limits and
Sphere of Influence are described, and the potential impacts relating to changes from the
previously approved General Plan are assessed.
Thresholds of Significance/Criteria for Determining Significance
The following thresholds or criteria are derived from Appendix G of the CEQA Guidelines, and
are used to determine the level of potential effect. The significance determination is based on the
recommended criteria set forth in Section 15064 of the CEQA Guidelines. For analysis purposes,
build out of the La Quinta General Plan would have a significant effect on air quality emissions
if it is determined that the project will:
a) Conflict with or obstruct implementation of the applicable air quality plan.
b) Violate any air quality standard or contribute substantially to an existing or projected air
quality violation.
c) Result in a cumulatively considerable net increase of any criteria pollutant for which the
project region is non-attainment under an applicable federal or state ambient air quality
standard (including releasing emissions which exceed quantitative thresholds for ozone
precursors).
d) Expose sensitive receptors to substantial pollutant concentrations.
e) Create objectionable odors affecting a substantial number of people.
f) Generate greenhouse gas emissions, either directly or indirectly, that may have a
significant impact on the environment.
g) Conflict with an applicable plan, policy or regulation adopted for the purpose of reducing
the emissions of greenhouse gases.
South Coast Air Quality Management District
The South Coast Air Quality Management District (SCAQMD or District) has established
thresholds for certain criteria pollutants. Based on the District’s emission thresholds for criteria
pollutants, any project would be considered to have significant impacts to air quality if the daily
emissions exceed the values shown in the table below during construction or operation:
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Table III-1
Emissions Thresholds for SCAQMD
Criteria Pollutant Daily Threshold (pounds)
Carbon Monoxide (CO) 550
Oxides of Nitrogen (NOx) 100
Volatile Organic Compounds (VOC) 75
Oxides of Sulfur (SOx) 150
Particulate Matter (PM10) 150
Particulate Matter (PM2.5) 55
Source: SCAQMD daily thresholds for construction and operation within the Coachella
Valley, March 2009.
In order to protect sensitive receptors from elevated concentration of pollutants, SCAQMD has
developed methodology to assist lead agencies in analyzing localized air quality impacts from
individual projects. Localized significance thresholds (LST) are not applicable to regional
projects, such as this General Plan, but can be considered for project specific development
proposals. The use of LST’s by local governments is voluntary and is to be implemented at the
discretion of the lead agency. The SCAQMD’s Final Localized Significant Threshold
Methodology, revised July 2008, should be referenced for additional information on LST’s.
Greenhouse Gas Emissions
In addition to the thresholds criteria set forth under Appendix G in the CEQA Guidelines,
consistency with Assembly Bill 32 and Executive Order S-3-05 are also considered in order to
make a significance determination for greenhouse gas emissions. Briefly, AB 32 was adopted in
2006 and requires the Air Resources Board (ARB) to develop regulation on how the state will
combat global warming. The goals of AB 32 are to achieve a statewide GHG emission reduction
to 1990 levels by 2020. The Executive Order calls for a statewide GHG emission reduction to
80% below 1990 levels by 2050. For analysis purposes emissions of greenhouse gases from
implementation of the proposed General Plan Update for the City of La Quinta would be
considered significant if the Plan were to interfere with the objectives of AB 32 and S-3-05.
In order to protect air quality locally and contribute to the State mandate to reduce air quality
emissions, the City of La Quinta has prepared a Greenhouse Gas Reduction Plan that is
consistent with the goals of AB 32 and S-3-05.
SCAQMD Interim Thresholds for Greenhouse Gases
In 2008, the SCAQMD established interim significance thresholds for GHG emissions and
published a guidance document for analysis. For the purposes of determining whether or not
GHG emissions are significant, project emissions are to include direct, indirect, and, to the extent
information is available, life cycle emissions during construction and operation. The interim
thresholds are based on a series of Tiers, under which projects being considered under CEQA
should be analyzed. The analysis of impacts is recommended to use modeling programs readily
available, which at the time of the writing of the guidance document, focused on the URBEMIS
model. Since that time, SCAQMD has completed a new modeling tool, CALEmod, which has
been used for the projection of both criteria pollutant emissions and GHG emissions in this
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document. The SCAQMD guidance document does not provide numerical thresholds for the
analysis of GHG emissions. Rather, it recommends compliance with AB 32 reductions, CARB
reduction percentages, and similar published data. These have been used in this analysis, as
described below.
Conformity
A project is considered to be in conformity with adopted attainment and maintenance plans if the
project adheres to the requirements of the South Coast Air Quality Management Rule Book12 and
Air Quality Management Plan13. Divergence from adopted attainment or maintenance plans
would result in non-conformance, and occurs when a proposed project conflicts with or would
result in a delay of implementation for any attainment or maintenance plan. A project is
conforming if it complies with all applicable District rules and regulations, adopted and
forthcoming control measures, and is consistent with the growth forecasts in the applicable
plan(s) (or is directly included in the applicable plan). Conformity with growth forecasts can be
established by demonstrating that the project is consistent with the land use plan that was used to
generate the growth forecast. A non-conforming project would be one that increases the gross
number of dwelling units, increases the number of trips, and/or increases the overall vehicle
miles traveled in an affected area relative to the applicable land use plan.
1. Existing Conditions
Air quality conditions are a result of the geographic setting and local and regional activities.
Local development and population growth, traffic, construction activities, and various site
disturbances in City of La Quinta result in the emission of air pollutants that affect the local air
quality. Although air pollution is emitted from various sources locally, regional air quality
emissions also have an effect on the local air quality. Activities outside of the Salton Sea Air
Basin (SSAB), in which La Quinta is located, result in the emission of pollutants that make their
way into the SSAB from adjacent air basins, including the South Coast Air Basin.
Climate and Geographic Setting
Air quality in a given locality is a function of the amount of pollutants emitted and dispersed, as
well as the local climatic and geographic conditions, which may reduce or enhance the formation
of pollutants. The City of La Quinta is located in the Coachella Valley, and is subject to weather
conditions that are typical of an inland desert climate. The San Jacinto and Santa Rosa Mountain
Ranges west of La Quinta effectively cut off the region from coastal influences. During the
summer, temperatures exceed 100ºF. In the summer months, daily highs are around 105ºF and
lows are around 75ºF. In the winter, temperatures can drop below 20ºF, although winters are
typically moderate, with daily average temperature highs around 70ºF and lows around 50ºF.
Annual rainfall is typically less than 4 inches on the Valley floor, with higher mountain slopes
receiving increased rainfall with increased elevation. Precipitation often occurs in relatively high
12 South Coast Air Quality Management District Rules and Regulations, Adopted February 4, 1977. 13 “Final 2007 Air Quality Management Plan,” prepared by South Coast Air Quality Management District, June
2007.
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volumes in short duration, and results in stormwater runoff with considerable sediment
deposition on the Valley floor.
The City of La Quinta is subject to high intensity wind events year round. During fall and winter
months, high-pressure systems from the north can conflict with low-pressure systems from the
south, and create a condition known as the Santa Ana winds, which can blow for multiple days at
high speeds. These strong winds sweep up, suspend and transport large quantities of sand and
dust, reducing visibility, damaging property and constituting a significant health threat.
Air Quality Management and Regulation
The federal and California Clean Air Acts regulate air quality management and establish air
quality standards. The United States Environmental Protection Agency (EPA) established the
National Ambient Air Quality Standards (NAAQS) for managing criteria air pollutants in 1971.
The California Clean Air Act (CCAA) became effective on January 1, 1989 and mandated
health-based air quality standards for criteria pollutants at the state level. The California Air
Resources Board (CARB) developed state standards, which are generally more stringent than
federal standards, particularly in regard to carbon monoxide and particulate matter.
State Implementation Plans (SIP) regulate regional air quality by requiring management districts
to develop strategic plans to meet the federal and state ambient air quality standards by the
deadlines specified in the federal Clean Air Act (CAA) and emission reduction targets imposed
by the California Clean Air Act. The Final 2007 AQMP, prepared by SCAQMD, satisfies the
State Implementation Plan requirements of the Clean Air Act.14
The Coachella Valley has become eligible for re-designation as being in attainment due to the
annual average PM10 concentrations meeting the revoked federal standard. The peak 24-hour
average PM10 concentrations have also not exceeded the current federal standard (150 µg/m3).
On February 25, 2010 the California Air Resources Board approved the Coachella Valley PM10
Redesignation Request and Maintenance Plan from serious non-attainment to attainment for the
PM10 National Ambient Air Quality Standard under CAA Section 107.
The SCAQMD is voluntarily requesting that EPA re-designate the Coachella Valley portion of
the SSAB from “Serious” non-attainment to “Severe-15” and extend the attainment date of the 8-
hour ozone standard to 2019. The District’s proposed control strategy includes two components,
including a strategy for the South Coast Air Basin, and control of locally generated emissions in
the Coachella Valley via regulations at the state and federal level.
Toxic Air Contaminants (TAC)
The US EPA regulates TACs through technology-based requirements that are implemented by
state and local agencies. California regulates TACs through the air toxics program and the Air
Toxics “Hot Spots” Information and Assessment Act.15 The CARB works alongside the Office
of Environmental Health Hazard Assessment (OEHHA) to identify TACs, and adopt Air Toxic
14 “2007 Air Quality Management Plan,” South Coast Air Quality Management District, June 1, 2007. 15 AB 2588.
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Control Measures (ATCMs) to reduce the identified TACs. Where there are federal standards,
CARB must, at minimum, adopt the standards established by the US EPA.
Criteria Air Pollutants
The following air pollutants are collectively known as criteria air pollutants and are defined as
those pollutants for which established air quality standards have been adopted by federal and
state governments. The following provides a summary description of each criteria pollutant,
detailed information can be found in the Air Quality and Greenhouse Gas Report (Appendix B).
Ozone (O3)
Ozone is a gas formed when byproducts of the internal combustion engine and other urban
processes, particularly nitrogen oxide (NOx) and volatile organic compounds (VOC), react in the
presence of ultraviolet sunlight. It is a pungent, colorless, toxic gas commonly referred to as
smog.
Carbon monoxide (CO)
Carbon monoxide is produced from the partial combustion of fossil fuels. EPA estimates that
85%-95% of all CO emissions come from motor vehicle exhaust. Carbon monoxide contributes
to the production of methane, ozone, and carbon dioxide. It is a colorless, odorless, and tasteless
toxic gas that at high concentrations can contribute to heart disease, anemia, and impaired
psychological behavior.
Nitrogen Oxide (NOx)
Nitric oxide (NO) and Nitrogen Dioxide (NO2) are the primary oxides of nitrogen that are
considered criteria pollutants. NOx emissions are byproducts from the operation of motor
vehicles, power plants, and off-road equipment. Short-term exposure to nitrogen dioxide can
result in airway constriction, diminished lung capacity, and is highly toxic by inhalation.
Sulfur Oxides (SOx)
Sulfur oxides occur naturally from volcanic activity, and are generated as a result of various
industrial processes. The most common sulfur oxide compound is Sulfur dioxide (SO2), which
results from the combustion of high-sulfur content fuels, such as coal and petroleum. Sources
include motor vehicle fuel combustion, fossil fuel power plants, chemical manufacturing plants,
and sulfur recovery plants. Sulfur dioxide acts as an acid, can result in the formation of acid rain,
and is a colorless, odorous gas.
Particulate Matter
Particulate matter of ten microns or smaller in diameter are referred to as PM10, whereas PM2.5
consists of particles smaller than 2.5 microns. Particulate matter (PM) may be from soil and dust,
soot and smoke, or aerosols, and is a byproduct of fuel combustion, tire wear, and wind erosion.
Particles less than ten microns in diameter can enter the throat, nose, and lungs. Fine particulate
matter poses a significant threat to public health and can cause increased respiratory infections,
asthma attacks, and lung cancer.
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Lead (Pb)
Lead occurs in the atmosphere from the manufacturing of batteries, paint, ink, and ammunition.
Excessive exposure to airborne lead can lead to anemia, kidney disease, gastrointestinal
dysfunction, and neuromuscular and neurological disorders.
Volatile Organic Compounds
Volatile Organic Compounds (VOC) are also known as Reactive Organic Gas (ROG). This class
of pollutants have no state or federal ambient air quality standards and are not classified as
criteria pollutants, however they are regulated because they are responsible for contributing to
the formation of ozone. They also contribute to higher PM10 levels because they transform into
organic aerosols when released into the atmosphere.
Air Quality Standards
State and federal governments have each established ambient air quality standards for pollutants
of concern, including the criteria pollutants listed above. The federal government sets primary
standards to protect public health, including the health of sensitive populations, such as
asthmatics, children, and the elderly, and sets secondary standards to protect public welfare,
including protection against decreased visibility, damage to animals, crops, vegetation, and
buildings.
Air quality standards are intended to project sensitive receptors, which are people or land uses
that may be especially subject to respiratory stress and/or significant adverse impacts as a result
of exposure to air contaminants. The ARB designates people with cardiovascular and chronic
respiratory diseases, children under 14, seniors over 65, and athletes as sensitive receptors.
Hospitals, nursing and retirement homes, schools, daycares, playgrounds, parks, athletic
facilities, and residential and transient lodging facilities are all considered sensitive land uses.
The following table shows state and federal (primary) air quality standards. State standards are
generally more restrictive than federal standards.
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Table III-2
State and Federal Ambient Air Quality Standards
State Standards Federal Standards**
Pollutant Averaging
Time
Max.
Concentration
Averaging Time Max.
Concentration
Ozone 1 hour
8 hour
0.09 ppm
0.07 ppm
1 hour
8 hour
0.075 ppm
Carbon Monoxide 1 hour
8 hours
20.0 ppm
9.0 ppm
1 hour
8 hours
35.0 ppm
9.0 ppm
Nitrogen Dioxide
(NO2)
1 hour
AAM
0.18 ppm
0.030 ppm
AAM
0.10 ppm*
0.053 ppm
Sulfur
Dioxide
(SO2)
1 hour
24 hours
0.25 ppm
0.04 ppm
1 hour
24 hours
AAM
.075ppm**
Particulate Matter
(PM10)
24 hours
AAM
50 µg/m3
20 µg/m3
24 hours
AAM
150 µg/m3
Particulate Matter
(PM2.5)
AAM
24 hours
12 µg/m3
35 µg/m3
AAM
24 hours
15 µg/m3
35 µg/m3
Lead 30 day Avg. 1.5 µg/m3 3 month Avg. 0.15 µg/m3
Visibility
Reducing Particles
8 hour
No federal
Standard
No federal
Standard
Sulfates 24 hour 25µg/m3 No federal
Standard
No federal
Standard
Hydrogen Sulfide
1 hour
0.03 ppm
No federal
Standard
No federal
Standard
Vinly Chloride 24 hour 0.01 ppm No federal
Standard
No federal
Standard
Notes: ppm = parts per million; ppb= parts per billion; µg/ m3 = micrograms per cubic meter of air;
AAM = Annual Arithmetic Mean;
Source: California Air Resources Board, 9/08/2010
Source: US EPA, September 2010
* Note that this standard became effective as of January 22,2010.
** Final rule signed June 2, 2010, effective as of August 23,2010
Regional Pollutants of Concern and Monitoring
The above standards are the thresholds by which regional ambient air quality is measured. In the
Coachella Valley air quality has exceeded state and federal standards for ozone and particulate
matter. In order to monitor regional pollutants of concern, the SCAQMD operates and maintains
two regional air quality monitoring stations in Source Receptor Area 30 (SRA 30), including one
at a Palm Springs Fire Station, and one in the City of Indio off of Jackson Street. These
monitoring stations report daily air pollutant concentrations and meteorological conditions.
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The following discussion summarizes the past few years of data collected at the monitoring
stations for PM10, PM2.5, and Ozone. The last 10-years of monitoring data can be seen in the Air
Quality and GHG Report.
PM10 Emissions
Natural sand migration, a process referred to as “blowsand,” generates two types of PM10 emissions: (1) natural PM10, which is produced by direct particle erosion and fragmentation, and
(2) secondary PM10, whereby sand deposited on roadways is further broken up by motor
vehicles, then re-suspended in the air.
PM10 levels in the Coachella Valley are attributed to fugitive dust emissions from grading and
construction activities, agricultural practices, and strong winds. In the past several decades a
concerted and joint effort has been made to limit fugitive dust emissions. SCAQMD establishes
measures to reduce particulate matter, sets forth new measures that could further reduce
particulate matter, and maintains a list of new measures that need further evaluation prior to
implementation. Applicable state code and AQMD Rules, including Rule 403 (Fugitive Dust),
enforce fugitive dust compliance.
The table below shows that the federal 24-hour standard for PM10 has not been exceeded at either
monitoring station within SRA 30. However, PM10 levels continue to exceed state standards
within SRA 30.
Table III-3
PM10 Monitoring Data for the Coachella Valley
Monitoring
Station
Year
Maximum
Concentration
(µg/m3/24hours)
No. (%) Samples
Exceeding 24-hr.
Standards
Annual Average
(µg/m3)
Federal1 State2 AAM3 AGM4
Palm Springs 2007 83 0 (0.0%) 6 (11.0%) 30.5 N/A
2008 73 0 (0.0%) 4 (8.0%) 23.2 N/A
2009 133 0 (0.0%) N/A N/A N/A
2010 145 0.0 0.0 19.4 18.3
2011 397 2.0 0.0 21.7 18.1
Indio 2007 146+ 0 (0.0%) 51 (59.0%) 53.5 N/A
2008 128 0 (0.0%) 25 (22.0%) 39.9 N/A
2009 132 0 (0.0%) N/A N/A N/A
2010 107 0.0 23.9 28.8 29.7
2011 376 2.0 18.6 32.6 35.4
Source: Annual air quality site monitoring reports, prepared by SCAQMD and ARB.
1 = > 150 µg/m3 in 24 hour period;
2 = > 50 µg/m3 in 24 hour period;
3 Federal Annual Average Standard AAM > 50µg/m3 revoked December 17, 2006. State standard is AAM >
20µg/m3
4 State Annual Average Standard = AGM > 20µg/m3
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PM2.5 Emissions
The Coachella Valley is defined as unclassifiable for PM2.5, based on the 2007 State Area
Designations and does not require a State Implementation Plan to demonstrate attainment. The
following table shows that the federal and state 24-hour PM2.5 standard has not been exceeded,
nor has the Federal AAM standard of 15 µg/m3. The AAM state standard of 12 µg/m3 has also
not been exceeded in the past few years.
Table III-4
PM2.5 Monitoring Data for the Coachella Valley
Monitoring
Station Year
Max
Concentration
(µg/m3/24hours)
No. Days
Exceeding 24-hr.
Standards
Annual
Average
(µg/m3)
Federala AAM b, c
Palm Springs 2007 32.5 0 8.5
2008 18.1 0 7.1
2009 21.8 0 6.6
2010 12.8 0 5.9
2011 26.3 0 6.0
Indio 2007 26.7 N/A N/A
2008 21.5 0 8.4
2009 27.5 0 7.8
2010 16.0 0 6.8
2011 35.4 0 7.1
Source: Annual air quality site monitoring reports, prepared by SCAQMD and ARB.
a = > 65µg/m3 in 24 hour period, Federal standard prior to December 17, 2006.
b = > 35 µg/m3 in 24 hour period, Federal standard as of December 17, 2006
c Federal Annual Average Standard = AAM > 15µg/m3
d State Annual Average Standard = AAM > 12µg/m3 as of July 5, 2003.
Ozone Emissions
Although the SSAB has a history of exceeding regulatory ozone standards, the number of days
and months that exceed the federal one-hour standard has dropped steadily over the past three
decades. Under the Federal Clean Air Act, the SSAB is classified as a “severe-15” area, which
must achieve attainment by June 15, 2019.
As previously noted, SCAQMD studies indicate that most ozone is transported to the Salton Sea
Air Basin from the upwind South Coast Air Basin, which contains large metropolitan areas
including Los Angeles. It is difficult to quantify the amount of ozone contributed from other air
basins; however, improved air quality in the Coachella Valley depends upon reduced ozone
emissions in the South Coast Air Basin.
The following table shows that the Palm Springs monitoring site exceeds the 1 hour and 8 hour
federal and state standards more frequently than the Indio site.
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Table III-5
Ozone Monitoring Data
No. Days Standard Exceeded
Stations Year Max. Concentration Federal1 State2
1 Hour ppm 8 Hour ppm 8 Hour 1 Hour 8 Hour
Palm Springs 2007 0.13 0.101 20 29 83
2008 0.11 0.101 20 26 70
2009 0.12 0.098 54 28 74
2010 0.114 0.099 52 20 78
2011 0.124 0.098 49 21 69
Indio 2007 0.11 0.094 6 8 48
2008 0.12 0.092 27 12 44
2009 0.10 0.090 24 6 41
2010 0.100 0.087 19 6 45
2011 0.099 0.090 19 3 42
Source: SCAQMD and ARB Annual Air Quality Data Tables.
1 = > 0.12 and 0.08 parts per million in 1 hour and 8 hour respectively.
2 = > 0.09 and 0.75 parts per million in 1 hour and 8 hour respectively.
Global Warming and Climate Change
According to the Intergovernmental Panel on Climate Change (IPCC), global mean temperatures
have risen 0.74oC between 1906 and 2005; global sea surface temperatures have increased to
depths of 3,000 meters since 1961; sea levels have risen by 0.17 mm since the beginning of the
20th century; and snow and glaciers continue to melt faster than new snow accumulation,
contributing to rising sea levels.
According to the National Oceanic and Atmospheric Administration (NOAA) and NASA
reports, the average surface temperature of the earth has warmed 1oF since the 1970s, and the
earth’s surface is warming at a rate of 0. 29oF per decade. These increases have become known
as global warming.
Industrialization, urban lifestyle, agricultural practices, production and manufacturing and other
human activities result in the emission of greenhouse gas that are contributing to global warming
and climate change, and include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O),
tetrafluoromethane, hexafluoroethane, sulfur hexafluoride, HFC-23 (fluoroform), HFC-134a (s,
s, s, 2 –tetrafluoroethane), and HFC-152a (difluoroethane).
These gases are termed greenhouse gases due to their shared characteristic of trapping heat, are
responsible for the global average increase in surface temperatures, and for the increase in the
rate of warming. There is a high degree of correlation between the concentration of CO2 and
average temperatures. At the beginning of the industrialized era compared to atmospheric
concentration in 2005, CO2 levels had increased by 35%, methane by 151%, and nitrous oxide by
18%. In 2005, carbon dioxide concentrations in the atmosphere were nearly 380 parts per million
(ppm). Comparatively, prior to the Industrial Revolution, about 250 years ago, CO2 levels were
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278 ppm, and over the past 650,000 years carbon dioxide levels have fluctuated between 180 and
300 ppm, making present day atmospheric CO2 levels substantially greater than at any point in
the past 650,000 years.
Under current projection models given business as usual conditions, carbon dioxide levels are
likely to increase to at least 730 ppm and possibly as high as 1,020 ppm by the year 2100, which
would have a substantial effect on environmental and socio-economic conditions. Although there
is much debate over what the effects of climate change will be, there is a general consensus that
the levels of greenhouse gas emissions need to be reduced in order to and limit air pollution and
minimize the potential impacts of climate change.16
Greenhouse Gases
The following provides a summary description of each greenhouse gas, detailed information can
be found in the Air Quality and Greenhouse Gas Report (Appendix B).
Carbon Dioxide (CO2)
Sources of carbon dioxide include the decomposition of dead organic matter, respiration of
bacteria, plants, animals and fungus, evaporation from oceans, volcanic out gassing, and from the
combustion of coal, oil, natural gas, and wood. Carbon dioxide is removed from the air by
photosynthesis, dissolution into ocean water, transfer to soils and ice caps, and chemical
weathering of carbonate rocks.
Methane (CH4)
Methane is released from low oxygen environments, the combustion of fossil fuels, and burning
biomass. Methane remains in the atmosphere for approximately 9-15 years and is a more
efficient absorber of radiation compared to CO2.
Nitrous Oxide (N2O)
Sources of nitrous oxide include releases from microbial processes in soil and water, including
those reactions that occur in fertilizer containing nitrogen, industrial processes, such as fossil fuel
fired power plants, nylon production, nitric acid production, and vehicle emissions. Nitrous oxide
can be transported into the stratosphere, deposited on the Earth’s surface, and converted to other
compounds by chemical reaction.
Halons
Halons are compounds consisting of bromine, fluorine, and carbon and are agents most typically
found in fire extinguishers. Halons have been identified as to contribute to ozone-depletion and
are known greenhouse gases. Halon production in the United States ended in 1993.
16 “Working Group III Contribution to the Intergovernmental Panel on Climate Change Fourth Assessment
Report, Climate Change 2007: Mitigation of Climate Change,” prepared by the Intergovernmental Panel on
Climate Change, May 2007.
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Chlorofluorocarbons
Chlorofluorocarbons (CFCs) are primarily used in air conditioners and refrigerators. They are
also used as solvents to clean electronic microcircuits. Federal regulations require service
practices that maximize recycling of ozone-depleting compounds during servicing and disposal
of air-conditioning and refrigeration equipment.
Hydro-chlorofluorocarbons
HCFCs are similar to CFC’s, are generally used in aerosols and refrigerants, but break down
more quickly in the atmosphere and are more chemically reactive due to their hydrogen
component. HCFC’s affect stratospheric ozone, but to a much lesser extent than CFCs.
Climate Change Regulation
The California Global Warming Solutions Act of 2006 (AB 32) has been passed in order to
comprehensively limit greenhouse gas emissions (GHG) at the state level by establishing an
annual reporting program of GHG emissions for significant sources and sets emissions limits to
cut the state’s GHG emissions to 1990 levels by 2020. On June 1, 2005 Governor Arnold
Schwarzenegger issued executive order S-3-05, which calls for reduction in GHG emissions to
1990 levels by 2020 and for an 80 percent reduction below 1990 levels by 2050.
In 2004 the State of California generated 492 million metric tons of carbon dioxide equivalent
(gross). Although the state’s population grew by 16 percent between 1990 and 2004 GHG
emissions were reduced by 9.7 percent. GHG emission reductions are attributed to energy
conservation measures such as use of energy efficient appliances and building materials that are
prescribed under Title 24 of the California Building Code.
AB 32 was adopted by the state legislature in 2006, and set in motion a statewide effort to
achieve reductions in greenhouse gas emissions through regulatory and market mechanisms. It
sets forth a program to achieve 1990 emission levels by 2020 and requires CARB to proclaim
1990 GHG emissions and develop a Scoping Plan that can be implemented by January 1, 2012.
CARB has reported that 1990 GHG levels were 427 million metric tons (MMT) for the state of
California. The Scoping Plan, adopted on December 11, 2008, includes measures like a cap and
trade program, green building strategies, recycling and waste reduction, and Voluntary Early
Actions and Reductions. CARB has released reduction requirements for regions throughout the
State.
California SB 375 was signed by the Governor in September 2008 and is intended to at least in
part implement greenhouse gas reduction targets set forth in AB 32. The bill encourages regional
land use planning to reduce vehicle miles traveled and requires jurisdictions to adopt a
sustainable communities strategy.
The CEQA Guidelines now require the analysis and mitigation of impacts associated with
greenhouse gases. The Guidelines require that all feasible mitigation measures be considered,
including the adoption of plans and programs to reduce emissions of future development
projects. The City’s Greenhouse Gas Reduction Plan has been prepared to address these
requirements.
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Greenhouse Gas Reduction Plan
The City of La Quinta has completed a Greenhouse Gas Inventory and has prepared a
Greenhouse Gas Reduction Plan as part of this General Plan Update. The intent of the
Greenhouse Gas Reduction Plan is to set goals, policies, and programs that will result in the
reduction of greenhouse gas emissions to targets identified in the Plan that meet the State’s
mandates. The provisions of the Plan have been included in the analysis of air quality and
greenhouse gas impacts provided below.
2. Project Impacts
The potential for air quality impacts in the La Quinta Planning Area will increase with
implementation of the proposed General Plan Update. Air pollutants will be generated from a
variety of activities occurring within the Planning Area, including grading and construction,
vehicle emissions, and daily operations. Emissions generated by vehicular traffic are projected to
be the greatest source of air pollutants. The use of natural gas and electricity for operation of
existing and new buildings and structures will also result in the emission of air pollutants.
Major sources of pollutants associated with build out of the General Plan are quantified and
described in detail in the Air Quality and Greenhouse Gas Report, which can be found in
Appendix B of this EIR. The following discussion summarizes the major findings of the Air
Quality Analysis and makes a significance determination based on CEQA criteria and SCAQMD
thresholds.
Compliance with SCAQMD AQMP
As mentioned above, the City of La Quinta is subject to the 2007 Air Quality Management Plan,
prepared by the South Coast Air Quality Management District. The proposed La Quinta General
Plan Update has the potential to increase development intensities and the City’s build out
population compared to the 2002 General Plan, upon which population projections for the 2007
AQMP were based. The size and composition of the population has a direct effect on the amount
of air quality emissions. The typical trend being that an increase in population results in a
correlated increase in the level of air quality emissions. However, state legislation, such as SB
375 and AB 32, as well as regional and local programs and policies have shown that with proper
land use planning, adherence to building codes, especially Title 24, and opportunities for
alternative modes of transport, this trend can be reversed.
Under business as usual conditions, the proposed General Plan Update has the potential to
conflict with or obstruct implementation of the adopted 2007 Air Quality Management Plan
prepared by SCAQMD due to the increased densities proposed in the eastern Sphere, and the
associated population projections. Although the proposed population projections for the General
Plan Update within City limits are comparable to those set forth under the 2002 General Plan, the
population for the Sphere of Influence is projected to nearly double. The projected increase in the
population size within the Sphere of Influence as set forth in the General Plan Update, when
compared with the Riverside County General Plan, has the potential to conflict with or obstruct
implementation of the Air Quality Management Plan.
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Implementation of mitigation measures, including adherence to the GHG Reduction Plan are
expected to substantially reduce emissions of air quality pollutants and reduce the per capita
emission contribution. Therefore, it is expected that with mitigation measures, the General Plan
Update will be consistent with the Air Quality Management Plan and impacts will be reduced.
Air Quality Standards
As mentioned above federal and state air quality standards have been established for several
pollutants. Within the Coachella Valley, ozone and particulate matter concentration have
exceeded air quality standards and are monitored and managed by SCAQMD.
The City of La Quinta requires best management practices (BMPs), adherence to building codes
and standards, and the adoption of dust control plans for all new development. In addition,
SCAQMD has established several programs specifically designed to limit the emission of ozone
and the generation of particulate matter. Adherence to established and forthcoming programs and
policies set forth by SCAQMD will assure that in and of itself, the proposed General Plan
Update will not violate any air quality standard or substantially contribute to any existing or
projected air quality violation.
Air Quality Emission Projections
Construction and operation of land uses set forth in the General Plan Update are expected to
result in the generation and emission of air pollutants. The following quantifies these emissions.
Construction
The General Plan Update has the potential to result in the development of 10,718 currently
vacant acres, including residential, commercial, recreational open space, major community
facilities, and street rights-of-way. As the General Plan is expected to build out over a 25-year
period, this corresponds to an average annual build out of approximately 428.72 acres per year,
1,153 dwelling units, and 251,529 square feet of retail/industrial development.
For analysis purposes, emissions from construction activities are averaged over the 25-year build
out period to estimate annual emissions. The Table below shows the emission projections for the
average annual development likely to occur under implementation of the General Plan Update.
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Table III-6
Construction Emissions for the Planning Area
(pounds per day)
CO NOx ROG1 SOx PM10 PM2.5
City Limits
Unmitigated 241.90 202.78 906.78 0.24 2,284.59 484.21
Mitigated 241.90 122.28 818.45 0.24 140.89 31.41
SCAQMD Threshold 550.00 100.00 75.00 150.00 150.00 55.00
Significant No Yes Yes No No No
Sphere of Influence
Unmitigated 206.06 172.73 772.45 0.21 1,946.14 412.47
Mitigated 206.06 104.16 697.20 0.21 120.01 26.76
SCAQMD Threshold 550.00 100.00 75.00 150.00 150.00 55.00
Significant No Yes Yes No No No
Planning Area Total
Unmitigated 447.96 375.51 1,679.23 0.45 4,230.73 896.68
Mitigated 447.96 226.44 1,515.65 0.45 260.90 58.17
SCAQMD Threshold 550.00 100.00 75.00 150.00 150.00 55.00
Significant No Yes Yes No Yes Yes
Source: Air Quality and GHG Report, prepared by Terra Nova Planning and Research, June 2012. 1Reactive Organic Gases (ROGs), sometimes referred to as Volatile Organic Compounds (VOC)
With implementation of mitigation measures, air quality emissions from construction activities
within City limits are projected to remain below established thresholds for all criteria pollutants
except for NOx and ROG. The sources of ROG’s during construction include the evaporation of
solvents found in paints, varnishes, primers, and other surface coatings. Even with
implementation of mitigation measures, air quality emissions of NOx and ROG have the potential
to result in significant and unavoidable impacts from construction activities occurring within
City limits.
Construction related air quality emissions from the development of lands within the Sphere of
Influence are projected to exceed established daily thresholds for NOx and ROG, even with
implementation of mitigation measures. Newly adopted and forthcoming fuel standards are
expected to dramatically reduce emissions of NOx. Given the projected levels of NOx, it is
conceivable that emission reductions from full implementation of the off-road diesel fuel
standard will result in reducing emission to below threshold levels. In addition, requiring the use
of the latest available technology and assuring that the construction fleet is properly maintained
and updated will contribute to further limiting emissions. Nonetheless, construction activities
within the Sphere of Influence have the potential to result in significant and unavoidable impacts
to air quality from the emission of NOx and ROG.
Air pollutant emissions from construction activities are considered temporary impacts and will
end once construction is complete. Nonetheless, during construction activities and assuming
simultaneous construction of vacant lands within the Planning Area, the proposed General Plan
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Update has the potential to result in a cumulatively considerable net increase of NOx, ROG, and
PM10. Projections of these criteria pollutants exceed established daily and have the potential to
result in significant and unavoidable impacts for these criteria pollutants.
Operation
Daily activities at operation will result in the emission of air quality pollutants from the use of
electricity and natural gas, and will be emitted from area sources and moving sources. The use of
electricity within the Planning Area results in offsite emissions from the production of electricity.
Although emission associated with electricity do not occur within the physically boundary of the
Planning Area, they are considered as part of the operational impacts from build out of the
General Plan Update. Emissions from natural gas occur from the combustion of natural gas
within the Planning Area for operational activities such as heating and cooling, and cooking.
Area source emissions include the use of consumer products, the application of architectural
coatings, hearth fuel combustion, and fuel used for landscaping purposes. Moving sources
include emissions from vehicles at build out of the General Plan Update.
Electricity and natural gas usage rates were obtained from the utility companies as part of the
inventory effort conducted for the GHG Reduction Plan. Per unit and per square footage usage
rates were calculated based on data provided and said factors were used to project build out
demand under business as usual conditions within the La Quinta Planning Area. The Urbemis
model was used to estimate emissions from area sources and moving sources. Detailed
methodology and assumption used to project build out demands and associated emissions are
described in the Air Quality and GHG Report (Appendix B).
The table below summarizes the projected emissions associated with daily operations within the
Planning Area, at build out, under business as usual conditions. Due to the size and scale of the
City Limits and the Sphere of Influence, air quality emissions for all criteria pollutants (CO,
NOx, SOx, Particulates and ROG’s) are projected to exceed established SCAQMD thresholds at
operation.
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Table III-7
Projected Daily Emissions at
General Plan Build Out
Stationary Source Emissions Moving
Source
Emission
Total
Emissions
SCAQMD
Threshold
Criteria
Electricity Natural
Gas
Area
Sources
All
Vehicles
Total
Lbs./Day
Total
Lbs./Day
City Limits
CO 597.49 219.14 7,044.98 8,471.50 16,333.11 550
NOx 3,435.58 377.96 375.10 788.00 4,976.64 100
SOx 358.50 0.004 18.16 23.00 399.66 150
PM10 119.50 0.71 1,001.99 3,894.00 5,016.19 150
PM2.5 N/a N/a 965.36 763.00 1,728.36 55
ROGs 29.87 28.54 4,112.07 949.00 5,119.48 75
Sphere of Influence
CO 303.96 109.51 5,217.98 4,787.50 10,418.94 550
NOx 1,747.76 209.85 329.45 442.50 2,729.56 100
SOx 182.37 0.002 13.18 13.00 208.56 150
PM10 60.79 0.40 726.75 2,262.00 3,049.94 150
PM2.5 N/a N/a 700.09 443.00 1,143.09 55
ROGs 15.20 15.98 2,984.34 515.50 3,531.02 75
Planning Area Total
CO 901.45 328.65 12,262.96 13,259.00 26,752.05 550
NOx 5,183.34 587.81 704.55 1,230.50 7,706.20 100
SOx 540.87 0.01 31.34 36.00 608.22 150
PM10 180.29 1.10 1,728.74 6,156.00 8,066.13 150
PM2.5 N/a N/a 1,665.44 1,206.00 2,871.44 55
ROGs 45.07 44.52 7,096.40 1,464.50 8,650.50 75
Source: Air Quality and GHG Report, prepared by Terra Nova Planning and Research, June 2012.
For build out of the General Plan Update, air quality emissions have the potential to result in a
cumulatively considerable net increase of CO, NOx, SOx, PM10, PM2.5, and ROG. Projections of
these pollutants exceed established daily thresholds and have the potential to result in significant
and unavoidable impacts.
Sensitive Receptors
The land use plan has been designed to provide a buffer between sources of air quality emissions
and sensitive receptors. Although daily criteria pollutant emission thresholds will be exceeded, it
is expected that state and federal standards for regional pollutants of concern will be unaffected
by the proposed General Plan. The 2007 AQMP has projected that ozone standards will be
achieved by 2018 for the Coachella Valley. With implementation of mitigation measures, the La
Quinta General Plan Update will not interfere with attainment of the 8-hour ozone standard. As
mentioned above, the Coachella Valley is eligible for redesignation as attainment due to the
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Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
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annual average PM10 concentrations meeting the revoked federal standard, and since the peak 24-
hour average PM10 concentrations have also not exceeded the current federal standard (150
µg/m3). Thus, the proposed General Plan Update is not expected to expose sensitive receptors to
substantial pollutant concentrations and air quality impacts to sensitive receptors are expected to
be less than significant.
Objectionable Odors
The proposed General Plan Update does not include any land uses that have the potential to
generate objectionable odors. Further, individual projects which may be proposed within the
City, or on Sphere lands if annexed, will be reviewed individually based on their potential to
generate odors under CEQA. Therefore, it is considered unlikely that implementation of the
General Plan Update, including lands within City limits and the Sphere of Influence, would
result in objectionable odors affecting a substantial number of people. The General Plan Update
is expected to have less than significant impacts in regards to odors.
Greenhouse Gas Emissions
Construction and operation of land uses set forth in the General Plan Update are expected to
result in the generation of greenhouse gas emissions. These emissions are characterized below.
Construction GHG Emissions
As mentioned above, construction emissions are based on the ground disturbance and
development of 10,718 acres, including residential, commercial, recreational open space, major
community facilities, and street right-of-ways. Urbemis was utilized to estimate the CO2
emissions that will be generated as a result of construction activities. For analysis purposes, CO2
emissions from annual average construction activities were multiplied by 25 years in order to
estimate the total GHG emissions likely to occur from construction activities. To determine the
amount of CH4 and N2O associated with the CO2 level, a ratio of 0.00006 for CH4 and a ratio of
0.00003 for N2O were assumed, per ton of CO2 emitted. Ratios for CH4 and N2O are pursuant to
figures for diesel operated construction equipment provided in the California Climate Action
Registry General Reporting Protocol, Version 3.1, January 2009. CO2 Equivalence (CO2e) was
calculated by using a global warming potential of 21 for CH4 and 310 for N2O.
The Table below shows the total summary of projected GHG emissions expected to occur from
construction activities of the General Plan Update.
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Table III-8
GHG Emissions from Construction of the General Plan
(metric tons)
CO2 CH4 N2O CO2e
City Limits 94,231.35 5.09 2.56 95,133
Sphere of Influence 80,271.15 4.33 2.18 81,039
Planning Area Total 174,502.49 9.42 4.75 176,172
Source: Air Quality and GHG Report, prepared by Terra Nova, June 2012.
It should be mentioned that projected GHG emissions are conservative in that they represent
emission levels using current factors. New standards for heavy-duty diesel construction
equipment are currently being developed and will be phased in beginning in 2012. Therefore, the
analysis conducted for GHG emissions represents a worst-case scenario assuming the continued
use of current model year or older construction equipment. In practice and as feasible, new
model construction equipment shall be utilized for all construction activities within the La
Quinta Planning Area.
Emissions of GHG’s during construction activities have the potential to either directly or
indirectly result in a temporary impact on the local and regional air quality conditions. GHG
emissions from construction will end once construction activities are complete. Therefore, the
generation and emission of GHG’s from construction are not expected to have a long term or
lasting impact on the environment and impacts to air quality from construction are expected to be
less than significant.
Operational GHG Emissions
The proposed project will result in the emission of greenhouse gases through the combustion of
fossil fuels during operation of vehicles, the generation of electricity at power plants, combustion
of natural gas, and the transportation of water. The following tables shows the projected GHG
emissions from operation at build out of the General Plan Update and includes activities within
City limits and the Sphere of Influence.
Table III-9
GHG Emissions from Operation at General Plan Build Out
(million metric tons)
Electricity
Natural
Gas
Moving
Sources
Water
Transport Total
City Limits 0.479 0.078 0.437 0.011 1.004
Sphere of Influence 0.243 0.044 0.253 0.007 0.548
Planning Area Total 0.722 0.122 0.690 0.018 1.552
Source: Air Quality and GHG Report, prepared by Terra Nova, June 2012.
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Operational activities would result in the generation and emission of greenhouse gases, which
could have significant impacts to air quality locally and regionally. Implementation of the
Greenhouse Gas Reduction Plan is intended to reduce impacts associated with the emission of
greenhouse gases within City limits to levels that are less than significant.
Lands within the Sphere of Influence are currently governed by the County of Riverside and are
not subject to compliance with the La Quinta Greenhouse Gas Reduction Plan. In the event that
the Sphere of Influence continues to be governed by the County jurisdiction, then impacts from
the emission of greenhouse gases are expected to be significant. Were the Sphere of Influence to
be annexed into La Quinta City jurisdiction, then lands would be subject to the Greenhouse Gas
Reduction Plan and compliance with said plan would assure that impacts to air quality from the
emission of greenhouse gases would be reduced to levels below significance.
Greenhouse Gas Reduction Plan
The City of La Quinta has prepared a Greenhouse Gas Reduction Plan as part of the General
Plan. The Greenhouse Gas Reduction Plan quantifies the baseline emissions, projects future
emission levels, and creates a plan to achieve greenhouse gas emission reductions consistent with
AB 32. As such, the targets set forth in the GHG Reduction Plan are to achieve 10% below 2005
emission levels by 2020 and 28% below 2005 levels by 2035.
The La Quinta Greenhouse Gas Reduction Plan identifies 2005 as the base year and estimates
that 460,946 metric tons of CO2e were emitted from community wide activities. With business as
usual conditions the community wide CO2e is projected to be 668,627 metric tons in 2020, and
828,538 metric tons in 2035. In order to achieve targeted reductions, CO2e emission will need to
be reduced by 253,775 metric tons by 2020, and by 496,657 metric tons by 2035. As seen in the
GHG Reduction Plan, implementation of reduction measures will achieve 253,950 metric tons by
2020 and 496,681 metric tons by 2035. As such implementation of the GHG Reduction Plan will
substantially reduce emission levels and assure consistency with state targets.
The La Quinta Greenhouse Gas Reduction Plan identifies 2005 as the base year and estimates
that 9,807 metric tons of CO2e were emitted from government activities. As set forth in the GHG
Reduction Plan under business as usual conditions CO2e emitted as a result of government
activities is projected to be 11,328 metric tons in 2020, and 12,671 metric tons in 2035. In order
to achieve targeted reductions, CO2e emission will need to be reduced by 2,502 metric tons by
2020, and by 5,610 metric tons by 2035. As seen in the GHG Reduction Plan, implementation of
reduction measures will achieve 2,514 metric tons by 2020 and 5,614 metric tons by 2035. As
such implementation of the GHG Reduction Plan will substantially reduce emission levels and
assure consistency with State targets.
The General Plan Update does not conflict with the GHG Reduction Plan or any other policies or
regulations that are intended to reduce the emissions of GHG’s. Rather, the GHG Reduction Plan
has been prepared as part of the General Plan Update process and with the intent to reduce GHG
emission to levels that are consistent with state goals. Adoption and adherence to the GHG
Reduction Plan will assure that emissions of GHG’s from the implementation of the proposed
General Plan are reduced to levels below significance.
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Cumulative Impacts
Global climate change is a cumulative impact by nature. For the most part an individual project
does not generate enough GHG emissions to significantly influence global climate change.
Nonetheless, individual projects may participate in a potential impact through incremental
contribution, combined with the contributions of all other sources of GHG. In assessing
cumulative impacts, it must be determined if a project’s incremental effect is cumulatively
considerable.17 To make this determination the incremental impacts of the project must be
compared with the effects of existing, proposed, and future projects.
For General Plan purposes, individual projects that are consistent with the greenhouse gas
reduction plan will not result in cumulatively considerable impacts to greenhouse gas emissions.
3. Mitigation Measures
In order to mitigate the potential air quality impacts associated with implementation of the
proposed General Plan Update, a comprehensive Greenhouse Gas Reduction Plan has been
prepared. The Greenhouse Gas Reduction Plan is intended to substantially reduce emissions of
criteria pollutants and greenhouse gases generated by activities within the City of La Quinta and
serve as mitigation to reduce emissions. Measures set forth within the Greenhouse Gas
Reduction Plan along with general measures set forth below will mitigate potential impacts to air
quality. However, as illustrated above, emissions associated with operation of land uses at build
out of the General Plan will exceed established thresholds, even when mitigated. Long term air
emission impacts, therefore, will be significant and unavoidable.
The following mitigation measures are required in order to limit air quality emission within the
Planning Area:
1. The City of La Quinta shall adopt and implement a comprehensive Greenhouse Gas
Reduction Plan that is consistent with targeted reductions set forth by the State.
2. As feasible, the newest model heavy-duty construction equipment shall be utilized for
construction activities. The construction equipment fleet shall be updated to include the
latest models; older equipment shall be phased out. Specifically, 2010 and newer diesel
haul trucks (e.g., material delivery trucks and soil import/export) shall be used. If the City
determines that 2010 model year or newer diesel trucks cannot be obtained, it shall use
trucks that meet EPA 2007 model year NOx and PM emissions requirements.
3. To reduce fugitive dust during construction activities, trucks leaving development sites
should be washed off; haul trucks should maintain 2 feet of freeboard or be covered;
equipment should be properly tuned and maintained; and low sulfur fuels should be used
for construction equipment. Effective fugitive dust control measures can substantially
reduce emissions as shown in the Table below.
17 CEQA Guidelines sections 15064(i)(1) and 15130.
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Table III-10
Air Quality Control Methods
PM10 PM2.5 NOx
Apply Soil Stabilizers to Inactive Areas 84% 84%
Replace Ground Cover in Disturbed Areas 5% 5%
Water Exposed Surfaces 3 Times Daily 61% 61%
Reduce speeds on unpaved roads 44% 44%
Use of aqueous diesel fuel 50% 50% 15%
Use of Diesel Particulate Filter 85% 85%
Use of Diesel Oxidation Catalyst1 15%-40%
Source: Urban Emissions Model (URBEMIS2007) version 9.2.4.
1. Emission reductions vary depending on equipment type.
4. To reduce construction-related traffic congestion, developers and contractors shall
configure construction parking to minimize traffic interference, provide a flag person to
ensure safety at construction sites, as necessary, designate onsite travel routes to
minimize impacts to nearby land uses, and schedule operations affecting roadways for
off-peak hours, as practical.
5. Construction equipment shall be staged in locations that minimize impacts to nearby
receptors.
6. La Quinta shall continue to coordinate with CVAG and SCAQMD regarding the
implementation of local and regional air quality programs.
The follow mitigation measures are derived from consensus recommendations for reducing a
project’s contribution to greenhouse gas emissions:
1. Landscaping designs shall consider the use of trees and other vegetation to maximize the
shading of buildings in order to reduce energy requirements for heating and cooling and
provide carbon storage.
2. Desert landscaping techniques shall be utilized, including the use of automated water
efficient irrigation systems and devices.
3. Smart scalping practices shall be encouraged to minimize fugitive dust emissions and
reduce water demands.
4. Building designs shall strive to exceed Title 24 requirements or achieve LEED or Energy
Star standard equivalence ratings or better; buildings shall be equipped with energy
efficient and water conserving appliances and fixtures; building design shall include
natural lighting and ventilation; and light colored “cool” roofs and cool pavement shall be
utilized.
5. New buildings and substantial remodels including new roofs, should be designed to
accommodate rooftop photovoltaic or above parking solar.
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6. Recycling and composting facilities and programs shall be readily available for all new
and existing land uses and every effort shall be made to divert the landfill waste stream.
7. Utilize educational programs and demonstration gardens to inform the public and
businesses of energy and water efficient techniques and sustainable practices.
The following design strategies will reduce reliance on traditional automobiles for transportation:
1. Promote the use of electric vehicles and alternative modes of transport by providing safe
and convenient bicycle, scooter and other non-motorized transport travel lanes, and
parking, as well as preferential plug-in stations for electric vehicle parking.
2. In designing and expanding travel corridors provide for pedestrian and bicycle paths that
interconnect to commercial, recreational, and institutional land uses.
3. Assure all new development has safe and convenient access to public transit routes that
include seated, shaded bus stop areas.
4. Incorporate recreational open space adjacent to or as part of residential land uses.
5. Expand and coordinate a Valley wide signal synchronization system within city limits
and adjacent jurisdictions.
6. Work with CVAG, SCAG and regional transit authorities to work towards more efficient,
region wide travel options.
Mitigation Monitoring and Reporting
A. Building and landscape plans shall be reviewed for energy efficiency and soil stabilization.
Landscapers and landscape-related businesses shall be required to show proof of completion
of the CVAG’ Landscaper Certification Source.
Responsible Parties: Public Works, Engineering, Planning, and Building Departments.
B. A report of air quality complaints and identified problems shall be provided in the annual
review of the General Plan.
Responsible Parties: Public Works, Code Compliance and Planning Department, and
SCAQMD.
C. A report of emission reductions achieved shall be provided in the annual review of the
General Plan.
Responsible Parties: Planning Department and SCAQMD.
D. The City shall conduct review and prepare conditions of approval for all grading and
development permits, as well as required dust control plans to assure that appropriate
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methods and technologies are in place to minimize the emissions of pollutants from the
development activities.
Responsible Parties: Public Works, Engineering, Planning, and Building Departments.
Biological Resources D.
Introduction
This section discusses the biological resources in La Quinta, and assesses impacts on these
resources from future growth and development brought on by the La Quinta 2035 General Plan
Update. It also provides mitigation measures to reduce impacts to important biological resources.
The following discussion is based on the Biological Resources Study prepared by AMEC in
2010.
Thresholds of Significance/Criteria for Determining Significance
The following standards and criteria have been drawn from Appendix G: Environmental
Checklist Form of the CEQA Guidelines. The following factors have been considered to ensure
that the General Plan EIR adequately addresses potential impacts to biological resources that
may result from the development facilitated by implementation of the La Quinta General Plan.
Build out of the proposed General Plan would have a significant impact on biological resources
if it would:
a) Have a substantial adverse effect, either directly or through habitat modifications, on any
species identified as a candidate, sensitive, or special status species in local or regional plans,
policies, or regulations, or by the California Department of Fish and Game or U.S. Fish and
Wildlife Service.
b) Have a substantial adverse effect on any riparian habitat or other sensitive natural community
identified in local or regional plans, policies, regulations or by the California Department of
Fish and Game or US Fish and Wildlife Service.
c) Have a substantial adverse effect on federally protected wetlands as defined by Section 404
of the Clean Water Act (including, but not limited to, marsh, vernal pool, coastal, etc.)
through direct removal, filling, hydrological interruption, or other means.
d) Interfere substantially with the movement of any native resident or migratory fish or wildlife
species or with established native resident or migratory wildlife corridors, or impede the use
of native wildlife nursery sites.
e) Conflict with any local policies or ordinances protecting biological resources, such as a tree
preservation policy or ordinance.
f) Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community
Conservation Plan, or other approved local, regional, or state habitat conservation plan.
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1. Existing Conditions
A comprehensive biological resources study was prepared for the General Plan Update by
AMEC Earth and Environmental.18 The report is included in Appendix C of this document.
AMEC consultants conducted a literature review that included the California Natural Diversity
Data Base (CNDDB 2010), a variety of botanical and wildlife references pertinent to the
Planning Area, biological surveys prepared by AMEC for projects in or near the planning area
(AMEC 2003), including species accounts, life histories, and distribution and status of covered
species, and a review of the Coachella Valley Multiple Species Habitat Conservation Plan
website (2010). The United States Department of Agriculture, Natural Resources Conservation
Service’s Web Soil Survey data available for La Quinta (NRCS 2010) was referenced to
determine soil types in the Planning Area. AMEC biologists also conducted a field survey of the
General Plan and Area as part of the biological resources assessment.
Regional Biological Setting
The Planning Area is located in a natural environment that displays substantial variation,
including elevations ranging from 190 feet below sea level in the southeastern corner of the
Sphere of Influence, to over 1,700 feet above sea level in the foothills of the Santa Rosa
Mountains. Most of the City and the Sphere of Influence occur on the Valley floor, which is
characterized by hot, dry summers and mild winters. Soil types and the natural habitats that can
be supported in the Planning Area are affected by climate. There are eleven primary soil types
found in the City and Sphere; most of these are sandy in nature, and well drained. Rock and
rubble occur in the Santa Rosa foothills. Soil types in the Planning Area include Carrizo stony
sand, Carsitas Sands, Coachella Sands, Fluvents, Gravel Pits and Dumps, Gilman Sands and
Loams, Indio Loams, Myoma Fine Sands, Rock Outcrop, Rubble Land, and Salton Fine Sandy
Loam. Soil properties in the Planning Area are further discussed in Section III-F, Geology and
Soils.
There are limited areas of naturally occurring habitat in the City and on the Valley floor, as a
result of agriculture and urban development. Lands on the slopes of the Santa Rosa Mountains
have little potential for development and native habitat still occurs. These lands are designated as
Open Space in the existing and proposed General Plans. Elsewhere in the City, vegetation is
primarily comprised of non-native ornamental plants introduced by developers and homeowners.
Natural Communities
The following natural communities occur within the Planning Area. The locations of these are
shown on Exhibit III-1, Vegetation Communities.
18 “City of La Quinta General Plan Update: Biological Resources,” prepared by AMEC Earth & Environmental,
Inc., June 2010.
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Stabilized Shielded Sand Fields
Regionally, Stabilized and Partially Stabilized Desert Sand Fields are those in which sand is
supplied through sand source and sand transport systems. In the Planning Area, these have
generally been interrupted or shielded by barriers such as roads, buildings, and landscaping. The
long-term persistence of stabilized shielded desert sand fields is compromised by the interruption
of the sand source and sand transport system and occur in the Planning Area as Stabilized
Shielded Sand Fields. Most of these areas have been developed for residential and commercial
projects. In La Quinta, this natural community is limited to the northern portion of the PA in the
vicinity of Highway 111, and largely consists of smaller, fragmented parcels heavily disturbed
by their proximity to roads. It includes most of the remaining sand fields south of U.S. Interstate
10 that historically comprised the Big Dune.
Representative plants found in this community include Sand Verbena (Abronia villosa), Fanleaf
Crinklemat (Tiquilia plicata), California Croton (Croton californicus), Four-wing Saltbush
(Atriplex canescens), and Indian Ricegrass (Achnatherum hymenoides). In the Planning Area, no
Stabilized Shielded Sand Fields community has been targeted for conservation in the MSHCP.
The non-native, invasive plant species Sahara Mustard (Brassica tournefortii) poses a serious
threat to this community, as well as to sandy communities throughout the Sonoran and Mojave
Deserts. Although present in the Coachella Valley since the 1920’s, Sahara Mustard has become
increasingly abundant. It has been demonstrated to negatively impact native flora as well as
certain wildlife species, among them the Coachella Valley Fringe-toed Lizard.
Sonoran Creosote Bush Scrub
The most common natural community in the Coachella Valley region is the Sonoran creosote
bush scrub. Dominant plants include Creosote Bush (Larrea tridentata), Burrobush (Ambrosia
dumosa), Brittlebush (Encelia farinosa), and other common desert perennials. Up to 75% of the
vegegation in this community may be represented by wildflowers.
In the Planning Area, this community is primarily found above the shoreline of ancient Lake
Cahuilla, as well as on the lower Santa Rosa Mountain slopes and portions of alluvial fans and
bajadas emanating from the mountains. In these areas it is often intermixed with other plant
communities, including Sonoran Mixed Woody and Succulent Scrub, and with Desert Dry Wash
Woodland.
Sonoran Mixed Woody and Succulent Scrub
Similar to creosote bush scrub, this community is typically more varied and contains a higher
density of plants. It has a sizeable dominance of cacti and other stem succulents, unlike other
Sonoran desert communities in the Planning Area. Typical species include Golden Cholla
(Opuntia echinocarpa), Buckhorn Cholla (Opuntia acanthocarpa), Pencil Cholla (Opuntia
ramosissima), Beavertail (Opuntia basilaris), California Barrel Cactus (Ferocactus
cylindraceus), and Ocotillo (Fouquieria splendens). Creosote bush and other associated
perennial shrubs are also associated with this community, which occurs on alluvial fans and
slopes of the Santa Rosa Mountains.
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Desert Dry Wash Woodland
This community is characterized by open to dense, drought-deciduous, microphyllous woodland
plants as tall as 30 to 60 feet. Members of the pea family are dominant, and may include Blue
Palo Verde (Cercidium floridum), Ironwood (Olneya tesota), and Smoketree (Psorothamnus
spinosus). Desert Lavender (Hyptis emoryi), Cheesebush (Hymenoclea salsola), Catclaw (Acacia
greggii), and Desert Willow (Chilopsis linearis) may also be associated with this community. In
the Planning Area, desert dry wash woodland occurs in association with canyon mouths and
alluvial fans in the Santa Rosa Mountains. It is typical of ephemeral washes, which are subject
to occasional flooding but without consistent surface flows.
Desert Saltbush Scrub
There are a variety of species of saltbush that may occur in this community, which is
characterized by a nearly uniform stand of shrubs that form a more complete cover than do plants
associated with creosote bush scrub. Soils are usually fine-textured, poorly drained with high
(ranging from 0.2-0.7%) salinity and/or alkalinity. Habitats are generally moist, with a sandy
loam soil. Dominant species are one or more Atriplex, including Big Saltbush (Atriplex
lentiformis), Allscale (Atriplex polycarpa) and Four-winged Saltbush (Atriplex canescens var.
linearis). In some areas, Alkali Goldenbush and Honey Mesquite are common representatives of
this habitat type. The latter are found east of Lake Cahuilla County Park in southern La Quinta.
In scattered fallow parcels throughout the eastern Sphere, diminished examples of this habitat
occur in various stages of re-growth. Where these “pseudo-Saltbush Scrub” areas occur, they
often include a mixture of non-native alkali-tolerant species as well as native Atriplex.
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Exhibit III-1
Vegetation Communities
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Common Species
There are primarily two categories of habitat associated with wildlife common to the planning
area. The most prevalent consists of the very disturbed and fragmented patchwork of remnant
sand field, saltbush scrub, weedy (ruderal), agricultural, and residential/recreational
development. Common species in this environment are those that are capable of surviving in
ruderal plant communities or near residential, commercial, agricultural, and golf course
developments.
Another habitat category is comprised of native, less altered habitats where the Santa Rosas and
associated alluvial fans and canyons overlap in the western and southern portions of the Planning
area. These remaining areas of native habitat sustain both common as well as some sensitive
desert wildlife species and plant communities. Common wildlife species include insects such as
several species of harvester and crater-nest ants, the native creosote bush grasshopper, burrowing
sand roaches and sand scorpions, a wide range of native and non-native bee and wasp species,
black widow spider and others.
Common species with potential to occur in the Planning Area are further described below.
Common amphibians include the California toad, Pacific Tree Frog and the non-native,
naturalized Bullfrog where habitat provides suitable moisture. A variety of common lizard and
snake species are found in the Planning Area. Lizard species include the Great Basin Whiptail,
Side-blotched Lizard, Desert Iguana and Common Chuckwalla. Common snake species known
from the Planning Area include Red Coachwhip, California Kingsnake, and Sonoran Gopher
Snake, as well as venomous snake species including the Colorado Desert Sidewinder, which
occurs in sandy habitats, and the Southwestern Speckled Rattlesnake, which is generally found in
rocky habitats.
The Planning Area is also home to or is utilized by a wide variety of common bird species. Non-
resident bird species may migrate through the area or utilize it for breeding or nesting only.
Certain species nest elsewhere but over-winter in the Planning Area, while others species
permanently reside in La Quinta. Verdin, Abert’s Towhee, Black-Tailed Gnatcatcher, Gambel’s
Quail, Mourning Dove and Ladder-Backed Woodpecker use Desert Dry Wash Woodlands and
wash habitats containing mixed shrub and tree habitat that provides primary nesting habitat.
Other nesting sites include shrubs, ground surfaces and animal burrows within Creosote Bush,
Saltbush and Woody Scrub communities. Landscaping within residential and/or recreational
areas, as well as agricultural plantings, especially date palm groves, also provide suitable nesting
habitat. Species utilizing agricultural areas include Red-Tailed and Red-Shouldered Hawk, Great
Horned Owl, and American Kestrel. Raptors and common Ravens utilize cliff faces, rock
outcrops and hillsides located in mountainous areas which occur primarily within Sphere areas.
Black-Throated Sparrow, Horned Lark, Loggerhead Shrike and Say’s Phoebe characteristically
utilize creosote bush, saltbush, and ruderal scrub communities within the Planning Area. A
variety of songbird species use both desert riparian and scrub habitats in the winter months only;
these include the Yellow-Rumped Warbler, White-Crowned Sparrow, Blue-Gray Gnatcatcher
and Ruby-Crowned Kinglet.
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These and other common species are not designated species of concern, however, most of them
are protected by the provisions of the Migratory Bird Treaty Act (MBTA). The MBTA prohibits
disturbing nests, eggs, and incubating birds, and of hatchling and fledgling birds during active
nesting. The Burrowing Owl is a “covered” species under the MSHCP and is also protected by
the MBTA. Although the MSHCP currently only requires surveys for Burrowing Owl within
Conservation Areas, the MBTA requires surveys and mitigation anywhere Burrowing Owl is
observed in the Planning Area.
Numerous larger common mammal species are found in the Planning Area, such as the Black-
Tailed Jackrabbit Desert Cottontail, Striped Skunk, Northern Raccoon, Kit Fox, and Coyote.
Smaller mammals include Pocket Mice, Cactus Mouse, Kangaroo Rats, Desert Woodrat, White-
Tailed Antelope Squirrel, and California Ground Squirrel. Many of these non-special status
species utilize a variety of habitat types within the Planning Area.
Special Status Species
There are several plant and animal species known or thought to occur within the Planning Area
that are designated as Special Status species by federal, state and/or local agencies. Certain
species within the Coachella Valley region are discussed herein as special status species in that
they are locally endemic or utilize unique habitat.
Lists of these sensitive species are maintained by the U.S. Fish and Wildlife Service (USFWS)
and the California Department of Fish and Game (CDFG), which provide information about
species ranges and occurrence probabilities. The California Native Plant Society (CNPS) is a
non-profit conservation organization that maintains listings of native flora and determines the
status of each species as rare, threatened, and/or endangered.
The following definitions are used by these agencies to determine the status of qualified species:
(1) “Endangered” species are those with such limited numbers that they are considered to be in
imminent danger of extinction; (2) “Threatened” species are those likely to become endangered
within the foreseeable future, particularly on a local scale; and (3) “Sensitive” and “rare” species
are those that are naturally rare or have been locally depleted or put at risk by human activities,
and although perpetuation of these species does not appear to be significantly threatened, they
are considered vulnerable and may be candidates for future listing.
Sensitive species listed in the following tables are those that have the potential to occur within
the Planning Area and vicinity. The Biological Report, included as an appendix to this document,
provides a comprehensive listing of sensitive species associated with the City, Sphere of
Influence and vicinity. Following the tables is a description of each of the sensitive species.
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Table III-11
Special Status Plants in the La Quinta General Plan Area and Vicinity
Common
Name
Scientific
Name
Habitat
State and Local
Status
Federal
Status
Chaparral
Sand-Verbena
Abronia villosa
var. aurita
Sandy areas
Chaparral/Desert
dunes
CNPS List 1B.1
State: S2.1
None
Glandular Ditaxis
Ditaxis claryana Sandy habitats
Sonoran Desert
scrub
0-465 meters
CNPS List 2.2
State: S1S2
None
California Ditaxis
Ditaxis serrata
var. californica
Sonoran Desert
Scrub
CNPS List 3.2
State: S2.2
None
Table III-12
Special Status Reptiles in the La Quinta General Plan Area and Vicinity
Common
Name
Scientific
Name
Habitat
State and Local
Status
Federal
Status
Flat-tailed Horned
Lizard
Phyrnosoma
mcallii
Sandy habitats with
adjacent hardpan, often
sparsely vegetated, also
saltbush habitats
State: S2
CDFG: CSC
CVMSHCP
None
Coachella Valley
Fringe-toed Lizard
Uma
inornata
Sand dunes, sand fields CDFG:
Endangered/S1
CVMSHCP
Threatened
Table III-13
Special Status Bird Species in the La Quinta General Plan Area and Vicinity
Common
Name
Scientific
Name
Habitat
State and Local
Status
Federal
Status
Burrowing Owl Athene
cunicularia
Burrows/abandoned
Foundation structures,
Creosote Bush & Ruderal Scrub
(edges of canals/agriculture)
State: S2
CDFG: CSC
CVMSHCP
None
Prairie Falcon
Falco
mexicanus
Cliff faces (nesting),
Open habitats for foraging
State: S3
CDFG: Watchlist
None
Black-tailed Gnatcatch Polioptila
melanura
Desert scrub and
desert wash woodland habitats
State: S4 None
Loggerhead Shrike Lanius
ludovicianus
Fairly common in a
variety of open
habitats
State: S4
CDFG: CSC
None
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Table III-14
Special Status Mammal in the La Quinta General Plan Area and Vicinity
Common
Name
Scientific
Name
Habitat
State and
Local Status
Federal
Status
Western Yellow
Bat
Lasiurus
xanthinus/ega
Primarily roosts in
the dead fronds of
palms, including
landscape specimens
State: S3
CDFG: CSC
CVMSHCP
None
Pocketed
Free-tailed Bat
Nyctinomops
femorosaccus
Variety of arid habitats
Desert Scrub, Palm
Oasis, Desert Wash,
roosts in rocky cliffs
State: S2S3
CDFG: CSC
None
Palm Springs
Round-tailed
Ground Squirrel
Xerospermophilus
tereticaudus
chlorus
Desert Scrub, Desert
Wash, Alkali Scrub,
& levees, golf course
edges w/ adjacent
native habitat
State: S1S2
CDFG: CSC
CVMSHCP
Candidate
Peninsular
Bighorn Sheep
Ovis canadensis
nelsoni DPS
Lower elevations of the
eastern Peninsular
Ranges, including
canyon
bottoms, alluvial fans,
and mountain slopes
Threatened
CVMSHCP
Endangered
Table Legend
Habitat: terrestrial natural community descriptions per Holland (1986)
State of California and Local Status: Endangered, Threatened, Protected, Special Concern status per the California Fish and
Game Code of 2007, as well as all species protected by the Coachella Valley Multiple Species Habitat Conservation Plan (species
covered by plan listed as CVMSHCP).
Federal Status: Endangered, Threatened and Candidate for listing status per the Endangered Species Act of 1973 (as amended).
It is mandatory that federally listed plant species be fully considered during preparation of environmental documents pertain ing
to the California Environmental Quality Act or National Environmental Policy Act, or any federal authorization.
California Native Plant Society (CNPS) listing rankings (CNPS 2010) are described as follows:
List 1A: Plants (29) presumed extinct in California because they have not been seen or collected in the wild in
California for many years.
List 1B: Plants considered rare and endangered in California and throughout their range. All of the plants
constituting List 1B meet the definitions of Section 1901, Chapter 10 (Native Plant Protection Act) or
Sections 2062 and 2067 (California Endangered Species Act) of the California Department of Fish and
Game Code and are eligible for state listing. It is mandatory that these plant species be fully
considered during preparation of environmental documents pertaining to the California Environmental
Quality Act.
List 2: Plants considered rare, threatened or endangered in California but which are more common elsewhere.
List 3: Plants about which more information is needed to assign them to one of the other lists.
List 4: Plants of limited distribution (a “watch list”) or infrequent throughout a broader area in California, their
vulnerability to threat appears low at this time.
Threat Rank
0.1 Seriously threatened in California (high degree/immediacy of threat)
0.2 Fairly threatened in California (moderate degree/immediacy of threat)
0.3 Not very threatened in California (low degree/immediacy of threat)
State Ranks
S1: 5 or fewer viable occurrences or fewer than 1,000 individuals statewide and/or less than 2,000 acres
S2: 6 – 20 viable occurrences or fewer than 3,000 individuals statewide and/or 2,000 – 10,000 acres
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S3: 21 – 100 viable occurrences or fewer than 10,000 individuals statewide and/or 10,000 – 50,000 acres
S4: Greater than 100 viable occurrences statewide and/or greater than 50,000 acres, apparently secure statewide
S5: Community demonstrably secure statewide
Where two ranks are given (eg. S1S2) the species’ rank falls between the two ranks
Threat Ranks
0.1: Very threatened
0.2: Threatened
0.3: No current threats known
Of the species shown in the preceding tables, seven are not covered by the MSHCP. The
following briefly describes these sensitive species and the likelihood of their occurrence in the
Planning Area. Exhibit III-2, CNDDB, Critical and Modeled Habitat shows the general location
of each species.
Sensitive Plant Species
Chaparral Sand-Verbena (Abronia villosa var. aurita) has been reported within the Planning
Area at one location, which is now developed. Therefore, no further discussion of this species is
included herein.
Glandular Ditaxis (Ditaxis claryana) is a small perennial herb of the Spurge family. It has been
recorded at two locations in the Planning Area, within Sonoran Creosote Bush Scrub habitat.
Both of these locations have been developed. The potential for this species to occur in the
Planning Area is low, limited to southern and western portions of the area where suitable habitat
is located. Mitigation for impacts to this species is primarily through spring or fall surveys after
sufficient rainfall, and avoidance where populations are identified.
California Ditaxis (Ditaxis serrata var. californica) is another small perennial herb of the Spurge
family. It is typically found in rocky alluvial fans, flood plains and dry washes, and in the
Planning Area has been recorded in one location, west of Avenida Montezuma and Calle
Nogales, in the Cove. This location still offers viable habitat for this species. Potential
occurrence is moderate to high in the southern and western areas of the City.
Sensitive Bird Species
Burrowing Owl
(Athene cunicularia)
uses man-made structures such as piles of tree branches or
debris, buildings or pipes, or burrows dug out by other wildlife, such as kit fox, desert tortoise or
ground squirrels. Burrowing owl is a species of special concern and a protected raptor.
Therefore, notification of CDFG and approved mitigation are required prior to any activity that
may impact the species. Potential occurrence locations in the Planning Area include wherever
undeveloped or fallow land occurs. It has been observed during surveys conducted in 2003 in the
southern portion of the Planning Area. Mitigation includes site-specific surveys to identify the
species.
Prairie Falcon (Falco mexicanus), a medium to large migratory raptor that winters in the region,
prefers cliffs or steep rock ledges in the western and southern parts of the Planning Area. This
species has been observed at the southwestern end of the City. It is a protected raptor as well as a
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species of special concern. Therefore, CDFG notification and approved mitigation prior to any
activity that might impact the species are required. Site-specific surveys are needed to identify
the species.
Black-tailed Gnatcatcher (Polioptila melanura) has a range that extends through the Sonoran and
Chihuahuan Deserts of the US and northern Mexico. It lives in pairs throughout the year. The
species is a small, resident songbird and has been identified at two locations in the Planning
Area. It is most likely to occur in the western and southern portions of the City and Sphere. Site-
specific surveys are needed to identify the species. Conservation of this species is served by
limiting impacts to Desert Dry Wash Woodland and Sonoran Creosote Bush Scrub habitats.
The Loggerhead Shrike (Lanius ludovicianus) is a reasonably common species in California,
although in other parts of the U.S. it has been significantly depleted. In the Planning Area is
occurs in undeveloped areas, hillsides to the south and west, and on the periphery of agricultural
fields. There are no specific study or preservation prescriptions associated with this species.
Sensitive Mammal Species
Pocketed Free-tailed Bat (Nyctinomops femorosaccus) is so named after the small fold, or
“pocket” in its wing membrane. The species has large ears and long wings; these bats fly
quickly and hunt insects on the wing. They roost in colonies of less than 100 in caves, crevices in
rocky cliffs, or buildings. In the Planning Area they have been observed in one location, which
has been developed as a golf course but still has suitable foraging and drinking use for this
species. There is also suitable roosting habitat still located east of the site. The greatest threats to
this species are habitat loss and unmanaged use of pesticides. Conservation prescriptions to
protect this species include limiting impacts to rocky habitats that the species utilizes for
roosting.
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Exhibit III-2
CNDDB, Critical Habitat & Modeled Habitat
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Habitat Protection
Coachella Valley Multiple Species Habitat Conservation Plan
The Coachella Valley Multiple Species Habitat Conservation Plan (MSHCP) is a joint regional
planning effort of the US Fish and Wildlife Service (USFWS), the California Department of Fish
and Game (CDFG), the Bureau of Land Management (BLM), the U.S. Forest Service (USFS),
and the National Park Service (NPS), as well as Riverside County and most local jurisdictions
within the Coachella Valley, including the City of La Quinta. The MSHCP is intended to
streamline and simplify compliance with the State and Federal Endangered Species Acts (CESA
and FESA, respectively) and other applicable laws and regulations; obtain Take Authorization
(Take Permits) pursuant to the FESA and the California Natural Community Conservation
Planning (NCCP) Act for Covered Activities in the Coachella Valley; and balance environmental
protection with regional economic objectives. The City is a permittee under the MSHCP.
The General Plan Area is within the planning area for the Coachella Valley Multiple Species
Habitat Conservation Plan (MSHCP). A portion of the Santa Rosa and San Jacinto Mountains
Conservation Area lies within the General Plan Area, on lands west of the eastern edge of the
Santa Rosa Mountains. The location of this Conservation Area is shown on Exhibit III-3, Land
Ownership and Conservation Areas. Should future development be proposed within the
Conservation Area, it will be subject to compliance with specific goals and measures set forth in
the MSCHP. These include conservation of lands for Essential Habitat for Peninsular Bighorn
Sheep, as well as conservation of lands for other MSHCP-protected species and habitat, such as
Le Conte’s thrasher, Desert tortoise, desert dry wash woodland natural community, and
conservation of occupied burrowing owl burrows.
Conservation goals for La Quinta are set forth in the MSCHP. They are:
2,545 acres of Essential Habitat for the Peninsular Bighorn Sheep
387 acres of Conserved Habitat for the Le Conte’s thrasher
1,409 acres of Conserved Habitat for Desert Tortoise
76 acres of desert dry wash woodland
Conserve occupied Burrowing Owl burrows as provided for in the MSHCP avoidance,
minimization and mitigation measures.
On lands not designated for conservation, future development will be required to pay a
mitigation fee to ensure the future availability of funds to purchase conservation lands. These
fees are intended to offset the potential impacts of that development on the natural environment.
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Exhibit III-3
Land Ownership and Conservation Areas
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Regulation of Streambeds and Watercourses
There are numerous washes and streambeds in the Planning Area. In addition to the Whitewater
River, there are several smaller, mostly unnamed streams that drain from the Santa Rosa
Mountains. Streambeds and washes are subject to regulation by a variety of state and federal
regulatory agencies. Where streambeds and washes qualify as Waters of the State of California,
they fall under the jurisdiction of the California Department of Fish and Game (CDFG). Water
bodies determined to be Waters of the U.S. also fall under the jurisdiction of the U.S. Army
Corps of Engineers (USACOE). Development projects that require construction activities within
these water bodies must secure applicable permits.
Projects within streams and washes under CDFG jurisdiction may require a Streambed Alteration
Agreement. Where USACOE holds jurisdiction, a Section 404 permit may be required to satisfy
requirements of the federal Clean Water Act. USACOE may also require a formal delineation of
the affected waterbody to determine the extent of jurisdictional Waters of the U.S. Compliance
with Section 401 of the Clean Water Act may also be required, necessitating a Water Quality
Certification through the State Regional Water Quality Control Board (RWQCB) for state
certification, and in some cases, the U.S. Environmental Protection Agency (USEPA) for federal
certification.
The Whitewater River, which is the primary ephemeral stream in the Coachella Valley, runs
generally northwest to southeast through the Coachella Valley. East of Washington Street, the
river is called the Coachella Valley Stormwater Channel. The Channel qualifies as both a Water
of the State of California, and a Water of the U.S. Therefore, construction activities within the
Channel require consultation with both CDFG and the USACOE, and permits must be secured
from both agencies. In general, when a 404 permit is required, a state 401 Water Quality
Certification is also required.
In the Planning Area, smaller streams emanating from the Santa Rosa Mountains include Bear
Creek, which enters the City at the south end of the Cove, and the La Quinta Evacuation
Channel, which extends northeasterly from the Bear Creek Channel. Such drainages constitute
waters of the State and are under the jurisdiction of the CDFG. They are not considered “waters
of the United States,” as defined by the USACOE. Project developers proposing construction
activities within these streams must consult with CDFG, and may be required to obtain a
Streambed Alteration Agreement as well as any other applicable permits and approves prior to
the initiation of work.
Migratory Bird Treaty Act
As previously discussed, nearly all common and special status birds in the Planning Area are
protected under the federal Migratory Bird Treaty Act (MBTA). Under the MBTA, disturbance
of nests, eggs or incubating birds while nests are active is prohibited. Within the Planning Area,
the nesting period generally extends from March through August. Pre-construction surveys are
required prior to project activities to determine if active nests are present within trees and bushes.
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2. Project Impacts
Potential Direct and Indirect Impacts
Implementation of the proposed General Plan will facilitate new development and growth that
will result in impacts to biological resources in the Planning Area. Population growth is expected
to result in increased disturbance on open space lands, including human use, vehicle travel,
garbage dumping, and potential increased frequency of wildfires. These activities have potential
to impact plant communities that are as yet undisturbed by human activity.
Over time, certain non-native, invasive plants, such as Sahara Mustard, may be expected to
spread in existing sand field habitat. While much of this habitat has already been developed, the
continued spread of this and other non-native, invasive species has potential to result in adverse
impacts to native species and supporting habitats.
Continued urban growth and development may be expected to result in displacement, injury or
even death to wildlife species occurring on currently undeveloped or sparsely developed lands.
Where native habitat is still present in the planning area, it may be impacted by increased vehicle
travel, alteration of soils, vegetation removal and habitat degradation associated with new
development. This is particularly true in the eastern Sphere as well as the southern and western
portions of the planning area. Individual development projects may disrupt courtship and
breeding behaviors of some native wildlife.
Future development in the planning area may also result in incidental take of listed species,
whether they are residents or seasonal migrants. Impacts to special status species are cumulative,
given other development that has or may be expected to take place in the Coachella Valley. It
should be noted that these impacts are addressed in the Coachella Valley Multiple-Species
Habitat Conservation Plan (MSHCP), which provides mitigation for incidental take resulting
from individual development projects. Mitigation includes payment of per-acre mitigation fees
for all new development within the MSHCP planning area.
Potential Impacts to Plant Communities
As development occurs within the General Plan Area, there is potential for the destruction of
entire populations of common and sensitive plant species. There are no federal Threatened or
Endangered plant species thought to occur in the Planning Area, however there are two special
status plant species with probability of occurring. It is expected that impacts to special status or
comment plant species will be less than significant if they are present, since they are most likely
to occur within the southern and western portions of the Planning Area. These areas are
designated for Open Space use within the existing and proposed General Plan and are not
planned for development. Introduction of non-native plant species associated with landscaping
could result in native plant species competing for water, nutrients and space.
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Potential Impacts to Invertebrates, Reptiles and Amphibians
Invertebrates, reptiles and amphibians that occur in the Planning Area will be impacted by
increased urbanization. These species are especially vulnerable to the impacts of off-highway
vehicle traffic, as well as crushing from grading and construction activities. The Coachella
Valley Fringe-Toed Lizard is the only federal listed Threatened and state listed Endangered
reptile species that is thought to occur in the Planning Area. As urban development has
encroached, the sandy habitat that supports this species has become increasingly compromised
through the construction of roads, buildings and fences and other barriers that disrupt the natural
blowsand process. Future development has potential to result in permanent loss of habitat that
will impact individuals as well as entire populations. The Coachella Valley Fringe-Toed Lizard
is a covered species under the MSHCP, which addresses impacts to this species through payment
of fees and other measures.
Potential Impacts to Birds
As development in the Planning Area continues, it may be expected to result in habitat
degradation and the direct loss of foraging and nesting sites for a variety of common and special-
status bird species. Predation by domestic pets, increased competition for limited nesting sites,
pesticide ingestion, and the introduction of parasites constitute indirect impacts that may occur.
Some species may be especially disrupted by off-road vehicle activity, particularly during
breeding season. Bird species that can tolerate human disturbance will likely continue to inhabit
developed areas, and may be attracted to newly landscaped areas. Burrowing Owl may be
impacted by the conversion of agricultural lands to urban development. This species is covered
by special survey requirements of the MSHCP and receives protection under California Fish and
Game code.
Potential Impacts to Mammals
Development activities involve mass grading and clearing, resulting in the removal of vegetation
and wildlife. A wide range of common and sensitive wildlife species occur in the Planning Area
and may be subject to increasing adverse impacts as urbanization encroaches. Bats may roost in
abandoned buildings, bridges over the Whitewater River, and untrimmed date palm trees, and
these should be surveyed prior to disturbance. The Pocketed Free-tailed Bat typically roosts in
rocky terrain of the Santa Rosa Mountains. The existing and proposed General Plan designated
these lands as Open Space, preserving them from development, and this is expected to avoid or
minimizing potential impacts to this species.
The direct and indirect impacts of continued development affect smaller mammals, including a
variety of common and sensitive species. Off-road vehicles, domestic pet predation, and surface
disturbance that could crush burrows pose specific hazards to these species, such as the Palm
Springs Round-Tailed Ground Squirrel, which is a candidate for Federal listing.
Peninsular Bighorn Sheep (PBS) habitat occurs on the rocky hillsides of the Santa Rosa
Mountains, including lands that occur in the southwestern portion of the Planning Area. Portions
of these lands fall within the MSHCP Santa Rosa and San Jacinto Mountains Conservation Area.
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It is expected that development within these areas will continue to be limited, both by the City’s
Hillside Conservation Zone Ordinance and restrictions on development within the MSHCP
Conservation Area. However, this species may be subject to indirect impacts associated with
development at the base of the mountain slopes. PBS are susceptible to toxic plants associated
with landscaping, collision with vehicles, and parasites. This species is generally intolerant to
human disturbance. They have been known to abandon hillside habitat as a result of human
activities such as hiking or other recreational activities. PBS are a covered species within the
MSCHP and development within or adjacent to PBS habitat is subject to a variety of
requirements set forth in the MSCHP.
Summary of Impacts
The ultimate build out of the General Plan Planning Area has the potential to significantly impact
biological resources by reducing native habitat areas and directly affecting fauna. However, the
majority of lands on which development will occur are on the Valley floor, in areas already
impacted by urban development or agricultural activities. These areas are part of the MSHCP,
and new development projects will be required to pay mitigation fees associated with the
MSHCP to allow for the preservation of habitat and species in designated conservation areas.
Further, areas where non-covered sensitive species occur are identified in the General Plan, and
the Plan requires the preparation of special studies for projects proposed in those areas. Those
studies will provide an assessment of the potential impacts, and recommend mitigation measures
if necessary.
The General Plan also designates Natural Open Space for hillside areas on the west and
southwest portions of the City, which are areas of potential habitat for the endangered Peninsular
Bighorn Sheep. The Natural Open Space designation will not result in development in these
areas, and will protect these lands for the long term.
Finally, existing regulations, including the provisions of the MSHCP, the requirements enforced
by the California Department of Fish and Game, the US Fish and Wildlife Service and the US
Army Corps of Engineers will continue to be enforced by the City. These requirements and
regulations are designed to protect species, water bodies and habitats from negative impacts
associated with development. The General Plan acknowledges these requirements, and includes
policies to maintain their implementation for future projects as they are proposed.
The imposition of the mitigation measures identified below will assure that impacts to biological
resources will be reduced to less than significant levels.
3. Mitigation
The build out of the General Plan will result in impacts to biological resources. With the
implementation of the following mitigation measures, however, these impacts will be reduced to
less than significant levels.
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1. The City shall require payment of Coachella Valley Multiple Species Habitat Conservation
Plan mitigation fees prior to issuance of occupancy permits for development projects
required to pay such fees.
2. The City shall refer land owners and developers of lands slated for conservation under the
MSHCP to the Coachella Valley Association of Governments and/or Coachella Valley
Conservation Commission for guidance and permitting assistance.
3. The City shall maintain and update as necessary all maps of conservation and mitigation fee
boundaries for the MSHCP.
4. Where appropriate, the City shall require site-specific, species-specific surveys for the seven
species not covered by the MSHCP.
5. Projects proposed for development within areas identified as having potential for occurrence
of Glandular Ditaxis, California Ditaxis, Prairie Falcon, Black-tailed Gnatcatcher,
Loggerhead Shrike and Pocketed Free-tailed Bat, as identified in the General Plan, shall be
required to retain a qualified biologist to prepare biological resource surveys.
6. Prior to the issuance of any ground disturbing permit for qualifying projects19 in a
Conservation Area, the City shall require a protocol compliant survey for Burrowing Owl, in
compliance with the MSHCP Section 4.4.
7. The City shall require protocol compliant surveys for burrowing owl prior to the issuance of
any ground disturbing permit for fallow lands outside MSHCP Conservation areas
8. The City’s Land Use Map shall designate as “Open Space” all publicly owned Conservation
lands for the MSHCP.
9. In compliance with the requirements of the Migratory Bird Treaty Act (MBTA), the City
shall continue to require that for development projects proposing removal of vegetation
between March and August, a qualified biologist shall be retained to determine whether any
bird nests or young occur on the site, and if they occur, to provide mitigation measures
compliant with the MBTA.
10. In compliance with the regulatory requirements of the California Department of Fish and
Game, the U.S. Army Corps of Engineers and the Regional Water Quality Control Board as
they relate to “waters of the State of California” and/or “waters of the United States”, and
prior to the initiation of any project within the Coachella Valley Stormwater Channel, the
City shall require that consultation and/or permitting by State and federal agencies by
demonstrated in writing.
19 Qualifying projects do not include single family residences, non-commercial accessory uses and structures
(including but not limited to second units on an existing legal lot), or the operation and maintenance of Covered
Activities other than levees, berms, dikes, and similar features known to contain burrowing owl burrows.
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11. Prior to the initiation of any project within any defined blueline stream other than the
Coachella Valley Stormwater Channel, the City shall require that consultation and/or
permitting by California Department of Fish and Game be demonstrated in writing.
12. The City shall encourage new development projects to incorporate native desert plant
materials into project landscaping to the greatest extent possible, and shall discourage the use
of invasive, non-native species.
13. The City shall use zoning standards and the design review process to assure that adequate
buffers are provided between urban development and environmentally sensitive areas,
including Conservation Areas for the MSHCP, to the greatest extent possible.
Mitigation Monitoring and Reporting
A. The City shall review the potential impacts of development projects on biological resources
through the Initial Study review process. Where appropriate, impacts shall be clearly
documented and mitigation measures recommended.
Responsible Parties: Planning Department, Project Developer/Consulting Biologist.
B. Prior to the issuance of occupancy permits, the City shall require that all applicable
biological resource mitigation actions, including payment of Coachella Valley Multiple
Species Habitat Conservation Plan mitigation fees by applicable projects, and compliance
with applicable state and federal regulatory permits, shall be satisfied.
Responsible Parties: Planning Department, Biologist, California Department of Fish and
Game, California Regional Water Quality Control Board, U.S. Army Corps of Engineers,
Project Developer/Consulting Biologist.
C. On an annual basis, City staff shall evaluate biological resources reference materials and
update City records and inventories to ensure that resource databases are maintained in a
timely and adequate manner.
Responsible Parties: Planning Department, Project Developer/Consulting Biologist.
D. During grading, construction and other development activities, development projects shall be
monitored to ensure that grading limits are observed and that native and other appropriate
landscape materials are preserved and integrated into all areas of the project in accordance
with approved landscape plans.
Responsible Parties: Planning Department, Developer/Consulting Biologist.
Cultural Resources E.
Introduction and Background
This section discusses the rich cultural resources in La Quinta, and assesses impacts on these
resources from future growth and development brought on by the General Plan Update. It also
provides mitigation measures to reduce cultural resource impacts. The following discussion is
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based on the Cultural Resources Technical Report and the Paleontological Technical Report
prepared by CRM Tech in 2010.
Thresholds of Significance/Criteria for Determining Significance
Article 5, Section 15064 of the CEQA Guidelines provides guidance for determining the
significance of the environmental effects caused by a project. Appendix G of CEQA provides a
list of environmental factors that potentially may be affected by completion of a project. The La
Quinta 2035 General Plan Update would have a significant effect on Cultural Resources if it is
determined the project will:
a) Cause a substantial adverse change in the significance of a historical resource as
defined in 15064.5.
b) Cause a substantial adverse change in the significance of an archaeological resource
pursuant to 15064.5.
c) Directly or indirectly destroy a unique paleontological resource or site or unique
geologic feature.
d) Disturb any human remains, including those interred outside of formal cemeteries.
The CEQA Guidelines define the term “historical resource” to include the following20:
1. A resource eligible by the State Historical Resources Commission as listed in the
California Register of Historical Resources (Public Resource Code 5024.1, Title 14 CCR,
Section 4850 et seq.)
2. A resource included in a local register of historical resources as defined in section
5020.1(k). This includes properties recognized as historically significant by a local
government pursuant to a local ordinance or resolution.
3. Any object, building, structure, site, area, place, record, or manuscript which a lead
agency determines to be historically significant or significant in the architectural,
engineering, scientific, economic, agricultural, educational, social, political, military, or
cultural annals of California. Generally a lead agency can determine a resource to be
‘historically significant’ if it meets criteria for listing on the California Register of
Historic Resources (Pub. Res. Code 5024.1, Title 14 CCR, Section 4852). The following
includes the criteria for listing:
a. Is associated with events that have made a significant contribution to the broad
patterns of California’s history and cultural heritage.
b. Is associated with the lives of person important in our past.
20 “California Environmental Quality Act 2010, Statutes & Guidelines”, prepared by AEP, January 1, 2010.
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c. Embodies the distinctive characteristics of a type, period, region, or method of
construction, or represents the work of an important creative individual, or possesses
high artistic values
d. Has yielded, or may be likely to yield, information important in prehistory or
history.
4. A lead agency is not precluded from determining a resource to be a ‘historical
resource’ as defined by Public Resources Code 5020.1(j) or 5024.1 when the resource is
not listed in the California Register of Historical Resources, included in a local register of
historical resources, or identified in an historical survey.
SB 18 and Native American Consultation
The purpose of SB 18 is to protect traditional tribal cultural places. In accordance with the Bill,
the City of La Quinta is required to offer consultation with California Native American Tribes
regarding proposed land use planning decisions involving General Plan adoption or amendment.
In preparation of the Cultural Resources Technical Report for the La Quinta General Plan
Update, contact has been made with regionally active Tribes provided by the Native American
Heritage Commission. CRM Tech received only one letter of response, including a letter from
the Cabazon Band of Indians, during preparation of the Cultural Resources Technical Report.21
1. Existing Conditions
Cultural Resources are important for understanding the history and heritage of the community,
and for preserving important archaeological and paleontological resources. The City of La
Quinta and the Coachella Valley region have a rich cultural past, as discovered through recent
paleontological and archaeological surveys.
Approximately 5 million years ago, the Coachella Valley was part of an inland sea, as the Gulf
of California extended up to the present day Banning Pass. Paleontological resources continue to
be found proving aquatic life was once part of the region’s past.
It is believed that the earliest human settlements occurred 8,000 to 12,000 years ago from Native
Americans. Prehistoric records show that early Native American peoples in the Coachella Valley
were from the Takic speaking Cahuilla tribe.
The first noted Spanish explorers in the Coachella Valley were Jose Romero, Jose Maria
Estudillo, and Romualdo Pacheco, who in 1823 led expeditions to find a route to current day
Yuma, Arizona. These explorers traveled through the Coachella Valley through what was known
as the Cocomaricopa Trail, which was an ancient Indian trading route.
21 “Cultural Resources Technical Report for City of La Quinta General Plan (2010 Update), prepared by CRM
Tech, July 8, 2010.
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Non-native settlements began to flourish across the Coachella Valley as new federal laws,
including the Homestead Act and Desert Land Act, opened lands for new settlers by the late
1870’s. The discovery of underground water sources began to increase farming activities
throughout the Valley in the early 20th century. By 1910, the date palm industry began to flourish
in the region.
Tourism reached La Quinta and the Coachella Valley in the 1920’s, as the rich and famous of
Hollywood began coming to the Valley to enjoy the beautiful scenery and climate. The entire
Coachella Valley began to boom after World War II as more residents and visitors came to the
area.22
Paleontological Resources
Paleontological Resources are fossilized records of previous life forms found beneath the ground
or among exposed geologic features. Fossils are nonrenewable remains of organisms that include
vertebrate, invertebrate, plant, or marine organisms typically of more than 10,000 years of age.
They are a significant record of ancient life, important for understanding evolutionary changes in
organisms, providing information on past climatic conditions and ecology, and helping scientists
determine ages of rocks and sediment in which they are found. Fossils are mostly found within
sedimentary rock, and commonly include marine shells, bones and teeth of fish, reptiles, and
mammals, leaf assemblages, and petrified wood. The location and type of soil that fossils are
found in are an important part of paleontological resources, as they indicate typical geologic
formations that are conducive to finding fossils.
Paleontological sensitivity refers to the degree to which a geologic formation is likely to produce
significant nonrenewable fossils, based on past discoveries within a particular geologic
formation. Sedimentary units tend to have high sensitivity due to their potential for significant
paleontological resources.
Significant paleontological resources include vertebrate or invertebrate fossils. In general,
vertebrate fossils, or those with backbones, including mammals, birds, reptiles, amphibians, and
fish, tend to be more rare than invertebrate fossils, and therefore are considered a more
significant paleontological resource. The geologic formations that vertebrate are found in are
considered areas of highest sensitivity. All identifiable fossils, however, are considered
potentially significant until determined to be insignificant by a qualified paleontologist.
The geologic formations and units in the General Plan Update Planning Area have been studied
to determine paleontological significance. The Planning Area is made up of five geologic
formations, including Dune Sand, Granitic Rock, Pleistocene Alluvium, Holocene Alluvium, and
Lake Cahuilla Beds. Exhibit III-4 shows the location of these geologic formations. Through
literature and map research, institutional records research, and past paleontological monitoring
from recent construction activities, these different geologic formations have been designated as
“high,” “low,” or “undetermined” according to their paleontological sensitivity. Pleistocene
22 “Cultural Resources Technical Report for City of La Quinta General Plan (2010 Update), prepared by CRM
Tech, July 8, 2010.
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Alluvium is considered to have the oldest sediments, and therefore likely to contain the greatest
source of fossil resources. The Lake Cahuilla beds are also designated as a high sensitivity area
due to an abundance of fossils. Granitic Rock sediments are considered low sensitivity due to
lack of fossil resources, and areas of Dune Sand and Holocene Alluvium are undetermined, due
to limited study or limited exposure of sediment likely to contain fossil resources. The locations
of each of these three paleontological sensitivity areas are also identified in Exhibit III-4.
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Exhibit III-4
Paleontological Sensitivity Map
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High Sensitivity Paleontological Areas
Areas that are determined to be of “high” paleontological sensitivity include areas made up of
Pleistocene sediments, and sediments from ancient Lake Cahuilla beds. Pleistocene sediments
are located in the southwestern portion of the Planning Area. Construction projects throughout
other areas of Riverside County have yielded significant fossil resources in Pleistocene sediment,
including highly significant vertebrate fossils. Recent studies and inventories conducted in the
General Plan Update Planning Area, however, have indicated that no significant paleontological
resources exist within local Pleistocene sediments. The closest paleontological resource found in
Pleistocene sediment was recorded three miles northeast of the northern portion of the Planning
Area, along the southern portion of the Indio Hills.23 Nevertheless, these areas are of high
sensitivity due to their potential for containing significant paleontological resources.
Sediments found within the Lake Cahuilla beds are associated with deposits from the ancient
Lake Cahuilla. These sediments cover a large portion of the eastern and southern portion of the
Planning Area. Although no Pleistocene age fossils have be reported in ancient Lake Cahuilla,
this area has yielded numerous vertebrate and invertebrate fossils that are less than 10,000 years
old. According to paleontological records, six paleontological localities have been recorded in
the southern section of the Planning Area, and include fish, lizards, snakes, rabbits, diatoms,
ostrapods, and mollusks. As a result of these finds, the Lake Cahuilla beds are of high
paleontological sensitivity, and potentially contain paleontological resources that could be
affected by earth-moving activities.24
Low Sensitivity Paleontological Areas
Areas determined as being of “low” paleontological sensitivity are areas made up of Granitic
Rock. These areas are located in the southwestern, southern and northwestern portion of the
Planning Area. Paleontological studies have shown these areas as not containing significant
paleontological resources and unlikely to contain fossil resources.
Undetermined Areas
Areas in the Planning Area made up of Holocene Alluvium and Dune Sand are considered the
youngest geologic formations, and therefore unlikely to contain significant fossil resources.
Holocene Alluvium is present in the western and southwestern portion of the Planning Area, and
Dune Sand is located in the northern portions of the Planning Area. Paleontological studies have
indicated that these young sediments may overlie older alluvium that contains Pleistocene age
fossils, and therefore may also be considered high sensitivity areas. Because of the complex
nature of these geologic formations, and lack of paleontological discoveries, these areas have
been designated as “Undetermined Areas” for paleontological resources.
Cultural Resources Discovered in Planning Area
The Planning Area is rich with history, as indicated by the large number of archaeological sites,
historic period buildings, and other historic and prehistoric discoveries found throughout it.
23 Paleontologic Resources Technical Report for City of La Quinta General Plan (2010 Update), prepared by CRM
Tech, August 12, 2010. 24 Ibid.
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These cultural resources include remnants from the Native Cahuilla people to more recent
residents of La Quinta. Cultural resources encompass all human related remnants as well as non-
traditional property types, such as citrus groves, date gardens, and natural features.
This section discusses the existing cultural resources that have been identified in the General
Plan Update Planning Area. Exhibit III-5 provides a map showing previously surveyed areas for
cultural resources within the Planning Area.25
Archaeological Resources
The archaeological resources found within the General Plan Update Planning Area are remnants
from prehistoric peoples who took advantages of the resources in ancient Lake Cahuilla. Lake
Cahuilla covered portions of La Quinta, primarily below the 42-foot above sea level contour.
Archaeological records show that ancient people followed the shoreline according to the various
lake levels, until A.D. 1650 when the lake rapidly receded to complete desiccation within 80 to
100 years. The Cahuilla people were believed to be the first inhabitants of the area dating back to
the Archaic Period, and thrived in the area until European settlers arrived in the early 1800’s.
Cultural surveys have identified approximately 500 archaeological sites, both historic and
prehistoric, in the Planning Area. In addition to these sites, approximately 170 isolates, or
localities with fewer than three artifacts, have also been discovered. The majority of these
archaeological finds are from Native American tribes and include pottery, burned animal bone,
grinding stones, chipped stone, cremation and other remains. Recent surveys in the sand dune
portions of La Quinta have found remnants from the Archaic Period, including the presence of
worked fine-grained, dark gray basalt and shell beads, and burial sites. Other Archaic sites have
been discovered throughout the Planning Area due to the presence of hunting remains, Olivella
beads, and basalt, which were common in the Archaic period. The oldest site recorded in the
Coachella Valley is located just outside the La Quinta city boundary, and includes a site proven
to be 2,700 years old. An archaeological survey prepared in the southwestern portion of the
Planning Area revealed more than 30 prehistoric archaeological sites, indicating that Village
sites were at one time concentrated along the shores of ancient Lake Cahuilla.
Recent contacts with local Native American tribes, including the Torres Martinez, Augustine,
and Cabazon bands of the Desert Cahuilla people have also uncovered culturally sensitive lands
within the Planning Area. Past development and earth-moving projects throughout the region
have uncovered Native American cremation and burial sites. Letters received from the Native
American Heritage Commission have also indicated that sacred Native American cultural
resources are located within a half-mile of the Planning Area.26
25 “Cultural Resources Technical Report for City of La Quinta General Plan (2010 Update), prepared by CRM
Tech, July 8, 2010. 26 “Cultural Resources Technical Report for City of La Quinta General Plan (2010 Update), prepared by CRM Tech,
July 8,2010.
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Historic Resources
Historic resources include culturally important buildings, structures, or features that are typically
related to non-Native settlements. The State of California has determined that historic buildings
are those older than 45-50 years of age. Over the last few decades, historic resources surveys
have revealed a large inventory of historic buildings, structures, and features in La Quinta.
The Riverside County Historical Commission prepared a historical survey between 1981 and
1983 and recorded 30 buildings and portions of the Coachella Canal within the La Quinta
Planning Area as historical resources. Between 1996 and 1997, the City of La Quinta recorded
60 additional properties and buildings as historical resources. As a result of that survey, the City
designated the Cove area as a potential historic district under the Historic Preservation
Ordinance, due to the large number of recorded historical buildings. In 2006, the City updated
the 1996-1997 survey and recorded an additional 183 buildings to the California Historical
Resources Inventory, and noted an additional 74 buildings as potentially significant historic
resources.
The combination of these past surveys have highlighted approximately 280 buildings and other
built features in the General Plan Update Planning Area as having the potential to be historically
significant and eligible for listing in the California Historic Resources Inventory. The majority of
these buildings are single-family homes of various ages, including both pre and post-WWII
vintage, and are representative of various architecture styles.27 The General Plan requires that
cultural resources, including potentially historic structures, be studied prior to their being
impacted by development.
27 “Cultural Resources Technical Report for City of La Quinta General Plan (2010 Update), prepared by CRM Tech,
July 8,2010.
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Exhibit III-5
Cultural Resources Survey Map
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2. Project Impacts
Impacts to Historical Resources
Implementation of the General Plan Update will facilitate new development throughout the
Planning Area. Within the City limits, the majority of new development will be associated with
redevelopment or infill. As discussed above, there have been approximately 280 buildings and
other built features identified as having the potential to be historically significant within the
Planning Area. As such, future development projects, including modifications to existing
buildings, demolition, grading activities, site excavation, and construction could potentially
result in direct or indirect disturbance or destruction of historic resources. Since these structures
and features are documented, site surveys should be conducted to assess potential harm to these
resources, if alteration or demolition is proposed. The General Plan requires that site specific
studies be conducted when development is proposed. These studies will include an assessment of
the potential impacts to cultural resources, and assure that impacts to these resources are reduced
to less than significant levels.
The Sphere is more rural and does not contain the intensity of development found within the City
limits. Historical resources throughout the Sphere may be associated with farming. As shown in
the Exhibit III-5, the level of study in the Sphere has been much more limited than within the
City. This is largely due to the limited number of development proposals in the area.
Implementation of the General Plan, however, could facilitate development within the Sphere, if
these areas are annexed. As a result, impacts to unknown historic resources would be potentially
significant. The City’s survey requirements for historic and prehistoric resources would be
applied for these properties, however, to assure that resources were identified and protected.
With such protective measures, impacts on historic resources would be reduced to less than
significant levels. Therefore, impacts to historic resources as a result of implementation of the
General Plan Update will be less than significant with mitigation.
Impacts to Archaeological Resources
As discussed above, previous cultural surveys have identified approximately 500 archaeological
sites, both historic and prehistoric, throughout the entire General Plan Update Planning Area.
Many of these prehistoric resources are from early Native Americans of the Cahuilla tribe.
Exhibit III-5, shows areas throughout the City Limit that have been assessed for cultural
resources. Vacant lands that have not been surveyed may contain buried archaeological
resources. Future construction activity on these lands, including grading activity, site excavation,
and general construction could potentially result in direct or indirect disturbance or destruction of
archaeological resources. Site surveys are required by the City as part of the entitlement process,
to assess potential harm to these resources. As such, new development projects will be required
to conduct surveys for possible archaeological resources.
The Sphere Planning Areas consist of more rural, undisturbed land which may contain buried
archaeological resources. Due to the lack of development activity, the majority of these areas
have not been previously surveyed. Implementation of the General Plan Update will facilitate
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new development on these lands, potentially impacting undiscovered archaeological resources.
Future construction and development activity in the Sphere, including grading activity, site
excavation, and general construction, could result in direct or indirect disturbance or destruction
of archaeological resources. Site surveys are required by the City as part of the entitlement
process, to assess potential harm to these resources. Development proposals made for these areas
after annexation, should it occur, will be required to conduct cultural surveys as part of the
entitlement process.
With proper mitigation measures, impacts to archaeological resources within the General Plan
Update Planning Area are expected to be less than significant.
Impacts to Paleontological Resources
Implementation of the General Plan Update will facilitate new development throughout the
Planning Area. As shown in Exhibit III-4, the City and its Sphere exhibit varying degrees of
paleontological sensitivity according to soil types. Sediments related to the ancient Lake Cahuilla
beds exhibit the highest paleontological sensitivity. In comparison, granitic rock soils found
along the Coral Mountains, which surround the Cove, have low paleontological sensitivity. New
development activity, including construction, grading, and other site disturbances in moderate
and high sensitivity areas has the potential to impact paleontological resources. Mitigation
measures will be required to reduce paleontological impacts to less than significant levels.
Impacts to Native American Resources
Senate Bill 18 requires contact with local tribes when a General Plan Update is prepared. The
City notified all Tribes listed by the State as potentially having sacred lands in the area, as
required by SB 18. Two letters were received, one from the Cabazon Band, and one from the
Agua Caliente Band. The letters stated that the Tribes have no specific information regarding
cultural resources within or near the General Plan Update Planning Area.28
3. Mitigation Measures
The following mitigation measures will reduce impacts to Cultural Resources to less than
significant levels.
1. The City will continue to pursue government-to-government consultation with pertinent
Native American representatives and tribal organizations, as required by SB 18.
2. All proposed project sites will be surveyed by a qualified archaeologist, historian, and/or
architectural historian, as appropriate, to identify any potential cultural resources that may be
affected, unless existing evidence shows that such survey is unnecessary.
28 “Cultural Resources Technical Report for City of La Quinta General Plan (2010 Update), prepared by CRM
Tech, July 8,2010.
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3. The City will maintain and expand as necessary the existing historical resources inventory to
provide a comprehensive and up-to-date register of known cultural resources in the Planning
Area.
4. New development projects proposed for areas of high sensitivity for paleontological
resources shall be required to prepare paleontological resource surveys as part of the
entitlement processing.
5. A paleontological resource evaluation shall be prepared in conjunction with site specific
geotechnical analysis required for grading and building permits for projects located in low
paleontological sensitivity and undetermined areas. Evaluation should include bore
samplings to understand whether grading and/or building will impact underlying Pleistocene
or older soils.
6. The City will require a paleontological monitor during earth moving activities in high
sensitivity areas.
Mitigation Monitoring and Reporting
A. The Planning Department shall review site-specific historic, archaeological, and
paleontological surveys prepared for new development projects in sensitive areas prior to
entitlement of new development projects.
Responsible Party: La Quinta Planning Department, developer, Professional
Archaeologist/Paleontologist.
Geology and Soils F.
Introduction
This section of the EIR addresses potential impacts associated with geology and soils that may
arise from implementation of the General Plan Update. The existing geologic and soil conditions
within the City and Sphere of Influence are described, and the potential impacts of build out are
assessed.
Thresholds of Significance/Criteria For Determining Significance
The following standards and criteria have been drawn from Appendix G: Environmental
Checklist Form of the CEQA Guidelines. The following factors have been considered to ensure
that the General Plan EIR adequately addresses potential impacts to geology and soils that may
result from the adoption and implementation development of the La Quinta General Plan.
Implementation of the General Plan would have a significant effect on soils and geology if it is
determined that the project will:
a. Expose people or structures to potential substantial adverse effects, including the risk of
loss, injury, or death involving:
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i. Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo
Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other
substantial evidence of a known fault.
ii. Strong seismic ground shaking.
iii. Seismic-related ground failure, including liquefaction.
iv. Landslides.
b. Result in substantial soil erosion or the loss of topsoil.
c. Locate the project on expansive soil, as defined in Table 18-1-B of the Uniform Building
Code, creating substantial risks to life or property.
d. Have soils incapable of adequately supporting the use of septic tanks or alternative
wastewater disposal systems where sewers are not available for the disposal of wastewater.
Seismic Hazard Mapping Act
The State of California enacted the Seismic Hazards Mapping Act (SHMA) in 1990. It is
intended to protect the health and safety of the public from seismically induced ground failure,
including ground shaking, liquefaction, and slope stability. The California Geological Survey
(CGS) is responsible for implementing the Act. It is charged with providing local governments
with maps that identify areas susceptible to such hazards.
Alquist-Priolo Earthquake Fault Zoning Act
The Alquist-Priolo Act was enacted in 1972 to mitigate hazards related to surface faulting by
identifying zones where surface fractures have occurred. It establishes Alquist-Priolo Zones to
identify and prohibit construction or development within areas that are at risk of surface
fractures. It is the responsibility of the State Geologist to establish regulatory zones around the
surface traces of active faults and to issue appropriate maps identifying Alquist-Priolo zones.
1. Existing Conditions
This section discusses the physical characteristics of the City and Sphere, as well as community
safety. It also summarizes the geologic and seismic hazards portions of the Technical
Background Report prepared for the General Plan29.
Geologic Setting
The General Plan Update Planning Area is located at the boundary of the Colorado Desert
Province, a low elevation basin extending from the Banning Pass to the U.S. border with
Mexico, and the Peninsular Ranges Province, which is characterized by a series of northwest-
trending Valleys and mountain ranges. The unique landscapes of each of these physiographic
provinces have been formed by diverse geologic and climatic process. Portions of La Quinta are
situated on the Valley floor, rising to the foothills lower slopes of the Santa Rosa Mountains.
29 “Technical Background Report to the Safety Element Update, City of La Quinta, California,” prepared by Earth
Consultants International, July 2010.
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Elevations within the Planning Area generally range from approximately 190 feet below sea
level at the southeastern corner of the Planning Area, to 1,700 feet above sea level in the foothills
of the Santa Rosa Mountains.
The Whitewater River traverses the northern part of the City. It is the primary drainage in the
Coachella Valley, and intermittently drains the surrounding mountains as well as the northern
portion of the Valley. For most of the year, streambeds in the Santa Rosa Mountains are dry.
However, following storms they may carry significant flows that accumulate within a short
period of time.
There are also numerous canals and aqueducts crossing the Planning Area. Ultimately, these
terminate at Lake Cahuilla, a man-made storage reservoir located in the southern portion of the
Planning Area.
In geological terms, the Valley portion of La Quinta is located at the edge of the Salton Trough, a
broad tectonic depression that has been sinking over millions of years and has filled with several
thick sediment layers that form what is now the Valley floor. The trough is physically continuous
from the San Gorgonio Pass to the Gulf of California.
Ancient Lake Cahuilla occupied the area where most of modern La Quinta is located, possibly as
recently as 400 years ago, when it evaporated. At one time, it covered an area of more than 2,000
square miles.
Soils and Geologic Units
Soil Types
There are seven soil units that have been mapped in the Planning Area, each of which is
described below. Exhibit III-6 shows the locations of these soils in the Planning Area.
Alluvial sand and gravel of the Whitewater River (Qg)
Soils in this unit are comprised of very young, unconsolidated alluvium deposited by the
Whitewater River, with crudely bedded sand, silt, gravel, boulders, and debris deposited by
floodwaters. River sediments are highly susceptible to erosion and may be re-distributed and/or
buried by flooding. In general, construction within floodways is limited to roadway crossings or
pipelines. These soils are highly compressible; therefore, construction of such improvements
must include bridge supports that are anchored in underlying, more stable soils. Hazards
associated with these soils include scour from flood flows and damage from large debris, such as
boulders.
Windblown sand (wind-lain dune sand) (Qs)
This is a common soil type in the region, and is mapped all through the northern portion of the
City. Windblown, or Aeolian deposits are generally comprised of reworked alluvium. Silty and
fine- to medium-grained sands are lifted by strong winds that occur frequently in the area, and
deposited to form shifting sand dunes (Qs). This soil unit has a high susceptibility to erosion,
settlement, and collapse.
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Interbedded lacustrine (clay of valley areas) (Ql)
As noted above, the region was the site of Ancient Lake Cahuilla, as well as other large lakes
that inundated the Salton Trough. These soils consist of lacustrine (lake) sediments up to 300 feet
thick, layered with alluvial fan and colluvial sediments deposited from mountain slopes.
Potential for soil collapse of lacustrine soils is considered low given the presence of deeper
sediments from the ancient lakes that underlies the youngest alluvium. Lacustrine soils have high
permeability, except for where they interbed with silt or clay layers, which slow the downward
percolation of water. There is generally low potential for expansive soils, with the exception of
lake deposits with silt and clay near structural foundation elements.
Alluvial deposits (sand of Valley areas) (Qa)
These soils are geologically young and near-surface, often containing organic debris, and have
been rapidly deposited by flash floods. Therefore, engineering issues include compressibility,
and soil collapse, with the introduction of irrigation water into dry soils. These soils are also
highly susceptible to erosion, with moderate to high permeability. They are appropriate for use as
fill after the removal of organic materials and oversized rocks, but for compaction generally
require the addition of water.
In the Planning Area, alluvial deposits generally occur along the base the Santa Rosa Mountains
to the west. Older, more developed portions of La Quinta, which occur downwind of Eisenhower
Mountain, are built on alluvium. Towards the south of the Valley, alluvial soils are interbedded
with fine-grained lacustrine sediments.
Alluvial fan sand and gravel deposits (Qf)
Alluvial fan deposits occur on active fans draining mountain canyons. They consist of poorly
bedded silt, sand, and gravel, with boulders sometimes present in the upper part of the fans.
Younger fans have a somewhat smooth surface, networked with braided ephemeral streams.
Older fans may have a slightly elevated surface divided by embedded stream channels. These
deposits progressively transition into finer-grained alluvial and ancient lake deposits that occur in
the lower Valley.
Because they are typically unconsolidated, younger fan deposits are susceptible to settlement or
collapse, as well as wind or water erosion. Although generally more consolidated, older fan
deposits may have a higher percentage of clay at and near the surface, with potentially expansive
soils.
Landslide deposits (Qls)
There are several large landslides that have been mapped in the Santa Rosa Mountains above La
Quinta. The Martinez Mountain Landslide is located south of the City, and partially encroaches
into La Quinta. It is one of the largest and most spectacular landslides in the area. It occurred in
prehistoric times and is a rock avalanche comprised of coarse debris that was transported nearly
six miles.
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Soils associated with landslides are generally considered unstable and may be compressible,
especially around perimeters, with the addition of increased loads such as deep fill
embankments. In the event of strong ground shaking or undercutting by streams at the toe, they
may be reactivated.
Quartz diorite (hard crystalline rock) (Qd)
This is the oldest geologic unit in the La Quinta area. Hard, crystalline rock forming the
mountains is buried beneath the alluvium. Crystalline rocks vary widely in texture, composition
and physical properties. Rocks underlying La Quinta are “plutonic,” meaning they have
crystallized from the molten state deep within the Earth’s crust. Those forming the mountains in
the Planning Area are comprised of minerals that are most closely associated with quartz diorite.
It is estimated that magma from which this rock crystallized over 65 million years ago.
Crystalline rock is highly durable and has formed the steep slopes and deep canyons within and
above the City. Where not highly weathered, deposits are very hard and cannot be excavated
easily. Typically they are non-water bearing, with low to moderately low permeability, except
where jointed and fractured. These rocks are generally non-expansive, and provide strong
foundation support. Rockfall hazard occurs where slopes are covered by boulders.
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Exhibit III-6
Geologic Map of the Planning Area
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Geologic Hazards in the La Quinta Area
Geologic hazards in the Planning Area include landslides and slope instability, compressible,
collapsible or expansive soils, soil corrosivity, ground subsidence, erosion, and wind-blown
sand.
Slope Failure
Slope failure may affect a relatively small area and often only for a very short time. However, it
can result in substantial damage to property, and can be quite costly. The Planning Area
encompasses foothills and mountain slopes associated with the Santa Rosa Mountains. Where
development occurs at the base of these landforms it may be susceptible to a variety of hazards
associated with slope instability, such as landslides and surficial failure, including soil slips, mud
or debris flows, and rockfalls. In La Quinta this hazard primarily affects more developed areas
located near the base of mountains. Perched on slopes, boulders can result in a rockfall hazard to
development adjacent to these slopes. Hazards may be increased by earthquakes, periods of
intense rainfall, or human activities associated with construction, such as grading and blasting.
A variety of factors influence the stability of the slope, including height, steepness, shear
strength and the orientation of underlying weak layers.
Free-falling or tumbling masses of bedrock that have disconnected from steep canyon walls or
cliffs are called rockfalls or rockslides. Rockfall hazards increase when rock slopes become
extremely steep, such as may occur as a result of erosion or human activities. Strong ground
shaking, intense rainfall, or grading and blasting can generate rockfall or rockslides. In the
Planning Area, rockfall hazard is primarily present for lands at or near the base of boulder-
covered slopes.
Rock types that occur in the Planning Area are generally resistant to landslides. In mountains
above the City, mapping shows several “rock avalanche” landslides. If cut to very steep
gradients, and depending on their overall composition and strength, these rocks may become
susceptible to slope failure.
Surficial failures associated with soil slip may result from strong winter storms when soils have
deposited in canyon sideslopes and in gullies and ravines. They occur most frequently on steep
slopes, which occur in higher hills and mountains within and adjacent to the Planning Area.
The most dangerous and destructive of all types of slope failure is debris flow, also known as
mudflow, mudslide, and debris avalanche. These flows are rapidly moving watery mixtures
containing mud, rock, vegetation, and are capable of transporting very large debris such as
boulders or trees. Debris flows are usually associated with prolonged storms. Within the
Planning Area, lands at the base of moderate to steep slopes or at the mouths of drainage
channels are most vulnerable to debris flows.
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Compressible Soils
Soils that are geologically young (Holocene age), have low density and are of unconsolidated
sediments. They may compress under the weight of fill embankments and structures. These soils
often include recently deposited alluvium, which occurs in the Valley portion of the Planning
Area.
A variety of factors may affect the soil’s overall compressibility. These include soil
characteristics such as texture and grain size, density and moisture and the thickness of the
compressible layer(s), as well as engineering parameters. In addition to the Valley floor, portions
of the Planning Area most likely to contain compressible soils include the Whitewater River, as
well as wind-blown deposits, hillside areas, especially at the base of natural slopes, and within
canyon bottoms and swales. Although older alluvial fan deposits in the Planning Area are
relatively dense, upper layers, which may be disturbed and/or weathered, are typically
compressible. Deep fill embankments, generally more than 60 feet deep, may also compress
under their own weight. Geotechnical analyses and the application of appropriate engineering
techniques are mitigation measures that may be used to reduce potential hazards associated with
compressible soils.
Collapsible Soils
Recently accumulated soils in arid or semi-arid environments may be subject to soil collapse, or
hydroconsolidation. These soils are typically dry and contain tiny voids. If partly supported by
clay or silt, they become rearranged and lose cohesion when inundated. Even relatively light
loads can cause these soils to settle substantially and quickly under these conditions. When
surface water permeates them, differential settlement can occur. Where settlement occurs at or
near buildings, particularly when heavy irrigation takes place near a building foundation,
structures such as walls or foundations may crack.
In the Planning Area, localized settlement can occur where soils such as alluvium or wind-borne
soils have been recently deposited. Hazards associated with collapsible soils can be addressed
through site-specific geotechnical studies and sound engineering and site design.
Expansive Soils
Varying amounts of fine-grained silts and clays within soils may shrink or swell as moisture
content changes. The presence of expansive soils may create pressure that can affect structures
or other surface improvements.
In the General Plan Update Planning Area, the Valley floor is underlain by alluvial sand and
gravel interbedded with fine-grained lakebed deposits such as silts and clays. There may be
considerable variation in the expansion characteristics of these soils after site grading. Typical
soil profiles on older alluvial fan deposits may include substantial amounts of clay material that
would be expected to be moderately expansive.
In general, rock formations in hills and mountains have low expansion characteristics, although
clays with expansive materials may be present in sheared zones within rock. Where engineered
fills near the finished surface include expansive soils, damage may result. This risk may be
minimized by ensuring that surface fill is free of expansive soils, as much as feasible. Surface fill
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may also be pre-saturated as determined by a soil engineer. Other measures include good surface
drainage and efficient irrigation systems that do not result in excessive watering.
Corrosive Soils
Soil and buried metallic structures, such as water mains or elements within building foundations,
may react in a variety of ways involving complex electrochemical and bacteriological processes.
The most common identifying factor for corrosive soils is electrical resistivity. Cumulative
impacts may occur over time, with substantial damage to underground metallic objects where
soils have low resistivity. Corrosive soil characteristics also include high acidity (low pH), high
moisture content, high chloride or low oxygen levels, and the presence of certain bacteria. The
risk of corrosion is also increased where sulfide compounds are present. These compounds may
occur when sulfate-reducing bacteria converts sulfates, which are not directly corrosive to
metals, to soluble sulfides, which can be corrosive to concrete.
On the Valley floor, sediments may be present that are corrosive to metallic objects, such as
pipelines. A corrosion engineer can test soils prior to construction. Other means to reduce risks
associated with corrosive soils may include the use of special cement mixes, specialized coatings
or protective wrapping materials, and specified soil water content.
Ground Subsidence
Ground subsidence occurs when the ground surface gradually sinks or settles, with no horizontal
movement. Subsidence is primarily caused by human activity. The extraction of sub-surface
water, oil or gas in sediment filled Valleys and floodplains are primary contributors. Although
less common, natural forces, such as earthquake movements, can also result in subsidence and
have in some cases resulted in abrupt elevation changes across faults.
The effects of regional subsidence include earth fissures, sinkholes or depressions, and surface
drainage disruption. Certain improvements may be sensitive to slight elevation changes,
including canals, levees, and underground pipelines; these are most at risk from subsidence.
Structures such as wells, buildings, roads and railroads can also be damaged where substantial
subsidence occurs.
When groundwater extraction surpasses supplies, a condition known as overdraft, a loss of
aquifer storage capacity can occur and create subsidence. This condition exists in the Coachella
Valley. Therefore, the regional water management district, Coachella Valley Water District, has
instituted a variety of measures to manage subsidence. These include the use of imported water,
artificially recharging groundwater basins, and reducing pumping of local wells.
The U.S. Geological Survey (USGS) has monitored subsidence rates in the Coachella Valley
over several decades. These data indicate rapid increases in subsidence rates, which is primarily
attributed to groundwater extraction in the Valley.
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Irreversible subsidence can occur when groundwater is removed from clay and silt layers in the
underlying aquifer, creating surface fissures and cracks. In the Coachella Valley, fissures have
been recorded in one instance in La Quinta, in 1948 near the base of the Santa Rosa Mountains.
Subsidence is most typical in valleys where overdraft is an issue.
CVWD is addressing this regional issue in its groundwater management program. The District
has implemented a range of programmatic measures, including groundwater recharge, imported
water, and a variety of water conservation techniques and programs.
Erosion
Climate, topography, soil and rock types, and vegetation are all factors that influence erosion,
runoff, and sedimentation. These issues are relevant to La Quinta given the area’s topography.
Adjacent mountains are composed of fractured bedrock that has undergone rapid geologic uplift.
The region is subject to infrequent but often powerful winter storms that generate high rates of
erosion. Where wildfires have removed vegetation from mountain slopes, erosion risk is further
increased. These conditions are intensified when storms create large volumes of sediment that
flow to areas downslope.
Within the Valley portion of the Planning Area, canyon bottoms and other areas contain soils
that are unconsolidated and most susceptible to erosion. Natural erosion processes may be
accelerated by human activities such as agriculture and development, even where soils are more
consolidated. Grading and clearing activities eliminate protective vegetation, modify natural
drainage patterns, and compress soils. Slopes created by cut and fill may be at greater risk of
erosion than natural slopes. Development also reduces the surface area available for water to
percolate. This increases the risk of downstream sedimentation and flooding.
Development plans for new projects in La Quinta are required to incorporate temporary and
permanent erosion control. Where such projects exceed one acre, developers must obtain
coverage under the Statewide General Construction Permit and the City’s National Pollutant
Discharge Elimination System (NPDES) Permit. Requirements associated with this coverage
include the preparation of a Stormwater Pollution Prevention Plan (SWPPP), Best Management
Practices (BMPs) and in some cases the preparation of a Water Quality Management Plan
(WQMP).
Wind Erosion
Wind erosion is common in flat, bare, dry and sandy areas. Wind erosion damages land and
natural vegetation through sediment transport and re-deposition. These processes result in soil
loss and deterioration of structures and air pollution.
Throughout the Coachella Valley, varying levels of hazards associated with wind-blown
(Aeolian) sand occur, and there are a variety of conditions that contribute to the creation and
transport of sand in the region. These include the orientation of landforms such as hills and
mountains, the nature of the bedrock, the location of the Whitewater River floodplain, slope of
the Valley floor, and sparseness of vegetation on undeveloped lands on the Valley floor. The
characteristic hot, dry desert climate is a major factor, as are precipitation rates. The Valley
receives low amounts of annual rainfall, with the exception of infrequent intense winter storms.
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Much of the Valley, including the Planning Area, is susceptible to wind and wind-blown sand
hazards. A variety of health problems are associated with wind and blowing sand, such as skin
disorders, allergies and respiratory irritation, and eye infections.
While some areas of La Quinta are sheltered at the base of the Santa Rosa Mountains, the
majority of the Planning Area is located with an active wind erosion zone. The northern portion
of the City is underlain by soils that are subject to erosion, as shown on Exhibit III-7. Soils may
be loosened and transported during grading and construction activities. For this reason, routine
site watering or cessation of construction on extremely windy days are used to mitigate
construction impacts.
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Exhibit III-7
Wind Erosion Susceptibility Map
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Seismic Activity
The majority of Southern California is located at the boundary between the North American and
Pacific tectonic plates, which are moving past each other at varying rates. Most of western
southern California, including the Coachella Valley, is located on the Pacific Plate. This plate is
moving at a rate of approximately 165 feet in 1,000 years (50 millimeters per year), generally in
a northwesterly direction.
The San Andreas Fault marks the boundary between these two plates. This major fault trends
generally northwest to southeast, approximately 4 miles north of the planning area. It
accommodates approximately 60% to 70% of the plate movement described above, while the rest
is distributed among other faults within the San Andreas system as well as those associated with
the Eastern California Shear Zone. As a result, the Planning Area is located in a physical and
geographic area that is susceptible to strong seismic activity.
Measuring Seismic Events
Earthquakes release seismic energy that is measured in terms of intensity and magnitude. Several
factors determine the intensity of ground shaking, including the earthquake’s magnitude,
distance from the epicenter, and soil and rock composition. A variety of logarithmic scales have
been used by seismologists to measure earthquakes.
The most common measure of seismic intensity is the Modern Mercalli Intensity (MMI) scale.
The MMI scale measures damage from partial or total collapse of masonry structures to severe
damage or devastation of underground infrastructure, bridges, overpasses or other improvements.
The Richter Scale measures earthquake magnitude as a function of amplitude of ground motion
at distance from the epicenter, based on a scale from one to ten. A tenfold increase in the wave
amplitude is represented by each increase along the scale.
The seismic moment (Mw) measure, which correlates the size of an earthquake to the amount of
energy released when a fault ruptures, is the measurement system currently favored by
seismologists. Each one-point increase in magnitude corresponds to a 32-fold increase in energy.
The term “Maximum Probability Earthquake” (MPE) is used to reference the largest earthquake
likely to occur on a fault or fault segment within a specified time period. The MPE is used to
assess potential seismic risk in a region, to prepare engineering or emergency plans, and to
develop design parameters and safe construction practices. The preparation of policies and
programs regarding potential earthquake hazards and impacts also reference the MPE.
The California Geological Survey assigns the highest magnitude earthquake a fault is capable of
producing based on physical limitations such as the length of the fault or fault segment. This is
known as the Maximum Magnitude Earthquake (Mmax). Faults that could result in significant
impacts in the La Quinta area are shown on Table III-15. The Table shows that the entire
Southern segment of the San Andreas fault has the potential to generate a magnitude 8.0
earthquake, or the equivalent to a Level X-XI on the Modified Mercalli Intensity Scale.
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Table III-15
Horizontal Peak Ground Accelerations and Seismic Intensities
Fault or Fault Segment
Distance to
La Quinta
(mi)
Distance to
La Quinta
(km)
Magnitude
of Mmax
PGHA (g)
from Mmax
(median)
MMI from
Mmax
San Andreas fault (entire
Southern) 3.4 – 8.8 5.4 – 14.2 8.0 0.50 – 0.34 XII - X
San Andreas (Coachella
segment) 3.4 – 8.8 5.4 – 14.2 7.2 0.50 – 0.36 XI - IX
San Andreas (Coachella + San
Bernardino) 3.4 – 8.8 5.4 – 14.2 7.7 0.6 – 0.41 XII - X
San Andreas (San Bernardino) 17.6 – 28.2 28.4 – 45.4 7.5 0.23 –0.15 IX - VIII
San Jacinto (Anza) 16.3 – 23.4 26.3 – 37.7 7.2 0.21 – 0.15 IX – VIII
Burnt Mountain 15.4 – 26.2 24.8 – 42.2 6.5 0.14 – 0.08 IX - VI
Eureka Peak 16 – 26.7 25.8 - 43 6.4 0.14 – 0.08 IX - VI
San Jacinto (Coyote Creek) 18 –23.8 29 – 38.3 6.6 0.13 – 0.10 IX – VII
Pinto Mountain 28 – 37.8 45.1 – 60.9 7.2 0.13 – 0.09 IX – VII
Pisgah – Bullion 31.5 – 39.5 50.7 – 63.6 7.3 0.12 – 0.09 VIII - VI
Abbreviations: mi – miles; km – kilometer; Mmax – maximum magnitude earthquake; PGHA – peak
ground horizontal acceleration as a percentage of g, the acceleration of gravity; MMI – Modified Mercalli
Intensity.
Several other faults have the potential to generate seismic shaking similar to that experienced in La Quinta
during the 1992 Landers earthquake. Faults that would generate a similar level of shaking include: North
Frontal (both East and West segments, individually), Calico-Hidalgo, Elsinore (Julian segment), Lenwood-
Lockhart-Old Woman Springs, Helendale-South Lockhardt, San Jacinto (San Jacinto Valley segment), San
Jacinto (Borrego segment), Brawley Seismic Zone, Earthquake Valley, and Elmore Ranch. All of these
faults would generate peak ground accelerations in the 0.05 to 0.09 range (median) and 0.08 to 0.16 range
(median plus 1 sigma), with Modified Mercalli intensities in the V to VIII range.
It is estimated that there is a 10% probability that a ground motion of approximately 0.5g will be
exceeded in 50 years near La Quinta City Hall. In the area of the City nearest the San Andreas
fault, in the northeastern most corner of the City, there is a 10% probability that a ground motion
of approximately 0.64g could be exceeded in 50 years. These are moderate to very high levels of
ground shaking, which would be expected to result in moderate to heavy damage, especially to
buildings that are older or poorly constructed.
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Major Faults Affecting La Quinta Planning Area and Vicinity
Earthquakes can result in impacts ranging from significant property damage to the loss of public
services and facilities and the loss of life. The most severe impacts in the La Quinta area would
be expected to result from strong ground shaking associated with earthquakes. Earthquakes and
associated groundshaking can also generate other impacts, such as landslides, damage or
destruction to structures, liquefaction, and settlement. Fires, hazardous materials releases,
disruption of essential facilities and services such as water, sewer, gas, electric, drainage, and
transportation can also occur. Flooding may happen when dam or water tanks fail as a result of
ground shaking.
The most significant faults with potential to affect the General Plan area are discussed below.
The locations of these faults are shown on Exhibit III-8, Faults and Historical Seismicity Map.
San Andreas Fault Zone
The San Andreas, which passes approximately 4 miles northwest of the Planning Area, is
considered the “Master Fault” in Southern California. This is because of the influence it has over
seismic hazards, as well as the frequency and magnitude of earthquakes it generates. The San
Andreas fault extends approximately 690 miles, from the Salton Sea to Cape Mendocino in
northern California. The 2007 Working Group on California Earthquake Probabilities (WGCEP)
estimated that the southern San Andreas fault has a 59% probability of causing an earthquake of
at least magnitude 6.7 (Richter scale) in the next 30 years.
A rupture along the entire southern San Andreas fault, including, from south to north, the
Coachella, San Gorgonio-Garnet Hill, San Bernardino and Mojave segments, with an epicenter
along the San Andreas fault closest to La Quinta represents the worst case scenario for La
Quinta. Such an occurrence would generate peak ground accelerations in the City between 0.5 g
and 1.1 g, which would result in severe to violent ground shaking.
San Jacinto Fault Zone
The San Jacinto fault zone is located between 26 and 38 miles south of the planning area.
Extending approximately 175 miles, it intersects with the San Andreas fault in San Bernardino,
and trends southeasterly toward the Brawley area. South of the U.S./Mexico border it continues
as the Imperial fault. The San Jacinto fault has historically produced more large earthquakes than
any other fault in southern California, albeit none as large as the 1857 and 1906 earthquakes on
the San Andreas fault. WGCEP estimates there is a average 31% probability of all the segments
of the San Jacinto fault rupturing between 1994 and 2024.
The Anza and Coyote Creek segments, respectively, are the segments of San Jacinto fault zone
closest to La Quinta. WGCEP studies (2008) indicate that there is an average recurrence interval
for earthquakes along the Anza segment of 238 years, with the most recent earthquakes
occurring between 205 and 235 years ago. Should a Mw 7.2 earthquake occur on this segment, it
would be expected to generate peak ground accelerations in the Planning area of between about
0.15g and 0.32g.
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Burnt Mountain Fault
The Burnt Mountain fault was unknown prior to 1992; it is one of several of the Eastern Mojave
Shear Zone faults. In 1992 a ground-surface rupture, thought to be a large aftershock of the
Landers earthquake, occurred along a 3.1-mile-length of this fault. Geologic mapping indicates
this fault is approximately 13 miles long and is approximately 15 miles north of the City at its
closest point. It is considered capable of producing a magnitude 6.0 to 6.5 earthquake. Based on
a Mw 6.5 earthquake along this fault, horizontal ground accelerations of between 0.08g and 0.21g
could occur in La Quinta, with higher accelerations in the northern portion of the City, closest to
this fault.
Eureka Peak Fault
The Eureka Peak Fault is approximately 12.5 to 15 miles long and is a right-lateral strike-slip
fault. Along with other faults, it ruptured during the 1992 Landers earthquake, and is thought to
have caused the Joshua Tree earthquake of April 22, 1992. The Eureka Peak fault is considered
capable of generating earthquakes of between Mw 5.5 and 6.8. In the event of a Mw 6.4
earthquake on this fault, estimates indicate it could generate horizontal peak ground accelerations
in the Planning Area of between 0.08g and 0.21g.
Pinto Mountain Fault
This fault occurs approximately 28 miles north-northwest of the city of La Quinta at its nearest
point, at the boundary of the north side of the Little San Bernardino Mountains. Its length is
thought to be between 45 and 56 miles. As defined in the Alquist-Priolo Act, it is considered an
active fault, in that it has ruptured at least four times within the last approximately 9,400 years.
A scenario entailing a 7.2 earthquake on this fault would generate peak horizontal ground
acceleration in La Quinta of about 0.09g to 0.21g. Damage in the City would be characteristic of
MMI intensities of between VII and IX.
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Exhibit III-8
Faults and Historical Seismicity Map
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Seismically Induced Geotechnical Hazards
Seismically induced hazards include strong ground shaking and ground failure as a result of
earthquakes. These can result in significant damage to development. The following discusses
potential geotechnical hazards that may occur in the Planning Area.
Groundshaking
Seismically induced ground shaking poses the most potentially significant geotechnical hazard to
the Planning Area. As discussed previously, large earthquakes along regional faults such as the
San Andreas and San Jacinto fault zones have the capacity of generating moderate to severe
ground shaking in the planning area.
There are several factors that determine the effects of ground motion and the degree of structural
damage that may occur. These include earthquake intensity, distance from the epicenter to the
site, composition of soil and bedrock, building design, as well as others. As distance from the
fault along which the earthquake occurs increases, peak ground accelerations and seismic
intensity generally decrease. Local conditions such as soft soils, shallow ground water, and the
presence of ridge tops may amplify the effects of seismic waves and may also result in higher
localized accelerations. There are many tools that local agencies have available to ensure
structural safety from seismic events. These include the Uniform Building Code, California
Building Code, and Unreinforced Masonry Law. These are further discussed under Mitigation of
Earthquake Hazards, below.
Groundshaking can result in various types of ground failure, including liquefaction and slope
failure, which are among the most destructive. Others, such as landslides, seismically induced
settlement, deformation of sidehill fills, and ridgetop fissuring and shattering can occur. These
are discussed categorically below.
Liquefaction
Liquefaction is a sudden increase in water pressure between soil grains that causes soils to take
on the qualities of a liquid or semi-viscous substance. It occurs when groundshaking occurs over
a relatively long duration, with intensity exceeding 0.2 g. Soils that are susceptible to
liquefaction are generally loose, unconsolidated, soils with relatively shallow groundwater
depths (50 feet or less). Liquefaction can substantially decrease soil shear strength, causing
settlement to occur and resulting in damage to structures. Structures may sink or tilt when
bearing capacity is weakened. Ground undulation, lateral spreading or displacement, and flow
failures or slumping may also take place.
Given its proximity to major, active regional fault systems, the entire Planning Area is subject to
strong ground shaking. Loose, unconsolidated soils occur primarily on the Valley floor portion
of the Planning Area. The southeastern area of the City and the entire eastern Sphere are
susceptible to liquefaction due to both shallow groundwater and soil type. Liquefaction potential
in this area is moderate where groundwater is at depths of 30 to 50 feet below the surface. It
ranges to high where groundwater is found at depths 30 feet and higher. Areas of the Planning
Area that are susceptible to liquefaction are shown on Exhibit III-9.
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Landslides and Rockfall
Strong ground motion from earthquakes can exacerbate unstable slope conditions, causing
landslides and rockfall. As described previously, landslide vulnerability is a function of a variety
of geologic and physical conditions.
Portions of the Planning Area wherein development is located downslope of mountain slopes and
steep canyon walls are considered most susceptible to rockfall. This includes much of the older,
more developed areas of the City, which are surrounded on three sides by mountains comprised
of granitic rock. These areas are shown on Exhibit III-9.
Seismically Induced Settlement
When strong ground shaking occurs, it can cause soils to become more tightly packed, collapsing
voids and pore spaces, and reducing the thickness of the soil column. Soils that are especially
subject to this risk include loose and unconsolidated sediments, such as young alluvial and wind-
deposited soils, as well as artificial fill that has not been properly compacted during construction.
As shown on Exhibit III-6, these soil units (mapping units Qa, Qa/Ql and Qs) occur throughout
many portions of the Planning Area.
Deformation of Sidehill Fills
Where roadways or level building pads are constructed on natural slopes, they may require
artificial fill wedges, also called sidehill fills. Differential settlement can also occur in the wedge
itself, or in building of the slope face. In the Planning Area, there is potential for sidehill fill
deformation in mountains and hillsides. Construction in these areas is most commonly required
when service roads and foundation pads are to be cut into the side of a slope for improvements
such as above-ground water tanks, or to create wider roads or building pads. The potential for
this hazard may be determined through site-specific geotechnical investigations. Implementing
sound engineering principles and practices will minimize this risk.
Ridgetop Fissuring and Shattering
Strong ground shaking can amplify seismic energy, and result in shattering surface soils on steep,
narrow ridgelines or linear fissures at ridge crests. Particularly susceptible are structures located
at high ridges bordered by steep slopes. Development along the ridgelines of the Santa Rosa and
San Jacinto Mountains within and bordering the Planning Area is generally limited to above-
ground water storage tanks. To mitigate these hazards, avoiding development along ridgelines is
indicated. Site-specific geotechnical evaluations, re-contouring topography to reduce conditions
that may contribute to amplification, and proper grading techniques may reduce this hazard and
should be implemented where any development or improvements are considered.
Seiche
Standing wave oscillations, or seiches, can occur in enclosed or partially enclosed water bodies
of shallow to moderately shallow depth. Waves continue in a back and forth motion after the
originating force has ceased. Seiches are caused by tides, wind, or seismic events, and may occur
in reservoirs, lakes, ponds, or swimming pools. The frequency of the seismic waves, distance and
direction from the epicenter, style of the fault rupture (dip-slip or strike-slip) and the design of
the enclosed water body all affect seismically induced seiching. Although seismically induced
seiche waves are generally less than 1.7 feet high, heights of up to 6.6 feet have been reported.
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The Planning Area contains numerous lakes, ponds, and reservoirs that may be subject to seiches
as a result of ground shaking, including Lake Cahuilla, the recharge basins south of La Quinta,
and smaller golf course lakes. As noted above, the variety of factors that affect the potential
seiche wave amplitude from these waterbodies make them difficult to predict.
Seiches may also result in damage to water storage reservoirs, such as those that occur within
and adjacent to the Planning Area. The Coachella Valley Water District has indicated that their
facilities have been constructed or updated based on criteria as set forth by the American Water
Works Association, which developed them following the 1992 Landers-Big Bear sequence and
the 1994 Northridge earthquakes. These issues are further discussed in the Section III-H,
Hydrology.
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Exhibit III-9
Seismic Hazards
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2. Project Impacts
As the General Plan Area builds out, the potential for a number of geologic and seismic hazards
will increase. New development will result in construction of structures and infrastructure that
could expose persons and property to geological hazards in the event of a seismic event. The
following discusses potential geological impacts associated with build out of the General Plan.
Geological Conditions
Seismicity
The City and Sphere are subject to potentially moderate to severe ground shaking as a result of
earthquakes along the San Andreas Fault Zone and associated faults in the area. Although no
active or potential active faults occur in the Planning Area, geological analyses conducted for the
General Plan indicates that the Planning Area could experience moderate to very high ground
shaking from earthquakes along the San Andreas Fault. These levels of ground shaking have
potential to cause moderate to heavy damage, especially to older and poorly constructed
buildings. Strong ground shaking can also result in indirect hazards, including slope instability,
liquefaction, settlement, landslides, and flood inundation. A variety of other hazards can also
occur, which are no less destructive. These may include urban fires, failure of water storage or
containment structures, such as levees, dikes or reservoirs, and toxic chemical releases.
Post-earthquake conditions may be worsened by damage to infrastructure and utility systems.
Roadways in the region and Planning Area may fail, thus restricting access into and through the
area, including by emergency response vehicles and personnel. Telephone, gas, energy, and
water may be substantially affected, impeding affect efforts to improve conditions and make
available necessary support such as fire suppression, and access to potable water as well as
heating and cooling. In addition, operations at critical facilities such as hospitals may be
impacted, with reduced functionality for a period of time depending on the intensity of the
earthquake.
Smaller structures may also be damaged by seismic activity. Unreinforced masonry buildings are
at the greatest risk. Foundations may shift, resulting in exposed power lines, gas leaks, and fires,
and exposed power lines. All new buildings in La Quinta must utilize reinforced masonry.
Further, new construction must comply with the Uniform Building Code (UBC), and it is
expected that this compliance will allow structures to resist major earthquakes without
collapsing, even if structural damage occurs. State law requires that unreinforced masonry
buildings be retrofitted, and the City has a mandatory mitigation program. In La Quinta, five of
seven unreinforced masonry buildings have been retrofitted. The two remaining buildings are
adobe structures; although still unmitigated, they are vacant and are not being used.
Liquefaction
Several areas in the City and Sphere have potential to be impacted by liquefaction, which is a
loss of shear strength when fine-grained soils become saturated. Damage can result when
buildings tilt or sink. There is a moderate potential for liquefaction in the southeastern portion of
the Planning Area, and a high potential in the eastern Sphere. To mitigate for this risk, site-
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specific studies should be conducted prior to any proposed development in areas considered to be
susceptible to liquefaction as mapped in the General Plan.
Seismically Induced Slope Instability
Areas at risk due to seismically induced slope instability occur within the southern and western
portions of the Planning Area near the base of steep slopes associated with the Santa Rosa and
San Jacinto Mountains. These areas have been mapped and are shown in the General Plan as
well as this EIR. For the most part, development is expected to be limited within these areas.
Nonetheless, lands downslope of mountain slopes and hillsides may be susceptible to risks
associated with landslide and rockfall. Therefore, as required in the Seismic Hazards Mapping
Act, future development in areas mapped as being at risk from slope instability should be
evaluated according to procedures recommended by the Division of Mines and Geology.
Seismically Induced Inundation
The Planning Area is not within an inundation area for a dam under the jurisdiction of the
California Division of Dam Safety. Potential for seismically induced inundation in the Planning
Area may occur in the event of levee failure along the Coachella Valley Stormwater Channel, the
Coachella Canal and Lake Cahuilla. Above-ground water storage reservoirs in the Planning Area
contain large quantities of water. If these structures are damaged in an earthquake, downslope
areas are at risk of flooding. Mitigation for these potential hazards are provided in Section III-H,
Hydrology, and include regular monitoring of these facilities to ensure their structural integrity.
Soil Characteristics
There are eleven soil types found in the City and Sphere of Influence areas, which exhibit a
variety of characteristics, of which some may influence geological hazards including slope
instability, collapsible, compressible, and expansive soils, corrosivity, ground subsidence, and
erosion. Soil structure also affects drainage, infiltration, and other hydrological processes. These
impacts are further analyzed in Section III-H of this EIR.
Development at the base of foothills and slopes of the Santa Rosa Mountains may be subject to
slope instability such as rockfall, and to a more limited extent landslides, debris flow and
rockslide. These risks are expected to increase as a result of seismically induced ground shaking.
Mitigation includes limiting development at the base of steep slopes, as well as measures that are
available to property owners such as installation of retaining structures and landscaping to
stabilize hillsides, and avoiding heavy irrigation.
Alluvial and windblown soils occur in various portions of the Planning Area. Windblown sand
deposits occur in the northern City and Sphere, while soils associated with alluvial fan deposits
occur throughout the southern and western/northwestern portions of the City. Soils associated
with alluvial (water) and aeolian (wind) processes are subject to loss of cohesion when saturated,
which may result in collapse and/or hydroconsolidation. Structures built on these soils may be
damaged as a result. Site-specific geotechnical studies should be conducted in areas where these
soils are present to analyze potential risks and provide specific engineering recommendations.
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Much of the Planning Area is underlain by lacustrine deposits associated with ancient Lake
Cahuilla. These soils contain varying amounts of clay and silt, which may be expansive.
Shrinking and swelling can result in damage to structures and other surface improvements.
Appropriate site design incorporating good surface drainage and other engineering techniques
are used to mitigate this hazard.
Ground subsidence, where in the ground surface sinks or settles due to extraction of groundwater
or oil and gas. Substantial and sudden elevation changes may occur during seismic ground
shaking, and can result in damage to canals, pipelines and drainage improvements. Subsidence
is a regional issue in that it is thought to be related to reductions in groundwater supplies in the
aquifer. It is being addressed through Coachella Valley Water District water management
programs, including groundwater recharge and water conservation programs.
Unconsolidated soils occur in many areas of the City and Sphere and are particularly subject to
erosion, including wind erosion. Erosion can result in soil loss and diminish soil productivity.
Wind erosion, which occurs through much of the Valley, including the Planning Area, affects
overall air quality, health, and can result in damage to structures. Much of the Planning Area is
within an active wind erosion zone. Mitigation measures include installation of wind barriers
and soil watering at construction sites. Erosion control measures are required for projects in the
Planning Area. These issues are also addressed in Section III-C, Air Quality.
3. Mitigation Measures
1. The City shall periodically confer with the California Geological Survey, Riverside County,
neighboring communities, and other appropriate agencies to improve and routinely update
the database of local and regional geologic conditions, including seismic and geotechnical
hazard in the General Plan Area.
2. The City shall continue to require that development in areas subject to rockfall, landslide,
liquefaction and/or other geotechnical hazards prepare detailed geotechnical analyses that
include mitigation measures intended to reduce potential hazards to less than significant
levels.
3. The City shall continue a cooperative agreement with the County Geologist, State Geologist,
or contract state-certified geologist and/or geological engineer to review and determine the
adequacy of geotechnical, fault hazard studies and/or soils studies for proposed projects in
the General Plan Area, and to enforce the implementation of mitigation measures.
4. The City shall require that development in areas subject to collapsible or expansive soils
conduct soil sampling and laboratory testing and implement mitigation measures that
minimize such hazards.
5. The City shall require that all new structures be built in accordance with the latest version of
the California Building Code (CBC).
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6. The City shall continue to encourage that structures that pose a safety threat due to
inadequate seismic design are retrofitted or removed from use. The City shall encourage all
other property owners to seismically upgrade their properties.
7. The City shall consult and coordinate with California Geological Survey, Coachella Valley
Water District and other appropriate agencies to support and participate in local and regional
efforts at groundwater conservation and recharge in order to minimize potential impacts of
subsidence due to groundwater extraction, including the periodic monitoring of groundwater
levels and surface elevations in the City.
8. The City shall coordinate and cooperate with public and quasi-public agencies to ensure that
major utilities shall continue to be functional in the event of a major earthquake.
Mitigation Monitoring and Reporting
A. During site preparation for any project, the City Engineer and/or Building and Safety
Department staff shall visit the site to assure compliance with applicable conditions of
approval, City ordinances, and erosion control plans.
Responsible Parties: City Engineer, Building and Safety Department, project developer,
grading contractor.
B. Subsequent to preparation of final development plans and specifications and prior to grading
and construction, the Geotechnical Consultant and/or the City Engineer shall review
foundation plans to confirm compatibility with site-specific geotechnical conditions and
conformance with the recommendations contained herein. The need for additional subsurface
exploration shall be determined on a project-by-project basis.
Responsible Parties: City Engineer, Geotechnical Consultant.
C. Rough grading shall be performed under geological and/or engineering observation by the
Geotechnical Consultant and the City Engineer, accordingly, as appropriate.
Responsible Parties: City Engineer and Geotechnical Consultant.
Hazards and Hazardous Materials G.
Introduction
The City of La Quinta is an urbanized area within the Coachella Valley. With any urbanized
region, the potential for exposure to hazards and hazardous material is always prevalent due
commerce and industrial activities, transportation and distribution of products, and use of
hazardous materials. La Quinta is not immune to these hazards, as numerous business and
households use hazardous materials for commerce and daily living, and due to the constant flow
of truck and rail traffic transporting hazardous materials through the City and region. Other
hazards to residents include the presence of airports, and presence of wildfire zones. This section
assesses impacts associated with hazards and hazardous materials on new growth likely to occur
as a result of implementing the General Plan Update. It also provides mitigation measures to
reduce hazardous impacts on existing and future residents.
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Thresholds of Significance/Criteria for Determining Significance
Article 5, Section 15064 of the CEQA Guidelines provides guidance for determining the
significance of the environmental effects caused by a project. Appendix G of the CEQA
Guidelines provides a list of environmental factors that potentially may be affected by
completion of a project. Build out of the La Quinta 2035 General Plan Update would have a
significant effect from hazards or hazardous materials if it is determined the plan will:
a) Create a significant hazard to the public or the environment through the routine
transport, use, or disposal of hazardous materials.
b) Create a significant hazard to the public or the environment through reasonably
foreseeable upset and accident conditions involving the release of hazardous materials
into the environment.
c) Emit hazardous emissions or handle hazardous or acutely hazardous materials,
substances, or waste within one-quarter mile of an existing or proposed school.
d) Be located on a site which is included on a list of hazardous materials sites compiled
pursuant to Government Code Section 65962.5 and, as a result, would it create a
significant hazard to the public or the environment.
e) For a project located within an airport land use plan or, where such a plan has not
been adopted, within two miles of a public airport or public use airport, would the
project result in a safety hazard for people residing or working in the project area
f) For a project within the vicinity of a private airstrip, would the project result in a
safety hazard for people residing or working in the project area.
g) Impair implementation of or physically interfere with an adopted emergency response
plan or emergency evacuation plan.
h) Expose people or structures to a significant risk of loss, injury or death involving
wildland fires, including where wildlands are adjacent to urbanized areas or where
residences are intermixed with wildlands.
1. Existing Conditions
Hazardous Materials Management
Hazardous waste is any liquid, solid, gas, or sludge that is potentially dangerous to human health
and the environment, including everyday commercial products, such as pesticides, cleaning
fluids, and household sprays, as well as byproducts of manufacturing processes. The United
States Environmental Protection Agency (EPA) has classified hazardous waste into four types of
hazardous waste including listed wastes, characteristic wastes, universal wastes, and mixed
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wastes.30 Listed wastes include wastes from common manufacturing and industrial processes,
waste from specific industries such as petroleum refining or pesticide manufacturing, and
discarded commercial products. Characteristic wastes include non-listed wastes that exhibit
ignitability, corrosivity, reactivity, and toxicity. Universal wastes include items such as batteries,
mercury-containing equipment, and fluorescent lamps and bulbs. Mixed wastes contain
radioactive and hazardous waste components. All hazardous waste poses a threat to humans and
the environment, and therefore is regulated by federal, state and local programs.
Federal Programs
The EPA has been given authority and responsibility to regulate hazardous waste by the
Resource Conservation and Recovery Act of 1976 (RCRA). Through the Act, the EPA is
responsible for monitoring the generation, transportation, treatment, storage, and disposal of
hazardous waste. Amendments to the RCRA, including the 1984 Federal Hazardous and Solid
Waste Amendments, and those established in 1986, forced the EPA to increase enforcement of to
underground storage tanks for petroleum and other hazardous substances, focus on waste
minimization programs, such as phasing out hazardous wastes from landfills, and finally
mandating corrective measures regarding the release of hazardous waste.31
The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA),
known as Superfund, is another federal act enacted on December 11, 1980. CERCLA created a
tax on chemical and petroleum industries to help fund cleanup of abandoned and uncontrolled
hazardous waste sites. The Act is also responsible for establishing the National Priorities List,
which lists nationwide hazardous waste sites that are a priority for EPA cleanup. As of December
6, 2010, there are no Superfund sites located in La Quinta or the Sphere of Influence.32
In October 17, 1986, CERCLA was amended by the Superfund Amendment and Reauthorization
Act (SARA). SARA provided important changes to CERCLA, including increasing the size of
the cleanup trust fund, encouraging more citizen participation on cleanup measures, increased
State involvement in the Superfund program, and providing more innovative treatment
technologies for cleaning up hazardous waste sites. SARA also revised the National Ranking
System, which is used by the EPA to assess whether a hazardous waste site should be placed on
the National Priorities List. As of December 6, 2010, there are no Superfund sites listed on the
National Priorities List located in La Quinta or the Sphere of Influence.33
More recent EPA efforts and responsibilities for managing hazardous waste include management
of wastes from homeland security incidents. The Waste Management for Homeland Security
Incidents requires EPA to provide technical support to Federal, state, local, and tribal authorities
on waste management and cleanup efforts resulting from natural disasters, terrorist attacks, major
accidents, and disease outbreaks. The main responsibility of the EPA is to promote pre-planning
efforts to deal will hazardous waste disasters and encourage various stakeholders to prepare for
30 “Wastes-Hazardous Waste-Waste Types”, http://www.epa.gov/waste/hazard/index.htm, accessed December 6,
2010. 31 “Wastes-Hazardous Wastes”, http://www.epa.gov/waste/hazard/index.htm, accessed December 6, 2010. 32 “CERCLA Overview”, http://www.epa.gov/superfund/policy/cercla.htm, accessed December 6, 2010. 33 “CERCLA Overview”, http://www.epa.gov/superfund/policy/cercla.htm, accessed December 6, 2010.
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natural and man-made disasters. The EPA is also required to review emergency response plans
for Federal agencies, and participate in exercises with Federal, state, local and tribal emergency
responders.
State Programs
The California Certified Unified Program Agencies, or CUPA, is a collection of state and
regional agencies in charge of regulating hazardous waste. They are responsible for the
administration, permits, inspection and enforcement of various environmental and emergency
management programs, including the Underground Storage Tank Program, the Aboveground
Petroleum Storage Act Program, Hazardous Materials Release Response Plans, and Hazardous
Waste Generator and Onsite Hazardous Waste Treatment Programs. The California
Environmental Protection Agency (Cal/EPA) is responsible for administrating and certifying the
CUPA’s. Two state agencies that are also heavily involved with CUPA activities include the
California Department of Toxic Substances Control (DTSC) and the State Water Resources
Control Board (SWRCB).
The California Department of Toxic Substances Control (DTSC) is responsible for protecting
public health and environment from the two millions of hazardous waste generated each year in
California. They regulate under the authority of the federal RCRA of 1976 and the California
Health and Safety Code. The DTSC operates a variety of programs including the following:
-Overseeing site cleanups at improperly managed waste sites
-Ensuring those who generate, handle, transport, store and dispose of hazardous waste do
so properly.
-Enforcement actions against those who fail to manage hazardous waste appropriately.
-Exploring and promoting pollution prevention and encouraging reuse and recycling.
-Evaluating soil, water and air samples at sites and developing new analytical methods
-Practicing other environmental sciences, including toxicology, risk assessment, and
technology development.
-Involving the public in DTSC’s decision-making.
DTSC is required to compile and update each year, or as appropriately, a list of hazardous waste
sites pursuant to Section 65962.5(a). The DTSC has created the EnviroStor database of
properties throughout California that may be contaminated. There are no hazardous waste sites in
La Quinta or Sphere of Influence that are listed pursuant to Section 65962.5(a). The closest listed
site is the Foster-Gardner facility in Coachella, located south of Avenue 50 between Highway 86
and Highway 111.34
The State Water Resources Control Board (SWRCB) is responsible for regulating wastewater
discharges to surface waters and groundwater. This includes discharges from all construction,
industrial, municipal, and agricultural activities. The SWRCB delegates these responsibilities to
various regional water quality control boards throughout California. La Quinta falls under the
jurisdiction of the Colorado River Basin Regional Water Quality Control Board, Region 7. The
Colorado River Basin Regional Water Quality Control Board is responsible for overseeing
34 Cortese List: Section 65962.5(a) http://www.calepa.ca.gov/sitecleanup/corteselist/SectionA.htm
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corrective actions associated with leaks and improper disposal from underground storage tanks,
such as gas station tanks, and provides assistance to County of Riverside Department of
Environmental Health on underground storage leaks.
Regional Programs
The Riverside County Department of Environmental Health (DEH) provides programs and
services related to protecting public health, safety and the environment. Within the DEH are two
divisions, including the District Environmental Service, and the Environmental Protection and
Oversight. The Environmental Protection and Oversight Division (EPO) is responsible for
handling and regulating hazardous materials, land use, water systems, underground storage
tanks, solid waste and business emergency plans. The Department of Health is responsible for
managing a list of all hazardous waste generators in the County. As of December 8, 2010, La
Quinta has 50 generators of hazardous waste. Generators include golf courses, gas stations,
cleaners, grocery stores, car dealerships and city maintenance facility yards.
Emergency response in La Quinta involves numerous state, regional, local, and non-profit
agencies whose goal is to prepare local residents for emergencies caused by natural or human
incidents. The State of California passed the California Emergency Services Act in 1970 to
provide the basic legal authorities for emergency management in the State. The Act created the
Governor’s Office of Emergency Services (OES), which serves as the lead agency for emergency
management and to organize all levels of government, businesses, community organizations and
volunteers to deal with local emergencies. The County of Riverside operates the Office of
Emergency Services through Riverside County Fire Department. Riverside County OES is
responsible for mitigation, preparedness, response and recovery activities from hazards and
threats occurring in Riverside County.35
Local Emergency Response
The City of La Quinta’s Emergency Services Division is responsible for the community’s
preparedness and response to natural and manmade disasters and emergencies. The City has
prepared the Emergency Operations Plan to plan and prepare for emergencies.
La Quinta has also established Code Red, which is an ultra high speed telephone communication
service that provides emergency notifications to local residents during emergencies. The City is
also involved in the Community Emergency Response Team (CERT) program, which educates
volunteers in the community about disaster preparedness and trains them in basic disaster
response skills. The CERT group is organized to support the City of La Quinta during
emergencies or disasters.36
Hazardous Waste Transportation
The General Plan Update Planning Area is near four major transportation routes commonly used
for transporting hazardous waste. The Union Pacific Railroad and Interstate 10 are located
approximately 2.5 miles north of the City boundary. The Union Pacific Railroad runs adjacent to
35 Office of Emergency Services, http://www.rvcfire.org/opencms/functions/oes/, accessed December 17, 2010. 36 “Emergency Services”, http://www.la-quinta.org/Index.aspx?page=80, accessed December 13, 2010.
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Interstate 10. Approximately 16% of goods carried by Union Pacific trains are chemical goods,
which may include hazardous waste.37 Highway 111 runs through the northern portion of the
Planning Area, between Washington and Jefferson Street. Finally, State Route 86 is located east
of La Quinta, and provides regional access to the Imperial Valley.
Hazardous waste cleanup on transportation routes is the responsibility of various state and
federal agencies. Caltrans has created the Hazardous Waste Management program to assist local
districts statewide with management and cleanup of hazardous materials encountered on roads
that are under Caltrans responsibility.38 The California Highway Patrol (CHP) and the US
Department of Transportation are responsible for regulating the shipment of hazardous waste by
requiring appropriate labeling, packaging, and loading of hazardous materials. The CHP also
requires motor carriers and drivers involved in transporting hazardous materials to obtain a
hazardous materials transportation license.39 The United State Department of Transportation has
created the Pipeline and Hazardous Materials Safety Administration Office of Hazardous
Materials Safety (OHMS) to ensure safe transport of hazardous materials by air, rail, highway
and water. 40
Existing Public and Private Airports
The General Plan Update Planning Area is located near two airports, including the Bermuda
Dunes Airport and the Jacqueline Cochran Regional Airport. The Bermuda Dunes Airport is a
small privately owned airport located north of the Planning Area, just south of Interstate 10, and
west of Jefferson Street in the Bermuda Dunes community. The Bermuda Dunes Airport has one
east-west runway measuring approximately 5,000 feet in length. The airport averages
approximately 110 flights a day.41
The Jacqueline Cochran Regional Airport is a public airport located just east of the Planning
Area, east of Harrison Street and between Airport Boulevard on the north and Avenue 60 on the
south. The airport is a general aviation airport and handles approximately 209 flights a day.
There are two runways, including Runway 17-35, which is an 8,500 foot north-south runway,
and Runway 12-30, which is a smaller 4,995 foot northwest-southeast runway. The majority of
flights are from single engine aircraft, and there are no commercial flights at the airport. The
airport houses a variety of private, corporate, and charter aircrafts that accommodate business
travelers, tourists, and residents.42
37 Union Pacific 2009 Annual Report” www.up.com, accessed December 17, 2010. 38 “Caltrans Hazardous Waste Management”, http://www.dot.ca.gov/hq/env/haz/, accessed December 17, 2010. 39 “Publications”, www.chp.ca.gov, accessed December 17, 2010. 40 PHMSA, http://www.phmsa.dot.gov/hazmat/about, accessed December 17, 2010. 41 Bermuda Dunes Airport, http://bermudadunesairport.com/, accessed December 17, 2010. 42 “Airport Operational Statistics” http://www.rcjcra.com, accessed December 17, 2010.
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Fire Hazards
Fire hazards exist where wildland areas are adjacent to or are intermixed with urbanized areas.
Many of these wildland areas include rugged topography with highly flammable vegetation. La
Quinta is situated at the base of the Santa Rosa Mountains, however, these areas are considered
low wildfire zones. The open space and wilderness areas on the western portion of the City are
made up primarily of Granitic rock and sparse desert vegetation. Therefore, there is limited
vegetation to burn that could cause a major wildfire. The flat urbanized areas of La Quinta are
considered very low wildfire areas.
2. Project Impacts
Implementation of the General Plan Update will facilitate new growth and development across
the City and the Sphere. Increased growth will not only result in an increased population
susceptible to hazards and hazardous materials, but will include businesses and development
projects that use, store, and/or transport hazardous material. As such, build out of the proposed
General Plan has the potential to increase the number of people that are susceptible to hazards
and hazardous materials in the Planning Area.
Transport of Hazardous Material Impacts
The Planning Area, as previously mentioned, is located near a network of roads, highway, and
rail lines that carry hazardous materials on a daily basis. New growth and development
facilitated by the General Plan Update will have the potential to increase populations living in
and around these routes. Although the primary travel corridors are located north of the Planning
Area, accidents and spills that occur during the transport of hazardous materials have the
potential to affect the La Quinta General Plan area.
Hazardous materials are highly regulated by various government agencies, such as Caltrans, the
California Highway Patrol, and the US Department of Transportation, and cleanup and
containment of these accidents is monitored by these same agencies. Emergency evacuation and
response plans, such as Code RED, are already developed in La Quinta to provide automated
notification to residents during an emergency, including hazardous waste spills.
The General Plan Update provides commercial and light industrial land use designations,
particularly the Sphere, that will potentially increase the amount of hazardous materials
transported throughout the area.
Cleanup of hazardous materials, and emergency evacuation response plans are already in place.
As such, significant hazards to the public or the environment through the routine transport, use,
or disposal of hazardous materials as a result of implementation of the General Plan Update is
expected to be less than significant.
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Hazardous Material Release Impacts
Household Hazardous Waste
The General Plan Update proposes approximately 8,114 additional residential units in the City
Limits, and 20,699 new units within the Sphere of Influence. These new residential uses have the
potential to use and store household cleaning supplies, chemicals, batteries, fluorescent bulbs,
and other potentially hazardous materials. The amount of hazardous materials used by these new
residential uses will be typical of what is found within existing neighborhoods throughout the
region. The relatively small amount of hazardous materials and chemicals found in households
may pose a minimal danger to the household during a spill or accidental release, however these
household spills and accidents are not expected to create significant hazards. Hazardous waste
centers throughout the Coachella Valley, including the Burrtec Waste and Recycling Center in
Palm Desert, and the household hazardous waste facility in Palm Springs, are available for
residents to dispose of household hazardous waste.
Non-residential Hazardous Materials
The General Plan Update also proposes new commercial, industrial, and institutional uses that
will potentially use, store, and transport hazard materials. These uses, such as gas stations, dry
cleaners, assembly plants, and mechanical shops rely on hazardous materials for everyday
business. The General Plan Update proposes approximately 3,218,039 square feet of additional
commercial uses in the City, 2,458,797 square feet of additional commercial in the Sphere of
Influence, 611,408 square feet of new industrial/light manufacturing uses in the Sphere of
Influence, and approximately 195 acres of new community facilities. New golf courses
throughout the Planning Area may also use and store hazardous materials, such as pesticides and
fertilizers.
All commercial, industrial and municipal generators of hazardous materials are regulated by
federal, state, and local agencies regarding the proper use, disposal and cleanup of hazardous
materials. The Riverside County Department of Health is responsible for managing a list of all
hazardous waste generators in the County. New hazardous waste generators that locate in the
Planning Area will be required to abide by County Department of Environmental Health policies,
and register on the hazardous waste generator list. This list provides residents and public officials
information as to where hazardous materials are located throughout La Quinta.
With the continued implementation of federal, State and local regulations and programs, these
impacts will be less than significant.
Impacts from Hazardous Materials Sites
The General Plan Update Planning Area is not located on the “Cortese” list of hazardous
materials sites compiled pursuant to Government Code Section 65962.5, and managed by the
California Environmental Protection Agency. The closest active hazardous materials site in the
region is located on the Jacqueline Cochran Regional Airport located east of the Planning Area.
Hazardous materials at this site are associated with the airport facilities, as well as historic Army
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and Navy uses. 43 No new development throughout the Planning Area will be located on
hazardous materials sites pursuant to Government Code Section 65962.5. As such, there will be
no impact related to new populations being located on hazardous materials sites.
Airports and Associated Hazards Impacts
The Jacqueline Cochran Regional Airport is immediately adjacent to the eastern boundary of the
Sphere of Influence. As a result, aircraft using the airport may fly over the Planning Area.
The Riverside County Airport Land Use Commission has prepared the Riverside County Airport
Land Use Compatibility Plan, which provides policies for Airport Influence Areas for most of
the airports in the County. Eastern portions of the La Quinta Planning Area are located within the
Jacqueline Cochran Airport Influence Area Zone D and E of the Compatibility Plan. A portion of
the Planning Area is located in Zone C, with a very small area in Zone B1. New development
within the eastern boundary of the Sphere of Influence will need to abide by Compatibility Plan
polices and land use regulations. Land uses such as schools, hospitals, and nursing homes are
discouraged in Airport Compatibility Land Use Zone D, and the number of residential dwelling
units is regulated in this zone. Within Zone E, there are no residential or commercial restrictions,
however prohibited uses include those that create hazards to flights, including tall objects, visual
and electronic forms of interference, and developments that attract birds, such as landfills.44
The General Plan Update proposes non-residential land uses, including both industrial and
commercial uses within Zone D, and residential uses are proposed in Zone E. These uses are
allowed according to the Compatibility Plan. Therefore, hazards related to the Jacqueline
Cochran Regional Airport will have a less than significant effect on development within the
Planning Area.
The General Plan Update Planning Area is also near the Bermuda Dunes Airport. This privately-
owned public use airport is located approximately 1.5 miles north of the northern Sphere of
Influence and City limit, along Interstate 10 west of Jefferson Street. The 5,000-foot runway is
oriented in an east-west direction, and approaches and takeoff patterns generally do not affect
any portion of the Planning Area.45 According to the Riverside County Airport Land Use
Compatibility Plan, the far northern portions of La Quinta, including the northern Sphere of
Influence, are located primarily in Compatibility Land Use Zone E (a portion of Compatibility
Zone D is in the City of La Quinta, but this area has already been developed with housing). As
previously mentioned, there are no residential or commercial restrictions in Zone E; however
prohibited uses include those that create hazards to flights, including tall objects, visual and
electronic forms of interference, and developments that attract birds, such as landfills.46 Proposed
land uses within Zone E are compatible with the Bermuda Dunes Compatibility Plan. Therefore,
43 “Hazardous Waste and Substances Site List”, www.envirostor.dtsc.ca.gov, accessed January 14, 2011. 44 “Riverside County Airport Land Use Compatibility Plan; Volume I”, prepared by Mead & Hunt, October 14,
2004. 45 Bermuda Dunes Airport, http://bermudadunesairport.com/, accessed December 17, 2010.
46 “Riverside County Airport Land Use Compatibility Plan; Volume I”, prepared by Mead & Hunt, October 14,
2004.
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implementation of the General Plan Update will have a less than significant impact within the
vicinity of this public use airport.
Impacts to Emergency Response and Evacuation Plans
The City currently contracts with Riverside County Fire Department for emergency services, and
the City’s Emergency Services Division is responsible for preparing the community for natural
and man made disasters and emergencies. The General Plan Update will facilitate new
development, and therefore will increase population throughout the Planning Area. This increase
in population has the potential to affect emergency response plans and emergency evacuation
plans. Additional emergency services, including new police and fire services, will be required as
development and population increases. In addition, the City’s Emergency Services Division will
need to accommodate the influx of new residents to the area. Impacts to emergency response as a
result of new development and population increases brought on by the General Plan Update will
potentially be significant, unless mitigated. Mitigation measures provided below will reduce
impacts to less than significant levels.
The City prepared the Emergency Operations Plan to prepare for emergencies, and has instituted
the Code RED notification system to help notify the public, through telephone calls, about
emergencies such as water contamination, evacuation notices, wildfires, bomb threats, hazardous
spills, and other emergency situation. The City is also involved in the Community Emergency
Response Team (CERT) program. New residents of La Quinta, as a result of new development
brought on by implementation of the General Plan, may allow for more volunteers for groups
such as CERT. The General Plan Update, therefore, is expected to have a less than significant
effect with an adopted emergency response plans or emergency evacuation plans.
Wildfire Hazard Impacts
The La Quinta Planning Area is situated in a Valley, along the base of the Santa Rosa and San
Jacinto Mountains. Much of the western portion of the Planning Area, particularly within the
City, such as the Cove, is located near the urban-wildland interface. The wilderness areas that
surround La Quinta, as well as other areas along the base of the Santa Rosa and San Jacinto, are
made up of Granitic rock and sparse desert vegetation. The sparse desert vegetation along these
mountainsides does not provide the explosive fuels needed for wildfires. Wildfire risk within the
General Plan Update Planning Area, therefore, is less than significant.
3. Mitigation Measures
The General Plan Update provides policies and programs to reduce the severity of hazards and
lower risks involved with accidental release of hazardous materials or other emergencies. The
following mitigation measures will also help promote a safe environment for existing and future
residents, and ensure impacts will be less than significant.
1. The City will ensure that new generators of hazardous materials will comply with all local,
state, and federal regulations, as required by law.
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2. The City will work with Riverside County Fire, Caltrans, CHP, and other local, state, or
federal agencies to regulate the transport or hazardous materials along local roadways, state
highways, and railways that run through the City or in the vicinity.
3. The City shall incorporate and abide by the policies and regulations highlighted in the
Jacqueline Cochran Regional Airport Master Plan and the Riverside County Airport
Compatibility Land Use Plans for all new development within the Compatibility Land Use
Zones of the Jacqueline Cochran Regional Airport and the Bermuda Dunes Airport.
4. The City shall update the Emergency Operations Plan as necessary to address and plan for
synchronized response to potential emergencies including release or spills of hazardous
materials.
Mitigation Monitoring and Reporting
A. Development plans and permits for uses that use, transport, and/or store hazardous materials
shall be submitted, reviewed, and regulated by proper agencies.
Responsible Parties: Riverside County Fire Department, Riverside County Department of
Environmental Health, City of La Quinta Planning Division, California Certified Unified
Program Agencies, CHP, Caltrans
Hydrology H.
Introduction
This section discusses the hydrological resources in La Quinta, and assesses impacts on these
resources from future growth and development brought on by the General Plan Update. It also
provides mitigation measures to reduce potential impacts to hydrology. The following section
describes the existing hydrological conditions, evaluates potential impacts to hydrological
resources from implementation of the proposed General Plan and sets forth mitigation to reduce
impacts to levels below significance.
It should be noted that Section P: Water Resources and Quality further addresses water quality.
Thresholds of Significance/Criteria For Determining Significance
The following standards and criteria have been drawn from Appendix G: Environmental
Checklist Form of the CEQA Guidelines. To ensure that the General Plan EIR adequately
addresses potential impacts associated with hydrology as a result from the adoption and
implementation development of the La Quinta General Plan, the following factors have been
considered. Implementation of the General Plan would have a significant effect on hydrology if
it is determined that the project will:
a.) Violate any water quality standards or wastewater discharge requirements.
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b.) Substantially alter the existing drainage pattern of the site or area, including through the
alteration of the course of a stream or river, in a manner which would result in flooding
on- or off-site.
c.) Substantially alter the existing drainage pattern of the site or area, including through the
alteration of the course of a stream or river, or substantially increase the rate of surface
runoff in a manner, which would result in flooding on- or off-site.
d.) Create or contribute runoff water, which would exceed the capacity of existing or planned
stormwater drainage systems or provide substantial additional sources of polluted runoff.
e.) Place housing within a 100-year flood hazard area as mapped on a federal Flood Hazards
Boundary or Flood Insurance Rate Map or other flood hazard delineation map.
f.) Place within a 100-year flood hazard area structures, which would impede or redirect
flood flow.
g.) Expose people or structures to a significant risk of loss, injury or death involving
flooding, including flooding as a result of a levee or dam.
h.) Inundation by seiche, tsunami, or mudflow.
1. Existing Conditions
The distribution and circulation of water in a given area is referred to as hydrology. Within this
EIR, hydrology is associated with the management of floodwaters and surface runoff, which are
significantly influenced by the geography and climate of a particular locale. The local
microclimate also affects the amount and intensity of precipitation and therefore plays an
important role in local hydrology. Hydrological conditions in the Planning Area been analyzed in
the Technical Background Study prepared for the General Plan, which is summarized herein.47
The Coachella Valley, including the Planning Area, is situated at the western end of a tectonic
depression, known as the Salton Trough, which extends from Baja California to the Salton Sea at
the eastern end of the Coachella Valley. In the Planning Area, the Valley floor encompasses a
broad, gently sloping basin. This basin forms where canyons of the Santa Rosa Mountains
emerge onto alluvial vans, the Whitewater River floodplain, and sediments of prehistoric lakes.
The foothills of the Santa Rosa Mountains rise in and adjacent to the western portion of the
Planning Area. Most development, including that along the base of the Santa Rosa Mountains in
the western portion of the City, occurs on the Valley floor.
The Planning Area and the region generally enjoy a temperate climate characterized by mild
winters and warm, dry summers. However, regional conditions are influenced by proximity to
the San Bernardino, San Jacinto, and Santa Rosa Mountain ranges and associated climatic zones.
47 “Technical Background Report to the Safety Element Update, City of La Quinta, California,” prepared by Earth
Consultants International, July 2010.
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Flooding can occur as a result of rapid melting of mountain snowpack. Occasional intense
thunderstorms can also cause flooding. Storms occur most frequently during the winter months,
between November and April, although the area also experiences monsoon storms during the
summer and early fall (July through September). While generally of short duration, these storms
may generate several inches of rainfall in localized areas.
Rainfall in the region varies widely. In the surrounding mountains, average rainfall is
approximately 25 inches annually, whereas on the Valley floor, including the Planning Area, it
averages 3 inches. Even in the absence of rain in the Valley itself, flooding can occur when
runoff and associated mud and debris flows from mountain slopes. When precipitation occurs
rapidly, dry soils quickly become saturated and cannot sufficiently percolate the increased
runoff.
Hydrological Conditions and Flood Hazards
Floodplains are meant to carry excess waters during flooding, which is a recurring, natural event.
Flooding becomes a hazard when human uses encroach into floodplains. This encroachment
occurs frequently since floodplains are optimal for agriculture, access to water supplies and
transportation routes. Flooding is among the most destructive and costly of all natural disasters
on a global level and causes more deaths per year than any other geologic hazard. Dollar-based
economic losses as a result of ever-expanding development on floodplains has steadily increased
over the last several decades.
It is difficult to predict rainfall in the region, since it varies widely from year to year. A review of
annual rainfall totals and peak streamflow gages on the Whitewater River demonstrates this
inconsistency. Although in most years, stream discharges have remained at at or near zero cubic
feet per second (cfs), by contrast, peak flows exceeded 10,000 cfs on November 22, 1965 and
January 25, 1969. There is potential for substantial damage when floodwaters reach such high
velocities.
In the planning area, flooding primarily occurs under two scenarios: 1) flash flooding along
natural or man-made channels and 2) sheet flooding across the Valley floor. Brief but powerful
storms can cause high peak volumes and velocities, which are often intensified by local
conditions including both the built environment as well as naturally occurring landforms and
geology. In La Quinta, mountain slopes comprised of impervious rock impede percolation.
Water quickly collects and flows into channels on the Valley floor, often transporting with it
large amounts of mud, sand, rock fragments and other debris.
Flows may exceed the existing natural or man-made channel capacities, or channels are impacted
by debris or structures. Water overflows channel banks, creating the condition known as sheet
flow or sheet flooding.
Increasing urban development results in an increase in impervious surfaces such as buildings,
sidewalks, parking lots, and roadways that reduce the area available for natural percolation.
Downstream areas are then subject to water that formerly would have been absorbed. Unless
new development provides storm drain systems to carry increased flows, downstream flooding
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risks may increase. In the La Quinta Planning Area, these risks are especially prevalent for
development downstream of canyons and the base of mountains, since surrounding mountain
slopes generally receive greater levels of rainfall.
Regional Stormwater Management
Analysis and design of regional flood control structures is the responsibility of the Coachella
Valley Water District (CVWD). In the Planning Area, CVWD manages regional facilities, which
collect runoff from areas outside the City, including surrounding mountains. Planning,
maintenance and construction of improvements for regional facilities fall within the broad
management responsibilities with which CVWD is charged. Of primary concern to CVWD are
rivers, major streams and tributaries, as well as areas of substantial sheet flow. Regional
facilities in the Planning Area include the Coachella Valley Stormwater Channel, Whitewater
River Stormwater Channel, the La Quinta Evacuation Channel, the Bear Creek System, the East
La Quinta Channel System, Dike No. 2, Guadalupe Dike, and Dike No. 4. These are further
described below.
Local Drainage Management
The City of La Quinta is responsible for local facilities, which collect and convey runoff from
local streets and properties to regional channels and basins. The recently updated City Master
Drainage Plan (2009) describes these local facilities. The City has not formally adopted the Plan,
but uses it to manage and document the location and condition of existing stormwater
management facilities. It has also been used to obtain FEMA Letters of Map Revision for some
flood areas.
Major Regional and Local Flood Control Facilities
Major flood control facilities in the planning area are described below and are mapped on
Exhibit III-10, FEMA Flood Zones and Flood Control Facilities.
Whitewater River/Coachella Valley Stormwater Channel
The Whitewater River, which flows into the Coachella Valley Stormwater Channel in the
Planning Area, is the principal drainage course in the City, extending through the Coachella
Valley for 50 miles, with an average cross section of 350 feet. The Channel is generally dry but
may be inundated during storm events. Most of the Coachella Valley Stormwater Channel
sections within the City have reinforced slope protection; the remaining portions are protected by
unreinforced earthen berms. Although the Channel generally follows the recent historical natural
river path, it deviates from this course where it passes through the City between Jefferson Street
and Miles Avenue. The Federal Emergency Management Agency (FEMA) has indicated the
potential for breakout of the levee system along this reach of the river in the event of a 100-year
storm. This is further discussed under Seismically Induced Flooding, below.
The aforementioned reinforced slopes and remaining unreinforced earthen banks are classified
by FEMA as “Provisionally Accredited Levees,” indicating that they provide protection from the
100-year flood. CVWD has recently (2009) submitted required documentation to FEMA
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demonstrating the protection capabilities of these levees in compliance with requirements of
Section 65.10 of National Flood Insurance Program (NFIP) regulations (Title 44, Chapter 1 of
the Code of Federal Regulations).
Bear Creek System
Runoff from the Santa Rosa Mountains to the west/southwest flows into the Upper Bear Creek
System, which is located along the southerly and westerly margins of the Cove. The system
includes the Upper Bear Creek Training Dike, Upper Bear Creek Detention Basin, Bear Creek,
as well as Bear Creek Channel and four associated side inlet channels and a downstream drop
structure. The dike diverts runoff from a 1.7 square mile drainage area, then directs it along Bear
Creek to the detention basin, which has a storage capacity of 752 acre-feet. Bear Creek Channel
receives outflows from the Basin. The Channel is approximately 2.5 miles long. It is a soil-
cement lined trapezoidal channel with 100-year flood flow capacity, with four inlet channels on
the western side that drain smaller canyons. From the Channel, flows continue into the Oleander
Reservoir downstream, thence into the La Quinta Evacuation Channel, and ultimately discharge
into the Coachella Valley Stormwater Channel. CVWD has applied for FEMA accreditation of
the Bear Creek Channel System, including the training dike, and is awaiting receipt of the formal
accreditation letter.
Oleander Reservoir
The Oleander Reservoir detention basin is located in the La Quinta Resort and Club Mountain
golf course. In collects runoff from the Bear Creek system as well as flows from drainage areas
north and west of it. Flows then discharge into the La Quinta Evacuation Channel. The Standard
Project Flood elevation is projected to be 54 feet at the reservoir.
La Quinta Resort Channel
The La Quinta Resort Channel is a man-made channel generally located along the western
boundary of the City northwest of the Cove. Runoff from mountains west of this area is collected
along this Channel and conveyed to the Oleander Reservoir.
East La Quinta System
The East La Quinta System is located along the southeastern edge of the Cove area, comprised of
the riprap lined, trapezoidal East La Quinta Channel and several detention basins. It collects
drainage from hills east and south of Calles Bermudas as well as outflows from the Calle
Tecolate Detention Basin located at the southwestern point of the Cove. The system channels
flows to the Avenida Bermudas Detention Basin, which manages runoff and debris from
surrounding drainage areas via a 60-inch reinforced concrete buried storm drain with 100-year
stormwater flows capacity. Flows from the basin are conveyed to the La Quinta Evacuation
Channel.
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La Quinta Evacuation Channel
The La Quinta Evacuation Channel flows northeasterly from the Bear Creek Channel,
approximately 3.5 miles through developed areas of the City to the Coachella Valley Stormwater
Channel. This Channel is designed to capture and carry stormwater from various flood control
systems in the City. There are two reaches, of which the lower is approximately 2.4 miles long
within a 50-foot wide trapezoidal earthen channel. The upper reach is a grass-lined, irregularly
shaped channel approximately 1.1 miles long.
La Quinta North Diversion Channel
This facility is described in the City Master Drainage Plan as conveying “the [Standard Project
Flood] SPF from off-site mountain areas northwest of the City . . . southerly to the Oleander
Reservoir.” It is unclear whether this is an additional facility or another name for the La Quinta
Resort Channel.
Lake Cahuilla
Lake Cahuilla, while not a flood control facility, constitutes a major regional facility managed by
CVWD and is therefore considered herein as part of the evaluation of flooding hazards. Lake
Cahuilla was constructed in 1969 as a reserve storage facility for irrigation water. The lake is
located on approximately 135 acres at the base of the foothills of the Santa Rosa Mountains,
between Avenues 56 and 58, west of Jefferson Street. It terminates the Coachella Branch of the
All-American irrigation canal. The Lake Cahuilla County Park, operated by Riverside County
Parks and Open Space District, is located at the same site on lands leased by CVWD to the Parks
District.
Lake Cahuilla has a capacity of approximately 1,500 acre-feet of water at depths of 11 to 12 feet,
protected by a levee system approximately 25 feet high and 100 feet wide. It is cement lined and
sealed with a six-inch layer of soil cement. Lake Cahuilla contains more than 50-acre feet of
storage capacity. Normally a facility with this capacity would fall under the purview of the
Division of Dam Safety. However, since Lake Cahuilla is not impounded by an artificial barrier
(dam), the Division does not oversee it. Nonetheless, the structural integrity of levees protecting
the lake have potential to be compromised in a severe earthquake and should therefore be
monitored routinely. This is further discussed under Seismically Induced Flooding, below.
Local Structures
Within the Planning Area there are a variety of local structures, including storm drains, culverts
and catch basins located within private development and area streets. These facilities collect and
retain stormwater and irrigation runoff, and in some cases, detain flows for eventual evaporation
or infiltration. The City requires that new developments retain project-related stormwater runoff
produced over the peak twenty-four-hour period of a 100-year storm, unless requirements are
waived by the City Engineer.
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Dikes
There are several dikes located near the base of mountains in the Planning Area, which have
been constructed to protect agricultural lands on the Valley floor from runoff from mountain
slopes. In addition to the Bear Creek Training Dike, previously discussed, these include two
dikes constructed by the Bureau of Reclamation: Dike 2 and Dike 4, which were constructed to
protect Lake Cahuilla as well as lands between Avenue 58 and Avenue 66. Dike 2 and Dike 4
total 5.2 miles, and are located south and southeast of Lake Cahuilla, respectively. Dike 4
encompasses the Guadalupe Dike and Guadalupe Training Dike. Dike 4 is accredited by FEMA;
Dike 2 is not yet accredited.
CVWD has constructed approximately 165 acres of groundwater recharge basins within the Dike
4 impound area. These basins comprise an important component of groundwater replenishment
programs discussed in CVWD’s Urban Water Management Plan for recharge of the groundwater
basin in the eastern Coachella Valley. These facilities are also discussed in Section III-P, Water
Resources/Quality.
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Exhibit III-10
FEMA Flood Hazard Zones and Flood Control Facilities
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National Flood Insurance Program
The Federal Emergency Management Agency (FEMA) evaluates flood hazards. As mandated by
the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of 1973, FEMA
administers the National Flood Insurance Program (NFIP) to provide subsidized federal flood
insurance to residents of communities where future floodplain development is regulated. FEMA
has developed Flood Insurance Rate Maps (FIRMs) for many areas in the United States so as to
determine the need for and availability of federal flood insurance. FIRMs assist the federal
government in establishing appropriate flood insurance premiums as well as determining
elevations and flood proofing measures. Through the National Flood Insurance Reform Act
(1994) established grant programs for flood mitigation to states and local communities. The
Community Rating System (CRS) was instituted through the 1994 legislation, and implements a
system by which communities that manage and protect natural floodplain functions and erosion
hazards are credited.
The City of La Quinta has held NFIP membership since 1985. Most recent La Quinta FIRM
maps were updated in 2008 and include 12 community panels. Riverside County has
participated in the NFIP since 1980. Property owners within the Planning Area are therefore
eligible for flood insurance, and must purchase insurance prior to obtaining financing to buy,
build or improve structures in a Special Flood Hazard Zone based on FEMA mapping.
FIRM maps include a variety of flood risk information based on historic, meteorological,
hydrologic and hydraulic data, as well as existing development, open space and topographic
conditions within an area. They also incorporate the results of engineering studies conducted by
FEMA, which establish the “base flood” (100-year flood). Areas subject to the 100-year flood
are considered at high risk of inundation. FEMA uses these data to delineate Special Flood
Hazards Zones.
FIRM maps are subject to updates as local conditions, including development, hydrologic
conditions, populations, and other variables may change frequently. All areas of flooding are not
necessarily identified on these maps. FEMA has instituted a Map Modernization Program to
improve the accuracy of FIRM maps. It has set a goal of creating digital maps to delineate 65%
of the continental U.S. and 92% of the population.
Flood Hazard Zones in the Planning Area
Flood Hazard Zone data from corresponding FIRM Community Panels (maps) for the La Quinta
planning area is described below and shown on Exhibit III-10, FEMA Flood Zones and Flood
Control Facilities. As noted above, FIRMs for La Quinta were published in 2008. There have
been two floodplain map revisions for the Planning Area approved by FEMA. As a result, all
developed areas in the City’s corporate limits are outside the 100-year flood zone and do not
require flood insurance.
Zone A: Areas of 100-year flood where no base flood elevations or depths are shown.
Requires flood insurance.
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Zone AO: Areas of 100-year flood with average depths of 1 – 3 feet, generally from sheet
flow on sloping terrain. Requires flood insurance.
Zone X: Areas of 500-year flood with average depth of less than 1 foot or less than one
square mile drainage area; and protected by levees from 100-year flood. No base flood
elevations or depths are shown. Flood insurance available but not required.
Zone D: Areas where flood hazards are undetermined but flooding is possible. Flood
insurance available but not required.
As shown on Exhibit III-10, Zones A or AO in the Planning Area (areas within the 100-year
flood plain) occur within the Coachella Valley Stormwater Channel, the La Quinta Evacuation
Channel, Bear Creek Channel, and detention basins.
Areas within Zone X include portions of the area north and south of the Coachella Valley
Stormwater Channel, the entire Cove area, several areas south and southeast of Lake Cahuilla,
and a portion of the City’s eastern Sphere of Influence.
All-Weather Crossings
There are two primary crossings over the Whitewater River in La Quinta. These are at
Washington Street and Jefferson Street, and provide all-weather access. Other all-weather
crossings include those at Eisenhower Drive and Washington Street at the La Quinta Evacuation
Channel. The City regularly inspects these crossings for scour damage during and after flooding.
The Coachella Branch of the All-American Canal extends through the City and is used for
irrigation purposes, and does not serve as a flood control facility. Canal crossings occur at
Avenue 50 and Avenue 52. Flows through the canal are managed by CVWD, and these
crossings are expected to remain passable during storm events. Nonetheless, periodic inspections
are needed to ensure the safety and reliability of these crossings.
Bridge Scour
Erosion in or along a streambed can damage bridge foundation supports, including piers and
abutments. Scour can occur when upstream flows are forced downstream, eroding the streambed
adjacent to bridge piers, when directional changes in flow result in erosion adjacent to
abutments, or when flows are forced through a narrow opening, increasing velocities and causing
erosion. This phenomenon can occur along highway or railroad bridges, and may take place
either on the floodplain, in the main channel, or in both areas. Scour has resulted in substantial
damage and even collapse of bridges elsewhere in the U.S. The State of California has
implemented a seismic retrofit program that includes inspection of bridge underpinnings. This
program is expected to help reduce potential impacts from scour to bridge foundations.
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Seismically Induced Inundation
Strong ground shaking or other effects resulting from earthquakes can undermine water retention
and storage structures, such as dams, levees, and above-ground water tanks. Resulting flooding
can inundate downslope or adjacent areas. The following describes conditions in the Planning
Area relative to this risk.
Dam Failure
The California Division of Dam Safety is charged with ensuring the structural reliability of large
capacity dams in the state. California State Water Code, Division 3, contains statutes governing
the safety of dams. The Division monitors structural safety of dams higher than 25 feet or with
more than 50 acre-feet of storage capacity. Data from the California Office of Emergency
Services indicates that there are no potential inundation risks from existing dams to the Planning
Area. As previously discussed, although Lake Cahuilla has a storage capacity of more than 50-
acre feet, it does not fall under the jurisdiction of the Division since it is not impounded by a
dam.
Levee Failure and Seiching
There are several major stormwater or irrigation facilities in the Planning Area, including the
Coachella Valley Stormwater Channel, the Coachella Canal and Lake Cahuilla. Levee systems
can be damaged or fail as a result of lateral spreading, which can occur as a result of strong
ground shaking. Lateral spreading is the lateral movement of underlying soils either which have
become liquefied or fractured. Levee damage has occurred in the Imperial Valley and other areas
as a result of liquefaction and lateral spreading. Although the potential inundation area of the
canal or Lake Cahuilla has not been demonstrated through engineering analyses, should either
fail completely, development directly downstream would be impacted.
Unreinforced banks along the Coachella Valley Stormwater Channel in the Planning area are
subject to damage from erosion and strong ground shaking associated with earthquakes. CVWD
periodically maintains these levees. Where the Channel passes through the City between
Jefferson Street and Miles Avenue, it diverges from the natural watercourse. FEMA flood
insurance studies (2008) indicate the potential for a “breakout” along this reach of the river
during a 100-year storm. In the event of such a breakout, a 50% loss of channel capacity could
occur, as well as flooding within a portion of the City’s northeast Sphere-of-Influence and in the
cities of Coachella and Indio.
Open bodies of water, such as canals, above-ground storage tanks, detention basins and
swimming pools are subject to seiching, or water sloshing, during strong ground shaking from
earthquakes. In the Planning Area, the water bodies listed above as well as Lake Cahuilla may be
subject to seiching during earthquakes. Downslope development may be inundated when water
overtops or damages containment structures as a result of seiching. The following further
describes risks associated with inundation from above-ground storage tanks, of which there are
several in the Planning Area.
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Inundation from Above-Ground Storage Tanks
Strong ground shaking can cause structural damage to above-ground water storage tanks,
especially when they are not adequately braced and baffled. Tanks can be lifted off of
foundations by the movement of sloshing water, damaging the shell and roof and causing the
bottom to bulge. Water may also be released when pipes leading to the tank are sheared off. In
California and Mexico, the Landers and Big Bear earthquakes in 1992, the Northridge (1994),
and the Sierra El Mayor-Cucupah in 2010 all resulted in damage to water tanks, with inundation
of homes down gradient also occurring in some cases. As a result of the 1992 and 1994
earthquakes, design standards for steel water tanks were revised. New tank design calls for
flexible joints at connection points so that movement can occur in all directions.
In addition to inundation of structures down slope, potable water supplies may be reduced,
impacting availability of drinking water as well as fire flows and other emergency services
needs. Water supplies may be impacted for 30 days or longer should damage occur to other
critical facilities, such as aqueducts that carry imported water throughout southern California,
wells, pipelines and other facilities associated with the domestic water system in the region and
Planning Area. This emphasizes the need to inspect and retrofit tanks to make certain their
structural reliability in the event of an earthquake, as well as to ensure that water supplies in
reservoirs are kept at or near capacity.
CVWD has ten water reservoirs in the Planning Area, with a total capacity of 44.6 million
gallons. These are of welded steel, constructed current seismic and American Water Works
Association standards. The oldest was constructed in 1982 and the most recent in 2008. Many
although not all of these are situated in elevated locations upslope of existing development.
Federal and State Regulatory Requirements
Federal Clean Water Act
The Clean Water Act (CWA) was enacted in 1972, and was intended to set goals for restoring
and maintaining water quality through reduction of point source pollution by industry and
sewage treatment facilities. Waterbodies containing “waters of the U.S.” fall under the
jurisdiction by the U.S. Army Corps of Engineers, which administers Section 404 of the CWA
for these waters. In the Planning Area, development projects proposing construction activities
within the Coachella Valley Stormwater Channel are subject to compliance with Section 404
regulations and may be required to obtain a 404 permit. Such projects may also be subject to
compliance with Section 401 of the CWA, which is administered in the Planning Area by the
State Regional Water Quality Control Board (RWQCB), Colorado River Basin Region. These
issues are further discussed in Section III-D, Biological Resources.
National Pollutant Discharge Elimination System (NPDES)
In 1987 the CWA was amended to require states to reduce runoff into waterways. These
requirements are implemented by the National Pollutant Discharge Elimination System (NPDES)
program. NPDES mandates the adoption of stormwater management plans and programs to
reduce runoff of pollutants in storm water systems into waters of the United States.
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The RWQCB implements the NPDES on a statewide basis. The Board issues NPDES permits to
local jurisdictions., which are held as joint permits among multiple jurisdictions in some regions,
including Riverside County. The NPDES program in which La Quinta participates also includes
Riverside County Flood Control & Water Conservation District, CVWD, Riverside County, and
all Riverside County cities except for Blythe.
California Fish and Game Code
When surface disturbance and/or land development has potential to alter the bed and banks of
streambed areas in the Planning Area, a site-specific Streambed Alteration Agreement (SAA)
may be required, pursuant to Section 1602 of the California Fish and Game code. This is also
further discussed in Section III-D, Biological Resources.
2. Project Impacts
Implementation of the proposed General Plan will facilitate urban development that will result in
an increase in impervious surfaces, such as roadways, sidewalks, and parking lots. Water that
would have been re-absorbed into the ground will runoff to downstream areas. The City and
CVWD have worked pro-actively to protect developed areas in the City from flood hazards.
Currently, with the exception of some golf courses that serve dual purpose as stormwater
retention areas, no developed areas in the City are within a FEMA Special Flood Hazard Zone.
Therefore, property owners in the City are not required to purchase flood insurance. However,
localized flooding can still occur in some areas, primarily where storm drains are not adequately
sized or temporary retention facilities are not present. Further, it is difficult to predict conditions
that may create localized flooding. This may occur when storm flows carrying debris clog catch
basins or inlets, or in the event that levees are compromised or overtopped. In such instances,
residents may need to evacuate, and the City should prepare evacuation plans for this potential.
Further, land use planning must consider the location of critical facilities, including schools, or
facilities where hazardous materials may be used, stored or generated on-site.
Substantial areas in the City are zoned by FEMA as having potential to flood during a storm
stronger than the 100-year event, or subject to shallow flooding during a 100-year storm.
Therefore, property owners outside Special Flood Hazard Areas are encouraged by FEMA to
purchase flood insurance. It should also be noted that flood zone mapping within areas subject to
moderate flood hazard is incomplete.
Given that the region is seismically active, the Planning Area may be susceptible to flooding if
water reservoirs or water retention structures or facilities should fail. The Planning area is not
located downstream of any State-regulated dam, or within a dam inundation area as identified by
the Division of Dam Safety. The City and Sphere are traversed by the Coachella Valley
Stormwater Channel, which is protected in many areas by a system of sand levees. These have
potential for seismic settlement or liquefaction, especially in the event of strong ground shaking
or long periods of rain. Earthquakes can also create seiche conditions within open waterbodies,
such as Lake Cahuilla, canals, reservoirs and catch basins. The sloshing movement of water
within containment structures can damage them, and water may overtop, potentially inundating
areas down slope.
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There is potential for the regional domestic water system to be damaged and potentially unusable
for a period of greater than 30 days in the event of a large-scale earthquake. Therefore, water
storage tanks should be maintained as full as possible, and their integrity ensured through
periodic inspections and repair as needed. Coachella Valley Water District has indicated that the
water storage tanks in the area are built to current seismic standards.
The General Plan includes goals, policies and programs to ensure that future development is
reviewed for potential risk of flood hazards and to require that it include on-site stormwater
retention facilities. It also encourages the retention of natural watercourses wherever feasible,
and/or providing for compatible open space and recreational uses within areas subject to
flooding.
Flood Protection Measures for Property Owners
Future development within the Planning Area may be subject to localized flooding risks,
especially where flood hazard mapping is incomplete. The General Plan includes a range of
policies intended to reduce these risks, including enforcement of existing County and City
ordinances that address hazards and floodplain regulations; updating hazards mapping regularly;
and public education about flood hazards. Project developers and property owners are
encouraged to implement site design and other means to avoid or reduce risks to personal
property, including structures. These are further addressed under Mitigation, below.
3. Mitigation Measures
1. The City shall continue to encourage project developers to use engineering and design
techniques that minimize the potential for the occurrence of inundation, including seismically
induced inundation.
2. The City shall continue to coordinate with the Coachella Valley Water District to monitor the
structural safety of the levees around Lake Cahuilla and along the Coachella Valley
Stormwater Channel within the City.
3. The City shall continue to coordinate with the Coachella Valley Water District to monitor the
structural integrity of above-ground water tanks and reservoirs, and where needed, to
implement bracing techniques to minimize potential structural damage and/or failure.
4. The City shall coordinate and cooperate with the Coachella Valley Water District in the filing
of FEMA applications to amend the Flood Insurance Rate Maps, as necessary.
5. The City shall continue to coordinate with CVWD to assure the adequate inspection of bridge
crossings for scour damage during and after significant flooding events, and shall coordinate
with the appropriate state agencies to participate in the state’s bridge scour inventory and
evaluation program.
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6. New development shall continue to be required to construct on-site retention/detention basins
and other necessary stormwater management facilities that are capable of managing 100-year
stormwater flows.
7. New development immediately adjacent to regional flood control facilities shall continue to
have the option of discharging 100-year stormwater flows directly into the stormwater
channel, subject to approval by the appropriate agencies.
8. The City shall refer developers of new projects within areas historically used for agriculture
to the Coachella Valley Water District to identify the location of subsurface agricultural
drains.
9. The City shall routinely update its Emergency Operations Plan to address flooding hazards
within the City.
Mitigation Monitoring and Reporting
A. The City Engineer shall report to the City Council on a regular basis to ensure that local
drainage plans are updated and drainage control projects are implemented. Reports shall
include information regarding the status of regional drainage facilities affecting flood control
in the City.
Responsible Parties: City Engineer, City Council, Coachella Valley Water District
B. Prior to issuance of building permits, the City shall review and approve project-specific
hydrology and hydraulic studies, Water Quality Management Plans and mitigation plans for
development proposals, and shall ensure they are adequate with regard to stormwater
management, on-site retention, best management practices and pollution control.
Responsible Parties: City Engineer, Project Developer
Land Use and Planning I.
Introduction and Background
This section of the EIR addresses potential impacts and opportunities associated with land use
and planning from implementation of the La Quinta General Plan. The existing conditions,
development and land use designations within the City and Sphere of Influence are described,
and the potential impacts relating to changes in the land use from the previously approved
General Plan are assessed.
Thresholds of Significance/Criteria for Determining Significance
The following thresholds or criteria are derived from Appendix G of the CEQA Guidelines, and
are used to determine the level of potential effect. The significant criteria are at least in part
based on the recommendations set forth in Section 15064 of the CEQA Guidelines. For analysis
purposes build out of the La Quinta General Plan would have a significant effect on land use and
planning if it is determined that the project will:
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a) Physically divide an established community;
b) Conflict with any applicable land use plan, policy, or regulation of an agency with
jurisdiction over the project (including, but not limited to the general plan, specific
plan, local coastal program, or zoning ordinance) adopted for the purpose of avoiding
or mitigating an environmental effect; or
c) Conflict with any applicable habitat conservation plan or natural community
conservation plan.
1. Existing Conditions
The City of La Quinta was first established as a rural and predominantly agricultural community.
Today, the City of La Quinta consists of an urban core with residential, resort, and commercial
development surrounded by hillside open space that offers recreational opportunities and land
preservation. Lands within city limits have mostly been developed with a few undeveloped infill
lots located throughout the urban area. The Sphere of Influence, east of the city limits contains
undeveloped lands that represent the greatest growth and land conversion potential.
The existing land uses in the Planning Area are governed by the 2002 Comprehensive General
Plan, which includes La Quinta City limits, as currently amended, two Sphere of Influence areas,
one north and one east of the City limits, and two Planning Areas, both of which are east of the
City limits beyond the Sphere of Influence. Planning Area 1 is west of Jackson Street and
Planning area 2 is to the east.
Surrounding Land Use
The City of La Quinta is located in the central portion of the Coachella Valley within the
southern region of Riverside County. The Coachella Valley contains several cities and a few
unincorporated communities of Riverside County. The Coachella Valley is located in between
the Santa Rosa and San Jacinto Mountain Ranges on the west and the Little San Bernardino
Mountains on the East.
There are a number of jurisdictions surrounding the City of La Quinta including Palm Desert,
Indian Wells, Bermuda Dunes, Indio. North of La Quinta are the cities of Indio and Coachella,
and Riverside County. The cities of Rancho Mirage, Cathedral City and Palm Springs are up-
Valley from La Quinta and consist of similar land use designations, while the communities of
Thermal and Mecca are located down-Valley and tend to include land uses associated with
agricultural production and light industry as well as residential land uses. Although the overall
region can be described as rural, with large swaths of open desert, the established communities
within the Coachella Valley constitute an urbanized area that include a range of residential,
commercial, industrial, public facilities and open space land uses. Lands immediately east of the
City are within unincorporated Riverside County and include the City’s Sphere of Influence and
Planning Areas 1 and 2. For the most part, these lands are largely vacant, undeveloped and
sparsely populated.
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Land uses east and south of the City Boundary and Planning Areas are designated for
agricultural purposes, residential uses, and open space and are within Riverside County. These
include Native American Tribal lands.
Lands to the west and south of the City Boundary are also within unincorporated Riverside
County and include mountain slopes of the Santa Rosa Mountains that are designated for open
space preservation as public lands.
Existing City Limits Land Use
Residential development in the City of La Quinta is consistent with residential development
patterns observed throughout the Coachella Valley. La Quinta consists primarily of low density
and resort residential development with scattered medium and high-density development
occurring in certain areas of the City. Residential development represents approximately 40% of
the City land uses with low density residential accounting for 76%, medium density 17% and
high density residential making up only 1% of the total designated land use for residential. Low-
density residential land uses range from 0 to 4 dwelling unit per gross acre. Medium and high-
density land uses range from 0 to 20 dwelling units per gross acre.
Commercial land uses are established throughout the City and account for approximately 6% of
the designated land uses. Commercial land uses generally occur at the intersection of two major
travel corridors. Highway 111, which transects the northern portion of the City, represents a
dense commercial corridor. The community center contains an established Village Commercial
area, which is located just north of the Cove neighborhood. The Tourist Commercial land use
designation serves to provide retail services in conjunction with the major tourist attractions such
as golf, dining, and resort facilities.
The City’s Open Space land use designation largely consists of golf course development in the
urban core and land use preservation in the surrounding hillsides. The City has integrated public
and private open space areas, including parks and recreational facilities. Recreational open
spaces include golf courses, open space associated with the Whitewater River and the La Quinta
Channel, and recreational trails and opportunities associated with the Santa Rosa and San Jacinto
Mountains.
The Whitewater River, an ephemeral stream that serves as the primary drainage corridor for the
Coachella Valley, runs generally west to east through the northern portion of the City. The La
Quinta Channel is another major drainage feature that conveys runoff flows from the mountains
surrounding the cove area from the southwest portion of the City diagonally through the central
portion of the City in an easterly direction, where it connect with the Whitewater River in the
northeast portion of the City. Various golf courses are developed in conjunction with these
ephemeral waterways.
Institutional development and public facilities, such as schools, libraries, fire and police stations
are characterized as major community facilities and are located throughout the City of La Quinta.
The City’s Civic Center complex is centrally located on Calle Tampico and contains government
and community facilities, the senior center, a library, and park land. The Civic Center and
associated facilities are situated in close proximity to the downtown Village Commercial area.
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Table III-16
Existing Land Use Designations within City Limits
2002 General Plan Designations Developed Undeveloped Total
VLDR Very Low Density up to 2 du/ac 261 198.2 459.2
LDR Low Density up to 4 du/ac 3,202.5 3,096.9 6,299.4
MDR Medium Density up to 8 du/ac 1,063.9 324.2 1,388.1
MHDR Medium-High Density up to 12 du/ac 14.5 69 83.4
HDR High Density up to 16 du/ac 0.6 86.7 87.3
Total Residential Acreage 4,542.4 3,775.0 8,317.5
M/RC Mixed Commercial 87.9 309 397
CC Community Commercial 24.2 93.7 117.9
NC Neighborhood Commercial 61.8 50.8 112.5
CP Commercial Park 0.0 64 64
O Office 0.0 39.9 39.9
TC Tourist Commercial 206.2 145.3 351.5
VC Village Commercial 64.4 68.8 133.2
Total Commercial Acreage 444.5 771.5 1,216.0
I Industrial 0.0 0.0 0.0
MC Major Community Facilities 178.3 13.1 191.3
P Park Facilities 601.3 128 729.3
OS Open Space 1,246.2 4,258.7 5,505.00
G Golf Course Open Space 3,125.3 986.7 4,111.90
W Watercourse/Flood Control 468.9 132.8 601.7
Total Other Acreage 5,619.90 5,519.3 11,139.2
Total Acreage 10,606.7 10,065.8 20,672.6
The general land use pattern described above reflects 2002 General Plan designations based on
current land use development throughout the City. The existing land uses within the City’s
Sphere of Influence are described below.
Existing Land Uses in the Sphere of Influence
The City of La Quinta has included adjacent lands to the north and east of the existing City
boundary as part of the Sphere of Influence. North and east of the existing City boundary are
small areas within the Sphere of Influence that currently contain vacant lands and limited
existing residential development, all land uses in these areas are currently designated as low
density residential. The larger Sphere of Influence located south of Avenue 52 also consists of
vacant parcels and limited residential development, and is designated as low density residential
with scattered medium density residential, open space golf course development, and a small area
designated for commercial land use.
The City has studied the land use pattern in the Sphere, and has considered several potential
annexation proposals in the past. These proposals included analyses relating to the availability
and cost of the provision of services in the Sphere. These analyses found that in the eastern
Sphere in particular, lands have been encumbered by the County as collateral for a regional bond
issue. As a result, there will be no property tax generation to the City from these lands for a
number of years. The fiscal analysis concluded that the annexation of property in the Sphere
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would have a negative fiscal impact on the City. At the time of the analysis, a per unit mitigation
fee was considered, but the proposed annexations did not proceed, and the mitigation program
was not implemented. The costs associated with annexation to the City, however, still exists, and
will remain an issue as annexation proposals occur in the future.
Table III-17
2002 Land Use Designations within Sphere of Influence
2002 General Plan Land Use Designations Developed Undeveloped Total
VLDR Very Low Density up to 2 du/ac 0.0 0.0 0.0
LDR Low Density up to 4 du/ac 549.5 286.5 836
MDR Medium Density up to 8 du/ac 171.7 66.2 237.9
MHDR Medium-High Density up to 12 du/ac 0.0 0.0 0.0
HDR High Density up to 16 du/ac 0.0 0.0 0.0
Total Residential Acreage 721.3 352.7 1,073.90
M/RC Mixed Commercial 4.5 0.0 4.5
CC Community Commercial 0.0 0.0 0.0
NC Neighborhood Commercial 0.0 0.0 0.0
CP Commercial Park 0.0 0.0 0.0
O Office 0.0 0.0 0.0
TC Tourist Commercial 0.0 0.0 0.0
VC Village Commercial 0.0 0.0 0.0
Total Commercial Acreage 4.5 0.0 4.5
I Industrial 0.0 0.0 0.0
MC Major Community Facilities 2 0.0 2
P Park Facilities 0.0 0.0 0.0
OS Open Space 0.0 0.0 0.0
G Golf Course Open Space 229.8 88 317.8
W Watercourse/Flood Control 0.0 0.0 0.0
Total Other Acreage 231.8 88 319.8
Total Acreage 957.6 440.7 1,398.3
Total Existing Land Uses in the Planning Areas
In addition to the Sphere of Influence, there are also two separate Planning Areas that were
considered as part of City’s planning efforts under the 2002 General Plan. Planning Area 1 is
located east of Monroe Street and Planning Area 2 is located east of Jackson Street. Planning
Areas 1 and 2, east of the existing city boundary, are currently governed by Riverside County.
The existing land uses in Planning Area 1 are comprised of vacant parcels, agricultural uses, and
very low density residential. Planning Area 2 contains vacant parcels, polo fields, agricultural
uses, and very low-density residential land uses. Lands within Planning Area 1 and 2 are
designated for a variety of land uses including mixed/regional commercial, office, and industrial
land uses. Existing land use designation for Planning Areas 1 and 2 can be seen in the following
Table.
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Table III-18
2002 Land Use Designations within Planning Areas
P1 P2
2002 LU Designations Developed UnDev. Total Developed UnDev Total
VLDR up to 2 du/ac 0.0 0.0 0.0 64.4 0.0 64.4
LDR up to 4 du/ac 2,447.20 551.2 2,998.4 5,213.6 846.8 6,060.3
MDR up to 8 du/ac 58.2 62.7 120.8 358.8 100.5 459.3
MHDR up to 12 du/ac 259.7 78.9 338.6 0.0 0.0 0.0
HDR up to 16 du/ac 0.0 0.0 0.0 93.7 71.4 165.1
Total Residential Acreage 2,765.0 692.7 3,457.8 5,730.4 1,018.70 6,749.1
M/RC Mixed Commercial 0.0 0.0 0.0 69.3 14.3 83.6
CC Community Commercial 7.2 2.9 10 219.7 33.1 252.8
NC Nhhd Commercial 47.2 2.5 49.7 0.0 0.0 0.0
CP Commercial Park 0.0 0.0 0.0 0.0 0.0 0.0
O Office 0.0 0.0 0.0 43.7 0.0 43.7
TC Tourist Commercial 0.0 0.0 0.0 0.0 0.0 0.0
VC Village Commercial 0.0 0.0 0.0 0.0 0.0 0.0
Total Commercial Acreage 54.4 5.3 59.7 332.7 47.3 380.1
I Industrial 0.0 0.0 0.0 319.7 60.6 380.3
MC Facilities 29 0.0 29 0.0 36.7 36.7
P Park Facilities 0.0 0.0 0.0 0.0 0.0 0.0
OS Open Space 0.0 44.5 44.5 496.2 149.4 645.6
G Golf Course OS 198.8 59.8 258.6 0.0 0.0 0.0
W Water/Flood Control 0.0 0.0 0.0 0.0 0.0 0.0
Total Other Acreage 227.8 104.3 332.1 815.9 246.6 1,062.5
Total Acreage 3,047.3 802.3 3,849.5 6,879.0 1,312.70 8,191.7
Summary of Existing Land Uses
The 2002 General Plan contains a total of 34,112 acres within City limits, the Sphere of
Influence and Planning Areas 1 and 2. Land use designations include a variety of residential,
commercial, open space, and public facility development. Overall, approximately 75% of the
designated land uses are developed and 25% remain undeveloped.
The following table shows the developed and undeveloped acreage for each land use type and
the total acreage assigned through the entire Planning Area.
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Table III-19
Existing Land Use Summary
2002 General Plan Land Use Designations Developed Undeveloped Grand Total
VLDR Very Low Density up to 2 du/ac 325.4 198.2 523.6
LDR Low Density up to 4 du/ac 11,412.8 4,781.4 16,194.1
MDR Medium Density up to 8 du/ac 1,652.6 553.6 2,206.10
MHDR Medium-High Density up to 12 du/ac 274.2 147.9 422
HDR High Density up to 16 du/ac 94.3 158.1 252.4
Total Residential Acreage 13,759.1 5,839.1 19,598.2
M/RC Mixed Commercial 161.7 323.3 485
CC Community Commercial 251.1 129.7 380.7
NC Neighborhood Commercial 109.0 53.3 162.2
CP Commercial Park 0.0 64.0 64
O Office 43.7 39.9 83.6
TC Tourist Commercial 206.2 145.3 351.5
VC Village Commercial 64.4 68.8 133.2
Total Commercial Acreage 836.1 824.1 1,660.2
I Industrial 319.7 60.6 380.3
MC Major Community Facilities 209.3 49.8 259
P Park Facilities 601.3 128.0 729.3
OS Open Space 1,742.4 4,452.6 6,195.1
G Golf Course Open Space 3,553.9 1,134.5 4,688.3
W Watercourse/Flood Control 468.9 132.8 601.7
Total Other Acreage 6,895.4 5,958.2 12,853.6
Total Acreage 21,490.6 12,621.5 34,112.0
Regional Land Use Planning
The Coachella Valley Association of Government (CVAG) is the Valley-wide planning authority
and the Southern California Association of Governments (SCAG) is the regional planning
authority for the City of La Quinta. The SCAG Regional Comprehensive Plan48 was adopted in
2008 and proposed policies, goals and programs that are intended to address regional issues such
as transportation, housing, air quality, water resources. Land use planning can be effective in
addressing these concerns by proving continuity and interconnectivity through a region, gaining
efficiencies through mixed use, and preserving open space and water course resources.
2. Project Impacts
Although several land use changes are proposed under the General Plan Update, the Preferred
Alternative does not significantly change the overall development pattern for the La Quinta
Planning Area. Planning Areas outside of City limits have been reduced to the Sphere of
Influence and no longer call out separate Planning Areas 1 and 2, which were part of the 2002
General Plan. Under the proposed General Plan Update similar land use designations have been
consolidated to simplify land use descriptions.
48 “Final 2008 Regional Comprehensive Plan,” prepared by the Southern California Association of Governments,
2008.
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Some land use designations under the 2002 General Plan have been grouped together and
consolidated into a single land use designation under the proposed update. For example, Very
Low and Low Density Residential land use designations have been combined under the Low
Density land use designation as set forth under the proposed land use plan. Similarly, the
Medium Density, Medium-High Density, and High Density Residential land uses under the 2002
General Plan have been consolidated under the new land use designation, Medium/High Density
Residential. Several of the commercial and retail land use designations that were individually
defined under the 2002 General Plan are reclassified into one of the three new commercial land
use designations: General Commercial; Tourist Commercial; and Village Commercial.
Proposed Land Uses within City Limits
The following describes the proposed land use designation set forth under the General Plan
Update for those lands within the City limits of La Quinta. The calculations of dwelling units and
square footage were based on the following assumptions:
For residential development, all lands are assumed to develop at 75% of the maximum
density allowed in that designation.
For commercial and industrial development, all lands are assumed to develop with 22%
building coverage, which is representative of single-story commercial development in the
City, and assumes surface parking and landscaping requirements consistent with current
standards.
The proposed General Plan includes 7,255.7 acres of residentially designated lands within the
City limits, and includes two land use designations for residential; Low Density Residential
(LDR) and Medium/High Density Residential (M/HDR). The General Plan Update has the
potential to result in a total of 25,585 LDR units and 6,017 M/HDR units in the City limits,
which would be an increase of 8,114 residential units, compared to the existing residential
development within City limits. The Low Density Residential Land Use Designation allows for 0
to 4 single-family residential units per acre and applies to existing and vacant lots, subdivisions,
country club communities, and the clustering of condominiums or town homes with common
area amenities. LDR also allows for equestrian uses on lots of 1/2 acre or larger. The M/HDR
Land Use designation allows for 0 to 16 attached or detached dwelling units on smaller lots, and
provides for multi-family units including condominiums, town homes and apartments.
Commercial land use designations have been grouped into one of the following categories:
General Commercial; Tourist Commercial; or Village Commercial. The total commercial
acreage under the General Plan Update within City limits is 1,005.1 and consists of 669.3 acres
that have been developed and 335.8 acres that are currently vacant. These acreages correspond to
6,414,036 square feet of existing commercial development and the potential for the development
of an additional 3,218,039 square feet at build out. Thus, the total commercial square footage in
the City limits at build out will be 9,632,074 square feet.
The Major Community Facilities land use designation, including schools, government buildings,
and service facilities, makes up 446.5 acres consisting of 252.7 developed acres and 193.8 acres
that are currently vacant. The land use designations assigned for Open Space include Natural and
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Recreational lands. Natural Open Space consists of 6,933.3 acres that are intended to be
preserved in perpetuity, including lands within the Santa Rosa and San Jacinto Mountains
National Monument, as well as public lands within the Santa Rosa Wilderness. It should be
mentioned that Natural Open Space lands within the said Monument and Wilderness areas are
federally managed public lands that are owned and regulated by the Bureau of Land
Management (BLM). Open Space Recreation consists of 4,392.2 acres that have been developed
and an additional 867 acres that are currently vacant but are designated for development as
recreational open space, golf courses, and watercourses. Street rights-of-way consist of 1,764.6
acres that have been developed as roadways and an additional 191.1 acres that have been
designated but remain undeveloped. As proposed, there are no designated industrial lands within
the City limits. All lands proposed for the industrial and light manufacturing land use
designations are located within the Sphere of Influence.
The Table below shows the proposed land use designations within City limits, along with the
developed and vacant acreages and existing and proposed unit development associated with
residential and commercial land uses. Based on the total developed and undeveloped acreage,
land within the city limits is approximately 64 percent built out.
Table III-20
Proposed Land Use for City Limits
Land Use Designation
Developed
(Acres)
Vacant
(Acres)
Total
(Acres)
Existing
Units
Potential
Units
Total
Units
Low Density Residential 4,006.0 1,583.7 5,589.7 20,834 4,751 25,585
High Density Residential 1,292.4 373.6 1,666.0 2,655 3,362 6,017
Subtotal 5,298.4 1,957.3 7,255.7 23,489 8,114 31,603
Existing SF Potential SF Total SF
General Commercial 385.6 184.0 569.6 3,695,282 1,763,309 5,458,591
Tourist Commercial 206.6 138.9 345.5 1,979,889 1,331,106 3,310,996
Village Commercial 77.1 12.9 90.0 738,865 123,623 862,488
Subtotal 669.3 335.8 1,005.1 6,414,036 3,218,039 9,632,074
MC Facilities 252.7 193.8 446.5
Open Space Natural 2,171.6 4,761.7 6,933.3
Open Space Recreation 4,392.2 867.0 5,259.2
Street Rights-of-Way 1,764.6 191.1 1,955.7
Grand Total 14,548.8 8,306.7 22,855.5
Land use designation as set forth under the General Plan Update are consistent with the existing
development pattern and land uses. Land use designation and development as proposed are not
expected to divide residents, businesses, or existing communities. Rather, the General Plan
Update assures continuity between existing development and planned future development by
refining land use designations and assigning land uses to vacant lands within City limits. The
proposed Land Use plan is also consistent with the Coachella Valley Multiple Species Habitat
Conservation Plan (CVMSHCP), which sets forth the regional conservation planning efforts
including the City of La Quinta. Therefore, as proposed the General Plan Update would not
conflict with the established CVMSHCP and impacts to habitat conservation planning or natural
community conservation planning will be less than significant.
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Sphere of Influence
The Sphere of Influence represents the greatest potential for land use conversion, since only
11.5% of the area is currently developed. Under the General Plan Update, the Sphere of
Influence is primarily designated for low-density residential development, consisting of 7,378
acres out of the total 8,101.4-acre area. The remaining land use designations include 24.6 acres
of medium/high density residential, 285.1 acres of general commercial, 63.8 acres of
industrial/light manufacturing, 29.8 acres of major community facilities, and 319.9 acres for
street rights-of-way. Although the proposed land use development pattern is consistent with the
2002 General Plan, implementation would result in a substantial change to the existing character
within the Sphere of Influence.
The Sphere of Influence is currently governed by Riverside County and lands within the Sphere,
east of the current City limit, have been conceptualized for development as the Vista Santa Rosa
(VSR) Community. A VSR Land Use Concept Plan was approved by the Riverside County
Board of Supervisors on June 17, 2008. The approved Land Use Plan with acreage and potential
unit build out is shown in Table III-21 below. The following acreage is limited to that portion of
the Vista Santa Rosa Land Use Plan that overlaps with the Sphere of Influence as defined by the
proposed General Plan Update for La Quinta.
Table III-21
Riverside County Vista Santa Rosa Land Use
Vista Santa Rosa Developed Vacant Total
Existing
Units
Potential
Units
Total
Units
Estate Residential 136.9 1,160.3 1,297.2 580 580
Very Low Residential 37.9 887.5 925.4 888 888
Low Residential 235.8 4,003.5 4,239.3 786 6,005 6,791
Medium Residential 73.4 128.5 201.9 482 482
Medium High Residential 2.5 249.6 252.1 1,498 1,498
High Residential 23.6 135.5 159.0 1,422 1,422
Residential Subtotal 510.0 6,565.0 7,075.0 786 10,875 11,661
Existing
SF
Potential
SF Total SF
Commercial Retail 1.2 16.6 17.8 11,928 158,985 170,913
Commercial Tourist 0.0 119.9 119.9 - 1,149,107 1,149,107
Business Park 34.0 247.3 281.3 325,445 2,370,213 2,695,658
Community Center 7.5 112.2 119.6 71,617 1,074,468 1,146,086
Retail Subtotal 42.7 495.9 538.6 408,991 4,752,774 5,161,764
Public Facilities 28.2 40.2 68.4
Street Rights of Way 313.9 0.0 313.9
TOTAL 894.7 7,101.1 7,995.9
Includes that portion of the VSR Land Use Concept Plan that falls within the proposed Sphere of
Influence for La Quinta.
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Under the Riverside County land use designations, the Sphere of Influence area north of city
limits is designated as medium density residential with 2 to 5 units per acres. Currently, this area
only contains an estimated 15 homes. Under the Riverside County Land Use designation, this
area could build out to contain as many as 285 dwelling units. The following Table shows the
Riverside County Land Use designation for the area north of City limits within the Sphere of
Influence.
Table III-22
Riverside County Land Use North Sphere
Land Use Developed Vacant Total
Existing
Units
Potential
Units
Total
Units
Medium Density Residential 27.5 71.9 99.4 15 270 285
Street Rights of Way 6.2 0.0 6.2 0 0 0
Total 33.7 71.9 105.6 15 270 285
The following summarizes the build out potential under the current Riverside County land use
designations.
Table III-23
Riverside County Land Use Sphere Summary
Land Use Developed Vacant Total
Existing
Units/Sq.Ft.
Potential
Units/ Sq.Ft
Total Units/
Sq.Ft
Residential 537.5 6,636.9 7,174.4 801 11,145 11,946
Retail 42.7 495.9 538.6 408,991 4,752,774 5,161,764
Public Facilities 28.2 40.2 68.4
Street Rights of
Way 313.9 - 313.9
Total 928.4 7,173.0 8,101.5
The La Quinta General Plan Update proposes different land use intensities compared to those set
forth under the Riverside County Land Use Plan. As proposed, the La Quinta General Plan
Update would result in the development of up to 21,270 residential units, 2.7 million square feet
of commercial, and 611,408 square feet of industrial land uses within the Sphere of Influence
east of City limits.
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Table III-24
General Plan Update East Sphere Land Use
Vista Santa Rosa Developed Vacant Total
Existing
Units
Potential
Units
Total
Units
Low Residential 524.0 6,754.84 7,278.82 786 20,265 21,051
Medium High Residential 0.24 24.36 24.6 0.0 219 219
Residential SubTotal 524.2 6,779.2 7,303.4 786 20,484 21,270
Sq. Ft. Sq. Ft. Total SF
General Commercial 28.57 256.57 285.14 273,792 2,458,762
2,732,554
Industrial/Lgt. Mfg. 0.0 63.8 63.8 0.0 611,408 611,408
MC Facilities 28.17 1.61 29.78
Street Rights-of-Way 313.74 313.7
TOTAL 894.7 7,101.2 7,995.9
Includes that portion of the Sphere that is located east of the city limits.
As proposed under the General Plan Update, that portion of the Sphere of Influence north of the
existing city limits would be developed as low density residential at 0 to 4 units to the acre,
which is slightly less (53 units) than that proposed under the County’s land use designation.
Table III-25
General Plan Update Land Use North Sphere
Land Use Developed Vacant Total
Existing
Units
Potential
Units
Total
Units
Low Density Residential 27.5 71.9 99.4 15 216 231
Street Right of Way 6.19 0 6.19
Total 33.7 71.9 105.6 15 216 231
Only 928 acres of the Sphere of Influence are currently developed, with the remaining acreage,
89% of the total area, vacant. The following table details the existing and proposed land use
designations within the Sphere of Influence, including the total number of existing dwelling units
and square footage associated with commercial and industrial land uses as set forth under the
General Plan Update. The proposed land use plan has the potential to result in the development
of 21,281 low-density residential units, 219 high-density residential units, 2,732,557 square feet
of commercial, and 611,408 square feet of industrial and light manufacturing within the entire
Sphere of Influence.
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Table III-26
General Plan Update Land Use Sphere Summary
Land Use Developed Vacant Total
Existing
Units/Sq.Ft.
Potential
Units/ Sq.Ft
Total
Units/ Sq.Ft
LD Residential 551.5 6,826.6 7,378.1 801 20,480 21,281
M/HD Residential 0.2 24.4 24.6 -- 219 219
General Commercial 28.6 256.6 285.1 273,760 2,458,797 2,732,557
Industrial/Lgt. Mfg. 0.0 63.8 63.8 0.0 611,408 611,408
MC Facilities 28.17 1.61 29.8
Street Right of Way 319.93 0.0 319.9
Total 928.4 7,173.0 8,101.4
Development within the Sphere of Influence is not expected to occur in the short term. There is
limited infrastructure currently available, and existing economic conditions do not favor
expansion at this time. However, in the mid- to long-term, the land use designations assigned
under the General Plan Update are expected to be developed accordingly.
The proposed land use plan represents an intensification of land use development compared to
the existing conditions. When compared to build out conditions as defined by the Riverside
County Land Use designations, the proposed General Plan Update would result in a substantial
increase in the development of residential land uses, but a decrease in commercial development.
Land uses proposed under the General Plan Update will not divide or displace existing homes or
businesses. However, the proposed land use designations would result in an intensification of
residential densities, which has the potential to substantially change the existing character within
the Sphere of Influence. The character of the existing development within the Sphere of
Influence has the potential to be transformed from a low-density rural community to an urban
low-density residential community through intensification of land use development.
The General Plan includes policies and programs designed to provide buffers between residential
and commercial or industrial land uses, and the City’s Municipal Code includes standards that
require any non-residential development to appropriately protect surrounding residential
development. Nonetheless, the intensification of the proposed residential densities within the
Sphere of Influence as proposed under the General Plan Update have to potential to conflict with
the County’s existing Vista Santa Rosa Land Use Concept Plan, which may result in significant
impacts to residential land uses. However, the General Plan Update requires the preparation of a
master plan prior to annexation of this area, which reflects the character of Vista Santa Rosa. The
development of this master plan is required to involve the community, and reflect the
neighborhood’s character.
As described above, the City has found that annexation of lands in the eastern Sphere would
have a negative fiscal impact on the City. Although past annexation requests were not completed,
conditions have not changed since this analysis was undertaken, and it would be expected that
annexation proposals in the future would have a similarly negative fiscal impact. The General
Plan includes policies that require both the preparation of fiscal impact analyses for annexation
proposals, and a Development Agreement in association with annexation. The Development
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Agreement would establish the parameters for development, and would include mitigation fee
payments for projects that are fiscally negative for the City. These Development Agreements
would eliminate the potential fiscal impacts to the City.
The imposition of these policies on future annexation proposals will assure that potential impacts
associated with land use planning are less than significant.
Summary of Impacts
Changes in land use designations as proposed in this General Plan Update do not significantly
differ from the 2002 General Plan. Rather, land use designations have been re-characterized and
consolidated to provide for more concise land use designation descriptions and a simplified land
use map. Each land use designation as set forth in the General Plan Update is summarized below:
Low Density Residential, (LDR) (0-4 dwelling unit per gross acres): Allows for larger lot single-
family residential development, subdivisions, country club communities, and the clustering of
condominiums or town homes with common area amenities. Equestrian uses are allowed on lots
of one acre or larger. This is the most common land use designation in the City.
Medium/High Density Residential, (M/HDR) (0-16 dwelling units per gross acres): Allows single
family attached and detached units on smaller lots – particularly in the Cove. Multi-family units
including condominiums, town homes and apartments with common area amenities are also
appropriate in this designation.
General Commercial (GC): Allows larger community scale shopping centers on parcels 20 acres
or larger in size along major arterials. Uses include a range of commercial activities, all types of
retail sales, grocery stores, automobile sales, professional and medical office buildings,
restaurants and similar activities. Also allows for Mixed Use developments, with combined
residential and retail uses.
Tourist Commercial (TC): Allows resort hotels, tourist commercial retail developments,
recreational uses, restaurants and timeshare or fractional ownership. Allows for resort mixed use
activities, such as single and multi-family residential units, golf courses, timeshares, RV parks
and resorts with the preparation of a Specific Plan.
Village Commercial (VC): Allows retail, professional office, hotels and pedestrian oriented retail
development. This designation also allows for Mixed Use developments, which combine,
residential and retail uses in one project.
Industrial/Light Manufacturing (I/LM): Allows for non-polluting industrial uses operating
entirely in an enclosed structure. Outdoor storage is permitted if fully screened from view. Uses
include clean manufacturing, airport related uses, warehousing/distribution, and mini-storage.
Major Community Facilities: This designation is applied to existing or planned municipal,
educational, non-profit and/or religious organizations, or public service facilities. Typical land
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uses within this designation include civic centers and other governmental offices, public parking
lots, fire stations, schools, facilities for non-profit organizations and utility substations.
Open Space-Natural (OS-N): This designation includes natural open space areas including the
surrounding Santa Rosa Mountains and hillsides, nature preserves and conservation areas, trails,
drainage channels, and watercourses/flood control.
Open Space-Recreational (OS-R): This designation includes regional and local parks, golf
courses, golf-course resorts, and watercourses/flood control.
General Plan Planning Area
As proposed, the General Plan Update includes 30,957 acres consisting of 22,856 and 8,101
acres within City limits and the Sphere of Influence, respectively. Implementation of the
proposed General Plan has the potential to result in a total of 53,103 dwelling units on 14,658
acres of residentially designated lands, 12,364,631 square feet of commercial development on
1,290 acres, and 611,408 square feet of industrial/light manufacturing on 63.8 acres.
Implementation of the General Plan has the potential to result in the designation of 476.3 acres of
Major Community Facilities, 6,933.3 acres of Open Space Natural, 5,259.2 acres of Open Space
Recreation, and 2,275.6 acres of street rights-of-way. The following table summarizes land uses
proposed within the entire La Quinta General Plan Update planning area.
Table III-27
Proposed Land Use Summary
Land Use Designation
Developed
(Acres)
Vacant
(Acres)
Total
(Acres)
Existing
Units
Potential
Units
Total
Units
Low Density Residential 4,557.5 8,410.3 12,967.8 21,635 25,231 46,866
High Density Residential 1,292.6 398.0 1,690.6 2,655 3,582 6,236
Subtotal 5,850.1 8,808.3 14,658.4 24,290 28,813 53,103
Existing SF Potential SF Total SF
General Commercial 414.2 440.6 854.7 3,969,042 4,222,106 8,191,148
Tourist Commercial 206.6 138.9 345.5 1,979,889 1,331,106 3,310,996
Village Commercial 77.1 12.9 90.0 738,865 123,623 862,488
Subtotal 697.9 592.4 1,290.2 6,687,796 5,676,835 12,364,631
Industrial/Lgt. Mfg. 0.0 63.8 63.8 -- 611,408 611,408
MC Facilities 280.9 195.4 476.3
Open Space - Natural 2,171.6 4,761.7 6,933.3
Open Space - Recreation 4,392.2 867.0 5,259.2
Street Rights-of-Way 2,084.5 191.1 2,275.6
Grand Total 15,477.2 15,479.7 30,956.9
The General Plan Update is consistent with land use development strategies outlined in SCAG’s
Regional Comprehensive Plan. Both Plans share a common goal of achieving sustainable
community(s) through thoughtful and integrated land use planning. The proposed General Plan
Update will not result in significant impacts to land use planning relative to the Regional Plan.
See the circulation element for a discussion of impacts relative to the SCAG’s Regional
Transportation Plan.
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The entire planning area is located within the Coachella Valley MSHCP fee area, with
conservation lands limited to the Santa Rosa Mountains, which are designated as Open Space
Natural. As proposed, the General Plan Update for the La Quinta Planning Area does not conflict
with the established CVMSHCP and impacts to habitat conservation planning or natural
community conservation planning will be less than significant.
City Limits
The proposed land use designations within the City of La Quinta incorporated City limits will
not significantly affect the pattern of development that has already occurred. The overall
character is not expected to be significantly impacted by the proposed land use plan, nor is the
plan, or development facilitated by the plan, expected to divide an established community. The
proposed land use plan is consistent with existing land use designations and the current
development pattern and does not represent a significant change to land uses within the city
limits.
Sphere of Influence
As described above, the Sphere of Influence land use designations, as set forth under the General
Plan Update, represent the greatest divergence from existing development and land use
designations proposed under the Riverside County General Plan, with the exception of the
Sphere north of City limits. That portion of the Sphere of Influence located north of City limits is
consistent with land use development intensities set forth under the Riverside County General
Plan. Therefore, residential land use development in the Sphere north of the City limits as set
forth under the General Plan Update would not result in significant impacts to established land
use designations.
Land use designations within that portion of the Sphere of Influence that overlaps with the
County’s Vista Santa Rosa Land Use Concept Plan have the potential to result in significant
impacts. The General Plan update proposes residential land use intensities that could nearly
double the residential development proposed under the Vista Santa Rosa Land Use Concept. This
is primarily due to the difference in allowable densities for low density residential, which is set at
a maximum of 2 units to the acre under the VSR Plan and allows for up to 4 units to the acre
under the proposed General Plan Update. Therefore, as proposed residential land use
designations conflict with established residential land use designations set forth in the VSR Land
Use Concept Plan, implementation of the General Plan Update has the potential to result in
significant impacts to future development in the eastern Sphere of Influence. In order to reduce
potential impacts, a master plan that is reflective of the community’s wants and needs will be
developed for the Sphere of Influence.
As proposed under the General Plan Update, non-residential land use designations are more or
less consistent with the land use designations set forth under the VSR Land Use Concept Plan.
Land use designations for commercial development are somewhat reduced compared to the VSR
Plan. Although the General Plan Update proposes an industrial and light manufacturing land use
designation, the permitted activities are not expected to conflict with the land uses set forth under
the VSR Plan. Commercial/retail and industrial land uses proposed under the General Plan
Update are consistent with the County’s VSR Land Use concept, and no significant land use
impacts have been identified.
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3. Mitigation Measures
Potential land use incompatibilities are addressed through policies and programs set forth in the
General Plan and through adherence to the Municipal Code. A Master Plan of Development
specific for the Sphere of Influence will be prepared that is reflective of the community’s wants
and needs. Development within the Sphere of Influence shall be subject to policies set forth in
the said Master Plan. The General Plan also includes policies and programs designed to assure
that adequate infrastructure is available prior to development occurring in an area; and that land
use compatibility and neighborhood character be preserved throughout the City and Sphere.
These policies and programs reduce the potential impacts associated with land use and planning
to less than significant levels. No mitigation is required.
Mineral Resources J.
Introduction
The City of La Quinta is located within a region known as the Palm Springs Production-
Consumption Region, containing significant mineral deposits, including sand and gravel, which
are important mineral resources for the state’s economy. The California Division of Mines and
Geology has classified areas throughout the Palm Springs Production-Consumption Region with
different mineral resource zones based on the value of resources available within the ground.
This discussion assesses impacts on mineral resources from future growth and development
brought on by the La Quinta 2035 General Plan Update. It also provides mitigation measures to
reduce impacts on mineral resources.
Thresholds of Significance/Criteria for Determining Significance
Article 5, Section 15064 of the CEQA Guidelines provides guidance for determining the
significance of the environmental effects caused by a project. Appendix G of the CEQA
Guidelines provides a list of environmental factors that potentially may be affected by
completion of a project. The La Quinta 2035 General Plan Update would have a significant
effect on Mineral Resources if it is determined the plan:
a) Results in the loss of availability of a known mineral resource that would be of value
to the region and the residents of the state.
b) Results in the loss of availability of a locally important mineral resource recovery site
delineated on a local general plan, specific plan or other land use plan.
1. Existing Conditions
The State of California has recognized the importance of mineral resources for construction
materials and other economic purposes. Mining and extraction of mineral resources continues to
be threatened by urbanization and development in areas where important mineral resources exist.
The California Surface Mining and Reclamation Act of 1975 (SMARA) addresses the loss of
regionally significant mineral deposits to urban development.
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The Act requires the Department of Conservation to create Production-Consumption Regions,
which are areas where significant mineral resources of statewide importance and regional
significance are produced and consumed, and a classification system that identifies lands where
significant mineral resource deposits are located. As mentioned earlier, La Quinta is located in
the Palm Springs Production-Consumption Region. The Palm Springs Production-Consumption
Region covers approximately 631 square miles of the Coachella Valley from near Cabazon to
Thermal49. Small portions of southern La Quinta, including lands south of Avenue 60, are
located outside the Palm Springs Production-Consumption Region, and therefore are not located
within a Mineral Resource Zone. Lands within the Production-Consumption Region are
classified according to the presence of valuable mineral resources. La Quinta has two Mineral
Resource Zones, MRZ-1 and MRZ-3. These zones are shown in Exhibit III-11. The definition of
each Mineral Resource Zone is provided below50:
MRZ-1: Areas where adequate information indicates that no significant mineral deposits
are present, or where it is judged that little likelihood exists for their presence.
MRZ-3: Areas containing known or inferred mineral deposits, the significance of which
cannot be evaluated from available data.
As seen in Exhibit III-11, the majority of incorporated regions of La Quinta and the Sphere of
Influence are located in MRZ-1, or areas where adequate information indicates that no
significant mineral deposits are present, or are likely to occur. Most areas within MRZ-1,
particularly within incorporated La Quinta, are urbanized and developed. Land designated MRZ-
1 in the Sphere of Influence is mostly agricultural land with small residential subdivisions and
large lot residential.
Lands that fall under the MRZ-3 designation make up a small portion of La Quinta. These areas
are known to contain mineral deposits, however there have been no evaluations on the
significance of these resources. The MRZ-3 designation is found only in the southwestern
portion of the City, including along the Coral Reef Mountains and within the Cove area. Aside
from the development that already exists within the Cove, the majority of land in the MRZ-3
zone is designated as open space. The Open Space designation does not permit mining activities,
and requires the land to be preserved in its natural state. A small portion of MRZ-3, located just
north of Avenue 60 and west of Madison, is undeveloped vacant land designated for low density
residential development.
49 “Update of Mineral Land Classification for Portland Cement Concrete-Grade Aggregate in the Palm Springs
Production-Consumption Region, prepared by California Department of Conservation, California Geologic
Survey, 2007. 50 “Update of Mineral Land Classification for Portland Cement Concrete-Grade Aggregate in the Palm Springs
Production-Consumption Region; Special Report 198,” prepared by California Department of Conservation,
California Geologic Survey, 2007.
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Exhibit III-11
Mineral Resource Zone Map
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2. Project Impacts
The General Plan Update will facilitate new development or redevelopment throughout the City
and Sphere. There are no mining operations occurring within the Planning Area.
The majority of lands within the City are developed. Remaining vacant lands include infill lots,
and scattered parcels located primarily within the Cove area and southwestern portion of the City
Limits, which may develop according to land use designations proposed by the General Plan
Update.51 As shown in Exhibit III-11, these areas are located in MRZ-3, or areas containing
known or inferred mineral deposits, the significance of which cannot be evaluated from available
data. These areas, however, are surrounded by urban development, and mineral extraction
activities are incompatible and unlikely on remaining vacant parcels.
According to Special Report 198, prepared by the California Department of Conservation, other
areas within the Coachella Valley, including the Whitewater area, and within the foothills north
and east of Indio, are more suitable for mineral extraction.52 The General Plan Update maintains
similar land use designations to those previously in effect on City parcels in the MRZ-3 area, and
does not provide land use designations conducive for mineral extraction. Therefore,
implementation of the General Plan Update does not result in loss of availability of locally-
important mineral resource considered valuable to the region and state, and does not result in the
loss of availability of mineral resource recovery sites delineated on a local general plan, specific
plan or other land use plan. Impacts on mineral resources caused by the implementation of the
General Plan Update will be less than significant.
The General Plan Update will also facilitate new development within the Sphere of Influence. As
mentioned earlier, however, the majority of these lands are located within the MRZ-1
designation, or an area determined as having no significant mineral resource deposits. Currently,
this area is used for agricultural purposes, and there are no known mineral leases, claims, or
prospects located in the Sphere of Influence or vicinity. Therefore, implementation of the
General Plan Update does not result in loss of availability of locally-important mineral resource
considered valuable to the region and state, and does not result in the loss of availability of
mineral resource recovery sites delineated on a local general plan, specific plan or other land use
plan. Implementation of the General Plan Update, therefore, will have no impact on mineral
resources within the Sphere of Influence.
3. Mitigation Measures
None Required.
Mitigation Monitoring and Reporting None Required.
51 http://maps.google.com, accessed July 5, 2011. 52 “Update of Mineral Land Classification for Portland Cement Concrete-Grade Aggregate in the Palm Springs
Production-Consumption Region; Special Report 198,” prepared by California Department of Conservation,
California Geologic Survey, 2007.
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Noise K.
Introduction
This section describes existing noise conditions in the General Plan Update Planning Area and
analyzes the potential impacts caused by various potential noise sources associated with build
out of the proposed General Plan Update. An acoustical analysis has been prepared in
conjunction with the General Plan Update, and the results have been used to prepare the analysis
of noise impacts presented in this section of the EIR.53 The study is included in its entirety in
Appendix F of this EIR. This section also sets forth noise-related mitigation measures, which
will effectively reduce construction, operational and traffic noise impacts to acceptable levels.
Thresholds of Significance/Criteria For Determining Significance
The following thresholds or criteria are derived from Appendix G of the CEQA Guidelines,
which are used to determine the level of potential effect. Build out of the proposed General Plan
will have a significant effect on noise levels if the project results in the following:
a.) Exposure of persons to or generation of noise levels in excess of standards established in
the local general plan or noise ordinance, or applicable standards of other agencies;
b.) Exposure of persons to or generation of excessive ground-borne vibration or ground-
borne noise levels;
c.) Causes a substantial permanent increase in ambient noise levels in the project vicinity
above levels existing without the project;
d.) Causes a substantial temporary or periodic increase in ambient noise levels in the project
vicinity above levels existing without the project;
e.) If located within an airport land use plan or, where such a plan has not been adopted,
within two miles of a public airport or public use airport, a project would expose people
residing or working in the project area to excessive noise levels;
f.) If located within the vicinity of a private airstrip, a project would expose people residing
or working in the project area to excessive noise levels.
1. Existing Conditions
Noise is defined as “unwanted sound.” Unwanted sound includes noise that interferes with
normal activities, inflicts physical harm on individuals, or causes adverse effect on health.
Excessive noise or prolonged exposure to noise can contribute to temporary and permanent
impairments, such as hearing loss, fatigue, stress, sleep deprivation, anxiety and annoyance.
Although noise has been accepted as a necessary by-product of urban development, it can
become an environmental hazard. A variety of components of the urban environment generate
53 “City of La Quinta General Plan Update Noise Element Technical Report,” prepared by Urban Crossroads, Inc.,
June 3, 2011.
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noise; these include construction equipment and activities, motor vehicles, air traffic, mechanical
equipment, household appliances, and other sources.
Existing Noise
The General Plan Update Planning Area enjoys a moderately quiet noise environment, especially
within residential areas. Primary sources of noise throughout the City are caused primarily by
motor vehicle traffic on City streets, particularly major roadways. This includes general
operation of cars, trucks, and bus lines. Other noise generators in the City include those
associated with commercial uses and construction noise. These noises include loading dock
operations, trucks entering and leaving commercial centers, and mechanical equipment, such as
fans, motors, and compressors.
Construction noise is generally short-term and is generated by construction equipment, including
trucks, bulldozers, graders, concrete mixers, pile drivers and other mobile and fixed construction
equipment.
This General Plan Update does not propose any construction, and as such, does not evaluate
specific construction related noises. Rather, this report gives a planning level analysis of future
impacts that will occur within the City and Sphere of Influence.
The Sphere of Influence consists primarily of agricultural and vacant lands, and vehicular traffic
is much less than that found throughout the City. As such, the Sphere of Influence enjoys a quiet
noise environment. Within the eastern Sphere, noise is generated from periodic flights and
general aviation operations at the Jacqueline Cochran Regional Airport. The airport is located
adjacent to the eastern boundary of the eastern Sphere, east of Harrison Street. Within the
northern Sphere of Influence, noise is also generated from occasional overhead flights associated
with the Bermuda Dunes Airport, which is located two miles northeast.
The effects of noise increase dramatically when incompatible land uses are located next to one
another. Potential land use incompatibilities include residential areas or other sensitive receptors
located near industrial and commercial uses.
Noise Fundamentals
The most common unit of measure for noise levels is the A-weighted decibel (dBA) scale. The
A-weighted decibel scale reflects only those frequencies that are audible to the human ear. The
decibel scale threshold ranges from 0 dBA to 140 dBA, with higher decibels considered painful
to the human ear. The most common sounds range is between 40 dBA (very quiet) and 100 dBA
(very loud). For example, a normal conversation at three feet is approximately 60 dBA, whereas
a loud jet engine flying overhead generates 110 dBA.
The logarithmic nature of the decibel means that a doubling of sound energy of a noise source
results in an increase in the decibel rating of only 3 dBA. For example, the doubling of traffic
noise on a busy street will generally only increase sound levels by 3 dBA. Changes of 3 dBA are
barely perceptible to the human ear. In order for a human ear to perceive a sound as being twice
as loud, the sound must increase by nearly 10 dBA. In community settings, changes in noise
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levels occur over a period of years. Changes of 5 dBA are readily perceptible and changes of 10
dBA are considered twice as loud.
The City of La Quinta measures intensity of sound and bases noise standards on the Community
Noise Equivalent Level (CNEL). CNEL is the average intensity of a sound over a 24-hour
period. It accounts for the decrease in background noise levels that occur during evening and
nighttime hours, as well as people’s increased sensitivity to noise during these times. Penalty
factors are added for sounds that occur in evening and nighttime hours.
Noise sources can result from “line sources” or “point sources”. Line sources include linear
sources of noise, such as a freeway or busy street. Point sources are generally stationary, such as
HVAC units or air compressors. Noise transmission is affected by a variety of factors, such as
temperature, wind speed and direction, as well as the type of ground surface. Soft ground
surfaces tend to reduce sound levels better than hard surfaces. This reduction of sound intensity
caused by surfaces, walls, vegetation or other material is called attenuation. A drop off rate of 4.5
dBA per doubling distance is typical across soft ground. In comparison, hard ground, such as
concrete, stone, and hard packed earth reduce sound by 3.0 dBA per doubling distance.
Effective noise barriers, such as walls or berms, can help reduce noise levels by 10 to 15
decibels. These types of barriers can provide relief from traffic noise. Vegetation, on the other
hand, is less effective for reducing noise levels. For a noise barrier to work, walls need to be high
enough and long enough to block the view of a road.
Regulatory Setting
The State has established guidelines for appropriate noise level ranges for a variety of land uses
within a community. The range of allowable exterior noise levels for various land uses is shown
in Exhibit III-12. This matrix is used to ensure noise compatibility of proposed land uses and
helps predict the future noise environment. Where sensitive land uses will be exposed to noise
levels of 60 dBA CNEL or higher, an acoustical study may be required. In residential areas in
California, the standard is a CNEL of 65 dBA. Mitigation measures are required where sensitive
land uses will be exposed to noise levels greater than 65 dBA CNEL. Interior noise standards are
provided by Chapter 12 of the California Building Code. According to the Code, interior noise
levels from exterior sources shall not exceed 45 dB in any habitable room. As discussed below,
the City of La Quinta uses the noise levels shown in Exhibit III-13, as a guideline to achieve
long-term noise compatibility for land uses.
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Exhibit III-12
Land Use and Noise Compatibility
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City of La Quinta Noise Ordinance
The City of La Quinta Municipal Code Section 9.100.210, Noise Control, establishes base
ambient noise level limits for noise sensitive and other non-residential uses based on time of day.
Table III-28 below shows the exterior noise limits established by the City. Noise sensitive land
uses include residential uses, schools, hospitals, churches, daycare, and similar uses. All other
uses must comply with the “Other Non-Residential” standard.
Table III-28
Exterior Noise Limits
Noise level
that may not
be exceeded
for a
cumulative
period more
than…
Noise Standard at Affected Land Use
Noise Sensitive Other Non-residential
Daytime
7 a.m. – 10 p.m.
Nighttime
7 a.m. – 10 p.m.
Daytime
7 a.m. – 10 p.m.
Nighttime
7 a.m. – 10 p.m.
30 min/hr 60 dBA 50 dBA 75 dBA 65 dBA
15 min/hr 65 dBA 55 dBA 80 dBA 70 dBA
5 min/hr 70 dBA 60 dBA 85 dBA 75 dBA
1 min/hr 75 dBA 65 dBA 90 dBA 80 dBA
Anytime 80 dBA 70 dBA 95 dBA 85 dBA
Note: For the purposes of this section, the term “cumulative period” means the number of
minutes that a noise occurs within any hour, whether such minutes are consecutive or not.
Source: “City of La Quinta General Plan Update Noise Element Technical Report, Urban Crossroads, June 3, 2011.
The Municipal Code also establishes limits on construction activity during the day. Construction
noise is considered temporary, but can often be disruptive for surrounding land uses. Section
6.08.050 of the Municipal Code limits construction to the following hours:
October 1st through April 30th: Monday – Friday: 7:00 a.m. to 5:30 p.m.
Saturday: 8:00 a.m. to 5:00 p.m.
Sunday and Holidays: None
May 1st through September 30th: Monday – Friday: 6:00 a.m. to 7:00 p.m.
Saturday: 8:00 a.m. to 5:00 p.m.
Sunday and Holidays: None
In addition, the Municipal Code Section 9.100.220 states, “No use, except a temporary
construction operation, shall be permitted which generates inherent and recurrent ground
vibration perceptible, without instruments, at the boundary of the lot on which the use is
located.”
Existing Noise Level Measurements in the General Plan Area
The existing noise environment in the City was determined by both short-term and long-term
noise level monitoring. There were thirteen short-term measurements conducted near major noise
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sources throughout the Planning Area. These short-term measurements were monitored for a
minimum time period of ten-minutes. Table III-29 below shows the results of the short-term
monitoring. Short-term noise levels ranged between 57.7 dBA Leq and 69.3 dBA Leq. When
expressed in terms of the 24-hour CNEL noise level, the noise levels ranged from 61.5 dBA
CNEL to 72.9 dBA CNEL. Data provided by Table III-29 shows elevated short-term exterior
ambient noise levels above 65 dBA CNEL at locations near residential uses and schools,
including locations S7 and S9.
Table III-29
Existing (Ambient) Short-Term Noise Level Measurements
Receptor
Location1 Description
Time of
Measurement
Primary Noise
Source
Noise
Levels
(Leq
dBA)
Noise
Levels
(dBA
CNEL)
S1
Located 100 feet from the
Washington Street
centerline north of the
Fred Waring Drive
intersection. 3:00 p.m.
Traffic on
Washington Street 66.1 68.4
S2
Located near the
Jefferson Street and Fred
Waring Drive intersection
at an existing Walgreens. 3:17 p.m.
Traffic on
Jefferson
St. and Fred
Waring Dr. 69.3 72.9
S3
Located near the
Eisenhower Health center
east of the Washington
Street centerline. 3:43 p.m.
Traffic on
Washington Street 69.3 71.6
S4
Located near the School
District Offices at the
intersection of 48th
Avenue and Dune
Palms Road. 4:11 p.m.
Traffic on Avenue
48 66.5 67.1
S5
Located approximately
100 feet east of the
Jefferson Street centerline
north of the 50th Avenue
intersection at the existing
commercial center. 10:27 a.m.
Traffic on
Jefferson
St. 64.3 68
S6
Located 50 feet east of
the centerline in the front
yard of 51915 Avenue
Bermudas across from the
community park south of
the 52nd Avenue
intersection. 11:12 a.m.
Traffic on Avenue
Bermudas 66.2 71.3
S7
Located south of 52nd
Avenue at the Cahuilla
Desert Academy School. 11:55 a.m.
Traffic on 52nd
Avenue 62 66.6
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Table III-29
Existing (Ambient) Short-Term Noise Level Measurements
Receptor
Location1 Description
Time of
Measurement
Primary Noise
Source
Noise
Levels
(Leq
dBA)
Noise
Levels
(dBA
CNEL)
S8
Located adjacent to the
single-family homes near
the intersection of
Avenue Bermudas and
Calle Arroba. 11:29 a.m.
Traffic on Avenue
Bermudas 59.2 64.3
S9
Located east of Madison
Street at the Troon Way
intersection near existing
single-familyhomes. 1:10 p.m.
Traffic on
Madison
Street 64.4 67.5
S10
Located 100 feet west of
the Harrison Street
centerline south of the
Airport Blvd. intersection. 12:16 p.m.
Traffic on
Harrison
Street 62.1 65.7
S11
Located north of 50th
Avenue centerline at the
existing Boy and Girls
Club. 10:46 a.m.
Traffic on 50th
Avenue 57.7 61.5
S12
Located 50 feet east of
the Monroe Street
centerline south of the
60th Avenue intersection
and the existing
residential uses. 12:40 p.m.
Traffic on Monroe
Street 60.4 64
S13
Located 100 feet west of
the Jefferson Street
centerline between 52nd
and 54th Avenue at the
proposed residential uses. 1:30 p.m.
Traffic on
Jefferson
Street 66.7 71
Source: City of La Quinta General Plan Update Noise Element Technical Report,” prepared by Urban Crossroads,
Inc., June 3, 2011
1. See Exhibit III-13 for the location of the monitoring sites.
In addition, seven long-term measurements were conducted near sensitive land uses throughout
the Planning Area. Long-term noise measurements were monitored for a 24-hour period to assess
ambient hourly noise levels. A summary of long term measurements is shown in Table III-30,.
Hourly noise levels at these locations ranged between 43.1 dBA Leq to 72.6 dBA Leq; the
weighted 24-hour noise levels ranged from 58.9.5 dBA CNEL to 72.7 dBA CNEL. Data indicate
that traffic peak hours generally resulted in the highest noise levels. Data provided in Table III-
30 shows elevated long-term exterior ambient noise levels above 65 dBA CNEL at site L7,
which is located near single-family homes at the intersection of Jackson Street and 50th Avenue.
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Table III-30
Existing (Ambient24-hour Noise Level Measurements
Receptor
Location1 Description
Time of
Measurement
Primary Noise
Source
Hourly
Noise
Levels
(Leq dBA)
Daily
Noise
Levels
(dBA
CNEL)
L1
Located north of
Westward Ho Drive at
La Quinta Park
across from the La
Quinta High School
baseball fields.
February 2-3,
2011
Traffic on
Westward Ho
Drive, Park
Activities,
Activities at La
Quinta High
School 44.9 - 63.6 60.2
L2
Located north of
Highway 111 on
southern portion of
the commercial center
west of La Quinta Dr.
February 2-3,
2011
Traffic on Highway
111 50.4 - 64.1 65.3
L3
Located near the
Washington St. and Via
Marquessa intersection
adjacent to existing
medical offices.
February 2-3,
2011
Traffic on
Washington Street 58.1 - 71.6 72.7
L4
Located north of
Coachella Drive and
Eisenhower Drive
intersection at the
Legacy Villas.
February 2-3,
2011
Traffic on
Eisnhower Drive,
Ambient 47.6 - 56.1 59.3
L5
Located next to the Crab
Pot Restaurant on
Avenida La Fonda in
"The Village".
February 2-3,
2011
Traffic on Ave. La
Fonda,
Ambient within
The Village 43.1 - 65.4 58.9
L6
Located northeast of the
52nd Avenue and
Jefferson Street inter-
section at land uses
proposed as multifamily
residential.
February 2-3,
2011
Traffic on 52nd
Ave. and
Jefferson St. 48.7 - 60.3 62.2
L7
Located on the northeast
corner of Jackson Street
and 50th Avenue near
existing single-family
homes.
February 2-3,
2011
Traffic on Jackson
St. 52.6 - 72.6 71.4
Source: City of La Quinta General Plan Update Noise Element Technical Report,” prepared by Urban Crossroads,
Inc., June 3, 2011
1. See Exhibit III-13 for the location of the monitoring sites.
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Exhibit III-13
Noise Monitoring Locations in the Study Area
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Primary Noise Sources
As discussed earlier, existing noise sources in La Quinta are generally associated with motor
vehicle traffic. This includes truck traffic and noise generated from local buses. Other noise
sources throughout the Planning Area include air traffic generated from the Jacqueline Cochran
Regional Airport and Bermuda Dunes Airport, noise from commercial and local business
operations, including truck loading and operation of mechanical equipment, and construction
noise, which impacts development in proximity to the construction activities and equipment.
Each of these noise sources is discussed categorically, below.
Motor Vehicle Noise
Motor vehicle traffic is the largest noise generator throughout the General Plan Update Planning
Area, particularly in the urbanized portions of the City Limit. The level of noise depends on
volume of traffic, vehicular speed, and number of trucks in the flow of traffic. Engine vibration,
vehicle tires, and vehicle exhaust systems also affect noise levels. Therefore, roads with heavier
traffic volumes, higher speeds, and larger mix of trucks will generally have high noise levels.
Table III-31 shows the traffic flow distribution on select roadway types in La Quinta, including
Eisenhower Drive, which represents a Primary Roadway, Washington Street, which represents a
Major roadway, and Highway 111. Highway 111 generally has the highest percentage of
medium and heavy truck use, and Washington Street the highest percentage of automobiles.
Traffic volumes along each selected roadway are greatest during daytime hours, or between 7 am
and 7 pm.
Table III-31
City of La Quinta Hourly Traffic Flow Distribution
Motor-Vehicle Type
Daytime
(7 am to 7 pm)
Evening
(7 pm to 10 pm)
Night
(10 pm to 7 am)
Total %
Traffic Flow
Collector, Secondary,
Primary1
Automobiles 76.8% 12.9% 10.3% 95.42%
Medium Trucks 84.1% 6.8% 9.1% 3.37%
Heavy Trucks 79.4% 4.8% 15.9% 1.21%
Major, Augmented
Major2
Automobiles 81.4% 10.4% 8.2% 96.05%
Medium Trucks 86.7% 5.3% 8.0% 2.65%
Heavy Trucks 89.2% 3.4% 7.3% 1.30%
Highway-1113
Automobiles 73.4% 9.7% 16.9% 91.40%
Medium Trucks 80.3% 5.5% 14.2% 6.49%
Heavy Trucks 71.7% 6.5% 21.8% 2.11%
Source: City of La Quinta General Plan Update Noise Element Technical Report,” prepared by Urban Crossroads, Inc., June 3, 2011
1 Based on axle counts on Eisenhower Drive between Calle Nogales and Calle Chihuahua, a Primary roadway on February 15-16, 2011.
2 Based on axle counts on Washington Street between Avenue 48 and Avenue 50, a Major roadway on February 15-16, 2011.
3 Based the Caltrans District 8 2009 Annual Average Daily Truck Traffic Report.
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Existing noise levels along major roadways in the General Plan Update Planning Area are shown
on Table III-32. These levels were determined based on modeling that replicates the Federal
Highway Administration (FHWA) Traffic Noise Prediction Model FHWA-RD-77-108. The
FHWA Model calculates predicted noise levels through adjustments to the Reference Energy
Mean Emission Level (REMEL). Adjustments account for roadway classification, roadway
width, the total average daily traffic (ADT), percentage of total ADT that flows each hour in a
24-hour period, travel speed, roadway grade, angle of view, percentage of vehicle types,
including automobiles, medium trucks, and heavy trucks, and site conditions. Results are
weighted for a 24-hour period and then expressed as CNEL.
Noise contours provided in Table III-32 were calculated using “soft-site” conditions in order to
account for the effective noise attenuation over natural surfaces such as normal earth and ground
vegetation. As mentioned above, noise drops off at a rate 4.5 dBA per doubling of distance over
soft ground, as compared to 3.0 dBA per doubling of distance over hard ground, such as
concrete, stone, or hard-packed earth. Existing contours provided in the table represent a
conservative estimate, and do not account for noise barriers, topography, or roadway grades that
may affect ambient noise levels.
As shown in Table III-32, many of the Planning Area’s major roadways, including Highway 111,
Washington Street, Jefferson Street, Avenue 44, and Avenue 48, have existing noise levels
exceeding 65 dBA CNEL at 100 feet from centerline. Many of these roads pass near sensitive
land uses, such as residential neighborhoods, churches, and schools. Highway 111 is the only
roadway not located along sensitive land uses. Noise barriers, such as walls or berms, can help
reduce noise levels by 10 to 15 decibels, providing relief from traffic noise. In most cases, noise
walls separate residential uses from roadways.
Truck and Bus Routes
As mentioned above, higher volumes of heavy trucks and buses along roadways generally
increases noise impacts. Noise impacts from heavy trucks and buses are generated from braking
systems, shifting gears, and engine noise during acceleration. Exhibit III-14 shows existing bus
and truck routes throughout the Planning Area. Bus service throughout La Quinta is focused
along travel ways with regional links, and is concentrated along Highway 111, Washington
Street, and in portions of the Cove. Currently, there are no bus routes in the far southern portions
of the City or Sphere.
Terra Nova/La Quinta General Plan EIR
Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-146
Exhibit III-14
Existing Truck and Bus Routes
Terra Nova/La Quinta General Plan EIR
Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-147
Table III-32
Existing Noise Exposure Adjacent to General Plan Update Study Area Roadways
Road Segment
CNEL at
100 Feet
(dBA)
Distance to Contour (Feet) from
centerline
70 dBA
CNEL
65 dBA
CNEL
60 dBA
CNEL
55 dBA
CNEL
Washington St. n/o Fred Waring Dr. 70.8 113 243 524 1,128
Washington St. btwn Fred Waring & Miles 71.1 119 257 553 1,192
Washington St. btwn Miles & Hwy 111 70.2 104 223 481 1,036
Washington St. btwn Hwy 111 & Avenue 48 70.7 111 240 517 1,114
Washington St. btwn Avenue 48 & Eisenhower Dr 70.3 105 226 486 1,047
Washington St. btwn Eisenhower Dr & Avenue 50 69.4 91 196 423 910
Washington St. btwn Avenue 50 & Calle Tampico 68.8 83 178 383 826
Eisenhower Dr. btwn Washington St & Avenue 50 65.4 RW 107 230 496
Eisenhower Dr. btwn Avenue 50 & Calle Tampico 64.6 RW 94 203 438
Avenida Bermudas btwn Calle Tampico & Avenue 52 58.5 RW RW 80 172
Avenida Bermudas btwn Avenue 52 & Calle Durango 62.9 RW 73 156 337
Adams St. btwn Westward Ho Dr & Hwy 111 64.6 44 94 203 437
Adams St. btwn Hwy 111 & Avenue 48 64.0 RW 86 186 401
Dune Palms Rd. btwn Westward Ho Dr & Hwy 111 62.9 RW 73 156 337
Dune Palms Rd. btwn Hwy 111 & Avenue 48 62.5 RW 68 146 314
Jefferson St. n/o Fred Waring 68.3 77 165 355 765
Jefferson St. btwn Fred Waring & Miles 68.8 83 180 387 833
Jefferson St. btwn Miles & Westward Ho Dr 68.3 77 166 357 768
Jefferson St. btwn Westward Ho Dr & Hwy 111 69.4 91 196 422 910
Jefferson St. btwn Hwy 111 & Avenue 48 69.4 91 195 420 905
Jefferson St. btwn Avenue 48 & Avenue 50 69.4 91 196 423 911
Jefferson St. btwn Avenue 50 & Avenue 52 67.1 64 139 299 645
Jefferson St. btwn Avenue 52 & Avenue 54 66.0 RW 116 251 540
Madison St. btwn Avenue 50 & Avenue 52 62.2 RW 65 139 300
Madison St. btwn Avenue 54 & Airport Blvd 64.3 RW 90 193 416
Madison St. btwn Airport Blvd & Avenue 58 62.7 RW 70 150 324
Madison St. btwn Avenue 58 & Avenue 60 58.5 RW RW 79 170
Monroe St. btwn Avenue 52 & Avenue 54 59.6 RW RW 94 203
Monroe St. btwn Avenue 54 & Airport Blvd 58.7 RW RW 81 176
Jackson St. btwn Avenue 54 & Airport Blvd 59.9 RW RW 98 211
Jackson St. btwn Airport Blvd & Avenue 58 58.3 RW RW 77 166
Jackson St. btwn Avenue 58 & Avenue 60 57.0 RW RW 63 136
Jackson St. btwn Avenue 60 & Avenue 62 56.6 RW RW 59 128
Van Buren St. btwn Avenue 52 & Avenue 54 61.3 RW 57 122 264
Van Buren St. btwn Avenue 54 & Airport Blvd 59.9 RW RW 98 211
Van Buren St. btwn Airport Blvd & Avenue 58 56.3 RW RW 57 122
Van Buren St. btwn Avenue 58 & Avenue 60 55.3 RW RW RW 105
Van Buren St. btwn Avenue 60 & Avenue 62 53.3 RW RW RW 77
Terra Nova/La Quinta General Plan EIR
Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-148
Table III-32
Existing Noise Exposure Adjacent to General Plan Update Study Area Roadways
Road Segment
CNEL at
100 Feet
(dBA)
Distance to Contour (Feet) from
centerline
70 dBA
CNEL
65 dBA
CNEL
60 dBA
CNEL
55 dBA
CNEL
Harrison St. btwn Airport Blvd & Avenue 58 63.3 RW 77 166 358
Avenue 44 e/o Washington St 68.5 80 172 370 797
Miles Ave. e/o Washington St 64.6 RW 93 201 434
Hwy 111 e/o Washington St 72.8 153 331 712 1,535
Hwy 111 e/o Adams St 73.0 159 343 738 1,590
Hwy 111 e/o Dune Palms 73.9 181 390 840 1,809
Avenue 48 e/o Washington St 65.7 52 112 241 520
Avenue 48 w/o Jefferson St 67.3 66 142 305 658
Avenue 50 e/o Washington St 64.4 RW 91 197 424
Avenue 50 w/o Jefferson St 64.5 RW 92 199 429
Avenue 50 e/o Jefferson St 64.6 RW 94 203 438
Calle Tampico
btwn Eisenhower Dr & Avenida
Bermudas 61.9 RW 62 134 289
Calle Tampico
btwn Avenida Bermudas &
Washington St 64.7 RW 95 204 440
Avenue 52 w/o Washington St 66.7 60 130 280 603
Avenue 52 w/o Jefferson St 65.9 54 116 249 537
Avenue 52 e/o Jefferson St 64.8 RW 96 208 448
Avenue 52 e/o Madison St 63.2 RW 76 164 354
Avenue 54 e/o Jefferson St 63.9 RW 84 181 390
Avenue 54 w/o Madison St 62.4 RW 67 145 312
Airport Blvd. e/o Madison St 57.4 RW RW 67 145
Avenue 58 w/o Monroe St 56.6 RW RW 60 129
Avenue 58 e/o Monroe St 55.1 RW RW 47 102
Avenue 60 e/o Madison St 58.1 RW RW 75 161
Avenue 60 e/o Monroe St 54.0 RW RW RW 85
Avenue 62 btwn Madison St & Monroe St 53.3 RW RW RW 78
Avenue 62 e/o Monroe St 52.3 RW RW RW 66
Avenue 62 e/o Jackson St 50.7 RW RW RW 52
Avenue 62 e/o Van Buren St 52.6 RW RW RW 69
Source: City of La Quinta General Plan Update Noise Element Technical Report,” prepared by Urban Crossroads, Inc., June 3, 2011
1 "RW" = Location of the respective noise contour falls within the right-of-way of the road
Terra Nova/La Quinta General Plan EIR
Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-149
Aircraft Noise
Two sources of aircraft noise have the potential to affect the noise environment in the City and
Sphere: the Jacqueline Cochran Regional Airport, and the Bermuda Dunes Airport. Each is
described individually below.
Jacqueline Cochran Regional Airport
The Jacqueline Cochran Regional Airport is a small regional airport located east of Harrison
Street, the eastern border of the Sphere of Influence. The airport houses approximately 127
aircraft, mostly single-engine airplanes, and air traffic consists of local flights or transients from
other small airports. As of December 2006, there were an average of 209 operations
(takeoffs/landings) a day, or over 70,000 annually. Of these operations, approximately 62% were
associated with transient general aviation.54
Lands adjacent to the airport are generally vacant and are under County of Riverside jurisdiction
and zoned for airport, industrial and agricultural uses.55 Although overflights may occasionally
be audible within the General Plan Update Planning Area, these impacts are not considered
significant. As shown on Exhibit III-15, aircraft noise does not generate a significant noise
impact. The noise contours of 65 dBA or greater are contained within the airport’s boundaries.
Bermuda Dunes Airport
The Bermuda Dunes Airport is a small privately owned commuter airport located approximately
two miles north of the northern City limits and Sphere of Influence. The airport lies just south of
Interstate 10, and west of Jefferson Street in Bermuda Dunes. The Bermuda Dunes Airport has
one east-west runway measuring approximately 5,000 feet in length. The airport averages
approximately 110 flights a day. Land uses surrounding the airport include residential, industrial
and commercial uses associated with the airport. According to the Riverside County Airport
Land Use Compatibility Plan, existing noise contours of 65 dBA or greater are contained within
the airport’s boundaries.56
54 “Airport Operation Statistics,” Jacqueline Cochran Airport,
http://www.rcjcra.com/AirportInformation/AirportStatistics/tabid/77/Default.aspx, accessed July 12, 2011. 55 As shown on Figure 3.20 “Final Draft Eastern Coachella Valley Area Land Use Plan,” Riverside County
General Plan, 2003. 56 “East County Airports Background Data: Bermuda Dunes and Environs,” Riverside County ALUCP,
December, 2004.
Terra Nova/La Quinta General Plan EIR
Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-150
Exhibit III-15
Existing Airport Noise Contours
Terra Nova/La Quinta General Plan EIR
Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-151
Industrial and Commercial Noise
Industrial and commercial noise is generally associated with loading dock operations, trucks
entering and leaving commercial and industrial districts, and interior and exterior mechanical
equipment uses. These types of noises can have a varying degree of impact on adjacent land
uses. Land use compatibility issues may arise when residential development is located adjacent to
commercial/industrial areas, which generates noise from air conditioning units, truck deliveries and
the use of mechanical equipment. All land uses are required to comply with exterior noise levels set
forth in the City’s Municipal Code, as discussed above.
Construction Noise
Noise from construction activity is generated from construction equipment, including trucks,
graders, bulldozers, concrete mixers and portable generators. Increases to the ambient noise
environment from construction activities are short-term but can reach high levels, especially from
grading activities. Noise levels from heavy equipment can range between approximately 68 dBA to
100 dBA at a distance of 50 feet. These noise levels diminish rapidly with a doubling of distance
from the noise source at a rate of approximately 6 dBA per doubling distance .57
The City does not have construction noise standards; however, construction noise can be most
effectively controlled through compliance with locally established construction hours. As discussed
above, the Municipal Code has established day and time restrictions on construction activities.
Ground-borne Vibration and Ground-borne Noise Levels
Ground-born vibration and noise is generally associated with construction activity, such as pile
driving and grading, but is also generated from traffic. Vibration is defined as the periodic
movement of mass over time, and is described in units of velocity (inches per second). It is
discussed in decibel (dB) units in order to compress the range of numbers required to describe
vibration. The human threshold of perception for vibration is 65 Vdb, or 0.0018 inches/second,
and is not usually significant until 70 Vdb, or 0.0031 inches/second. Typical levels of ground
vibration range between 50 Vdb and 100 Vdb. Vibration caused by bus and heavy truck traffic,
for example, is generally around 65 Vdb. In comparison, construction related vibration can range
between 90 Vdb and 100 Vdb. Blasting from construction projects, for example, can be as high
as 100 Vdb. The effects of ground-borne vibration generally include movement of building
floors, rattling of windows, and rumbling sounds. Ground-borne vibrations associated with
construction and traffic attenuate rapidly as one moves away from the source. According to
Caltrans, vibration caused by truck traffic attenuates to below perception levels at distances
greater than 130 feet. 58
In order to minimize impacts from ground-borne vibration and noise, future noise sensitive land
uses should have limited exposure to truck routes, high traffic areas, and other ground-borne
vibration producing activities. The City should also ensure that new developments minimize
vibration impacts during construction. 59
57 “City of La Quinta General Plan Update Noise Element Technical Report,” prepared by Urban Crossroads, Inc.,
June 3, 2011. 58 Ibid. 59 “City of La Quinta General Plan Update Noise Element Technical Report,” prepared by Urban Crossroads, Inc.,
June 3, 2011.
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Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-152
2. Project Impacts
The La Quinta General Plan Update will facilitate new development and redevelopment
throughout the City of La Quinta and Sphere of Influence. Build out of the General Plan Update
will generate increased noise levels associated with increased traffic, construction, and increased
commercial and industrial activity. In addition, increased development near the eastern boundary
of the eastern Sphere of Influence will potentially increase exposure to noise impacts associated
with the Jacqueline Cochran Regional Airport. In a similar fashion, new development within the
northern Sphere of Influence and the northern part of the City will also potentially increase
exposure to noise impacts associated with the Bermuda Dunes Airport. Each of these impacts is
discussed below.
Impacts Related to Noise Levels in Excess of General Plan or Noise Ordinance
As mentioned, the City of La Quinta currently regulates noise levels for sensitive land uses. The
City uses the noise levels shown in Exhibit III-12 above, as a guideline to achieve long-term
noise compatibility for land uses. For example, the maximum exterior noise level within
residential areas is a CNEL of 65 dBA. Mitigation measures are required where residential uses
will be exposed to noise levels greater than 65 dBA CNEL. Existing noise sources in La Quinta
Planning Area are generally from motor vehicle traffic, however noise is also generated from
commercial and local business operations, and construction noise.
Traffic Noise
Future noise contours have been provided along roadways throughout the Planning Area based
on build out of the General Plan Update. As shown in the tables below, traffic conditions
associated with the build out of the General Plan Update help determine the extent of future
noise impacts associated with implementation of the General Plan Update. As mentioned, most
noise in the Planning Area is associated with traffic, and level of traffic noise is based on
volumes, speed, and number of trucks in traffic. The FHWA model, used to model existing noise
contours, was applied to future Average Daily Traffic (ADT) volumes obtained from the City of
La Quinta General Plan Circulation Element Update Traffic Impact Analysis prepared by Iteris.60
The Traffic Study is further discussed in section III-O, Traffic/Circulation, and is presented in
the appendices of this EIR.
The majority of traffic in the Planning Area is made up of automobiles. Truck and bus traffic is
located along primarily along designated truck and bus routes. Future land use designations
provided by the General Plan Update continue to show General Commercial land uses along
Highway 111, which are considered non-sensitive land uses.
With the increased likelihood of more automobiles, trucks, and buses as a result of
implementation of the General Plan Update, noise levels along roadways throughout the
Planning Area will increase. Noise contours represent the distance to noise levels of a constant
value and are measured from the centerline of the roadway. Table III-33 below presents the noise
contours projected to result from build out of the proposed General Plan Update. It presents the
60 Ibid.
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Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-153
CNEL noise contour boundaries for the 55, 60, 65 and 70 dBA noise levels, as well as a
summary of the predicted noise contours and the estimated CNEL exterior noise level at a
distance of 100 feet throughout the City.
As the Coachella Valley continues to grow, an increased regional emphasis on improving public
transit, including increased bus service, will likely occur. New SunLine bus routes will likely be
needed across the Planning Area to meet growing demands. Existing bus service is limited to the
City limit currently, including along Highway 111, Washington Street, and within the Cove.
New service will likely expand along roadways within the eastern Sphere. While additional bus
service has potential to result in noise impacts to residential development and other sensitive
receptors, these impacts are also expected to be at least partially off-set by reductions in other
vehicular traffic associated with increased use of public transportation. The City of La Quinta
will need to continue to monitor noise impacts associated with expanded and additional bus
routes and bus stops when planned near sensitive receptors.
Table III-33
Year 2035 Build Out Conditions Noise Contours
Road Segment
CNEL
at
100
Feet
(dBA)
Distance to Contour (Feet) from
centerline
70
dBA
CNEL
65
dBA
CNEL
60
dBA
CNEL
55
dBA
CNEL
Washington St. n/o Fred Waring Dr. 72.7 152 327 705 1,519
Washington St. btwn Fred Waring & Miles 73.3 165 356 766 1,650
Washington St. btwn Miles & Hwy 111 72.5 148 318 685 1,476
Washington St. btwn Hwy 111 & Avenue 48 73.0 158 341 736 1,585
Washington St. btwn Avenue 48 & Eisenhower Dr 72.3 142 306 658 1,418
Washington St. btwn Eisenhower Dr & Avenue 50 71.7 129 278 599 1,290
Washington St. btwn Avenue 50 & Calle Tampico 70.9 115 248 534 1,150
Eisenhower Dr. btwn Washington St & Avenue 50 68.1 74 160 346 745
Eisenhower Dr. btwn Avenue 50 & Calle Tampico 66.6 59 128 275 593
Avenida
Bermudas btwn Calle Tampico & Avenue 52 59.1 RW RW 87 188
Avenida
Bermudas btwn Avenue 52 & Calle Durango 63.6 RW 80 173 372
Adams St. btwn Westward Ho Dr & Hwy 111 66.6 60 129 277 597
Adams St. btwn Hwy 111 & Avenue 48 66.8 61 132 284 613
Dune Palms
Rd. btwn Westward Ho Dr & Hwy 111 65.5 50 108 232 500
Dune Palms
Rd. btwn Hwy 111 & Avenue 48 66.7 60 129 278 598
Jefferson St. n/o Fred Waring 70.4 107 230 496 1,068
Jefferson St. btwn Fred Waring & Miles 71.8 132 284 613 1,320
Jefferson St. btwn Miles & Westward Ho Dr 72.2 141 304 654 1,409
Jefferson St. btwn Westward Ho Dr & Hwy 111 72.2 140 302 651 1,402
Jefferson St. btwn Hwy 111 & Avenue 48 72.1 139 299 645 1,389
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Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-154
Table III-33
Year 2035 Build Out Conditions Noise Contours
Road Segment
CNEL
at
100
Feet
(dBA)
Distance to Contour (Feet) from
centerline
70
dBA
CNEL
65
dBA
CNEL
60
dBA
CNEL
55
dBA
CNEL
Jefferson St. btwn Avenue 48 & Avenue 50 72.7 151 326 702 1,513
Jefferson St. btwn Avenue 50 & Avenue 52 71.1 119 256 551 1,186
Jefferson St. btwn Avenue 52 & Avenue 54 70.7 111 239 516 1,112
Madison St. btwn Avenue 50 & Avenue 52 70.4 107 231 497 1,071
Madison St. btwn Avenue 54 & Airport Blvd 72.0 136 292 629 1,355
Madison St. btwn Airport Blvd & Avenue 58 70.8 113 244 527 1,134
Madison St. btwn Avenue 58 & Avenue 60 68.2 76 164 354 762
Monroe St. btwn Avenue 52 & Avenue 54 70.4 106 228 492 1,060
Monroe St. btwn Avenue 54 & Airport Blvd 70.6 110 237 510 1,099
Jackson St. btwn Avenue 54 & Airport Blvd 70.0 101 217 467 1,006
Jackson St. btwn Airport Blvd & Avenue 58 70.2 103 221 476 1,026
Jackson St. btwn Avenue 58 & Avenue 60 69.5 93 199 429 925
Jackson St. btwn Avenue 60 & Avenue 62 68.3 77 166 358 770
Van Buren St. btwn Avenue 52 & Avenue 54 70.0 101 217 467 1,006
Van Buren St. btwn Avenue 54 & Airport Blvd 69.0 86 185 399 859
Van Buren St. btwn Airport Blvd & Avenue 58 69.3 90 195 419 904
Van Buren St. btwn Avenue 58 & Avenue 60 69.4 91 196 422 908
Van Buren St. btwn Avenue 60 & Avenue 62 65.8 52 113 243 523
Harrison St. btwn Airport Blvd & Avenue 58 73.7 176 378 815 1,756
Avenue 44 e/o Washington St 72.0 136 292 629 1,356
Miles Ave. e/o Washington St 66.6 59 127 274 590
Hwy 111 e/o Washington St 75.4 230 496 1,068 2,301
Hwy 111 e/o Adams St 74.2 191 411 885 1,906
Hwy 111 e/o Dune Palms 75.2 223 481 1,036 2,233
Avenue 48 e/o Washington St 67.0 64 137 295 635
Avenue 48 w/o Jefferson St 70.0 100 215 464 999
Avenue 50 e/o Washington St 64.4 RW 91 197 424
Avenue 50 w/o Jefferson St 67.0 63 136 294 634
Avenue 50 e/o Jefferson St 69.7 96 207 447 962
Calle Tampico
btwn Eisenhower Dr & Avenida
Bermudas 61.9 RW 62 134 289
Calle Tampico
btwn Avenida Bermudas &
Washington St 64.7 RW 95 204 440
Avenue 52 w/o Washington St 66.7 60 130 280 603
Avenue 52 w/o Jefferson St 70.1 102 220 475 1,023
Avenue 52 e/o Jefferson St 69.7 95 206 443 955
Avenue 52 e/o Madison St 69.2 88 190 410 883
Avenue 54 e/o Jefferson St 69.9 98 212 457 984
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Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-155
Table III-33
Year 2035 Build Out Conditions Noise Contours
Road Segment
CNEL
at
100
Feet
(dBA)
Distance to Contour (Feet) from
centerline
70
dBA
CNEL
65
dBA
CNEL
60
dBA
CNEL
55
dBA
CNEL
Avenue 54 w/o Madison St 62.4 RW 67 145 312
Airport Blvd. e/o Madison St 67.3 66 141 304 656
Avenue 58 w/o Monroe St 63.8 RW 83 179 386
Avenue 58 e/o Monroe St 66.0 54 117 252 542
Avenue 60 e/o Madison St 64.9 46 99 213 460
Avenue 60 e/o Monroe St 65.3 RW 105 226 488
Avenue 62 btwn Madison St & Monroe St 64.3 42 90 195 419
Avenue 62 e/o Monroe St 67.5 68 146 314 677
Avenue 62 e/o Jackson St 63.7 RW 82 178 383
Avenue 62 e/o Van Buren St 60.1 RW 47 102 220
Source: City of La Quinta General Plan Update Noise Element Technical Report,” prepared by Urban Crossroads, Inc., June 3, 2011
1 "RW" = Location of the respective noise contour falls within the right-of-way of the road
Noise standards in La Quinta allow sensitive land uses to experience a maximum noise level of
65 dbA CNEL in outdoor living areas (patios, balconies and rear yards). Many of the roadway
segments provided in the above table exhibit future noise levels greater than 65 dBA CNEL
beyond the established right-of-way. Sensitive land uses, including residential uses, back up to
many of these roads, and may potentially experience noise levels beyond noise standards. The
noise contours provided in the above table, however, are based upon soft site conditions, and do
not account for noise barriers, topography, or final roadway grades that may affect ambient noise
levels.
Effective noise attenuation barriers can reduce noise levels by 10 to 15 decibels. In addition,
appropriate noise-compatible land use planning, such as encouraging less sensitive land uses
next to highways, has been considered and included in the Land Use Map of the General Plan.
Proper mitigation measures, including the requirement to provide walls or berms, will be
required to reduce noise levels to below 65 dBA CNEL near sensitive land uses. Noise studies
shall be required when noise-sensitive development occurs near roads and highways. With the
implementation of mitigation measures, traffic noise levels impacts in excess of local General
Plan or Noise Ordinance standards on sensitive land uses will be less than significant.
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Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-156
Industrial and Commercial Noise
In addition to new residential development, implementation of the General Plan Update will
facilitate construction of new commercial and industrial land uses throughout the Planning Area.
Approximately 3,218,039 square feet of new commercial uses will be developed at build out in
the City Limits. Within the Sphere of Influence, new commercial and industrial uses are also
proposed at build out, including 2,458,797 square feet and 611,408 square feet, respectively.
With increased commercial and industrial development, land use compatibility issues may arise
when sensitive land uses are located adjacent to commercial/industrial areas. All land uses are
required to comply with exterior noise levels set forth in the City’s Noise Ordinance and General
Plan, as discussed above, however additional mitigation measures provided below will be required
to reduce impacts on sensitive uses. As a result, noise levels in excess of established noise standards
generated from industrial and commercial uses are expected to be less than significant with proper
mitigation.
Construction Noise
Implementation of the General Plan Update will likely increase the amount of construction
related noises associated with new development, especially within the Sphere of Influence.
Increased construction noise has the potential to increase noise levels in excess of noise
standards set by the General Plan Update or Noise Ordinance. As shown in Table III-28, the La
Quinta Municipal Code establishes base ambient noise level limits for noise sensitive and other
non-residential uses based on time of day. In addition, construction activity is limited during
established days and hours to reduce disruption of surrounding land uses. Future construction
activity will be required to abide by these standards, and as a result, will have less than
significant impacts on noise standards set by the General Plan Update and Noise Ordinance.
Impacts from Excessive Ground-borne Vibration or Ground-borne Noise Levels
As discussed above, ground-borne vibration and noise is generally associated with heavy truck and
bus traffic, as well as the use of heavy equipment at construction sites. Implementation of the
General Plan will facilitate development throughout the Planning Area, which will likely lead to
increased truck and bus traffic, as well as increased construction activity.
The increase in volume of large trucks and buses associated with new growth may potentially cause
increased vibration along designated truck and bus routes. Although the truck traffic will likely
increase along these routes, future land uses along Highway 111 and other major roadways will
remain General Commercial, which are not considered sensitive land uses. Any future truck routes
proposed throughout the Planning Area will need to consider the amount of sensitive land uses
along the proposed corridor.
Existing bus routes are currently located near sensitive land uses, such as the Cove, and new routes
may develop throughout the Planning Area, including the Sphere of Influence, as a result of new
growth caused by the General Plan Update. New bus routes may increase temporary vibration levels
for sensitive land uses. Caltrans truck traffic vibration data, however, suggests that vibrations caused
by trucks and buses diminish to below the threshold of perception at approximately 130 feet from
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Section III. Existing Environmental Concerns, Project Impacts, and Mitigation Measures
III-157
the road.61 Mitigation measures associated with traffic caused vibrations are set forth below. With
implementation of these measures, excessive ground-borne vibration or noise generated from
truck and bus traffic is expected to be less than significant.
New development throughout the Planning Area will require grading, trenching and other activities
that may produce increased ground-borne vibration and noise. Construction noise is generally short
term and may be mitigated to acceptable levels by a variety of measures, including equipping
construction equipment with mufflers, locating stationary equipment away from noise sensitive
receptors and placing equipment staging areas as far from sensitive receptors as is practicable. In
addition, construction activity is required to abide by noise standards set by the General Plan
Update and Noise Ordinance. Mitigation measures for construction related vibrations are set forth
below. With implementation of these measures, impacts from excessive ground-borne vibration or
noise generated from construction activity are expected to be less than significant.
Impacts from Permanent Increase in Ambient Noise levels Above Existing Noise Levels
Permanent increases in ambient noise levels are generally associated with increased traffic in the
Planning Area. Table III-34 shows the comparison between Year 2035 CNEL contours under the
2002 General Plan at 100 feet from centerline, compared to the proposed 2035 General Plan
Update conditions. The Preferred Alternative represents 2035 conditions from implementation of
the General Plan Update. As shown below, the 2035 General Plan Update is expected to result in
both increases and decreases to noise levels compared to the 2002 General Plan conditions,
shown in the “Difference” column. Implementation of the General Plan Update will not,
however, increase noise levels perceptibly anywhere in the Planning Area.
Table III-34
Year 2035 Preferred Alternative Noise Contour Comparison
CNEL at 100 Feet (dBA) from centerline
Roadway Segment
Existing
Network
Preferred
Alternative Difference1
Washington St. n/o Fred Waring Dr. 72.7 72.7 0.1
Washington St. btwn Fred Waring & Miles 73.2 73.3 0.1
Washington St. btwn Miles & Hwy 111 72.5 72.5 0.1
Washington St. btwn Hwy 111 & Avenue 48 72.9 73.0 0.1
Washington St. btwn Avenue 48 & Eisenhower Dr 73.0 72.3 -0.7
Washington St. btwn Eisenhower Dr & Avenue 50 71.5 71.7 0.1
Washington St. btwn Avenue 50 & Calle Tampico 70.8 70.9 0.2
Eisenhower Dr. btwn Washington St & Avenue 50 68.1 68.1 0.0
Eisenhower Dr. btwn Avenue 50 & Calle Tampico 66.7 66.6 0.1
Avenida Bermudas btwn Calle Tampico & Avenue 52 59.2 59.1 0.1
Avenida Bermudas btwn Avenue 52 & Calle Durango 63.7 63.6 -0.1
Adams St. btwn Westward Ho Dr & Hwy 111 66.5 66.6 0.1
Adams St. btwn Hwy 111 & Avenue 48 66.9 66.8 -0.1
61 “City of La Quinta General Plan Update Noise Element Technical Report”, prepared by Urban Crossroads, Inc.,
June 3, 2011.
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Table III-34
Year 2035 Preferred Alternative Noise Contour Comparison
CNEL at 100 Feet (dBA) from centerline
Roadway Segment
Existing
Network
Preferred
Alternative Difference1
Dune Palms Rd. btwn Westward Ho Dr & Hwy 111 65.4 65.5 0.1
Dune Palms Rd. btwn Hwy 111 & Avenue 48 66.7 66.7 0.0
Jefferson St. n/o Fred Waring 70.4 70.4 0.0
Jefferson St. btwn Fred Waring & Miles 71.7 71.8 0.1
Jefferson St. btwn Miles & Westward Ho Dr 72.2 72.2 0.0
Jefferson St. btwn Westward Ho Dr & Hwy 111 72.2 72.2 0.0
Jefferson St. btwn Hwy 111 & Avenue 48 72.1 72.1 0.0
Jefferson St. btwn Avenue 48 & Avenue 50 72.6 72.7 0.1
Jefferson St. btwn Avenue 50 & Avenue 52 71.1 71.1 0.0
Jefferson St. btwn Avenue 52 & Avenue 54 70.6 70.7 0.1
Madison St. btwn Avenue 50 & Avenue 52 70.5 70.4 0.1
Madison St. btwn Avenue 54 & Airport Blvd 71.9 72.0 0.0
Madison St. btwn Airport Blvd & Avenue 58 70.7 70.8 0.2
Madison St. btwn Avenue 58 & Avenue 60 68.0 68.2 0.2
Monroe St. btwn Avenue 52 & Avenue 54 70.3 70.4 0.1
Monroe St. btwn Avenue 54 & Airport Blvd 70.5 70.6 0.1
Jackson St. btwn Avenue 54 & Airport Blvd 70.1 70.0 0.0
Jackson St. btwn Airport Blvd & Avenue 58 70.2 70.2 0.0
Jackson St. btwn Avenue 58 & Avenue 60 69.3 69.5 0.2
Jackson St. btwn Avenue 60 & Avenue 62 68.0 68.3 0.3
Van Buren St. btwn Avenue 52 & Avenue 54 69.8 70.0 0.3
Van Buren St. btwn Avenue 54 & Airport Blvd 69.1 69.0 -0.1
Van Buren St. btwn Airport Blvd & Avenue 58 69.4 69.3 -0.1
Van Buren St. btwn Avenue 58 & Avenue 60 69.5 69.4 0.1
Van Buren St. btwn Avenue 60 & Avenue 62 66.0 65.8 0.1
Harrison St. btwn Airport Blvd & Avenue 58 73.4 73.7 0.2
Avenue 44 e/o Washington St 71.9 72.0 0.0
Miles Ave. e/o Washington St 66.5 66.6 0.0
Hwy 111 e/o Washington St 75.5 75.4 -0.1
Hwy 111 e/o Adams St 74.3 74.2 -0.1
Hwy 111 e/o Dune Palms 75.2 75.2 0.0
Avenue 48 e/o Washington St 67.0 67.0 0.0
Avenue 48 w/o Jefferson St 70.1 70.0 -0.1
Avenue 50 e/o Washington St 64.4 64.4 0.0
Avenue 50 w/o Jefferson St 67.2 67.0 0.1
Avenue 50 e/o Jefferson St 69.6 69.7 0.1
Calle Tampico btwn Eisenhower Dr & Avenida
Bermudas 61.9 61.9 0.0
Calle Tampico btwn Avenida Bermudas & 64.7 64.7 0.0
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Table III-34
Year 2035 Preferred Alternative Noise Contour Comparison
CNEL at 100 Feet (dBA) from centerline
Roadway Segment
Existing
Network
Preferred
Alternative Difference1
Washington St
Avenue 52 w/o Washington St 66.7 66.7 0.0
Avenue 52 w/o Jefferson St 70.0 70.1 0.2
Avenue 52 e/o Jefferson St 69.7 69.7 0.0
Avenue 52 e/o Madison St 69.2 69.2 0.0
Avenue 54 e/o Jefferson St 69.8 69.9 0.1
Avenue 54 w/o Madison St 62.4 62.4 0.0
Airport Blvd. e/o Madison St 67.3 67.3 0.0
Avenue 58 w/o Monroe St 63.3 63.8 0.1
Avenue 58 e/o Monroe St 65.6 66.0 0.1
Avenue 60 e/o Madison St 63.5 64.9 1.4
Avenue 60 e/o Monroe St 65.0 65.3 0.3
Avenue 62 btwn Madison St & Monroe St 64.2 64.3 0.1
Avenue 62 e/o Monroe St 67.5 67.5 0.0
Avenue 62 e/o Jackson St 63.4 63.7 0.3
Avenue 62 e/o Van Buren St 59.9 60.1 0.3
Source: “City of La Quinta General Plan Update Noise Element Technical Report,” prepared by Urban Crossroads, Inc., June 3, 2011
1. A significant impact is considered both a level above 65 dBA CNEL and an increase greater than 3.0 dBA
Due to the logarithmic nature of traffic noise levels, a doubling of the traffic volume would result
in an increase in noise levels of 3 dBA. As discussed above, this increase is considered “barely
perceptible” based on FHWA community noise assessment criteria. Therefore, increases to noise
levels of less than or equal to 3 dBA are considered less than significant. As shown by Table
III-34, increases in noise levels throughout the Planning Area associated with the General Plan
Update are expected to be, on the average, only 0.1 dBA CNEL compared to the 2002 General
Plan conditions. Because this increase is minimal (less than 3 dBA), permanent increases in
ambient noise levels as a result of the General Plan Update are expected to be less than
significant.
Impacts from Temporary or Periodic Increases in Ambient Noise Levels Above Existing
Noise Levels
Temporary or periodic increases in ambient noise levels are generally associated with construction
activity. Implementation of the General Plan Update will facilitate new residential, commercial,
municipal, and industrial development throughout the Planning Area. Within the City,
approximately 8,114 new residential units, 3,218,039 square feet of new commercial
development, and 193.8 acres of new community facilities are expected at build out. Within the
Sphere of Influence, approximately 20,699 new residential units, 2,458,797 square feet of new
commercial space, and 611,408 square feet of new industrial uses are expected at build out.
Development of these land uses will increase the amount of construction related noise, especially
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within the Sphere of Influence. Increased construction noise has the potential to increase
temporary or periodic noise levels above existing noise levels. As mentioned above, the La
Quinta Municipal Code establishes base ambient noise level limits for noise sensitive and other
non-residential uses based on time of day. In addition, construction activity is limited during
established days and hours to reduce disruption of surrounding land uses. Future construction
activity will be required to abide by these standards, and as a result, will have less than
significant impacts on temporary noise levels.
Impacts from Airport Operations
As the population of the Coachella Valley expands, existing airport facilities will also experience
growth. The Jacqueline Cochran Regional Airport is expected to increase annual operations and
average daily takeoffs and landings. Annual operations are expected to increase from 70,000
annual operations as of 2006, 62 to 110,000 annual operations by 2025. Average flights per day
are expected to increase from 178 to 301 over the same time period. Noise generated from the
Jacqueline Cochran Regional Airport is expected to affect the eastern Sphere of Influence. The
General Plan Update proposes compatible land uses nearest the airport, including industrial and
general commercial land uses.
As shown on Exhibit III-16, future noise levels above 65 dBA CNEL will be contained within
the boundaries of the airport. Noise impacts from future aviation operations, therefore, will have
a less than significant impact on land uses proposed within the eastern Sphere of Influence.
The Bermuda Dunes Airport is a private airport located approximately 2 miles from the northern
City limits and Sphere of Influence. The airport is expected to experience an increase in annual
operations and average daily takeoffs and landings. Annual operations are expected to increase
from 42,000 annual operations in 2004 to 75,000 annual operations by 2025. Average flights per
day are also expected to increase from 115 to 205 over the same time period. Although
occasional overhead flights may occur over the northern end of the City and Sphere, future noise
levels above 65 dBA CNEL will be contained within the boundaries of the airport. No significant
impacts are anticipated to residential development or other land uses in the vicinity.
62 “Airport Operation Statistics,” Jacqueline Cochran Airport,
http://www.rcjcra.com/AirportInformation/AirportStatistics/tabid/77/Default.aspx, accessed July 12, 2011.
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Exhibit III-16
Future Airport Noise Contours (Jacqueline Cochran Airport)
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Sphere of Influence
The Sphere of Influence, particularly the eastern Sphere of Influence, is expected to experience a
majority of the growth and development as a result of the implementation of the General Plan
Update. As mentioned above, approximately 20,699 new residential units are proposed at build
out in the Sphere of Influence. This will significantly increase the number of sensitive land uses
in the Sphere. The Sphere of Influence is mostly undeveloped agricultural land. Noise impacts
are expected to be primarily associated with temporary construction noises and gradually
increasing traffic volumes as these areas develop. Site-specific design features that mitigate noise
impacts may need to be implemented to limit noise impacts to acceptable levels. All noise
associated with new development in the Sphere of Influence areas will be subject to the City’s
noise ordinance and other mitigation measures described below. Without mitigation, build out of
the General Plan Update could result in significant impacts associated with noise in the Sphere.
Summary of Impacts
There are approximately 24 roadway segments in the Planning Area that currently experience
noise levels greater than 65 dBA CNEL at 100 feet from the centerline under existing conditions.
Future noise levels along roadways throughout the Planning Area are expected to increase with
implementation of the General Plan Update. Approximately 54 roadway segments are expected
to experience noise levels greater than 65 dBA CNEL at 100 feet from centerline in year 2035 at
build out of the 2002 General Plan. Implementation of the General Plan Update will only cause
one additional roadway segment (55 roadway segments in total) to experience noise levels
greater than 65 dBA CNEL at 100 feet compared to Existing Network. The greatest increase in
noise level generated by the Preferred Alternative will only cause a 1.4 dBA CNEL increase
compared to the 2002 General Plan. This small increase in noise level will be barely perceptible
to the human ear. Therefore, there will not be a substantial increase in future permanent noise
levels as a result of the General Plan Update compared to the Existing Network.
Future increases in activity associated with commercial and industrial activity, including loading
dock operations and noises associated with stationary equipment, will also likely increase
permanent noise levels. These land uses, however, are required to comply with exterior noise levels
set forth in the City’s Noise Ordinance. Additional mitigation measures provided below, such as
land use compatibility analysis, and building orientation requirements, will be required to reduce
impacts on sensitive uses. As a result, noise levels in excess of established noise s tandards generated
from industrial and commercial uses are expected to be less than significant.
The La Quinta Municipal Code establishes base ambient noise level limits for noise sensitive and
other non-residential uses based on time of day. In addition, construction activity is limited
during established days and hours to reduce disruption of surrounding land uses. Future
construction activity will be required to abide by these standards, and as a result, will have less
than significant impacts on noise standards set by the General Plan Update and Noise Ordinance.
In summary, build out of the proposed General Plan Update, including City Limit and Sphere of
Influence Planning Areas, will result in overall increases to community noise levels from
increased urbanization and associated activities including short-term construction noise,
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increases in motor vehicle traffic and other modes of transportation. These impacts may be
significant if not mitigated. Measures set forth below, however, provide broad-based mitigation
and are intended to ensure the reduction of potential noise impacts to acceptable levels.
3. Mitigation Measures
The City of La Quinta has adopted exterior noise standards in Section 9.100.210 of its Municipal
Code, which establishes base ambient noise level limits for noise sensitive and other non-
residential zones according to time of day. Municipal Code Section 9.100.220 also provides
standards for ground-borne vibrations and noises. In addition Section 6.08.050 provides limited
hours for construction to alleviate construction noise. The City’s exterior noise standards for
various land uses are consistent with those set forth by the State of California in its “Land Use
Compatibility for Community Environments” matrix.
The mitigation measures that follow shall be implemented within the General Plan area to ensure
the reduction of potential noise impacts to less than significant levels. Additional site-specific
noise mitigation measures may also be required as appropriate for future development.
General Mitigation Measures
1. The City shall continue to maintain and enforce noise standards provided by the Municipal
Code to ensure that noise impacts throughout the General Plan area are maintained at
acceptable levels.
2. The City shall continue to ensure that interior noise levels for residential development do not
exceed 45 dBA by requiring that all project designs comply with Title 25 (California Noise
Insulation Standards).
3. Acoustical studies shall be required in conjunction with entitlement applications for sensitive
receptor projects proposed adjacent to roadways shown in Table III-34. The study shall
analyze noise levels within the proposed project, and include mitigation measures to assure
that the exterior noise levels meet the City’s standards.
4. The City shall require an acoustical studies for all commercial and industrial projects that are
proposed adjacent to residential land uses or land use designations. The acoustical analysis
shall evaluate potential noise impacts of the project and provide mitigation measures that are
adequate to meet the City’s noise standards for residential land uses.
5. Sensitive receptors, which include schools, libraries and hospitals, shall, to the greatest extent
feasible, be located away from major noise generators.
Roadway Traffic Noise
6. The City shall continue to implement a planning area-wide circulation pattern that loads
primary traffic onto major arterials in order to limit local roadway traffic to the greatest
extent feasible and thereby preserve local neighborhood noise environments.
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7. The City shall evaluate and monitor noise impacts associated with the addition of new bus
routes, including bus stops near noise sensitive uses, located along collector and local roads.
8. The City shall evaluate and monitor noise impacts associated with new truck routes proposed
throughout the Planning Area, and discourage new truck routes along roadway segments near
sensitive land uses.
Construction Noise
9. All fixed and mobile construction equipment operating in the Planning Area shall be
equipped with properly operating and well-maintained mufflers to limit noise emissions.
Stationary construction equipment shall be placed away from sensitive noise receptors.
10. New construction site staging areas, stockpiling, earth moving activities, and hauling routes
should be situated away from sensitive noise land uses to the greatest extent possible.
11. All construction activities shall comply with the City of La Quinta Municipal Code Section
6.08.050.
12. Ground-borne vibration activities shall be conducted in compliance with the City of La
Quinta Municipal Code Section 9.100.220.
Stationary Noise Sources
13. Appropriate sound barriers shall surround all commercial, industrial and public facilities
located adjacent to sensitive land uses.
14. Outdoor equipment such as cooling towers, air cooled condensers and refrigeration
compressors and/or condenser units, as well as at air intake and discharge openings for
building ventilation systems, shall be provided with silencers and/or barriers at or
surrounding them, where necessary.
15. Truck deliveries to commercial and industrial areas adjacent to sensitive land uses shall be
limited to daylight hours, or shall provide noise mitigation measures to reduce noise impacts.
Mitigation Monitoring/Reporting Program
A. The City shall periodically review land-use patterns and the community noise environment,
and amend the Land Use map as appropriate to ensure reasonable land use/noise
compatibility.
Responsible Parties: Planning Department
B. The Planning Department shall review acoustical analyses for new sensitive receptor projects
located adjacent to major roadways, and commercial and industrial project located to
sensitive receptors.
Responsible Party: Planning Department
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C. The City shall work with SunLine Transit Agency to locate future bus stops and routes to
ensure noise impacts to sensitive receptors are minimized.
Responsible Party: Planning Department, SunLine Transit Agency.
Population and Housing L.
Introduction
This section of the EIR addresses potential impacts and opportunities associated with population
and housing that may exist or arise from implementation of the La Quinta General Plan Update.
The existing population and housing conditions, forecast growth and housing projections within
the City and Sphere of Influence are described, and the potential impacts relating to changes
from the previously approved General Plan, are assessed.
Thresholds of Significance/Criteria for Determining Significance
The following thresholds or criteria are derived from Appendix G of the CEQA Guidelines, and
are used to determine the level of potential effect. The significance determination is based on the
recommended criteria set forth in Section 15064 of the CEQA Guidelines. For analysis purposes,
build out of the La Quinta General Plan would have a significant effect on population and
housing if it is determined that the project will:
a.) Induce substantial population growth in an area, either directly (for example, by
proposing new homes and businesses) or indirectly (for example, through extension of
roads or other infrastructure).
1. Existing Conditions
The General Plan Update Planning Area consists of the incorporated City limits and the
unincorporated Sphere of Influence. Residential development within City limits is 73% built out,
whereas residential development within the Sphere of Influence is 7.5 % built out.
Demographic Information
Population
In 2000, there were 23,694 people living in La Quinta. The 2010 U.S. Census reports a
population size of 37,467 for the City of La Quinta. In 2000, the median age was 36.4 years,
while in 2010 the median age was 46.6. According to the 2010 U.S. Census, the population of La
Quinta is 63.1% White, 30.3% Hispanics, 3.1% Asian, 1.9% Black or African American, and
1.6% other. Approximately 36.3% of the population within the City of La Quinta is above 55
years of age.63
Currently, there are approximately 23,489 dwelling units within the City, 14,820 of which are
occupied. Assuming an average household population size of 2.53 and full occupancy of all
63 Profile of General Population and Housing Characteristics, for the City of La Quinta, 2010 US Census.
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existing dwelling units, the existing population in La Quinta’s City limits is estimated to be
59,427.
In the Sphere of Influence, under Riverside County’s land use designations, there are
approximately 7,173 acres of residentially designated lands, of which 538 acres are currently
developed. According to Riverside County, the developed acreage contains an estimated 801
existing low density residential dwelling units. Based on the persons per household figure of
2.53, the existing population within the Sphere of Influence is estimated to be 2,027.
In total, the General Plan Update Planning Area is estimated to contain an existing population of
61,454.
Housing Units
In 2000, there were 11,812 housing units within the City of La Quinta, and by 2005, there were
18,762 dwelling units. The 2010 Census accounted for a total of 23,489 dwelling units, the
majority of which are single family detached units -- approximately 80% of the housing stock is
single family detached, 10% is single family attached, 9% is multi-family, and 1% is mobile
homes.64 Nearly 37% of all housing units are unoccupied. The 2010 population of 37,467 and the
14,820 occupied dwelling units yields an average household population size of 2.53 persons per
household.
It should be noted many of La Quinta homeowners are second homeowners and are considered
part-time residents. According to the 2010 U.S. Census, approximately 27.5% of La Quinta
dwelling units were vacant due to seasonal, recreational, or occasional use.
In the second quarter of 2011 the median home price for existing homes in La Quinta was
$232,000 and the median new home price was $360,000.65 At current levels, home ownership is
considered affordable to moderate income households. Home prices exceed those of Riverside
County for the same period, which were $189,000 for existing homes and $290,000 for new
homes.
Employment
In 2007, there were 14,918 jobs within the City. Based on the 2009 Riverside County progress
report, La Quinta’s civilian labor force was comprised of 14,700 persons, with 13,700 employed
and 1,100 unemployed. The majority of jobs within City limits are in the resort, service, and
hospitality industry, followed by retail trade, professional and business services, and
construction. The median household income in La Quinta in 2000 was $54,552, and had risen to
$78,898 by 2010.
2. Project Impacts
There are 23,489 dwelling units within City limits, and 801 units within the Sphere of Influence,
for a total of 24,290 existing dwelling units throughout the Planning Area. The General Plan
64 Average Housing Characteristics for 2005-2009, prepared by the American Community Survey. 65 “Inland Empire Quarterly Economic Report,” prepared by John E. Husing, Ph.D., October 2011.
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Update allows for a total of up to 31,603 residential dwelling units within City limits and 21,500
dwelling units within the Sphere of Influence, which has the potential to result in a total of
53,103 dwelling units throughout the Planning Area. Development of these residential units
could support an additional 72,897 residents beyond the existing population of 61,454, which
would result in a build out population of 134,352 in the General Plan Update Planning Area. It
should be noted that these figures assume an average household population size of 2.53 people
and full occupancy of seasonal, recreational, and occasional occupancy dwelling units, as well as
permanent residency.
La Quinta City Limits
Within the La Quinta City limits, build out of the proposed General Plan Update has the potential
to result in the development of an additional 8,114 dwelling units, which could support an
additional 20,528 people, assuming an average household occupancy of 2.53. At General Plan
build out, the population size within city limits is projected to be 79,956, based on full
occupancy of the 31,603 dwelling units that are proposed under the General Plan Update. This
represents a 34% increase over the existing number of dwelling units and the associated
population size.
According to the Southern California Association of Government’s (SCAG) May 2011 growth
forecasts, it is projected that by 2035 La Quinta’s permanent population will be 46,297 people,
and there will be 17,948 occupied dwelling units within the City of La Quinta. SCAG projections
assume an annual growth rate of approximately 0.85%. These projections do not account for
seasonal, recreational, and occasional occupancy. As such, to determine consistency with the
SCAG forecasts, projections set forth in the La Quinta General Plan are discounted by 27.5%.
Discounting the proposed General Plan projections by 27.5% yields an estimated 22,912
dwelling units and an associated population of 57,969 in 2035, which assumes an annual growth
rate of 1.38%. Projections set forth in the La Quinta General Plan are approximately 20% greater
than the SCAG forecast in 2035. This difference is expected given the variation in growth rates,
and the conservative assumptions of the EIR analysis including full occupancy of seasonal units
and a build out year of 2035.
Assuming that the proposed General Plan Update builds out by 2035, the population would have
increased by 34% compared to the 2010 population. As such, the General Plan Update has the
potential to induce population growth. Given that this rate of growth is estimated to be 1.38% per
year, the proposed General Plan is not expected to be substantially growth inducing.
When considering the entire Planning Area, the build out population under the General Plan
Update is reduced compared to the 2002 General Plan (See Planning Area discussion below).
Therefore, although the proposed General Plan has the potential to increase the population and
housing development within city limits, it is not expected to result in significant growth inducing
impacts.
The General Plan Update would allow for the development of an additional 3,218,039 square
feet of commercial development within City limits. While it is difficult to estimate the exact
number of jobs that may be created as a result of this development, the Riverside County Center
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for Demographic Research projects that, by 2035, there will be a total of 21,678 jobs within La
Quinta City limits. The 2002 General Plan allowed for up to 7,899,431 square feet of commercial
development within city limits at built out. The level of commercial development proposed under
the General Plan Update is a reduction from the commercial development proposed under the
2002 General Plan. Therefore, the General Plan Update will not induce growth as a result of
commercial or business development and impacts are considered to be less than significant.
Employment Projections
According to the SCAG Integrated Growth Forecast, it is projected that in 2020 there will be
10,565 La Quinta residents that are employed, and by 2035, there will be 11,864 La Quinta
residents who are employed. The City of La Quinta is projected to contain 21,678 jobs by 2035.
As such, over half of the jobs offered in La Quinta City limits could be filled by La Quinta
residents.
Sphere of Influence
In the Sphere of Influence, under the County’s land use designation, there are approximately
7,175 acres of residentially designated lands. If the Sphere were to build out under the current
County land use designations, a total of 11,946 residential units would be developed. Based on
the persons per household rate of 2.53, the population within the Sphere of Influence would be
30,222.
For purposes of analysis, this document assumes build out of the Sphere under the designations
assigned to these lands on the Land Use Map. However, the General Plan Update requires the
completion of a master plan for the eastern Sphere, which could significantly change the number
of units that are developed in this area. The General Plan Update allows for the development of
up to 21,500 residential dwelling units, which would result in a built out population size of
54,396 within the Sphere of Influence. As proposed, implementation of the General Plan Update
would increase the population within the Sphere of Influence by 24,174 people or 80% over the
current County land use designations. Therefore, the General Plan Update has the potential to
induce growth and result in a substantial increase to the population size. The proposed
development for residential land uses in the Sphere of Influence has the potential to result in
significant impacts to population and housing. The development of the master plan for the area
will change the land use distribution in this area, and provide greater specificity regarding
building density and intensity. The master plan, therefore, will mitigate potential impacts
associated with population and induced growth.
In addition, the General Plan Update would allow for the development of up to 2,732,557 square
feet of commercial development and 611,408 square feet of industrial uses within the City’s
Sphere of Influence. Under the General Plan Update, all land outside of the incorporated city
limits are contained within the Sphere of Influence, and said area, including proposed square
footage, has been reduced compared to the 2002 General Plan.
Under the County’s Vista Santa Rosa Land Use Concept Plan, a total of 5,161,764 square feet of
retail is proposed. The proposed General Plan Update would result in less commercial
development relative to the 2002 General Plan and the County’s Plan. Therefore, commercial
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development set forth in the General Plan Update is not expected to be growth inducing, and
impacts will be less than significant.
Planning Area Summary
The overall Planning Area for the La Quinta General Plan Update has the potential to result in
the development of 53,103 residential units, which could support a population of 134,352 people.
As described above, implementation of the General Plan Update is not expected to substantially
induce growth within City limits. However, the proposed development within the Sphere of
influence has the potential to increase the population by 80% compared with that permitted under
current County land use designations. Thus, the proposed General Plan Update has the potential
to result in significant impacts to population and housing from growth inducing development
within the Sphere of Influence. In order to mitigate potential impacts from proposed
development within the Sphere of Influence, a Master Plan of Development will be prepared.
Adherence to such a plan would be sufficient to reduce potential impacts to population and
housing within the Sphere of Influence to levels below significance.
3. Mitigation Measures
1. A Master Plan of Development shall be prepared for the Vista Santa Rosa area. Development
within this area shall be subject to policies set forth in the said Master Plan.
Monitoring and Reporting
A. New development proposed for the Sphere of Influence will be reviewed for consistency
with the Master Plan of Development.
Responsible Parties: Planning Department
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Public Services & Utilities M.
Introduction
Current public services, utilities and service systems in the General Plan Planning Area and the
vicinity are described in this section. It also analyzes potential constraints, risks and
opportunities associated with these existing conditions. Potential impacts associated with
implementation of the proposed General Plan Update are also considered, and mitigation
measures set forth to reduce impacts.
In order to research and assess these impacts, a variety of resources have been consulted,
including personal communication with service providers and other sources. Please also see
Existing Conditions, below, for further discussion of these resources.
Thresholds of Significance/Criteria For Determining Significance
The following standards and criteria have been drawn from Appendix G Environmental
Checklist Form of the CEQA Guidelines to assess the significance of potential impacts to public
services and facilities that may result from the adoption and implementation development of the
La Quinta General Plan. Impacts would be considered significant if implementation of the
General Plan would result in the following:
a.) Conflict with or obstruct construction of new public utilities or facilities, including
above-ground and subsurface energy, fuel or telecommunication transmission facilities.
b.) Conflict with or obstruct the operation and maintenance of existing public utilities or
facilities, including aboveground and subsurface energy, fuel or telecommunication
transmission facilities.
c.) Result in substantial adverse physical impacts associated with or create substantial
impediments to the provision of new or physically altered government facilities.
d.) Exceed wastewater treatment requirements of the applicable Regional Water Quality
Control Board.
e.) Require or result in the construction of new or wastewater drainage facilities or
expansion of existing facilities, the construction of which could cause significant
environmental effects.
f.) Require or result in the construction of new stormwater drainage facilities or expansion
of existing facilities, the construction of which could cause significant environmental
effects.
g.) Not have sufficient water supplies available to serve the project from existing
entitlements and resources, or new expanded entitlements are needed.
h.) Have inadequate landfill capacity to accommodate the project’s solid waste disposal
needs.
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i.) Fail to meet the water supply assessment requirements of Water Code Section 10910, et
seq. (SB 610), and the requirements of Government Code Section 664737 (SB 221).
j.) Fail to result in a determination by the wastewater treatment provider which serves or
may serve the project that it has adequate capacity to serve the project’s projected
demand in addition to the provider’s existing commitments.
k.) Not be served by a landfill with sufficient permitted capacity to accommodate the
project’s solid waste disposal needs.
l.) Fail to comply with federal, state, and local statues and regulations related to solid waste.
m.) Result in substantial adverse physical impacts associated with the provision of new or
physically altered governmental facilities, or create a need for new or physically altered
governmental facilities, the construction of which could cause significant environmental
impacts, in order to maintain acceptable service ratios, response time or other
performance objectives for fire protection, police protection, schools, parks, and other
public facilities.
Service Providers
There are a wide range of public services and facilities serving the General Plan Update area.
These include:
Public Schools: Desert Sands Unified School District, Coachella Valley Unified School
District
Library Services: Riverside County Library System
Law Enforcement: La Quinta Police Department/Riverside County Sheriff’s Department
Fire Protection: La Quinta Fire Department
Electricity: Imperial Irrigation District
Natural Gas: The Gas Company
Domestic Water: Coachella Valley Water District
Wastewater Collection/Treatment: Coachella Valley Water District
Solid Waste Management: Burrtec Waste and Recycling Services, LLC
Schools
1. Existing Conditions
Public Schools
There are two school districts providing public education to students in Kindergarten through
12th Grade in La Quinta: Desert Sands Unified School District (DSUSD) and Coachella Valley
Unified School District (CVUSD). Each is described below.
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Desert Sands Unified School District
DSUSD services students to students living west of Jefferson Street and north of Avenue 48.
This includes the northern Sphere of Influence. District administrative offices and the bus yard
are located on Dune Palms Road in La Quinta.
There are seven DSUSD schools in La Quinta. The following table lists each school as well as
enrollment and design capacity.
Table III-35
Desert Sands Unified School District Enrollment and Capacity
School Location
2010
Enrollment1 Capacity2
John Adams Elementary School 50-800 Desert Club Drive 432 750
Benjamin Franklin Elementary School 77-800 Calle Tampico 631 750
Harry S. Truman Elementary School 78-870 Avenue 50 614 750
La Quinta Middle School 78-900 Avenue 50 662 1,200
Colonel Mitchell Paige Middle School 43-495 Palm Royale Drive 993 1,200
La Quinta High School 79-255 Westward Ho Drive 2,948 2,200
Summit Continuation School (K-12) 43-330 Palm Royale Drive 475 N/A
1 Enrollment as of November, 2010. Source: Personal communication, Linda Lawson, DSUSD Fiscal Department,
December 16, 2010. 2 Represents design capacity; school facility capacities expand to meet enrollment using portable classrooms.
Source: Personal Communication, James Kozero, DSUSD Facilities Department, December 16, 2010.
As noted above, current enrollment at the La Quinta High School exceeds design capacity. The
District utilizes portable classrooms to accommodate over-capacity student enrollment at its
schools until enrollment warrants construction of new school facilities. DSUSD recently opened
the Shadow Hills High School north of US I-10 near Jefferson Street, which it expects will
gradually absorb some of the excess student population currently served by La Quinta High
School. Shadow Hills has a current enrollment of between 900 and 1,000 students.
In general, DSUSD student populations have remained stable or declined slightly as a result of
recession-related impacts on local development. Facilities staff has indicated it expects that no
new school facilities will be required in the short term (2 to 4 years). However, the District
continues to plan for expansion. Although there are few if any sites available for new DSUSD
school facilities within La Quinta, DSUSD has identified future school site properties near the
Shadow Hills campus and in the cities of Indio and Coachella.66
Coachella Valley Unified School District
The CVUSD district boundaries within La Quinta include lands east of Jefferson Street and East
of Avenue 48. This includes the City’s eastern Sphere of Influence. There are four CVUSD
schools serving students in La Quinta and the eastern Sphere. These are shown in Table III-36.
66 Personal communication, James Kozero, Project Manager, DSUSD Facilities Department, December 16, 2010.
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Table III-36
Coachella Valley Unified School District Enrollment and Capacity
School Location
2010
Enrollment1 Capacity
Westside Elementary School 82-225 Airport Boulevard (Sphere) 636 678
Cahuilla Desert Academy 82-489 Avenue 52 (Sphere) 721 990
Mountain Vista Elementary School 49-750 Hjorth Street (NE of Sphere) 991 750
Coachella Valley High School 83-800 Airport Boulevard (City limits) 2,551 1,712
1 Enrollment as of December, 2010.
Source: Personal communication, Marcella Valdez, CVUSD Facilities Department, December 16, 2010.
The over-capacity student population at Mountain Vista Elementary School is currently housed
in portable classrooms. The District has no plans for a new elementary school; however, a new
school to serve students grades 7 through 12 is planned near Avenue 49 and Monroe Street, east
of the City. No construction start date has been specified.67
Other Public School Facilities
DSUSD also provides adult education programs, such as GED test preparation, citizenship
classes and English as a Second Language. It also offers early childhood education, special
education services, and after-school programs. The Alternative school provides independent
learning and home schooling support for students in grades Kindergarten through 12th grade.
Other CVUSD services include an adult school with vocational training, citizenship classes, and
GED test preparation. CVUSD also offers tutoring and special education services.
School Funding
There are a variety of funding sources for these school districts, including a portion of local
property taxes as well as State funds. In addition, State Assembly Bill 2926 (AB 2926), enacted
in 1986) authorizes school districts to levy an impact fee on developers. These fees may be used
to construct new facilities. They are updated periodically. Fees are $2.97 per square foot of new
residential development and $0.47 per square foot of commercial/industrial development.68
Higher Education Institutions
There are three regional higher education institutions in the eastern Valley. They include the
College of the Desert, a community college with Associates degree programs and adult
education. Bachelor’s and Master’s degree programs are offered through California State
University, San Bernardino and University of California, Riverside. All three campuses are
located in Palm Desert, approximately 8 miles northwest of the City.
67 Personal communication, Marcella Valdez, CVUSD Facilities Department, December 16, 2010. 68 “Facilities: Demographics,” http://www.coachella.k12.ca.us/interport/default.aspx?tabid=59, accessed
November 23, 2010.
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2. Impacts
The following tables show estimated student enrollment in the City limits and Sphere of
Influence. These estimates include existing and future units based on General Plan build out.
Table III-37
Potential Student Generation La Quinta City Limits
Grade Level Max. Student Projected
Enrollment Build out Units Generation Rate
Elementary (K-6)
Single Family 25,585 0.214 5,475
Multi-Family 6,017 0.1267 762
Elementary Subtotal 6,237
Middle (7-8)
Single Family 25,585 0.1093 2,796
Multi- Family 6,017 0.0522 314
Middle School Subtotal 3,110
High School (9-12)
Single Family 25,585 0.1427 3,651
Multi-Family 6,017 0.0543 327
High School Subtotal 3,978
Total 31,603 13,325
Terra Nova Staff Estimates based on Student Generation Rates, Desert Sands Unified School District
Master Facilities Plan, October 2008.
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Table III-38
Potential Student Generation Sphere of Influence
Grade Level Max. Student Projected
Enrollment Build out Units Generation Rate
Elementary (K-6)
Single Family 21,281 0.214 4,554
Multi-Family 219 0.1267 28
Elementary Subtotal 4,582
Middle (7-8)
Single Family 21,281 0.1093 2,326
Multi- Family 219 0.0522 11
Middle School
Subtotal
2,337
High School (9-12)
Single Family 21,281 0.1427 3,037
Multi-Family 219 0.0543 12
High School Subtotal 3,049
Total 21,500 9,968
Terra Nova Staff Estimates based on Student Generation Rates, Desert Sands Unified School District
Master Facilities Plan, October 2008.
Table III-39
Potential Student Generation Planning Area Summary
Grade Level Max.
Build out Units
Student
Generation Rate
Projected
Enrollment
Elementary (K-6)
Single Family 46,866 0.214 10,029
Multi-Family 6,236 0.1267 790
Elementary Subtotal 10,819
Middle (7-8)
Single Family 46,866 0.1093 5,122
Multi- Family 6,236 0.0522 325
Middle School Subtotal 5,447
High School (9-12)
Single Family 46,866 0.1427 6,688
Multi-Family 6,236 0.0543 339
High School Subtotal 7,027
Total 53,103 23,293
Terra Nova Staff Estimates based on Student Generation Rates, Desert Sands Unified School District
Master Facilities Plan, October 2008.
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New development in the planning area will occur over time, and student populations are also
expected to increase gradually. Both school districts employ facilities planning that provides for
new school sites as population within their respective boundaries increases. CVUSD and
DSUSD will continue to receive developer’s impacts fees for residential, commercial and
industrial development. These measures are expected to minimize impacts to CVUSD and
DSUSD schools. However, schools in both districts are currently operating at or beyond
capacity, and new facilities will be needed to serve the build out student population in the
Planning Area. Mitigation measures are set forth below to ensure that any potential adverse
effects to public schools are reduced to less than significant levels.
At this level of analysis, there is not sufficient site-specific development data to calculate
developer impact fees; further these fees are periodically adjusted. It is to be expected, however,
that these fees will be substantial and will assist the school districts in the General Plan Area to
offset impacts of new development on their respective schools.
3. Mitigation Measures
The following mitigation measures shall be implemented to ensure that impacts are reduced to
less than significant levels for schools in the Coachella Valley Unified School District and Desert
Sands Unified School District.
1. Developers shall continue to be assessed statutory school mitigation fees for residential and
commercial development.
Mitigation Monitoring and Reporting
A. The City shall continue to coordinate with the Coachella Valley Unified School District and
Desert Sands Unified School District to assure that statuary developer impact fees are
collected.
Responsible Party: Planning Department
Libraries
1. Existing Conditions
The La Quinta Library is located at 78-275 Calle Tampico. The City owns the library facility,
which is operated by Riverside County. Currently, the Library contains 89,060 volumes within a
20,000 square foot space. Although the City has not established a standard for library facilities,
the County Library system aims for an un-adopted standard of two volumes per capita. Based on
this standard, existing library facilities are sufficient to serve the current population.
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2. Impacts
Based on the County Library System’s target standard, the estimated build out population of
79,956 in the City limits will require 159,912 volumes at build out of the General Plan. The
Sphere build out population of 54,396 will require 108,792 volumes. In total, the Planning Area
will require 268,704 volumes at build out. Additional facilities would also likely be required to
house the additional volumes and serve patrons.
The City assesses Developer Impact Fees (DIF) on residential development for library services
and facilities. Currently, fees are assessed at $355 for single-family detached units, $266 for
single-family attached units, and $348 for multi-family units.69 These are one-time fees assessed
when new units are constructed. Based on these fees, new residential development in the City
limits could generate up to approximately $2.86 million in library fees; up to an additional $7.35
million could be generated in the Sphere. In total, new residential development in the planning
area is expected to generate approximately $10.21 million in library development fees. Fees will
be assessed as new development occurs, so these revenues will not be available to the City all at
one time. The City’s DIF schedule would be expected to increase over the course of General
Plan build out. These fees have been developed based on a rational nexus, and will therefore be
sufficient to accommodate growth through General Plan build out, reducing impacts to less than
significant levels.
The City has studied the land use pattern in the Sphere, and has considered several potential
annexation proposals in the past. These proposals included analyses relating to the availability
and cost of the provision of services in the Sphere. These analyses found that in the eastern
Sphere in particular, lands have been encumbered by the County as collateral for a regional bond
issue. As a result, there will be no property tax generation to the City from these lands for a
number of years. The fiscal analysis concluded that the annexation of property in the Sphere
would have a negative fiscal impact on the City. At the time of the analysis, a per unit mitigation
fee was considered, but the proposed annexations did not proceed, and the mitigation program
was not implemented. The costs associated with annexation to the City, however, still exists, and
will remain an issue as annexation proposals occur in the future.
As described above, the annexation of lands in the eastern Sphere would have a negative fiscal
impact on the City, including the library. Although past annexation requests were not completed,
conditions have not changed since this analysis was undertaken, and it would be expected that
annexation proposals in the future would have a similarly negative fiscal impact. The General
Plan includes policies that require both the preparation of fiscal impact analyses for annexation
proposals, and a Development Agreement in association with annexation. The Development
Agreement would establish the parameters for development, and would include mitigation fee
payments for projects that are fiscally negative for the City. These Development Agreements
would eliminate the potential fiscal impacts to the City in providing library services to newly
annexed lands.
The implementation of these policies would reduce impacts to less than significant levels.
69 “City of La Quinta Development Impact Fee Summary,” December 8, 2008.
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3. Mitigation
None required.
Mitigation Monitoring and Reporting
None required.
Law Enforcement
1. Existing Conditions
The City contracts annually with the County of Riverside for police staffing. In 2010-2011, the
City’s contract provided for the equivalent of 51 sworn officers and 5 community service
officers. City-assigned officers conduct investigations, manage traffic control, and provide
general patrol duties. Patrol division staff is augmented by a Special Enforcement Team, which
provides investigative services and support for prevention activities in the community.
Community programs include the School Resource Officer program at local schools; the Junior
Cadet program; a Crime Stoppers program; the volunteer Citizens on Patrol Program; and
Community Service Officers. The latter, which are assigned to each division, serve as
community liaisons and are responsible for coordinating Community Programs such as
Neighborhood Watch.
There are two Police Department offices in the City: a station at 51-351 Avenida Bermudas, and
a Business District Office located at 79-440 Corporate Center Drive.
The Riverside County Sheriff’s Department maintains a staffing level of one staff per 1,000
population.70 The City has no established staffing ratio, and police staffing in La Quinta is based
on the safety needs of the local community and the available resources to provide these safety
needs.71 Based on the City’s 2010 full occupancy population of 59,427, the current level of
police staffing is approximately 1.06 staff per 1,000 population.
70 Written communication, Lt. Jason Huskey, Assistant Police Chief, La Quinta Police Department, Riverside
County Sheriff’s Department, December 2, 2010. 71 Written communication, Bret Plumlee, Assistant City Manager, City of La Quinta, December 6, 2010.
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2. Impacts
At build out, the City and Sphere of Influence are expected to have a total population of 134,352.
Based on the Riverside County staffing ratio, the police department will require 134 sworn
officers at build out. This is an increase of 78 sworn officers as compared with current staffing
levels, which represents a substantial additional demand for police protection and associated
equipment and patrol vehicles. Increases in cost to the City could be significant. Demand will
increase gradually, and revenues to the City are also expected to occur as the General Plan builds
out. Demand for police protection will depend on actual development in the future.
The City has studied the land use pattern in the Sphere, and has considered several potential
annexation proposals in the past. These proposals included analyses relating to the availability
and cost of the provision of services in the Sphere. These analyses found that in the eastern
Sphere in particular, lands have been encumbered by the County as collateral for a regional bond
issue. As a result, there will be no property tax generation to the City from these lands for a
number of years. The fiscal analysis concluded that the annexation of property in the Sphere
would have a negative fiscal impact on the City. At the time of the analysis, a per unit mitigation
fee was considered, but the proposed annexations did not proceed, and the mitigation program
was not implemented. The costs associated with annexation to the City, however, still exists, and
will remain an issue as annexation proposals occur in the future.
As described above, the annexation of lands in the eastern Sphere would have a negative fiscal
impact on the City, including police services. Although past annexation requests were not
completed, conditions have not changed since this analysis was undertaken, and it would be
expected that annexation proposals in the future would have a similarly negative fiscal impact.
The General Plan includes policies that require both the preparation of fiscal impact analyses for
annexation proposals, and a Development Agreement in association with annexation. The
Development Agreement would establish the parameters for development, and would include
mitigation fee payments for projects that are fiscally negative for the City. These Development
Agreements would eliminate the potential fiscal impacts to the City in providing police services
to newly annexed lands.
The implementation of these policies would help to reduce impacts.
3. Mitigation
1. All new development projects shall be subject to Police Department review to assure that the
Department can provide adequate police protection.
2. The City shall monitor City population and Police Department staffing levels to ensure the
provision of police protection services at sufficient levels.
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Mitigation Monitoring and Reporting
A. On an annual basis, the City shall evaluate response times and police activity to assure
adequate protection.
Responsible Parties: City Manager, Police Department.
Fire Protection
1. Existing Conditions
Fire protection is provided through a contract with the Riverside County Fire Department, which
also serves the Sphere of Influence areas. There are three City-owned fire stations, each staffed
with full-time paid and volunteer firefighters, and equipped as listed below:
Fire Station No. 32 at 78-111 Avenue 52; equipment includes a primary and reserve fire engines,
and volunteer squad and rescue vehicles.
Fire Station No. 70 at 54001 Madison Street; equipped with a primary engine, a brush fire
engine, and a volunteer squad vehicle.
Fire Station No. 93 at 44-555 Adams Street; equipped with a primary engine and a reserve
engine.
Emergency response in the Planning Area is also available through Riverside County Fire
Department stations in other cities. These include Station No. 55, located in Indian Wells;
Station No. 88, in Indio; and Station No. 39, located at the Desert Resorts Airport, east of the
City’s eastern Sphere of Influence. County Fire dispatches all calls through its centralized
Emergency Command Center, where responding stations are determined based on location and
need.
Average Fire Department response times are between 5 and 7 minutes. La Quinta has an
Insurance Service Office (ISO) of 4, based on a scale of 1 through 10, with 1 being the highest
rating. Ratings are reviewed periodically. A variety of criteria are used to determine the ISO
rating, such as staffing levels, response times, safety history and building code standards.
The County Fire Department cites thresholds established in its 1986 Master Plan,72 which call for
one new fire station per every 2,000 dwelling units or 3.5 million square feet of commercial
development.73 The Fire Department has developed a Strategic Plan to update thresholds and
plan for staffing, facilities and services through 2029. Goals and strategies include developing a
“standard of cover” analysis to establish appropriate staffing levels to meet operational needs
within the various jurisdictions the Department serves.74
72 “Riverside County Fire Protection and Emergency Medical Master Plan”, January 2, 1986. 73 Personal communication, Jason Newman, Riverside County Fire Department Strategic Planning, December 22,
2010. 74 “Riverside County Fire Department Strategic Plan 2009-2029”, prepared by Management Partners, Inc.,
November 2009.
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2. Impacts
Implementation of the General Plan Update and the increase in population in the General Plan
Planning Area is expected to result in an increase in demand for fire protection services. The
need for additional services will be determined as the Planning Area develops; additional staff,
equipment and vehicles, and fire stations will be needed. The extension of water mains and
installation of new fire hydrants may also be required which are currently undeveloped or less
developed. The potential cost to the City may be substantial, and on-going monitoring and
evaluation of the need for additional facilities and staff will be necessary throughout build out.
The County Fire Department evaluates specific development proposals based on their potential
to demand additional fire department facilities and staffing. It considers existing conditions in the
area as well as future needs of such new development in determining whether it is appropriate to
require new fire facilities based on the standards set forth in the 1986 Master Plan, as cited
above.75 It is expected that as the General Plan Area builds out, new “standards of cover”
developed in association with the Department’s Strategic Plan will be applied to new
development. Future development will continue to be subject to Fire Department review and new
fire facilities will be constructed as needed to ensure adequate provision of fire protection
services in the Planning Area.
The City has studied the land use pattern in the Sphere, and has considered several potential
annexation proposals in the past. These proposals included analyses relating to the availability
and cost of the provision of services in the Sphere. These analyses found that in the eastern
Sphere in particular, lands have been encumbered by the County as collateral for a regional bond
issue. As a result, there will be no property tax generation to the City from these lands for a
number of years. The fiscal analysis concluded that the annexation of property in the Sphere
would have a negative fiscal impact on the City. At the time of the analysis, a per unit mitigation
fee was considered, but the proposed annexations did not proceed, and the mitigation program
was not implemented. The costs associated with annexation to the City, however, still exists, and
will remain an issue as annexation proposals occur in the future.
As described above, the annexation of lands in the eastern Sphere would have a negative fiscal
impact on the City, including fire protection services. Although past annexation requests were
not completed, conditions have not changed since this analysis was undertaken, and it would be
expected that annexation proposals in the future would have a similarly negative fiscal impact.
The General Plan includes policies that require both the preparation of fiscal impact analyses for
annexation proposals, and a Development Agreement in association with annexation. The
Development Agreement would establish the parameters for development, and would include
mitigation fee payments for projects that are fiscally negative for the City. These Development
Agreements would eliminate the potential fiscal impacts to the City in providing fire protection
services to newly annexed lands.
75 Personal communication, Jason Newman, Riverside County Fire Department Strategic Planning, December 22,
2010.
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The implementation of these policies would help to reduce impacts.
3. Mitigation
Impacts associated with provision of fire protection services will be reduced to less than
significant levels with the implementation of the following mitigation measures:
1. The City and Riverside County Fire Department shall continue to confer and coordinate to
ensure that facilities and services are expanded in a timely manner.
2. The City shall plan for siting of industrial facilities that store hazardous, flammable or
explosive materials so as to assure the highest level of safety in strict conformance with
Uniform Fire Code and other applicable codes and regulations.
3. The Riverside County Fire Department shall continue to review and evaluate new
development proposals and project plans to make certain that it can provide adequate fire
protection.
Mitigation Monitoring and Reporting
A. Riverside County Fire Department shall review all development plans prior to issuance of
building permits to ensure that development complies with City and Fire Department
standards.
Responsible Parties: Planning Department, Riverside County Fire Department
Electricity
1. Existing Conditions
Imperial Irrigation District (IID) provides electric power in the City and the Sphere of Influence.
IID delivers electric service by means of power generation and contractual agreements. There are
six IID substations within or near the Planning Area, as follows:76
North La Quinta Substation – northwest corner of Adams Street and Westward Ho;
La Quinta Substation – southwest corner of Avenue 48 and Jefferson Street;
Jefferson Substation – Jefferson Street at the northeast corner of Avenue 52;
Marshall Substation – northeast corner of Washington Street and Avenida Ultimo;
Avenue 58 Substation – northwest corner of Avenue 58 and Monroe Street;
Thermal Substation – south of Airport Boulevard and east of Highway 111.
Substations are gauged at 92 or 161 kilovolts (kV), and from there electrical power is decreased
for distribution to customers at 12.47 kV. There are 8 proposed substations in the Planning Area
and vicinity. Of these, one was discussed in the previous General Plan update between the
76 Written communication provided by Guillermo Barraza, Customer Operations and Planning, Imperial Irrigation
District, December 21, 2010.
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easterly Sphere boundaries and the Jacqueline Cochran Regional Airport. This substation is still
in the planning stages. Other proposed substation locations include:77
Near Avenue 54 and Monroe Street;
At Van Buren Street and Avenue 64;
Near Avenue 60 and Monroe Street;
At Avenue 58 and Harrison Street;
At Madison Ave and Avenue 64;
At 54 and Harrison Street;
At Avenue 62 and Harrison Street.
The City’s Municipal Code (Chapter 13.24.110) requires that all utilities in new residential
districts and subdivisions be undergrounded.
Based on historical use data for the Planning Area provided by IID, it was estimated that
residential development consumes approximately 16,798 kilowatt hours per year. Estimated
electricity usage rates by land use type are shown in Table III-40.
Table III-40
Estimated Electricity Usage Rates
Land Use Annual Usage Rate
Residential 16,798 Kilowatt-hour/unit/year
Commercial 57.88 Kilowatt-hour/square feet/year
Industrial 57.88 Kilowatt-hour/square feet/year
Source: Terra Nova Staff estimates based on 2005 demand data for Planning Area
provided by Hugo Valdez, Imperial Irrigation District, October 22, 2010.
Based on these factors, existing residential and commercial development in the City consumed
an estimated 765,590,714 kilowatt hours, while residents and commercial users in the Sphere
consumed 29,242,547 kilowatt hours.
2. Impacts
Estimates of annual electrical demand for General Plan build out are based on the annual usage
rates shown above. These rates applied to the proposed General Plan land uses at build out will
result in electrical consumption of 1,645,145,600 kilowatt-hours per year (kwh/year). Single-
family residential uses will account for 791,924,912 kwh/year of this amount, while multi-family
uses will account for 101,224,748 kwh/year. Commercial uses will consume 716,607,636
kwh/year, and industrial development will use 35,388,304 kwh/year.78
In the overall, increased demand associated with implementation of the General Plan will
contribute to the regional demand for electricity. The City is completing a Greenhouse Gas
77 Written communication provided by Guillermo Barraza, Customer Operations and Planning, Imperial Irrigation
District, December 21, 2010. 78 “La Quinta General Plan Air Quality Report,” prepared by Terra Nova Planning and Research, July 2011.
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Reduction Plan as part of the General Plan Update. The Reduction Plan includes measures to
reduce energy use. In addition, the General Plan’s Sustainable Community Element includes
policies for resource conservation, including energy conservation for development projects in the
City. These policies will reduce the relative consumption of electricity in the City as the General
Plan builds out.
Imperial Irrigation District is a publicly traded company. It has established a rate structure that
accommodates growth through the extension of facilities. Build out of the General Plan Area is
expected to occur over time. Therefore, IID’s expansion plans will be adjusted to accommodate
it, and impacts are expected to be less than significant.
3. Mitigation
IID’s rate structure includes expansion to accommodate expansion, which is expected to occur
gradually over time. No significant impact is expected, and no mitigation measures are required.
Natural Gas
1. Existing Conditions
Southern California Gas Company provides natural gas services and facilities within the City and
its Sphere of Influence. Residents use natural gas as the primary energy source for cooking and
for heating space and water.
High-pressure transmission lines are located north of US Interstate 10 and deliver natural gas to
the region. These lines are 36-inch diameter lines with 400 to 700 pounds per square inch (psi)
pressure capacities. Limiting stations located throughout the region reduce pressure, and from
there gas is distributed through supply lines ranging in diameter from 2 to 8 inches. Within the
Planning Area, there are major natural gas supply lines within Washington Street and Highway
111. Regulator stations further reduce pressure and transfer it to distribution lines for delivery to
residential and business customers.
Some areas of the City and Sphere have limited access to natural gas service. These include the
southern portion of the City and Sphere, especially south of Airport Boulevard and east of
Monroe Street, as well as within portions of the La Quinta Cove, and some older developments
in the Sphere. In these areas, propane gas purchased from private firms is utilized.
Based on estimates provided by the Southern California Gas Company, average annual natural
gas consumption for residences is 29,093 cubic feet (cf). The following table shows estimated
natural gas consumption factors for various land uses.79
79 Data provided by Southern California Gas Company, August 13, 2010.
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Table III-41
Natural Gas Consumption Factors
Residential 29,093 cubic feet/unit/year
Commercial 53.22 cubic feet/square feet/year
Industrial 53.22 cubic feet/square feet/year
Source: Terra Nova Staff estimates based on .2005 historical data provided by Southern
California Gas Company, August 13, 2010.
Based on these factors, residential, commercial and industrial gas customers in the City
consumed 1,025 million cubic feet of natural gas. In the Sphere for the same period, residential
and commercial customers used 37,819,780 cubic feet. In the overall, natural gas customers in
the Planning Area used over 1 billion cubic feet of natural gas.80
2. Impacts
At build out, there are expected to be 46,866 single-family and 6,236 multi-family dwelling units
in the Planning Area. There is expected to be 12,364,631 square feet of commercial space, and
611,408 square feet of industrial space.
Applying the factors in Table III-41 to these land uses, single-family units will use
approximately 1,371,560,392 cubic feet of natural gas per year (cf/year), and multi-family units
will use approximately 175,314,418 cf/year.81
For commercial and industrial uses, consumption will be approximately 658,912,550 cf/year and
32,539,142 cf/year, respectively. At build out, all development in the General Plan Planning
Area is expected to consume approximately 2,238,326,502 cubic feet per year. This accounts for
both existing and future development in the Planning Area. A variety of factors will determine
actual natural gas consumption, including future levels of development, individual project
designs, and the effectiveness of energy-conserving measures.
3. Mitigation
Southern California Gas Company has developed a rate structure that provides for facilities’
expansion. Therefore, impacts are not expected to be significant impact and no mitigation
measures are required.
80 Terra Nova Staff estimates based on 2005 historical data provided by Southern California Gas Company,
August 13, 2010. 81 Terra Nova Staff estimates based on 2005 historical data provided by Southern California Gas Company,
August 13, 2010.
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Domestic Water Services
1. Existing Conditions
Domestic and irrigation water within the City and most of the Sphere is provided by Coachella
Valley Water District (CVWD). Groundwater is CVWD’s primary domestic water source; water
is extracted from deep wells located throughout the City and region. CVWD also relies on
imported water, which is used to supply recharge basins located near Palm Springs, as well as in
southern portion of the Planning Area south of Lake Cahuilla, and in Martinez Canyon, south
and east of the City.
In general the water distribution system, owned and operated by CVWD, is located within the
public right of way under existing streets. CVWD has water storage reservoirs within its service
area. In the La Quinta Planning Area, there are 10 existing or planned tanks. The tanks range in
capacity from 250,000 to 12 million gallons.
California Water Code requires that CVWD prepare and periodically update an Urban Water
Management Plan (UWMP) to analyze current and future water supplies to ensure that it has
sufficient supplies to serve land uses within its service area. Additional information regarding
water resources is provided in Section III-P, Water Quality and Resources.
2. Impacts
A Water Supply Study (WSS)82 has been prepared to assess future water demands relative to
supplies for the proposed General Plan at build out. As discussed in the WSS, the proposed
General Plan will result in increased water demand associated with development, such as
residential, commercial, and industrial, as well as open space amenities, street rights-of-way and
others. An estimate of increased demand is shown in Section III-I. Water consumption factors
and methodology utilized to project water demand are explained in the WSS. Based on the
assumptions set forth therein, build out of the proposed General Plan Update is expected to result
in an annual water demand of 54,467 acre-feet.
The General Plan will facilitate development that will cumulatively increase impacts to
groundwater supplies in the region. The amount of potable groundwater in storage will also be
reduced. As discussed in Section III-I, development in the region will occur gradually, as will
impacts to groundwater supplies. For a more thorough discussion of impacts to water resources
and quality, please see Section III-P.
3. Mitigation
Mitigation measures to reduce potential impacts associated with domestic water to less than
significant levels are shown below. Additional measures are included in Section III-P, Water
Resources/Quality.
82 “La Quinta General Plan Water Supply Study,” prepared by Terra Nova Planning & Research, July 2011.
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1. The City and Coachella Valley Water District shall review and evaluate all future
development projects for their potential impact on local groundwater supplies.
2. The City shall continue to require the use of drought tolerant landscaping in new and
rehabilitated public and private development, and shall encourage its use in existing
development.
3. Future development shall be required to conform to standards set forth in Section 17921.3 of
the Health and Safety Code, Title 20, California Administrative Code Section 1601(b), and
applicable sections of Title 24 of the State Code. Measures set forth in these statutes include
the installation of low-flow showerheads and faucets and low-flush toilets in all new
construction.
Mitigation Monitoring and Reporting
A. All development proposals shall be reviewed by the Planning Department and the City
Engineer for their potential to result in adverse impacts to water quality and quantity. The
City shall require that any potential significant impacts be mitigated prior to project approval.
Responsible Parties: Planning Department, City Engineer, Coachella Valley Water District
Wastewater Collection and Treatment
1. Existing Conditions
Sanitary sewer collection and treatment facilities are provided by the Coachella Valley Water
District within most of the City and Sphere. Where sewer facilities are not available, residences
utilize septic systems. These occur primarily in the Sphere.
There are two CVWD wastewater treatment plants that serve La Quinta. Water Reclamation
Plant 7 (WRP-7) is located at Madison Street and Avenue 38, northeast of the City in Indio. It
provides wastewater treatment for development in the City north of Miles Avenue. The capacity
of WRP-7 is 5 million gallons per day (mgd), and the plant processes approximately 2.8 to 3.0
mgd. It has the capacity to expand to 7.5 mgd. Currently there is sufficient excess capacity;
therefore, although expansion capacity exists, no such plans are imminent.83
WRP-7 has facilities to treat wastewater to tertiary levels, which is suitable for irrigation but is
not potable. The plant’s tertiary capacity is 2.5 mgd. Planning is currently underway to design
expansion of the tertiary system to 5.0 mgd, however no target date has been set for completion
of this expansion. Current economic conditions have resulted in steady or slightly reduced
demand. WRP-7 tertiary water provides irrigation for the Del Webb and Shadow Hills
developments. 84
83 “Engineer’s Report on Water Supply and Replenishment Assessment: Lower Whitewater River Subbasin Area
of Benefit, 2010-2011,” prepared by Coachella Valley Water District, April 2010.” 84 Personal communication, Ray Salazar, CVWD-WRP-7, December 15, 2010.
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The Mid-Valley Water Reclamation Plant (WRP-4), located in Thermal, serves lands in the City
and Sphere that are located south of Miles Avenue. The Mid-Valley plant has a current capacity
of just under 10 mgd, and processes approximately 5 mgd per day. Given the excess capacity,
there are currently no plans for expansion at the Mid-Valley plant. WRP-4 does not include
tertiary treatment facilities. 85 CVWD indicates that such facilities could be located at this plant
in the future should demand warrant.86
CVWD sewer lines utilize a system of trunk lines ranging in diameter from 4 to 24 inches. There
are 18-inch diameter force mains in Washington Street, Jefferson Street, Madison Street, and
Avenues 50, 58 and 60.
2. Impacts
Implementation of the General Plan will facilitate development that will increase demand on
existing wastewater collection and treatment facilities. It is assumed that domestic wastewater
flows are equivalent to the potable water demand projections, which average approximately 69.3
gallons per capita per day in 2010 and are projected to average 55.44 gpcd at build out. Using
this approach, it is estimated that in 2010 the City of La Quinta generated approximately 4.1
million gallons per day (gpd) of wastewater. It is expected that, at build out, the City of La
Quinta will generate approximately 4.4 million gallons per day of wastewater. Wastewater
generation in the Sphere is estimated to be 140,471 gallons per day in 2010. At build out, the
Sphere is projected to generate approximately 3.0 million gallons of wastewater per day, which
is an increase of about 2.8 million gallons by 2035. Total wastewater generation in the Planning
Area at build out is projected to be approximately 7.4 million gpd, which is an increase of
approximately 3.1 million gallons over estimated 2010 conditions.
This level of wastewater generation is substantial; however it will not exceed the combined
treatment capacity at the CVWD treatment plants serving the Planning Area. Further, CVWD
continues to plan for expansion as needed. As future development occurs, existing facilities may
need to be expanded to build out capacity to accommodate wastewater generation. Further, it is
expected that existing development currently served by private septic systems will connect to
community sewer systems over the course of General Plan build out.
Development in the General Plan area will occur gradually over time. The City and CVWD will
have an opportunity to plan for increased development, including construction of new sewer
collection facilities and increased treatment capacity. Nevertheless, growth trends will need to be
monitored to ensure that adequate wastewater treatment facilities are provided to serve the
Planning Area. As future development connects to sewer facilities, it will continue to be subject
to connection fees.
3. Mitigation
85 Personal communication, Kim Halsey, CVWD WRP-4, December 14, 2010. 86 “Draft Coachella Valley Water District Urban Water Management Plan,” prepared by Montgomery Watson
Harza, December 2010.
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Although sufficient capacity appears to be available to serve future development through existing
treatment facilities, the City and CVWD will need to continue to monitor growth to ensure that
adequate capacity is available as the Planning Area builds out.
In order to ensure that potential impacts associated with wastewater collection and treatment are
reduced to less than significant levels, the following mitigation measures will be implemented.
1. To the greatest extent practicable, the City shall require that all new development be
connected to sanitary sewer service.
2. The City shall ensure coordination with the Coachella Valley Water District and to assure
that existing and future extended sanitary sewer facilities are adequate to meet the needs of
existing and expected future development.
3. The City and Coachella Valley Water District should encourage the replacement of existing
septic systems with connection to sanitary sewer facilities to the greatest extent feasible.
Mitigation Monitoring and Reporting
A. The City Planning and Public Works Departments shall confer and consult with Coachella
Valley Water District to implement City-wide wastewater collection and treatment facilities
and service.
Responsible Parties: Planning Department, Public Works Department, Coachella Valley
Water District.
B. All development proposals for future development shall be reviewed by the Planning and
Public Works Departments to ensure connection with sanitary sewer services.
Responsible Parties: Planning Department, Public Works Department, Coachella Valley
Water District.
Solid Waste Management
1. Existing Conditions
The City has a franchise agreement with Burrtec Waste and Recycling Services, LLC (Burrtec)
for the provision of solid waste disposal in the City and Sphere. Non-hazardous household,
commercial and most non-hazardous industrial solid waste collected in the Planning Area is
taken to the Edom Hill Transfer Station in Cathedral City. From there, waste is transported to the
Lamb Canyon regional landfill, which is owned and operated by Riverside County.
The Lamb Canyon landfill is located between the cities of Beaumont and San Jacinto at 16411
Lamb Canyon Road (State Route 79). The landfill is permitted to receive a maximum of 5,000
tons per day. As of January 2010, the landfill had a total remaining capacity of approximately
9.2 million tons. During second and third quarter 2009, average daily receipts totaled
approximately 1,697 tons per day. The landfill site encompasses 1,189 acres, of which
approximately 581 acres are currently permitted for landfill use, and 145 acres are permitted for
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waste disposal. It is projected that current landfill capacity will extend to 2021, at a minimum.
The Lamb Canyon landfill has potential for expansion. 87
In future, solid waste from the Planning Area may also be transported to other regional landfills,
including the Badlands facility, located in Moreno Valley, and the El Sobrante landfill in
Corona. Both of these landfills currently have excess capacity.
Solid waste recycling is also provided by Burrtec, which collects paper, plastic, glass and
aluminum from residences and businesses. Mixed recyclables are transferred to Burrtec facilities
in northern San Diego County.88
Burrtec also has green waste recycling capabilities. Brush and other greenwaste from La Quinta
are taken to the Edom Hill Transfer Station, and are eventually composted or sent to the Colmac
Energy plant in Mecca for use as bio fuel.
The Integrated Waste Management Act (AB 939), passed in 1989, requires California cities and
counties to meet a variety of recycling and reuse goals, including diverting at least 50% of their
solid waste stream through new and ongoing waste and recycling programs. La Quinta is
meeting these State-mandated goals.
Data from the California Integrated Waste Management Board indicates that as a result of the
enactment of this legislation, recycling efforts annually conserve enough energy to provide
power for 1.4 million California homes, reduce water pollution by 27,047 tons, save 14 million
trees, reduce air pollution by 165,142 tons, and reduce greenhouse gas emissions by an amount
equal to taking 3.8 million passenger cars off the highway.89
Solid waste generated by construction and demolition sites may accounts for as much as 22% of
the solid waste stream.90 Prior to the issuance of grading permits, the City refers developers to
Burrtec environmental staff to develop a recycling plan to recycle at least 50% of these
materials.91 Although not yet mandated, these reductions can result in substantial cost savings to
developers. It is expected that these will be required in the near future.
In 2009, residential development in the City generated 11,414.6 tons of solid waste; commercial
development generated 3,615.3 tons. Approximately 4,393.4 tons of recyclables were collected
from residential curbside pick ups; approximately 3,908.1 tons of residential greenwaste were
collected curbside. Commercial on-site pick up units accounted for 1,050.5 tons of recyclables,
and on-site greenwaste totaled 4,607.1 tons.92
87 Written communication, Ryan Ross, Riverside County Waste Management Department, December 17, 2010. 88 Personal communication, Ken Stevens, Burrtec District Environmental Coordinator, December 14, 2010.
89 National Recycling Coalition’s Environmental Benefits Calculator using California data from 2001 studies by
UC Berkeley and the National Recycling Coalition, found at CalRecycle Internet Search, December 20, 2010.
90 Statewide Waste Characterization Study, prepared by the California Integrated Waste Management Board,
December 2004. 91 Personal communication, Ken Stevens, Burrtec District Environmental Coordinator, December 14, 2010. 92 Data for City of La Quinta provided by Burrtec, January 2010.
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Hazardous Waste93
The information above is applicable for non-hazardous household, commercial and most
industrial solid waste. Household hazardous waste (HHW), such as household cleaning
chemicals, flammables, batteries, motor oil, antifreeze and paint, and others are collected at three
permanent facilities provided by the Riverside County Waste Management Department. These
facilities also accept sharps and needles. The HHW collection facilities are located in Palm
Springs, Lake Elsinore, and Riverside, and are open every Saturday except for designated
holidays. There are also a number of one-day collection “events” at various locations and dates
throughout the County, including the City’s Civic Center.
Coachella Valley Area Regional Antifreeze, Battery, Oil (and Filter) and Paint (Latex)
Collection Facilities (ABOP) collect only these specified HHWs. There are three facilities,
including two in the Coachella Valley: at the Edom Hill Transfer Station in Cathedral City and
the Coachella Valley Transfer Station in Coachella. The Edom Hill ABOP facility operates on
Saturdays, and the Coachella facility is open Monday through Saturday.
The County also administers special programs such as collection of construction and demolition
materials and commercial recycling.
County-approved hazardous waste disposal firms (private contractors) collect hazardous
industrial waste, which is disposed of at sites other than County landfills. In general these wastes
have been disposed of at Cattleman’s Hill in central California. Hazardous waste and hazardous
waste disposal is discussed in further detail in Section III-G, Hazards and Hazardous Materials.
2. Impacts
Development facilitated by build out of the General Plan will result in increased generation of
solid waste. The three existing landfills have long-term capacity sufficient for expected solid
waste generated in the Planning Area, and Burrtec plans on providing service to accommodate
future development. As the City continues to implement existing and initiate new recycling
efforts, it expected that impacts to regional landfills will be decreased.
Based on solid waste generation factors provided by the California Integrated Waste
Management Board applied to land uses in the proposed General Plan Land Use Plan provides an
estimate of solid waste generation at build out. The following tables show estimated solid waste
generation in the Planning Area.
93 http://www.rivcowm.org/HHW_Schedule.htm#_HHW_Collection_Locations
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Table III-42
Solid Waste Generation at
General Plan Build Out
Land Use Type
Generation
Rate Unit Type
Units
(DU/Sq. Ft.)
Annual Tons
of Solid Waste
Single Family 2.0400 tons/unit/year 46,866 95,606.64
Multi Family 1.1700 tons/unit/year 6,236 7,296.12
Retail/Commercial1 0.0024 tons/sf/year 12,364,631 29,675.11
Industrial 0.0108 tons/sf/year 611,408 6,603.21
Total 139,181.08
1 Assumes development of all General, Tourist and Village Commercial based on retail/commercial factor.
Source: Terra Nova staff estimates based on California Integrated Waste Management Board compilation of
waste generation rates. Rates used are from Ventura County Solid Waste Management Department,
“Guidelines for Preparation of Environmental Assessments of Solid Waste Impacts”, September 1992, and
“DEIR for North Hills Development in Santa Clarita”, December 1991.
At build out, implementation of the General Plan is expected to result in approximately 53,103
dwelling units. Of these, approximately 46,866 will be single-family units, and approximately
6,236 will be multi-family units. Up to approximately 12,364,631 square feet of commercial
development, which is assumed to be primarily retail uses, and 611,408 square feet of industrial
development will also be constructed. As shown above, based on this level of development,
approximately 139,181 tons of solid waste would be generated per year. On a daily basis, this
equates to 381 tons of solid waste. Actual waste generation will depend on future levels of
development, and participation in stream flow diversion programs.
There are no proposed land uses that are expected to generate large quantities of solid waste or
create conditions where severe hazardous wastes are produced. Development facilitated by the
General Plan will nonetheless result in increased volumes of solid waste generation. Therefore,
the City and Burrtec will need to continue to monitor these levels to ensure that disposal of solid
and hazardous wastes generated in the Planning is safe and cost-effective.
3. Mitigation
The most effective way to reduce impacts to landfills is through reduction of solid waste at the
source. The following mitigation measures are intended to further reduce the amount of waste
generated in the Planning Area, promote the City’s compliance with AB 939 and AB 341, and
mitigate impacts to landfills by reducing the amount of waste generated.
1. The City shall continue to consult and coordinate with Burrtec to sustain and exceed the
provisions of AB 939 and AB 341 where possible through expanding its recycling programs
and divert resources from the waste stream for return to productive use.
2. Commercial and industrial establishments shall be required to comply with State mandates
established under AB 341 to reduce the amount of packaging and potential waste associated
with product manufacturing and sales.
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3. The City and Burrtec shall continue to include recycling provisions for single-family and
multi-family residential dwelling units in their solid waste disposal contracts.
4. Prior to the issuance of building permits, the City shall continue to refer project developers to
Burrtec for development of construction and demolition solid waste recycling plans to divert
a minimum of 50% of C&D debris from the waste stream.
Mitigation Monitoring and Reporting
A. Prior to the issuance of building permits, the City Planning and Building and Safety
Departments shall review project development plans and confer and coordinate with project
developers to assure the provision and maintenance of recycling containers that correspond
with current City programs and those planned in the future, including those for construction
and demolition solid waste.
Responsible Parties: Planning Department, Building and Safety Department, Burrtec Waste
and Recycling Services, LLC.
Public Transportation Services
1. Existing Conditions
The Sunline Transit Agency provides public transportation services to residents and visitors
throughout the Coachella Valley, including the City of La Quinta. There are two primary Sunline
routes within the City of La Quinta. Bus line 111 generally runs along Highway 111, thereby
providing public transportation serveries to destinations located in the vicinity of Highway 111.
Bus Line 70 generally runs along Washington Street, providing public transportation to northern
and southern destinations within the City of La Quinta.
2. Impacts
Implementation of the proposed General Plan is expected to increase the demand for public
transportation services. The Traffic and Circulation discussion, Section III-O below further
addresses current and planned future bus routes, other public transportation opportunities, and
potential impacts associated with build out of the General Plan.
3. Mitigation Measures
1. The City of La Quinta shall continue to coordinate with SunLine Transportation Agency
to establish new bus stop locations and facilities as demands warrant.
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Recreational Resources N.
Introduction
The City of La Quinta has numerous recreational resources that improve the quality of life for its
residents and make La Quinta a desirable destination. This section assesses impacts on
recreational resources from future growth and development brought on by the La Quinta 2035
General Plan Update. It also provides mitigation measures to reduce impacts on existing
recreational facilities and impacts associated with development of new facilities.
Thresholds of Significance/Criteria for Determining Significance
Article 5, Section 15064 of the CEQA Guidelines provides guidance for determining the
significance of the environmental effects caused by a project. Appendix G of the CEQA
Guidelines provides a list of environmental factors that potentially may be affected by
completion of a project. The La Quinta 2035 General Plan Update would have a significant
effect on Recreational Resources if it is determined the plan:
a) Would increase the use of existing neighborhood and regional parks or other
recreational facilities such that substantial physical deterioration of the facility would
occur or be accelerated.
b) Includes recreational facilities or require the construction or expansion of recreational
facilities, which might have an adverse physical effect on the environment.
1. Existing Conditions
The General Plan Update Planning Area, and particularly land within the City limits, offers a
variety of passive and active recreational opportunities for residents and visitors to the region.
There are approximately 5,259 acres of open space areas set aside for recreational facilities in the
City. These developed open space recreational areas include a variety of city owned and
maintained parks and facilities, County owned parks, Desert Recreation District facilities and
public and private golf courses. In addition, there are approximately 6,933 acres of natural open
space areas in the City Limit offering hiking trails, equestrian trails, and other passive recreation
opportunities. The City of La Quinta also offers numerous golf courses and resorts, making it a
premier destination for golf.
City Recreational Resources
The City owns, operates and maintains numerous park facilities throughout incorporated areas of
the General Plan Update Planning Area. Within the City Limits are five mini parks, including
Eisenhower Park, Seasons Park, Saguaro Park, Desert Pride and Velasco Park. These parks are
generally one acre or less than one acre in size and are located within neighborhoods. Mini parks
provide limited amenities including small children play areas, playground equipment, turf areas,
walking paths and areas for seating.
Neighborhood parks are larger than mini parks and provide both active and passive recreational
needs for the community. These include parks such as Fritz Burns Park, Adams Park, Monticello
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Park, and Pioneer Park. Neighborhood parks are generally two to ten acres in size and can
include large field facilities for sporting events, children play areas, interactive water features,
dog park facilities, picnic and barbecue amenities, restroom, and other additional community
features. Pioneer Park is the newest neighborhood park in La Quinta and provides 2 acres for a
playground, dog park, and passive seating areas. The Fritz Burns Park provides a swimming pool
operated by Family YMCA of the Desert.
The third type of city-operated park includes community parks. Community parks are generally
15 to 40 acres in size and provide both large-scale recreational amenities, such as baseball fields,
soccer fields, softball fields, basketball courts, skate parks, and playgrounds, and also restrooms,
barbecues, public art displays, water features, picnic facilities, and benches. There are three
community parks in La Quinta including the 16.75-acre La Quinta Sports Complex, the 18-acre
La Quinta Park, and the 17.5-acre Civic Center Campus. Community parks provide recreational
resources for City residents and the surrounding region.
The City of La Quinta owns and operates open space areas and trail systems throughout the
incorporated limits. The Fred Wolff Nature Preserve is a 19-acre natural open space area located
just off the Bear Creek Trail, on the western portion of the Cove area. The City purchased the 19
acres in June of 2003 as a nature preserve, and to provide additional opportunities for hiking and
learning about the desert plant species and wildlife. The Cove Oasis Trailhead is another natural
open space area located at the southernmost part of the Cove. This open space area includes 114
acres and includes amenities such as hiking trails, picnic tables and benches, water fountains,
public art displays, and areas available for event rentals. Many area trails connect at the Cove
Oasis Trailhead including the Cove to Lake Trail, Boo Hoff Trail, Bear Creek Oasis Trail, Bear
Creek Canyon and the city maintained Bear Creek Trail. Bear Creek Trail is a 4.75-acre hiking
path that connects the Fred Wolff Nature Preserve with the Cove Oasis Trailhead.94
The City also operates and maintains the La Quinta Senior Center and La Quinta Museum. The
La Quinta Senior Center provides services such as classes, seminars, special events, and weekly
programs to adults 55 years of age and older. The La Quinta Museum provides local residents
cultural activities, including art exhibits, programs, and events.
Desert Recreation District Facilities
The Desert Recreation District provides park facilities and recreation programs throughout the
Coachella Valley. Once known as the Coachella Valley Recreation and Park District, the Desert
Recreation District owns and operates the La Quinta Community Center, and is proposing a
Discovery Center near Lake Cahuilla.
The La Quinta Community Center and Park is located off Avenida Montezuma, and includes a
6.5-acre park and 5,000 foot community center. The 6.5-acre park includes ballfields, basketball
courts, playground, picnic tables, barbecues, restrooms, an outdoor amphitheater, outdoor
exercise facilities, and drinking fountains. The Community Center includes the La Quinta Fitness
Center, kitchen, and concessions.
94 “Parks and Trails” www.la-quinta.org, accessed November 22, 2010.
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The proposed Coral Mountain Discovery Park will be a partnership between the Bureau of Land
Management and the Desert Recreation District, and encompass 620 acres of open space, of
which 123 acres will be available for public access. The public access area will provide
interpretive trails, picnic areas and a learning center. The Discovery Park will be the Coachella
Valley’s first archaeological park and provide residents the opportunity to learn about the regions
rich cultural and natural heritage. 95
Riverside County Regional Park and Open Space District
Riverside County operates Lake Cahuilla Regional Park located in southwestern portion of La
Quinta. The 710-acre Regional Park includes a 113-acre lake, 20 equestrian campsite, 30
primitive individual campsites, showers, and dump stations, as well as other amenities including
shore fishing, equestrian and hiking trails, and picnicking facilities. Swimming is not allowed in
Lake Cahuilla, however a seasonal swimming pool is open from mid April to mid October. 96
Bureau of Land Management Land
The Bureau of Land Management (BLM) provides and manages large areas of open space
throughout the southwestern portion of the City limits and the Sphere of Influence. Although
located within City of La Quinta jurisdictional boundaries, the General Plan Update will not have
jurisdiction over these federally managed public lands. The Santa Rosa and San Jacinto National
Monument were established by the federal government in 2000 “in order to preserve the
nationally significant biological, cultural, recreational, geological, educational, and secure now
and for future generations the opportunity to experience and enjoy the magnificent vistas,
wildlife, land forms, and natural and cultural resources in these mountains and to recreate
therein.”97 The Monument encompasses nearly 272,000 acres, however the portion closest to La
Quinta includes the 61,600-acre Santa Rosa Wilderness. The Bear Creek Canyon Trail, located
in the southern portion of the Cove area, provides entrance into the Santa Rosa Wilderness.
Golf Courses
La Quinta has numerous public and private courses throughout the community. There are several
well-known courses throughout the incorporated Planning Area, including PGW West,
SilverRock Resort, La Quinta Resort Golf Course, Trilogy Golf Club, and a number of private
courses within country club communities.98
95 Desert Recreation District, www.myrecreationdistrict.com, accessed November 22, 2010. 96 Lake Cahuilla, Riverside County Parks, www.rivcoparks.org/parks/lake-cahuilla/lake-cahuilla-recreation-area-
home/, accessed July 5, 2011. 97 Santa Rosa and San Jacinto Mountains National Monument, http://www.blm.gov/, accessed November 22,
2010. 98 http://www.playinlaquinta.com/golf.html
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Sphere of Influence Recreational Resources
The Sphere of Influence has no parks or other recreational uses. The eastern Sphere of Influence
Planning Area also has schools, including Westside Elementary School, and is adjacent to
Coachella Valley High School.99 These schools provide athletic fields and hardtop courts,
however these uses are generally for school purposes. Equestrian facilities are found in the
eastern Sphere of Influence, including the Mountain View Equestrian Center along Jackson
Street, just south of Avenue 58th Avenue.100 There are local equestrian trails throughout the
eastern Sphere of Influence that provide places for riding.
Quimby Act
California passed the Quimby Act in 1975, allowing local governments to pass ordinances
requiring developers to set aside land, donate conservation easements, or pay in-lieu of fees for
the development of new parks and recreational facilities. Local governments have come to
depend on the Quimby Act for new facilities, or to upgrade existing facilities, as a result of new
growth and development. La Quinta Municipal Code Section 13.48 establishes criteria for
dedicating land, or payment of in lieu fees for construction of new parks or recreational facilities
or rehabilitation of existing facilities. The ordinance states that residential subdivisions,
containing less than five parcels, and nonresidential subdivisions, are exempt from dedication or
park fees. All other residential developments are required to pay a park development fee,
dedicate land, or both. Section 13.48.050 states that parkland dedication requirements shall equal
three acres of parkland per one thousand people in a new subdivision. The number of people in a
new subdivision is determined by multiplying the number of dwelling units in the subdivision by
the average household size. Average household size is based on the latest U.S. Census
information.
2. Project Impacts
The La Quinta 2035 General Plan Update will facilitate new development that will create
demand for new parks and recreational facilities. Implementation of General Plan Update will
result in approximately 8,114 new residential units within the City Limits and 20,669 new
residential units within the Sphere of Influence. At build out, the total number of dwelling units
within the City will be approximately 31,603 units, and 21,500 within the Sphere of Influence.
Total build out population is expected to be 79,956 in the City Limits and 54,396 within the
Sphere of Influence, for a grand total of 134,352 throughout the General Plan Update Planning
Area.
Impacts on Existing Neighborhood and Regional Parks
The General Plan Update will facilitate new residential development throughout the Planning
Area, and increase the population within City Limits. New growth will put pressure on existing
facilities, if no new recreational facilities are built. As mentioned above, however, there are
99 http://www. maps.google.com/ 100 http://www.mountainviewequestriancenter.com/About-Us.html
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already 5,259 acres of recreational open space, and 6,933 acres of natural open space within the
City.
The General Plan requires the provision of 5 acres of parkland for each 1,000 population. Based
on this standard, a population of 79,956 at build out would require a total of 395 acres of
parkland. With implementation of required fees for new development projects, implementation
of the General Plan Update will have less than significant impacts to existing parks within the
City.
Implementation of the General Plan Update has the potential to result in the development of
approximately 20,699 new residential units within the Sphere at build out. Total population
within the Sphere is expected to reach 54,396 residents. The General Plan requires 5 acres of
parkland per 1,000 residents. Based on this standard, a population of 54,396 residents at build
out would require a total of 272 acres of parkland, if the Sphere were annexed to the City. With
implementation of required fees for new development projects, implementation of the General
Plan Update will have less than significant impacts to existing parks within the City.
3. Mitigation Measures
None required.
Transportation/Traffic O.
Introduction
This section of the EIR describes the existing condition of traffic and circulation within the City
and Sphere-of-Influence, the vicinity and the region. It also analyzes the potential impacts of the
proposed La Quinta General Plan update and sets forth strategies and mitigation measures that
will be effective in reducing impacts. A wide range of data and information, ranging from
research and analysis conducted for specific projects in the area, to regional-scale planning and
environmental documents, have been used in researching and analyzing the General Plan project
and its potential effects. 101, 102, 103 These include detailed analysis of major roadway segments,
as well as detailed analysis of future traffic and circulation conditions104,105.
General Plan Traffic Impact Analysis
A traffic impact analysis was prepared for the General Plan update by Iteris, Inc. to assess the
existing roadway network, collect data on and measure the level of use and service along the
existing roadways in the General Plan study area. The traffic impact analysis also identifies
potentially significant traffic-related impacts associated with build out of the City’s General
101 “City of La Quinta General Plan Circulation Element Update Traffic Impact Analysis” prepared by Iteris, Inc. May 2012. 102 "County of Riverside General Plan”, prepared by County of Riverside Transportation and Land Use Management Agency,
October 2003.
103 “Riverside County Transportation Analysis Model (RivTAM)” prepared by the Riverside County Transportation
Department, 2008. 104 “Washington Street & Highway 111 TSM/TDM Corridor Study” prepared by VRPA Technologies, Inc. June 2009. 105 "Panorama (Specific Plan No. 362) Traffic Impact Analysis" prepared Urban Crossroads, Inc., July 5, 2007.
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Plan, as well as surrounding lands, and sets forth detailed mitigation measures and strategies
designed to reduce potential impacts to levels that are less than significant.
The primary goals of the La Quinta General Plan traffic analysis was to: (1) documentation of
existing traffic volumes and operating conditions at all major intersections and along major r oadway
within the City and Sphere of Influence; (2) evaluation of existing plus projected background
growth, plus General Plan build out traffic for 2035 conditions; (3) evaluation of existing plus
General Plan build out traffic for 2035 conditions; and (4) determination of improvements and
system management action needed to achieve City level of service requirements.
Thresholds of Significance/Criteria For Determining Significance
The following thresholds or criteria are not strictly those recommended in Section 15064 of the
CEQA Guidelines. Rather, they are derived from Appendix G of the CEQA Guidelines, which is
used to determine the level of potential effect, and whether a Negative Declaration or Mitigated
Negative Declaration may be issued, or whether an Environmental Impact Report is to be
prepared. The subject La Quinta General Plan update, and the General Plan Land Use
Alternatives, would have a significant effect on transportation/traffic if they:
a.) Conflict with an applicable plan, ordinance or policy establishing measures of effectiveness
for the performance of the circulation system, taking into account all modes of
transportation including mass transit and non-motorized travel and relevant components of
the circulation system, including but not limited to intersections, streets, highways and
freeways, pedestrian and bicycle paths, and mass transit?
b.) Conflict with an applicable congestion management program, including, but not limited to
level of service standards and travel demand measures, or other standards established by
the county congestion management agency for designated roads or highways?
c.) Result in a change in air traffic patterns, including either an increase in traffic levels or a
change in location that results in substantial safety risks.
d.) Substantially increase hazards due to a design feature (e.g., sharp curves or dangerous
intersections) or incompatible uses (e.g., farm equipment).
e.) Result in inadequate emergency access.
f.) Result in inadequate parking capacity.
g.) Conflict with adopted policies, plans, or programs regarding public transit, bicycle, or
pedestrian facilities, or otherwise decrease the performance or safety of such facilities.
The following discussion provides some essential background information to facilitate a better
understanding of the analysis, which follows.
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Levels of Service
The capacity of a segment of roadway or an intersection is typically characterized as “Level- of-
Service”. As gauged for mid-block (segment) travel, Level-of-Service (LOS) is a qualitative
measure describing the character and efficiency of the flow of traffic. For intersections, the LOS
is defined quantitatively as the number of seconds the vehicle is delayed in passing through the
intersection. LOS includes a range of alphabetical connotations “A” through “F”, used to
characterize roadway operating conditions. LOS A represents the best/free-flow conditions and
LOS F indicates the worst/system failure.
Intersections generally represent the most constrained portion of the roadway network. The
Transportation Research Board Highway Capacity Manual expresses the Level of Service at an
intersection in terms of delay or waiting time to get through the various intersection approaches.
For signalized intersections, average total delay per vehicle is used to determine the LOS.
Intersection LOS is defined quantitatively in Table III-43 below. A more detailed discussion of
LOS values can be found in the General Plan Traffic Impact Analysis in the EIR Technical
Appendices.
Mid-block Levels of Service are represented as volume to capacity ratios, or vehicle demand
divided by roadway capacity. In general terms, as the ratio approaches 1.00 or maximum
capacity, the roadway approaches LOS F. However, it is important to keep in mind that for mid-
block, the LOS is meant to define a qualitative rather than a quantitative measure of operation.
The LOS assignment is only marginally useful in characterizing capacity, and is not meant to
determine actual volumes that a particular roadway segment can carry. Mid-block volumes and
volume to capacity ratios (V/C) should be used as a means of monitoring traffic flows toward the
intersections and can inform traffic engineers of areas where further analysis is warranted.
A variety of conditions and mix of improvements can enhance mid-block roadway capacity.
Adding through and turning lanes increases capacity, as do the inclusion of raised medians and
restricted access on a roadway. Restricted access and raised medians increase roadway capacity
by reducing the number of vehicle conflict points and improving traffic flows. Restricted access
avoids loss of capacity caused by interruptions and disruptions to traffic flow resulting from
vehicles coming onto or leaving the roadway.
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Table III-43
Level Of Service Description
Mid-Link and Uninterrupted Flow
Level of Volume/Capacity
Service Quality of Traffic Flow Ratio
A Free flowing, low volumes, high speed; speed not restricted by
other vehicles in the traffic stream. 0.00 - 0.60
B Operating speeds and maneuverability in the range of stable flow,
but presence by other traffic begins to be noticeable. Freedom to
select desired speeds is relatively unaffected, but there is a slight
decline in the freedom to maneuver. 0.61 - 0.70
C Operating speeds and maneuverability significantly controlled by
other traffic Quality of operations still within the range of stable flow. 0.71 - 0.80
D Tolerable operating speeds, high traffic density but stable flows;
often used as design standard in urban areas. At this level, speed and
freedom to maneuver are severely restricted. Drivers experience
general discomfort and inconvenience. 0.81 - 0.90
E At or near maximum traffic volume a roadway can accommodate
during peak traffic periods. Low speed but uniform traffic density.
“Maximum Capacity”. Highly susceptible to breakdowns in flow. 0.91 - 1.00
F System failure; long queues of traffic; unstable flows; stoppages of Not Meaningful
long duration; traffic volume and speed can drop to zero; traffic
volume will be less than the volume which occurs at Level
of Service E.
Source: Highway Capacity Manual, Transportation Research Board - Special Report 209,
National Academy of Science, Washington, D.C. 2000.
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Table
III-‐44
Intersection Level Of Service Descriptions
Level of
Service
Description Signalized
Intersection Delay
(seconds per
vehicle)
Unsignalized
Intersection Delay
(seconds per
vehicle)
A Excellent operation. All approaches to the
intersection appear quite open, turning
movements are easily made, and nearly all
drivers find freedom of operation.
< 10 < 10
B Very good operation. Many drivers begin to
feel somewhat restricted within platoons of
vehicles. This represents stable flow. An
approach to an intersection may occasionally be
fully utilized and traffic queues start to form.
>10 and < 20 >10 and < 15
C Good operation. Occasionally drivers may have
to wait more than 60 seconds, and back‐ups
may develop behind turning vehicles. Most
drivers feel somewhat restricted
>20 and < 35 >15 and < 25
D Fair operation. Cars are sometimes required to
wait more than 60 seconds during short peaks.
There are no long‐standing traffic queues.
>35 and < 55 >25 and < 35
E Poor operation. Some long‐standing vehicular
queues develop on critical approaches to
intersections. Delays may be up to several
minutes.
>55 and < 80 >35 and < 50
F Forced flow. Represents jammed conditions.
Backups form locations downstream or on the
cross street may restrict or prevent movement of
vehicles out of the intersection approach lanes;
therefore, volumes carried are not predictable.
Potential for stop and go type traffic flow.
> 80 > 50
Source: Highway Capacity Manual, Special Report 209, Transportation Research Board, Washington,
DC, 2000.
The following table describes the various capacity values assigned for differing roadway sizes
and levels of service. Capacity is generally defined as the number of vehicles that may pass over
a section of roadway in a given time period under prevailing conditions. However, capacities of
roadways are most restricted by intersection design and operation, which are discussed further
below. Typically, the PM peak hour is the heaviest traffic flow of the day. It should be noted that
in the planning area the peak hour operations are spread across a greater time period.
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Table III-45
City Roadway Classifications
Level of Service Volumes/Capacity Values
(Average Daily Trips – ADT)
Facility
Type
Lane
Config-
uration
LOS A
(60%)
LOS B
(70%)
LOS C
(80%)
LOS D
(90%)
LOS E
(100%)
LOS F
Local 2U <5,490 5,490 -
6,390
6,390 -
7,290
7,290 -
8,190
8,190 -
9,000 >9,000
Collector 2U <8,540 8,540 -
9,940
9,940 -
11,340
11,340 -
12,740
12,740 -
14,000 >14,000
Modified
Secondary 2D <11,590 11,590 -
13,490
13,490 -
15,390
15,390 -
17,290
17,290 -
19,000 >19,000
Secondary 4U <17,080 17,080 -
19,880
19,880 -
22,680
22,680 -
25,480
25,480 -
28,000 >28,000
Primary 4D <25,560 25,560 -
29,800
29,800 -
34,080
34,080 -
38,340
38,340 -
42,600 >42,600
Major 6D <36,600 36,600 -
42,700
42,700 -
48,800
48,000 -
54,900
54,900 -
61,000 >61,000
Augmented
Major 8D <45,600 45,600 -
53,200
53,200 -
60,800
60,800 -
68,400
68,400 -
76,000 >76,000
Source: La Quinta General Plan Traffic Impact Analysis, 2012 and Highway Capacity Manual,
2010.
Regional and Local Traffic Model
As noted in the introduction to this discussion, the La Quinta General Plan Traffic Analysis
Model (LQTAM) is a highly detailed, fine-grained level of analysis that has been developed in a
manner consistent with the Riverside County Transportation Analysis Model (RivTAM), which
is also the basis for regional transportation planning coordinated by CVAG. In addition to
providing modeling consistency from the local through the regional level, RivTAM minimizes
the time and effort needed to maintain and update this transportation planning and management
tool.
Specifically, the La Quinta traffic model consists of a traditional four step modeling process
including (1) trip generation, (2) trip distribution, (3) mode split (choice), and (4) traffic
assignment. Two model scenarios were included in the La Quinta TAM, namely the base year
2009 and the forecast year 2035. To work from a more refined level, the traffic modeling process
begins with defining the traffic analysis zones (TAZ) and the roadway network, establishing
efficient/logical traffic routes, collecting land use and socio-economic data on each TAZ,
calculating trip generation in each TAZ, distributing traffic and its assignment to individual road
segments. Each major component of the La Quinta model is described below.
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Zone and Network System
The regional traffic model divides the General Plan planning area from just a few TAZs to a
detailed modeling area of 123 TAZs following RivTAM zone boundaries, General Plan land use
boundaries, digital street centerlines and other GIS data, thereby greatly increasing the detail of
the analysis. Traffic volumes have been generated for each TAZ based upon the mix and acreage
of each land use in each TAZ, with land uses being factored into the model as either trip
“productions” or “attractions.” Traffic from outside the planning area is based upon the larger
scale, regional RivTAM TAZ structure, and interacts with planning area traffic at various cordon
stations located along planning area boundaries. A forecast of traffic volumes is produced by the
model and is based upon the TAZ system.
The model then loads the traffic onto the roadway network, and approximates how actual traffic
enters and utilizes the local roadway system. The roadway network focuses on major streets and
generally excludes local streets. Traffic generated in each zone is placed on the network at
primary connectors, called “centroids," identified by the model.
The model also considers a variety of roadway characteristics, including the type of roadway,
free-flow speeds, and hourly travel per lane. Likely network operations are also refined by speed
adjustments developed to increase sensitivity to roadway constraints (Please refer to the La
Quinta General Plan TIA for an illustration of the TAZ’s and a complete breakdown of the
various land uses within each TAZ).
The current land use patterns were used as the basis for the La Quinta General Plan TAZ system.
The TAZ pattern is tailored specifically to the City and planning area in order to provide the
most accurate data possible. The model distributes the projected volume of traffic that will occur
due to the build out of the General Plan land use plan and factors growth in other areas of the
Valley. From this information the design requirements to maintain acceptable traffic flows are
determined.
Depending upon the level of land use integration within each TAZ, traffic generated within each
TAZ may stay within the TAZ or cross TAZ boundaries, which typically requires travel on a
higher capacity street such as a collector or arterial roadway. TAZs are selected planning
subareas typically defined by major roadways. The interaction of land uses within each TAZ is a
measure of land use efficiency, depending on the degree to which development generates local
traffic or requires extended use of the arterial roadway network.
Trip Generation
Trip generation provides the raw data for traffic modeling. Vehicle trips generated within each
TAZ of the modeling area are based on land use data as designated by existing land uses and the
General Plan Land Use Element. The RivTAM model first analyses sixteen (16) "land use to
employment" conversion rates, ranging from very low density residential to commercial, and
also including industrial, institutional and open space uses.
The General Plan traffic analysis also uses eleven (11) separate “home-based” trip definitions
and two “non-home-based” definitions. Some trips originate from or are destined to the home,
while other trips are between non-home destinations, such as from work to lunch or the doctor’s
office, or from dinner to a movie.
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The RivTAM and La Quinta models were used to derive the average trip generation rates per the
various land uses, and were modified for City-specific application. The total number of vehicle
trips produced in or attracted to a geographic area is directly related to the land use and
demographic variables found in each TAZ. The model estimates the number of peak season
vehicle trips that will be produced on an average weekday for each analysis zone.
Trip Distribution and Traffic Assignment
For each of the 123 TAZs developed for the La Quinta model, the volume of traffic has been
calculated and broken down and the trip generation associated with each has been calculated.
Once accomplished, the trip distribution and assignment functions of the City traffic model were
then implemented. Next a general directional distribution of these trips was made and then
finally assigned to specific streets. As mentioned, trips are either attractions or productions; that
is, land uses are either drawing trips into the TAZ or are exporting trips. Typically, this
distribution of trips is accomplished using a “gravity distribution model”, based on the formula
that the distribution of trips is proportional to the “attractiveness” of the land use and the distance
(or travel time) from the point of trip production. Each type of trip or trip purpose has its own
specific travel time distribution function or curve.
Traffic is assigned to the roadway network over distinct time periods and to specific route paths
of the various trip interchanges between TAZs identified in the trip distribution process. The end
result of these forecasts of daily traffic volumes yields the aggregate assignment of trips to
roadways between and connecting TAZs throughout the City and planning area. The traffic
assignment process for the General Plan traffic model has also been adapted from procedures
used in the Valley-wide RivTAM model.
1. Existing Conditions
Within the urbanized and developing areas of the City and planning area, the roadway network
has been constructed and is conveying traffic. The following briefly discusses the major regional
and local roadways serving the planning area, as well as conditions at major intersections within
the City. While Levels of Service for roadway links or segments are discussed, Levels of Service
at intersections are a more meaningful measure of actual roadway operating conditions. The
tables that follow provide additional information on existing roadway link and intersection
conditions in the City and General Plan study area. It should also be kept in mind that operating
conditions are gauged against current and not ultimate levels of street and intersection
improvements.
Regional Roadways
Those roadways that provide intra-Valley and super regional connections are herein termed
regional roadways. They include State Highways 111 and 86, and U.S. Interstate-10. State
Highway 111 begins at its juncture with Interstate-10 three miles west of Palm Springs and
extends southeast to Brawley in the Imperial Valley. Highway 86 connects the planning area and
other parts of the Coachella Valley with Imperial County and Mexico. Interstate-10 connects the
Los Angeles region with Arizona and other cities and states to the east. Together, these important
roadways provide regional, interstate and international connections for the City and the
Coachella Valley.
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State Highway 111
State Highway 111 has been built along the old Bradshaw Trail, which extended along the base
of the Santa Rosa Mountains. Highway 111 is an important intra-regional connector serving the
local cities. Portions of this route have been relinquished by the State to local cities, which have
agreed to accept ownership, maintenance, operation, and liability for their respective roadway
segments. Some through-traffic appears to have moved north to Fred Waring Drive and I-10 in
response to congestion along Highway 111. However, the La Quinta traffic model shows that
approximately 58 percent of traffic on Highway 111 does not originate in and is not destined for
locations within the City, and is simply passing through along this roadway. In the City, this
roadway is built out to six-lanes divided. Highway 111 serves a wide mix of commercial land
uses. Existing traffic volumes range from approximately 29,726 VPD east of Washington Street
and approximately 38,037 VPD west of Jefferson Street. Intersections with Highway 111 are
currently operating at Level of Service (LOS) C, with the exception of its intersection with
Washington Street (LOS D in 2010) and mid-block segments operate at LOS C or better. Sunline
bus service is available along its length and this roadway serves as a designated truck route.
Highway 86S Expressway
Highway 86S is a semi-limited access expressway and an intra-regional arterial highway
providing indirect but important access to the eastern portion of the planning area. Highway 86S
is a northwest-southeast trending expressway designated as a “Freeway” in the County of
Riverside General Plan, with a variable right-of-way. In the vicinity of the planning area,
Highway 86S has been improved as a four-lane high volume roadway with a wide median island
and with slip and turn lanes at major surface crossroads. Existing traffic volumes range from
approximately 20,000 VPD north of Avenue 60 to approximately 12,900 VPD south of Avenue
62. Due to high future volumes, the current at-grade intersection of SR-86 and Avenue 62 has
been planned for expansion to provide a grade-separated facility utilizing a partial cloverleaf
design.
U.S. Interstate-10
US Interstate-10 is currently built as a six to eight-lane divided freeway accessed from both loop
and diamond interchanges spaced a minimum of one mile apart. I-10 provides essential inter-city
and inter-regional access, and is also a critical part of the local road network moving people and
goods into and out of the Valley. Direct City access to I-10 is currently provided through
interchanges with Washington Street and Jefferson.
Local Major Roadways
The City has developed and maintains an extensive arterial roadway network, which, in addition
to the regional facilities serving the community, also serves both local and inter-city traffic. The
City road network has been built essentially along a north-south grid, with interconnections with
major arterials passing through adjacent jurisdictions. The location of trip attractors along these
roads or the convenience they provide in traversing the City varies with each road.
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Washington Street
Washington Street, oriented in a north-south direction, has a variable roadway with and consists
of three lanes in each direction through the majority of the planning area. It is currently classified
as a Major Arterial. Current traffic volumes range from approximately 23,434 to 40,633 VPD.
Washington Street provides access to State Highway 111 and to Interstate 10 (I‐10) north of the
city limits. Intersections with Washington Street are currently operating at Level of Service
(LOS) C or better, with the exception of its intersection with Highway 111 (LOS D in 2010).
Mid-block segments operate at LOS C or better. Bicycles are accommodated and Sunline bus
service is also available on the fully improved segments of this roadway.
Eisenhower Drive
Eisenhower Drive is oriented in an east-west direction at Washington Street, and transitions to a
north-south roadway at Avenue 50. Eisenhower Drive consists of two lanes in each direction and
is classified as a Primary Arterial. Current traffic volumes range from 10,000 to 12,000 VPD.
Intersections with Eisenhower Drive are operating at LOS C or better and mid-block segments
operate at LOS A. Bicycles and golf carts are accommodated on the fully improved segments of
this roadway.
Avenida Bermudas
Avenida Bermudas is oriented in a north-south direction and consists of two lanes in each
direction, extending from Calle Tampico on the north to the top and along the east side of the
cove on the south. This roadway is classified as a Secondary Arterial with traffic volumes
ranging from 3,400 to 9,200 VPD. Avenida Bermudas provides a variable paved section ranging
from four lanes in the Village area to two lanes near the top of the cove. Bicycles and buses are
accommodated on the fully improved segments of this roadway.
Adams Street
Adams Street is oriented in a north-south direction and consists of two lanes in each direction. It
is classified as a Secondary Arterial and has been built as a Primary Arterial between Highway
111 and Avenue 48, with traffic volumes ranging from 12,000 to 14,000 VPD. Its intersections
all currently operate at LOS C and mid-block segments operate at LOS A. Bicycles and buses are
accommodated on the fully improved segments of this roadway. A bridge to carry Adams Street
over the Coachella Valley Stormwater Channel (Whitewater River) is expected to be completed
in 2013.
Dune Palms Road
Dune Palms Road is oriented in a north-south direction and consists of two lanes in each
direction between Fred Waring Drive and Westward Ho Drive, one lane in each direction
between Westward Ho Drive and Highway 111, and two lanes in each direction between
Highway 111 and Avenue 48. Dune Palms Road is classified as a Secondary Arterial. Current
traffic volumes range from 10,000 to 12,000 VPD. Intersections with Dune Palms Road are
operating at LOS C and mid-block segments operate at LOS A. Bicycles are accommodated on
the fully improved segments of this roadway. There is an at-grade crossing of the Whitewater
River with long-term plans for at least a low-flow crossing at this location.
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Jefferson Street
Jefferson Street is oriented in a north-south direction and consists of three lanes in each direction.
It is classified as a Major Arterial north of Avenue 54 and as a Modified Secondary Arterial
between Avenue 58 and Avenue 62. Jefferson Street provides access to State Highway 111,
southern parts of the City and to Interstate 10 (I‐10) north of city limits. Current traffic volumes
range from 12,000 to 27,000 VPD. Intersections with Jefferson Street are operating at LOS C or
better; the roundabout at Avenue 52 is operating at LOS A. Mid-block segments operate at LOS
A. Bicycles are accommodated on the fully improved segments of this roadway.
Madison Street
Madison Street is oriented in a north-south direction and consists of one lane in each direction
between Avenue 50 and Avenue 54 and two lanes in each direction between Avenue 54 and
Avenue 60. Madison Street is classified as a Primary Arterial between Avenue 50 and Avenue
58, as a Secondary Arterial between Avenue 58 and Avenue 60, and as a Modified Secondary
Arterial between Avenue 60 and Avenue 62. Current traffic volumes range from 3,300 to 9,200
VPD. Most intersections with Madison Street are operating at LOS A or B, with its intersection
with Avenue 50 operating at LOS C in the AM and LOS D in the PM peak hours. Mid-block
segments operate at LOS A. Bicycles are accommodated on the fully improved segments of this
roadway.
Monroe Street
Monroe Street is oriented in a north-south direction and consists of one lane in each direction. It
is classified as a Primary Arterial between Avenue 52 and Avenue 60 and as a Secondary
Arterial between Avenue 60 and Avenue 62. Monroe Street provides access to State Highway
111 and to Interstate-10 north of city limits. Current traffic volumes range from 2,500 to 3,100
VPD. Intersections with Monroe Street are operating at LOS B or better, with mid-block
segments operating at LOS A. Bicycles are accommodated on the fully improved segments of
this roadway.
Jackson Street
Jackson Street is oriented in a north-south direction and consists of one lane in each direction. It
is classified as a Primary Arterial. Jackson Street is located in the City’s Sphere and provides
access to State Highway 111 and to Interstate-10 north of city limits. Current traffic volumes
range from 1,700 to 3,300 VPD. In the planning area, intersections with Jackson Street are
expected to operate at LOS B or better, with mid-block segments operating at a LOS A. Bicycles
are accommodated on the fully improved segments of this roadway.
Van Buren Street
Van Buren Street is oriented in a north-south direction and consists of one lane in each direction.
It is classified as a Primary Arterial between Avenue 52 and Avenue 60 and as a Secondary
Arterial between Avenue 60 and Avenue 62. Van Buren Street is located in the City’s Sphere. In
the planning area, intersections with Jackson Street are expected to operate at LOS B or better,
with mid-block segments operating at a LOS A. No alternative modes of travel are
accommodated on the fully improved segments of this roadway.
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Harrison Street
Harrison Street is oriented in a north-south direction and consists of one lane in each direction. It
is classified as a Major Arterial. Harrison Street is located in the City’s Sphere. In the planning
area, intersections with Jackson Street are expected to operate at LOS B or better, with mid-
block segments operating at a LOS A. No alternative modes of travel are accommodated.
Fred Waring Drive
Fred Waring Drive (Avenue 44) is oriented in an east-west direction and consists of three lanes
in each direction between Washington Street and Adams St and between Dune Palms Road and
Jefferson Street. Between Adams Street and Dune Palms Road, Fred Waring Drive consists of
two lanes in the eastbound direction and one lane in the westbound direction. Fred Waring Drive
is classified as a Primary Arterial. Current traffic volumes are approximately 24,500 VPD.
Intersections with Fred Waring Drive are operating at LOS C, with mid-block segments
operating at LOS A. Bicycles are accommodated . on the fully improved segments of this
roadway.
Miles Avenue
Miles Avenue is oriented in an east-west direction and consists of two lanes in each direction. It
is classified as a Primary Arterial. Current traffic volumes between Washington Street and
Adams Street are approximately 24,500 VPD. Intersections with Miles Avenue are currently
operating at LOS C, with mid-block segments operating at LOS A. Bicycles and a bus route are
accommodated on the fully improved segments of this roadway.
Avenue 48
Avenue 48, oriented in an east-west direction, consists of two lanes in each direction, and is
classified as a Primary Arterial. Current traffic volumes between Washington Street and Madison
Street range from 9,600 VPD east of Jefferson Street to about 18,400 VPD east of Dune Palms
Road. Intersections with Avenue 48 are currently operating at LOS C, with mid-block segments
operating at LOS A. Bicycles are accommodated along on the fully improved segments of this
roadway.
Avenue 50
Avenue 50, oriented in an east-west direction, consists of two lanes in each direction, and is
classified as a Primary Arterial. Current traffic volumes between Washington Street and Madison
Street are average 9,800 VPD. Intersections with Avenue 48 are currently operating at LOS C,
with the exception of the Avenue 50 intersection with Washington Street, which is operating at
LOS D. Mid-block segments are operating at LOS A. Bicycles are accommodated along on the
fully improved segments of this roadway.
Calle Tampico
Calle Tampico, oriented in an east-west direction, consists of two lanes in each direction, and is
classified as a Primary Arterial west of Washington Street. East of Washington Street, Calle
Tampico consists of one lane in each direction and is classified as a Collector Street. Current
traffic volumes range from 5,300 VPD west of Avenida Bermudas and about 10,000 VPD west
of Washington Street. Intersections with Avenue 48 are currently operating at LOS C, with the
exception of the Avenue 50 intersection with Washington Street, which is operating at LOS D.
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Mid-block segments are operating at LOS A. Bicycles, golf carts and buses are accommodated
along on the fully improved segments of this roadway.
Avenue 52
Avenue 52 is oriented in an east-west direction and consists of two lanes in each direction
between Avenida Bermudas and Jefferson Street. Between Jefferson Street and Monroe Street,
Avenue 52 consists of two eastbound lanes and one westbound lane. Between Monroe Street and
Jackson Street, Avenue 52 consists of one eastbound lane and two westbound lanes. Avenue 52
is classified as a Primary Arterial throughout the City and the City’s Sphere. Current traffic
volumes range from 7,200 VPD west of Monroe Street to about 16,100 VPD west of Washington
Street. Intersections with Avenue 52 are currently operating at LOS C or better, with the
exception of the Avenue 52 intersection with Avenida Bermudas, which is operating at LOS D.
Mid-block segments are operating at LOS A. Bicycles, golf carts and buses are accommodated
along on the fully improved segments of this roadway.
Avenue 54
Avenue 54 is an east-west street consisting of two lanes in each direction between Jefferson
Street to east of Monroe Street. East of Monroe Street, Avenue 54 is a variable roadway with two
westbound lanes and one eastbound lane. East of Monroe Street, Jefferson Street provides one
lane in each direction. Avenue 54 is classified as a Primary Arterial between Jefferson Street and
Monroe Street and is classified as a Secondary roadway between Monroe Street and Van Buren
Street. Current traffic volumes are 7,200 VPD between Jefferson and Madison Streets.
Intersections with Avenue 52 are currently operating at LOS C or better, with the exception of
the Avenue 52 intersection with Avenida Bermudas, which is operating at LOS D. Roadway
segments are operating at LOS A. Bicycles, golf carts and buses are accommodated on the fully
improved segments of this roadway.
Avenue 56 (Airport Boulevard)
Airport Boulevard or Avenue 56 is an east-west street extending east of Madison Street, and
consisting of two lanes in each direction between Jefferson Street Monroe Street. East of Monroe
Street, Avenue 56 is a two-lane roadway. Avenue 56 is classified as a Primary Arterial. Current
traffic volumes are 1,900 VPD east of Madison Street. Intersections are currently operating at
LOS C or better, with the exception of the Avenue 52 intersection with Avenida Bermudas,
which is operating at LOS D. Roadway segments are operating at LOS A. Bicycles, golf carts
and buses are accommodated on the fully improved segments of this roadway.
Avenue 60
Avenue 60 is an east-west street extending from the US Bureau of Reclamation Dike 4, eastward
to the Coachella Valley Stormwater Channel. Local two lane segments also occur between the
stormwater channel and the Highway 111/86S Expressway corridor, east of which it continues as
a local street serving primarily agriculture. Avenue 60 is designated as a Secondary roadway
from Madison Street on the west to Monroe Street, east of which it is classified as a Primary
Arterial. Avenue 60 is currently improved as a two-lane roadway, except between Madison
Street and Monroe Street where it provides one eastbound through lane, two westbound through
lanes, median islands and turn lanes. Current traffic volumes are 3,000 VPD east of Madison
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Street and 1,500 east of Monroe Street. Bicycles are accommodated on the fully improved
segments of this roadway.
Avenue 62
Much of the southern boundary of the General Plan planning area is east-west running Avenue
62, which is partially improved from USBR Dike No. 4 eastward to the east end of the Valley,
crossing the stormwater channel, as well as Highway 111 and the 86S Expressway. Avenue 62 is
classified as a Modified Secondary west of Monroe Street extended), and is classified a
Secondary east of Monroe Street. Current traffic volumes are 1,000 VPD west of Monroe Street
and ranging from 500 to 800 VPD east of Monroe Street. No alternative modes of travel are
accommodated on this roadway.
The following exhibit shows the existing average daily traffic volumes on the major roadways in
the General Plan study area.
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Exhibit III-17
Existing (2010) Average Daily Traffic Volumes
General Plan Planning Area
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General Plan Roadway Classifications
Each major roadway in the planning area has been assigned a specific design classification based
upon existing and projected traffic demands generated by build out of the General Plan. The need
for and appropriateness of each classification has been based upon modeled future traffic
volumes and overall community design goals set forth in the General Plan. Each of the
classifications corresponds with the street cross sections illustrated in the General Plan
Circulation Element. Certain refinements or adjustments may be required when securing right-
of-way and constructing improvements at specific locations, and provisions for such adjustments
are included in the Circulation Element.
Existing Daily Traffic Volumes
As a direct result of the analysis conducted on existing traffic and roadway conditions, and on
projections of future traffic resulting from General Plan build out, the roadway classification
system has been developed and assigned to existing and future roads. This process has also taken
into consideration special issues of concern and opportunities to enhance community circulation.
Table III-46 lists these General Plan roadways and also provides information on existing daily
volumes, number of lanes, roadway capacity, volume to capacity (V/C) ratios, and LOS.
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Exhibit III-18
General Plan Roadway Classifications
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Exhibit III-19
General Plan Street Cross Sections
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Table III-46
Existing Daily Volumes and Capacity Summary
General Plan Study Area
Roadway Link Existing
ADT
Roadway
Designation
Existing
Number
of
Lanes
Existing
Capacity
Existing
V/C
Ratio -
LOS
Washington St
Ave 42 to Fred Waring Dr 37,426 Major 6 59,300 0.63 – B
Fred Waring Dr to Miles Ave 40,633 Major 6 59,300 0.69 – B
Miles Ave to Hwy 111 32,915 Major 6 59,300 0.56 – A
Hwy 111 to Ave 48 36,710 Major 6 59,300 0.62 – B
Ave 48 to Eisenhower Dr 33,465 Major 6 59,300 0.56 – A
Eisenhower Dr to 600’ north of Ave 50 27,129 Major 6 59,300 0.46 – A
600’ north of Ave 50 to Ave 50 27,129 Major 5 47,500* 0.57 – A
Ave 50 to Calle Tampico 23,434 Major 6 59,300 0.40 – A
Eisenhower Dr
Washington St to Ave 50 12,0131 Primary 4 41,400 0.29 – A
Avenue 50 to Calle Tampico 9,9751 Primary 4 41,400 0.24 – A
Avenida Bermudas
Calle Tampico to Ave 52 3,3881 Secondary 4 28,000 0.12 – A
Ave 52 to Calle Durango 9,2751 Secondary 4 28,000 0.33 – A
Adams St
Westward Ho Dr to Hwy 111 13,724 Secondary 4 41,400 0.33 – A
Hwy 111 to Ave 48 12,035 Secondary 4 41,400 0.29 – A
Dune Palms Rd
Westward Ho Dr to Hwy 111 9,282 Secondary 2 19,000 0.49 – A
Hwy 111 to Ave 48 8,373 Secondary 4 41,400 0.20 – A
Jefferson St
Country Club Rd to Fred Waring Dr 20,913 Major 6 59,300 0.35 – A
Fred Waring Dr to Miles Ave 23,764 Major 6 59,300 0.40 – A
Westward Ho Dr to Hwy 111 27,112 Major 6 59,300 0.46 – A
Hwy 111 to Ave 48 26,889 Major 6 59,300 0.45 – A
Ave 48 to Ave 50 27,133 Major 6 59,300 0.46 – A
Ave 50 to Ave 52 16,169 Major 6 59,300 0.27 – A
Ave 52 to Ave 54 12,399 Major 6 59,300 0.21 – A
Madison St
Ave 50 to Ave 52 5,664 Primary 2 14,000 0.40 – A
Ave 54 to Airport Blvd 9,219 Primary 4 41,400 0.22 – A
Airport Blvd to Ave 58 6,348 Primary 4 41,400 0.15 – A
Ave 58 to Ave 60 3,341 Secondary 4 41,400 0.08 – A
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Table III-46
Existing Daily Volumes and Capacity Summary
General Plan Study Area
Roadway Link Existing
ADT
Roadway
Designation
Existing
Number
of
Lanes
Existing
Capacity
Existing
V/C
Ratio -
LOS
Monroe St
Ave 52 to Ave 54 3,147 Primary 2 14,000 0.22 – A
Ave 54 to Airport Blvd 2,532 Primary 2 14,000 0.18 – A
Jackson St
Ave 54 to Airport Blvd 3,338 Primary 2 14,000 0.24 – A
Airport Blvd to Ave 58 2,326 Primary 2 14,000 0.17 – A
Ave 58 to Ave 60 1,734 Primary 2 14,000 0.12 – A
Ave 60 to Ave 62 1,569 Primary 2 14,000 0.11 – A
Van Buren St
Ave 52 to Ave 54 4,663 Primary 2 14,000 0.33 – A
Ave 54 to Airport Blvd 3,346 Primary 2 14,000 0.24 – A
Airport Blvd to Ave 58 1,472 Primary 2 14,000 0.11 – A
Ave 58 to Ave 60 1,176 Primary 2 14,000 0.08 – A
Ave 60 to Ave 62 1,017 Secondary 2 14,000 0.07 – A
Harrison St
Airport Blvd to Ave 58 6,690 Major 2 14,000 0.48 – A
Fred Waring Dr (Ave 44)
Washington St to Adams St 24,492 Primary 6 59,300 0.41 – A
Miles Ave
Washington St to Adams St 9,828 Primary 4 41,400 0.24 – A
Hwy 111
Washington St to Adams St 29,726 Major 6 59,300 0.50 – A
Adams St to Dune Palms Rd 31,348 Major 6 59,300 0.53 – A
Dune Palms Rd to Jefferson St 38,037 Major 6 59,300 0.64 – B
Ave 48
Washington St to Adams St 12,903 Primary 4 41,400 0.31 – A
Dune Palms Rd to Jefferson St 18,364 Primary 4 41,400 0.44 – A
Ave 50
Washington St to Jefferson St 9,663 Primary 4 41,400 0.23 – A
Jefferson St to Madison St 9,990 Primary 4 41,400 0.24 – A
Calle Tampico
Eisenhower Dr to Avenida Bermudas 5,3501 Primary 41,400 0.13 – A
Avenida Bermudas to Washington St 10,0631 Primary 41,400 0.24 – A
Ave 52
Avenida Bermudas to Washington St 16,133 Primary 4 41,400 0.39 – A
Washington St to Jefferson St 13,529 Primary 4 41,400 0.33 – A
Jefferson St to Madison St 10,306 Primary 2 19,000 0.54 – A
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Table III-46
Existing Daily Volumes and Capacity Summary
General Plan Study Area
Roadway Link Existing
ADT
Roadway
Designation
Existing
Number
of
Lanes
Existing
Capacity
Existing
V/C
Ratio -
LOS
Madison St to Monroe St 7,238 Primary 2 19,000 0.38 – A
Ave 54
Jefferson St to Madison St 8,386 Primary 4 41,400 0.20 – A
Airport Blvd
Madison St to Monroe St 1,893 Primary 4 41,400 0.05 – A
Ave 58
Madison St to Monroe St 2,188 Secondary 4 41,400 0.05 – A
Monroe St to Jackson St 1,554 Secondary 2 14,000 0.11 – A
Ave 60
Madison St to Monroe St 3,067 Secondary 2 19,000 0.16 – A
Monroe St to Jackson St 855 Primary 2 14,000 0.06 – A
Ave 62
Madison St to Monroe St 1,0251 Modified
Collector 2 14,000 0.07 – A
Monroe St to Jackson St 804 Secondary 2 14,000 0.06 – A
Jackson St to Van Buren St 557 Secondary 2 14,000 0.04 – A
Van Buren St to Harrison St 866 Secondary 2 14,000 0.06 – A
As shown in the above table, the roadway segments analyzed are currently operating at LOS A,
with the exception of three segments of Washington Street and one segment of Highway 111 that
are operating at LOS B. Clearly, all analyzed roadway segments are currently operating well
within the acceptable levels of service.
Existing Operating Conditions at Major Intersection
As noted above, a total of thirty-seven (37) intersections were analyzed as part of the General
Plan update. As with the analysis of existing conditions for various roadway segments, the
intersection analysis also evaluated intersection volumes and levels of service for the peak
season period. The following Table III-47 sets forth this information.
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Table III-47
Existing Peak Hour Intersection LOS
Peak Season
Intersection Traffic
Control
AM Peak
Hour
PM Peak
Hour
LOS Delay
(Sec) LOS Delay
(Sec)
1. Washington St & Fred Waring Dr Signal C 34.9 C 34.1
2. Washington St & Miles Ave Signal C 29.2 C 28.0
3. Washington St & Channel Dr Signal B 18.2 C 25.3
4. Washington St & Hwy 111 Signal D 35.3 D 42.3
5. Washington St & Ave 48 Signal C 32.3 C 25.1
6. Washington St & Eisenhower Dr Signal C 23.7 C 20.7
7. Washington St & Ave 50 Signal C 30.3 C 25.6
8. Washington St & Calle Tampico Signal C 24.7 C 25.4
9. Washington St & Ave 52 Signal C 20.6 C 23.9
10. Eisenhower Dr & Calle Tampico Signal C 24.1 C 27.2
11. Avenida Bermudas & Ave 52 Signal D 38.6 C 26.3
12. Adams St & Fred Waring Dr Signal C 34.6 C 28.8
13. Adams St & Miles Ave Signal C 31.4 C 30.8
14. Adams St & Hwy 111 Signal C 29.0 C 28.7
15. Adams St & Ave 48 Signal C 29.6 C 27.7
16. Dune Palms Rd & Fred Waring Dr Signal C 25.4 C 20.2
17. Dune Palms Rd & Miles Ave Signal C 31.9 C 31.0
18. Dune Palms Rd & Westward Ho Dr Signal C 30.8 C 31.4
19. Dune Palms Rd & Hwy 111 Signal C 30.3 C 26.6
20. Dune Palms Rd & Ave 48 Signal C 24.1 C 25.9
21. Jefferson St & Fred Waring Dr Signal C 31.2 C 30.6
22. Jefferson St & Hwy 111 Signal C 30.3 C 30.8
23. Jefferson St & Ave 48 Signal C 32.5 C 31.4
24. Jefferson St & Ave 49 Signal C 23.9 C 20.1
25. Jefferson St & Ave 50 Signal C 32.7 C 32.6
26. Jefferson St & Ave 52 Roundabout A 7.5 A 7.0
27. Jefferson St & Ave 54 AWSC B 11.6 B 11.6
28. Madison St & Ave 50 AWSC C 17.1 D 32.4
29. Madison St & Ave 52 AWSC B 12.1 B 13.0
30. Madison St & Ave 54 AWSC B 10.8 B 11.5
31. Madison St & Ave 58 AWSC A 8.4 A 9.1
32. Madison St & Ave 60 AWSC A 8.0 A 9.1
33. Monroe St & Ave 52 AWSC B 13.8 B 14.4
34. Monroe St & Ave 54 AWSC B 10.2 B 10.6
35. Monroe St & Ave 58 AWSC A 7.7 A 8.5
36. Monroe St & Ave 60 AWSC A 7.9 A 8.1
37. Monroe St & Ave 62 AWSC A 7.5 A 7.4
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During the peak season, and as shown in the above table, all but four of the 37 study
intersections operate at LOS C or better. The intersection of Washington Street/Highway 111
operates at LOS D, very near LOS C, during the a.m. peak hour. During the p.m. peak hour, this
intersection operates at a slightly worse delay during peak season conditions, but remains at LOS
D. The intersection of Avenida Bermudas/Avenue 52 operates at LOS D and very near LOS C,
during the a.m. peak hour. The intersection of Madison Street/Avenue 50 operates at LOS D
during only the p.m. peak hour. This intersection is all-way stop-controlled, therefore LOS
ranges are smaller than those applied to signalized intersections. All study intersections are
operating at acceptable levels of service (LOS D or better).
All-Weather Access
Major drainages that affect roadway access both within the City and the planning area include
the Whitewater River (aka Coachella Valley Stormwater Channel east of Washington Street) and
the La Quinta Evacuation Channel. The Whitewater River is the principal drainage affecting all-
weather access in the City. Current all-weather crossings exist on Washington Street, Eisenhower
Drive, Adams Street and Jefferson Street. Dune Palms Drive is currently a low-flow crossing.
Future all-weather crossings are also planned for the southern extensions of Jefferson Street over
the Dike 2 flood protective levee and Madison Street over the Dike 4 levee. All-weather access
and roadway capacity are also affected by stormwater runoff, which is frequently conveyed by
local streets into dedicated surface and sub-surface stormwater facilities. Areas of inadequate
drainage can result in on-road ponding, unsafe conditions, and reduced accessibility and
capacity.
SunLine Transit Agency and Public Transportation
The provider of public transit service within La Quinta and the Coachella Valley is the SunLine
Transit Agency. In addition to SunLine’s fleet of new buses powered by compressed natural gas
and other clean-burning fuels, SunLine is also integrating other innovative technologies and fuels
into the local public transit system. In 2002 SunLine introduced a bus powered entirely by zero-
emission fuel cell technology.
Local and Supplemental Bus Service
The City and Sphere of Influence are directly served by two bus routes, Line 111 and Line 70.
Line 111 runs along Highway 111 from Indio to Palm Springs and is a main trunk line in the
SunLine system. Line 70 extends from the south end of the La Quinta Cove, north to and east
along Avenue 47, then north along Adams Street where it turns west to Washington Street and
north to Country Club Drive.
The SunDial is a Valley-wide, ADA-compliant service providing curb-to-curb next day service
that is wheelchair accessible. Sunline is putting into service a new "Riverside Commuter Express
Route 210" service that will run between Palm Desert and Riverside. This service will be an
expansion of existing the RTA CommuterLink Route 210 service between Banning and
Riverside, with local stops to include Thousand Palms/I-10 area, Cabazon and other communities
to the west.
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Air Transportation
La Quinta and the Coachella Valley region are served by three airports, each of which is briefly
described below:
Palm Springs International Airport
Palm Springs International Airport is located west of Gene Autry Trail and north of Ramon Road
in the City of Palm Springs, and is the primary air transportation link for the Coachella Valley.
The airport is classified in the National Plan of Integrated Airport Systems (NPIAS) as a long-
haul commercial service airport. It is capable of supporting non-stop commercial service to
destinations over 1,500 miles and is classified as a small hub air passenger airport based upon the
percentage of national airline enplanements it supports. Airport enplanements are projected to
reach approximately 809,256 by the year 2015
Jacqueline Cochran Regional Airport
The Jacqueline Cochran Regional Airport is located immediately east of the City’s Sphere of
influence, on the east side of Harrison Street, between Avenue 56 (Airport Boulevard) and
Avenue 62. Annual aircraft operations at Jacqueline Cochran Regional Airport were estimated at
65,000 in 2002, none of which were of a commercial nature. The airport's master plan projects
this activity to reach some 110,000 operations by 2022 and to continue to grow along with the
urbanization of the Coachella Valley. While commercial passenger services are anticipated there
is no projected date when these might be offered.
Bermuda Dunes Airport
Bermuda Dunes Airport is a General Aviation Airport located on 100± acres adjacent and
parallel to the Union Pacific Railroad/ Interstate-10 corridor, approximately three miles north of
the City limits. The airport is bounded on the north by Country Club Drive, on the south by
Avenue 42, on the west by Adams Street and on the east by Jefferson Street. A total of
approximately 25,332 operations occur each year at this airport, of which about 6.6% are
business jets. The expansion of facilities at this airport is essentially precluded by surrounding
development. Annual maximum capacity is estimated at 75,000 operations per year.
Railway Facilities
Rail lines of the Union Pacific Railroad (UPRR) are located north and east of the La Quinta
planning area. Rail freight service is provided to the Coachella Valley by the Union Pacific
Railroad, with freight transfer facilities located in Indio and Coachella. There is also Amtrak
service to Indio and Palm Springs. These rail facilities carry approximately 40 trains per day,
almost all of which are freight. The County and local jurisdictions are exploring possible future
access to Union Pacific Rail lines for future passenger and freight service access.
2. Project Impacts
The consequences of General Plan build out, and within the context of continued development
outside the planning area, have been evaluated for the 63 major roadway segments and 37
intersections that have been analysed. Based on this analysis, the proposed General Plan Land
Use Plan is projected to generate a total of approximately 635,905 average daily trips. Of these,
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449,489 ADT would be generated within the City's corporate limits and 186,416 would be
generated in the City Sphere-of-Influence (Sphere).
Within the City's corporate limits, the proposed Land Use Plan will generate about 3.6% more
traffic than build out of the 2002 General Plan. Within the City's Sphere, the proposed Land Use
Plan will generate about 34% more traffic than build out of the 2002 General Plan land use
designations in the Sphere. The following discussion and tables detail the impacts associated
with implementation and build out of the Preferred Alternative land use plan.
Roadway Segment Impact Analysis
As noted, for traffic analysis purposes General Plan build out is projected for the Year 2035. The
following Table III-48 identifies each roadways segment, projected 2035 ADT volumes, the
roadway designation/classification, the number of through lanes required based on the roadway
classification, future roadway capacity and volume to capacity ratios and level of service
projected in 2035.
Table III-48
General Plan Build Out (2035) Roadway Segment Analysis
(Peak Season)
Roadway Link 2035
ADT
Roadway
Designation
2035
Number
of
Lanes
2035
Capacity
2035
V/C Ratio
- LOS
Washington St
Ave 42 to Fred Waring Dr 58,241 Major 6 61,100 0.95 – E
Fred Waring Dr to Miles Ave 64,210 Major 6 61,100 1.05 – F
Miles Ave to Hwy 111 54,141 Major 6 61,100 0.89 – D
Hwy 111 to Ave 48 57,955 Major 6 61,100 0.95 – E
Ave 48 to Eisenhower Dr 58,267 Major 6 61,100 0.95 – E
Eisenhower Dr to Ave 50 41,381 Major 6 61,100 0.68 – B
Ave 50 to Calle Tampico 36,164 Major 6 61,100 0.59 – A
Eisenhower Dr
Washington St to Ave 50 21,435 Primary 4 42,600 0.50 – A
Avenue 50 to Calle Tampico 15,291 Primary 4 42,600 0.36 – A
Avenida Bermudas
Calle Tampico to Ave 52 3,919 Secondary 4 28,000 0.14 – A
Ave 52 to Calle Durango 10,836 Secondary 4 28,000 0.39 – A
Adams St
Westward Ho Dr to Hwy 111 21,347 Secondary 4 42,600 0.50 – A
Hwy 111 to Ave 48 22,132 Secondary 4 42,600 0.52 – A
Dune Palms Rd
Westward Ho Dr to Hwy 111 16,547 Secondary 4 28,000 0.59 – A
Hwy 111 to Ave 48 20,999 Secondary 4 28,000 0.75 – C
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Table III-48
General Plan Build Out (2035) Roadway Segment Analysis
(Peak Season)
Roadway Link 2035
ADT
Roadway
Designation
2035
Number
of
Lanes
2035
Capacity
2035
V/C Ratio
- LOS
Jefferson St
Country Club Rd to Fred Waring Dr 34,274 Major 6 61,100 0.56 – A
Fred Waring Dr to Miles Ave 44,436 Major 6 61,100 0.73 – C
Westward Ho Dr to Hwy 111 48,090 Major 6 61,100 0.79 – C
Hwy 111 to Ave 48 46,656 Major 6 61,100 0.76 – C
Ave 48 to Ave 50 53,649 Major 6 61,100 0.88 – D
Ave 50 to Ave 52 35,143 Major 6 61,100 0.58 – A
Ave 52 to Ave 54 31,532 Major 6 61,100 0.52 – A
Madison St
Ave 50 to Ave 52 34,204 Primary 4 42,600 0.80 – C
Ave 54 to Airport Blvd 47,529 Primary 4 42,600 1.12 – F
Airport Blvd to Ave 58 35,638 Primary 4 42,600 0.84 – D
Ave 58 to Ave 60 26,920 Secondary 4 42,600 0.63 – B
Monroe St
Ave 52 to Ave 54 32,749 Primary 4 42,600 0.77 – C
Ave 54 to Airport Blvd 34,453 Primary 4 42,600 0.81 – D
Jackson St
Ave 54 to Airport Blvd 28,524 Primary 4 42,600 0.67 – B
Airport Blvd to Ave 58 28,380 Primary 4 42,600 0.67 – B
Ave 58 to Ave 60 23,174 Primary 4 42,600 0.54 – A
Ave 60 to Ave 62 16,826 Primary 4 42,600 0.39 – A
Van Buren St
Ave 52 to Ave 54 28,531 Primary 4 42,600 0.67 – B
Ave 54 to Airport Blvd 22,172 Primary 4 42,600 0.52 – A
Airport Blvd to Ave 58 21,641 Primary 4 42,600 0.51 – A
Ave 58 to Ave 60 20,134 Primary 4 42,600 0.47 – A
Ave 60 to Ave 62 11,627 Secondary 4 28,000 0.42 – A
Harrison St
Airport Blvd to Ave 58 79,828
Augmented
Major 8 76,000 1.05 – F
Fred Waring Dr (Ave 44)
Washington St to Adams St 52,881 Primary 6 61,100 0.87 – D
Miles Ave
Washington St to Adams St 15,151 Primary 4 42,600 0.36 – A
Hwy 111
Washington St to Adams St 53,511 Major 6 61,100 0.88 - D
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Table III-48
General Plan Build Out (2035) Roadway Segment Analysis
(Peak Season)
Roadway Link 2035
ADT
Roadway
Designation
2035
Number
of
Lanes
2035
Capacity
2035
V/C Ratio
- LOS
Adams St to Dune Palms Rd 40,481 Major 6 61,100 0.66 – B
Dune Palms Rd to Jefferson St 50,659 Major 6 61,100 0.83 – D
Ave 48
Washington St to Adams St 16,902 Primary 4 42,600 0.40 – A
Dune Palms Rd to Jefferson St 32,855 Primary 4 42,600 0.77 – C
Ave 50
Washington St to Jefferson St 16,121 Primary 4 42,600 0.38 – A
Jefferson St to Madison St 30,593 Primary 4 42,600 0.72 – C
Calle Tampico
Eisenhower Dr to Avenida Bermudas 5,350 Primary 4 42,600 0.13 – A
Avenida Bermudas to Washington St 10,063 Primary 4 42,600 0.24 – A
Ave 52
Avenida Bermudas to Washington St 16,133 Primary 4 42,600 0.38 – A
Washington St to Jefferson St 31,770 Primary 4 42,600 0.75 – C
Jefferson St to Madison St 28,944 Primary 4 42,600 0.68 – B
Madison St to Monroe St 26,510 Primary 4 42,600 0.62 – B
Ave 54
Jefferson St to Madison St 29,390 Primary 4 42,600 0.69 – C
Airport Blvd
Madison St to Monroe St 17,177 Primary 4 42,600 0.40 – A
Ave 58
Madison St to Monroe St 10,199 Secondary 4 28,000 0.36 – A
Monroe St to Jackson St 18,633 Secondary 2 28,000 0.67 – B
Ave 60
Madison St to Monroe St 14,846 Secondary 4 28,000 0.53 – A
Monroe St to Jackson St 9,960 Primary 4 42,600 0.23 – A
Ave 62
Madison St to Monroe St 9,624
Modified
Collector 4 28,000 0.34 – A
Monroe St to Jackson St 19,822 Secondary 4 28,000 0.71 – C
Jackson St to Van Buren St 7,022 Secondary 4 28,000 0.25 – A
Van Buren St to Harrison St 3,631 Secondary 4 28,000 0.13 – A
Table III-48, above, indicates that the majority of the roadway segments are forecast to operate
at acceptable levels of service (V/C ratios less than or equal to 0.90 or LOS D or better), the six
roadway segments identified below are forecast to operate at an unacceptable LOS (V/C greater
than 0.90) based on assigned roadway classifications. Three segments are projected to operate at
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LOS E and three at LOS F at 2035 build out.
Washington Street segments between Avenue 42 and Miles Avenue and between Highway
111 and Eisenhower Drive (6-lane Major Arterial) are forecast to exceed theoretical
maximum carrying capacity by up to 3,000 VPD with the most problematic segment between
Fred Waring Drive and Miles Avenue. LOS D service volumes are exceeded by over 9,000
VPD.
Madison Street between Avenue 54 and Airport Boulevard (4-lane Primary Arterial) is
forecast to exceed theoretical maximum carrying capacity by approximately 4,900 VPD.
LOS D service volumes are exceeded by over 9,000 VPD.
Harrison Street between Airport Boulevard and Avenue 58 (8-lane Augmented Major) is
forecast to exceed theoretical maximum carrying capacity by approximately 3,800 VPD.
Although the capacity of Harrison Street was assumed to be that of an Augmented Major
Road (76,000 vehicles per day), it would likely operate as an Expressway due to limited
accessibility compared to an Augmented Major Road, thus carrying a larger capacity. Prior
study by the County raised the potential of grade-separated intersections to further enhance
capacity.
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Exhibit III-20
General Plan Build Out (2035) Average Daily Traffic Volumes
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Intersection Impact Analysis
A level of service analysis was conducted to evaluate forecast year 2035 operating conditions
with implementation of the Preferred Land Use Plan intersection operations during the a.m. and
p.m. peak hours. The projected levels of service reflect additional improvements (such as
signalization of stop-controlled intersections and intersection widening), which were deemed
feasible and are described in detail in the mitigation section of this discussion. Table III-49,
below, sets forth 2035 operating conditions assuming all required improvements are provided.
Table III-49
General Plan Build out (2035) Intersection Analysis
(Peak Season)
Intersection Traffic
Control
AM Peak Hour PM Peak Hour
LOS Delay
(Sec) LOS Delay
(Sec)
1. Washington St & Fred Waring Dr Signal D 37.3 D 54.2
2. Washington St & Miles Ave Signal C 25.5 D 40.8
3. Washington St & Channel Dr Signal B 13.1 C 24.3
4. Washington St & Hwy 111 Signal D 41.5 D 52.5
5. Washington St & Ave 48 Signal D 38.9 D 46.9
6. Washington St & Eisenhower Dr1 Signal C 28.3 C 31.4
7. Washington St & Ave 50 Signal C 23.3 C 33.8
8. Washington St & Calle Tampico2 Signal C 20.4 C 24.2
9. Washington St & Ave 52 Signal C 31.8 C 25.3
10. Eisenhower Dr & Calle
Tampico Signal C 23.1 C 24.6
11. Avenida Bermudas & Ave 52 Signal C 27.2 C 26.5
12. Adams St & Fred Waring Dr Signal C 31.9 D 37.0
13. Adams St & Miles Ave Signal C 34.7 D 46.6
14. Adams St & Hwy 111 Signal C 32.8 D 35.8
15. Adams St & Ave 48 Signal D 38.6 D 54.0
16. Dune Palms Rd & Fred Waring
Dr Signal B 19.3 C 30.3
17. Dune Palms Rd & Miles Ave Signal D 36.3 D 50.8
18. Dune Palms Rd & Westward Ho
Dr Signal C 32.5 D 43.5
19. Dune Palms Rd & Hwy 111 Signal C 32.4 D 41.1
20. Dune Palms Rd & Ave 48 Signal C 25.3 C 31.2
21. Jefferson St & Fred Waring Dr Signal D 36.9 D 44.9
22. Jefferson St & Hwy 111 Signal C 32.1 D 53.8
23. Jefferson St & Ave 48 Signal D 40.4 D 46.2
24. Jefferson St & Ave 49 Signal B 17.7 B 16.9
25. Jefferson St & Ave 50 Signal C 33.9 D 43.4
26. Jefferson St & Ave 52
Roundab
out A 3.0 A 3.4
27. Jefferson St & Ave 54
New
Signal3 B 15.3 B 15.4
28. Madison St & Ave 50
New
Signal3 D 38.2 D 51.4
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Table III-49
General Plan Build out (2035) Intersection Analysis
(Peak Season)
Intersection Traffic
Control
AM Peak Hour PM Peak Hour
LOS Delay
(Sec) LOS Delay
(Sec)
29. Madison St & Ave 52
New
Signal3 D 39.8 D 54.5
30. Madison St & Ave 54
New
Signal3 D 38.2 D 52.7
31. Madison St & Ave 58
New
Signal3 C 24.7 D 52.6
32. Madison St & Ave 60
New
Signal3 D 51.8 D 38.7
33. Monroe St & Ave 52
New
Signal3 C 33.9 D 53.7
34. Monroe St & Ave 54
New
Signal3 C 30.2 D 44.8
35. Monroe St & Ave 58
New
Signal3 C 34.9 D 46.6
36. Monroe St & Ave 60
New
Signal3 C 30.7 D 43.3
37. Monroe St & Ave 62
New
Signal3 B 10.3 B 13.5
Notes:
LOS = Level of Service, Delay = Average Vehicle Delay (Seconds), V/C = Volume‐‐to‐‐
Capacity Ratio.
1 = Calculation based on implementation of a second southbound right‐‐turn lane (per 2011
CIP).
2 = Calculation based on implementation of a third eastbound left‐‐turn lane (per 2011 CIP).
3 = 2035 Conditions assume signalization of existing lanes.
A thorough analysis has been made of the physical improvements that are required to assure that
all the major intersections operate at acceptable levels of service (LOS D or better) in 2035. Of
the 37 intersections analyzed, the following four are not expected to be able to accommodate all
the required build out improvements and therefore have the potential to be operating at
unacceptable levels of service by 2035 General Plan build out:
Washington Street @ Fred Waring Drive;
Adams Street @ Miles Avenue;
Jefferson Street @ Highway 111;
Madison Street @ Avenue 50.
It should also be noted that three of the four impacted intersections are shared between more than
one jurisdiction. For instance, the Washington Street/Fred Waring Drive intersection is located
within the corporate boundaries of the cities of La Quinta, Palm Desert and Indian Wells. In
these cases, close and on-going coordination between cities will be necessary provide optimum
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intersection improvements and to otherwise address forecast operational deficiencies.
All-Weather Access
The City's roadway network and the neighborhoods it serves are generally well protected from
isolation due to flooding. Multiple points of access across the Whitewater River and the La
Quinta Evacuation Channel and additional all-weather facilities are planned in conjunction with
future development, which will preclude their isolation from flood events. Therefore, the
implementation of the proposed general Plan will not have a significant adverse impact on limits
of accessibility, including limits associated with flooding.
Public Transportation
Implementation of the proposed General Plan is expected to have a less than significant impact
on public transit facilities in the Valley. The major corridors where bus service is currently
provided are expected to continue to serve the areas of major demand for such services. The
General Plan Circulation Element provides policies and programs that will facilitate continued
coordination between the City and SunLine Transit to assure that the levels of transit service are
maintained and, where necessary, expanded.
Air Transportation
The continuing build out of the La Quinta planning area and the Coachella Valley in general will
contribute to increased demand for air transport services, particularly passenger service. In
addition to substantial capacity at the Palm Springs International Airport, current and planned
development at the Jacqueline Cochran Regional Airport will increase services at this airport.
Implementation of the proposed General Plan is expected to have a less than significant impact
on air transportation facilities in the Valley.
Railway Facilities
Union Pacific Railroad has recently expanded their rail facilities passing through the Valley and
there are substantial rail siding and associated facilities adjacent to UPRR lines that are expected
to meet future demand for several decades to come. Therefore, Implementation of the proposed
General Plan is expected to have a less than significant impact on public transit facilities in the
Valley.
3. Mitigation Measures
Mitigation Overview
The General Plan Circulation Element and the associated Traffic Impact Analysis identify and
address potential roadway network inadequacies that could result in unacceptable levels of
service. Areas of mitigation include roadway segment (mid-block) design, intersection design, as
well as a wide range of system improvements, management strategies, and the implementation of
a "Complete Streets" program, as set forth in the Circulation Element. How these mitigation
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measures and strategies are applied to the City's roadway network and the efficacy are discussed
below.
General Mitigation Measures and Strategies
In addition to standard mitigation involving physical street and intersection widening, a variety
of largely non-physical improvements will be applied and include the development and
implementation of transportation systems management and transportation demand management
(TSM and TDM) strategies. Also available are Intelligent Transportation System strategies,
which are primarily technologic add-on that can significantly enhance the operation of the City's
transportation system. Each of these mitigation programs is described below and will be applied
throughout the City
Transportation Demand Management
To the greatest extent practicable, the City will implement TDM strategies in both land use and
transportation planning. TDM programs are designed to put more person trips into fewer
vehicles, by increasing vehicle occupancy or car-pooling, vanpools, and transit ridership. TDM is
also integral to integrated land management consistent with SB 375 and also includes planning
efforts that increase the use of bicycling, golf carts and neighborhood electric vehicles (NEVs),
as well as increased pedestrian modes of travel. The effectiveness of TDM strategies depends on
their levels of application.
Transportation Systems Management
To the greatest extent practicable, the City will implement TSM strategies in transportation
planning. TSM programs and projects are designed to support travelers with real time travel
information so that they can make smart travel choices in selection of time, mode and routes of
travel. TSM projects can also offer Intelligent Transportation Systems (ITS) projects for the most
efficient traffic signal coordination and for informing motorists of routes around traffic
congestion that may result from special events and traffic incidents. TSM programs are very
effective when integrated into planned major events, such as scheduled music and art festivals,
golf or tennis matches, and other special events that generate significant amounts of event traffic.
Roadway Segment Impact Mitigation
As noted in the impacts discussion, six roadway segments have been identified where the City
may not be able to implement all the required physical improvements needed to assure LOS D or
better operation in 2035. As noted in the Circulation Element and the General Plan Traffic
Impact Analysis, getting all roadway segments to operate at LOS D or better in 2035 will require
ongoing focus on well coordinated operations of traffic signals and access control along the
segments to maximize efficient circulation. Roadway segment theoretical maximum carrying
capacities, also called “service volumes,” can be increased with delivery of more uniform travel
speeds and less slowing and stopping at red lights.
The following mitigation strategies are recommended to further improve operating conditions
along these segments.
Ongoing and diligent focus on well-coordinated operations of traffic signals will help maximize
efficient circulation along these segments. Maximum roadway carrying capacities (or “service
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volumes”) can be increased with more uniform travel speeds and less slowing and stopping at
red lights. This is best accomplished with implementation of an Intelligent Transportation
Systems master plan. The following recommendation should be implemented to increase
roadway capacity without the addition of travel lanes along segments operating unacceptably:
1. Commit to ongoing funding and operations of intelligent transportation systems
management, as described above, to:
a. Deliver traffic signal coordination along corridors in “real time” to optimize the
progression of vehicles at the most efficient travel speeds;
b. Operate Transit Signal Priority at signals along major transit routes to optimize traffic
flow;
c. Operate Dynamic Message Signs to route traffic around congestion/to available parking
during peak periods and planned events.
2. Continue with the City’s established minimum driveway spacing and access restrictions;
3. Construct median islands with minimum opening spacing; and/or;
4. Add bus turnouts at bus stops along major transit routes.
The following segment-specific recommendations will further enhance operating efficiencies
along these segments.
Washington Street Roadway Segment Deficiencies: The application of Transportation Demand
Management (TDM) and Transportation Systems Management (TSM) strategies will effectively
reduce peak hour traffic volumes along this segment, but it may still operate at unacceptable
levels of service (LOS E or F) during peak hour upon General Plan build out. Therefore,
potential impacts may not be fully mitigated below levels of significance.
Madison Street Roadway Segment Deficiency: The General Plan traffic analysis identified a
segment deficiency on Madison Street between Airport Boulevard (Ave 56) and Avenue 54.
There is some question whether this level of impacts will actually occur. Nonetheless, mitigation
measures include the application of TDM and TSM strategies to reduce peak hour traffic
volumes along this segment. It may still operate at unacceptable levels of service (LOS E or F)
during peak hour upon General Plan build out. Therefore, potential impacts may not be fully
mitigated below levels of significance.
Harrison Street Roadway Segment Deficiency: As an 8-lane Augmented Major Arterial,
Harrison Street between Airport Boulevard (Ave 56) and Avenue 58 is forecast to exceed
theoretical maximum carrying capacity by approximately 3,800 VPD. Harrison Street is assumed
to function as an Augmented Major Road (76,000 vehicles per day), and would likely operate as
an Expressway due to limited accessibility. Application of TDM and TSM strategies will help
reduce peak hour traffic volumes along this segment but it may still operate at unacceptable
levels of service (LOS E or F) during peak hour upon General Plan build out. Therefore,
potential impacts may not be fully mitigated below levels of significance.
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Intersection Impact Mitigation
As discussed above, intersections constitute the most constrained portion of the roadway network
in the City the planning area. The following exhibit identifies the 37 intersections analyzed and
illustrates the improvements (mitigation measures), both those already programmed and
new/additional improvements, needed to provide acceptable levels of service (LOS D).
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Exhibit III-21
Prescribed Intersection Improvement
Achieving LOS D Operations in 2035
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Special Intersection Management Provisions
As noted in the General Plan Traffic Impact Analysis (TIA) and this Circulation Element, it may
not be possible to implement all of the recommended intersection improvements. These
constrained intersections have been identified above, and recommendations for further enhancing
the operation of these intersections and further mitigating adverse impacts by other means is
described below.
The intersection improvements necessary to provide acceptable LOS upon build out of the
preferred General Plan were detailed above. Some of the potential improvements would affect
and require the cooperation of neighboring cities. In some instances, needed improvements could
affect existing buildings and other structures, and may not be feasible. In addition, some
recommendations from the Washington Street/Highway 111 Transportation Systems
Management (TSM)/Transportation Demand Management (TDM) Corridor Study (VRPA,
September 2009) are also considered. Special considerations for constrained intersections are as
follows:
Washington Street @ Fred Waring Drive: Two approaches to achieving acceptable intersection
operations may be combinations of 1) street widening, and 2) TSM/TDM measures. The
application of TSM/TDM will depend on the extent of widening that is determined to be feasible,
as presented below:
a. Intersection Widening
1. City of La Quinta jurisdiction widening could add a third northbound left-turn lane and a
fourth northbound through lane. This would improve AM peak hour conditions to LOS E.
The PM peak hour conditions would remain at LOS F but the average intersection delay
would be reduced by 38 seconds per signal cycle.
2. Coordinate with the City of Palm Desert to consider the potential for improvements in the
northwest intersection quadrant, specifically the adding of a fourth southbound through
lane, a fourth westbound through lane, and a westbound right-turn overlap phase. With
construction of these added to the widening recommended in the City of La Quinta, PM
peak hour conditions would remain at LOS F but the average intersection delay would be
reduced by an additional 20 seconds.
The City of Palm Desert General Plan (2004) does not call for these improvements, but
does call for consideration of a third northbound left-turn lane in the City of Indian Wells,
which is consistent with improvements in the City of La Quinta identified above. The
City of Palm Desert should be encouraged to continue to coordinate with the City of
Indian Wells for construction of an eastbound free-right turn lane.
3. Coordinate with the City of Indian Wells to consider improvements in the southwest
intersection quadrant, specifically the adding of a fourth eastbound through lane and a
second eastbound right-turn lane with a right-turn overlap phase. With construction of the
two City of Indian Wells improvement-impacting lanes, but not assuming improvements
in the City of Palm Desert, PM peak hour conditions would remain at LOS F but the
average intersection delay would be reduced by an additional 26 seconds.
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4. If the recommended improvements in the Cities of La Quinta, Palm Desert, and Indian
Wells are all implemented, the PM peak hour conditions would be improved to LOS D
operations.
5. Implement TSM/TDM measures for trip rerouting, in addition to some of the above listed
improvements that are determined feasible.
a. Design and implement an Intelligent Transportation Systems (ITS) Master Plan in
coordination with the cities of Palm Desert and Indian Wells, and in coordination
with the Indian Wells Tennis Event Center. An ITS Plan would enable dynamic route
reassignment of traffic around congestion and direct traffic to available parking
through the use of Dynamic Message Signs and adaptive traffic signal control. The
Plan would deliver the best access to events for attendees, and around event traffic for
residents that are not attending the events.
To achieve non-event LOS E operations, and to minimize the level of impacts
experienced at nearby intersections, approximately 200 northbound left-turning
vehicles would need to be diverted, approximately 100 southbound left-turning
vehicles would need to be diverted, and approximately 100 southbound through
movement vehicles would need to be diverted. Assuming these trip diversions, the
necessary roadway widening improvements would be reduced to the addition of
the third northbound left-turn lane (City of La Quinta), the second eastbound
right-turn lane with a right-turn overlap phase (City of Indian Wells), and a fourth
westbound through lane (Cities of La Quinta and Palm Desert). Therefore, the 4th
northbound through lane, 4th southbound through lane, 4th eastbound through lane,
and westbound right-turn overlap phase, recommended previously, would no
longer be necessary.
In order to achieve non-event LOS D operations, assuming the same approximate
ranges of trip diversion shown above, the addition of the fourth eastbound through
lane, the westbound right-turn overlap phase, and third eastbound left-turn lane
would be required. Therefore, the 4th northbound through lane and 4th southbound
through lane, recommended previously, would continue to no longer be
necessary.
Adams Street @ Miles Avenue: Add a dedicated westbound right-turn lane, converting the
number two through lane to a through only lane. Implementation of this improvement alone will
achieve LOS E operations in the PM peak hour. Consider adding a dedicated northbound right-
turn lane, converting the number two through lane to a through only lane order to achieve LOS D
operations. This could impact three to four residential property yards and require relocation of
power poles. This measure may not be feasible.
Jefferson Street @ Highway 111: Coordinate with the City of Indio in optimizing future
intersection improvements. To the extent practicable, add a fourth northbound through lane. Add
a fourth southbound through lane. Add a third southbound left-turn lane. While the prescribed
third southbound left-turn lane may be feasible, the fourth north and southbound through lanes
do not appear to be. Intersection operations will benefit from TSM programs and overall TDM
efforts.
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Madison Street @ Avenue 50: – Add a third northbound through lane and a dedicated right-turn
lane, converting the new number three through lane to a through only lane. Add a dedicated
southbound right-turn lane, converting the new number two through lanes to a through only lane.
Add a westbound dedicated right-turn lane with a right-turn overlap phase, converting the new
number two through lane to a through only lane. Add a second eastbound through lane and a
dedicated eastbound right turn lane. Management prescriptions include coordinating with the
City of Indio to signalize this intersection. It should be noted that the City of Indio plans to
maintain the planned four-lane roadway segment on Madison Street between Avenue 50 and 48.
Therefore, further analysis and the application of TDM and TSM strategies are warranted.
Madison Street @ Avenue 52: - Although not required by the traffic analysis, add a second
northbound left turn lane to help transfer future northbound traffic to the west and reduce
otherwise anticipated volumes on the northbound leg at the intersection of Madison Street and
Avenue 50.
In summary, while a variety of improvements and management strategies are prescribed for these
four intersections, not all improvements may be possible and these intersections could operate at
LOS E or F during peak periods by 2035.
Mitigation via Implementation of General Plan Policies and Programs
The Circulation Element of the Comprehensive General Plan includes twenty-six (26) policies
and twenty-nine (48) programs, which are designed to enhance the operation and efficiency of all
aspects of the transportation system serving the planning area. Policies and programs address the
on-going monitoring and management of traffic volumes and operating conditions, and the
timing of required improvements to maintain acceptable levels of service.
Summary of Mitigation
The General Plan, this EIR and the General Plan Traffic Study provide both programmatic and
concrete/prescriptive actions and measures that are expected to reduce transportation impacts
associated with the implementation of the proposed General Plan. In conjunction with the
existing various regional transportation initiatives coordinated through the City and CVAG, the
performance of transportation systems serving the City and planning area can be further
enhanced. The continued thoughtful integration of land uses will also increase opportunities for
mass transit and non-motorized means of transportation. Controlling access onto major arterial
roadways will also serve to preserve capacity and limit the costs associated with expanded
roadway infrastructure.
Even with the substantial feasible improvements and the implementation of TDM and TSM
programs and strategies, up to six roadway segments and four intersections may operate at LOS
E or F in build out year 2035.
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Mitigation Monitoring/Reporting Program
A. The City shall review and update the master plan of roads, including standards for ultimate
rights-of-way and pavement width, and update Capital Improvement Programs (CIP) to
ensure the timely securing of rights-of-way and construction of improvements consistent
with the projected needs and standards set forth in the Circulation Element and Program
EIR.
Responsible Parties: City Council, Planning Department, Public Works Department
B. The City shall establish and maintain ongoing consultation and coordination with planning
and engineering staffs of adjoining cities and transportation planning agencies to study and
implement effective means of preserving and improving capacity along major roadways.
Coordination efforts may include synchronized signalization, consolidation of access drives
and restriction of access, construction of additional travel and turning lanes, raised median
islands, and improvements to critical intersections.
Responsible Parties: Public Works Department, Planning Department, Adjoining Cities,
CVAG, Riverside County, Caltrans
C. The City shall periodically evaluate the operating conditions at each of the constrained
intersections, and shall make recommendations to responsible agencies regarding needed
improvements.
Responsible Parties: Public Works Department, Planning Department, Caltrans, Riverside
County, CVAG
D. The City shall pro-actively consult and coordinate with CVAG, SCAG and Caltrans and
represent the City in transportation planning meetings to assure that City policies, programs
and strategies are given full consideration in resolving regional transportation issues
affecting the community.
Responsible Parties: City Council, Planning Department, Public Works Department,
CVAG, SCAG, Caltrans
E. The City shall continue to pro-actively promote the mass transit system expansion and
innovation through ongoing consultation and coordination with the SunLine Transit
Agency and CVAG.
Responsible Parties: City Council, Planning Department, Public Works Department,
SunLine Transit Agency, CVAG
F. The City shall continue to consult and coordinate with the SunLine Transit Agency and
encourage the development of rideshare and other alternative, high occupancy transit
programs for employers with sufficient numbers of employees, and for individuals seeking
to locate potential rideshare partners.
Responsible Parties: City Council, Planning Department, SunLine Transit Agency
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G. The City shall monitor the effectiveness of land use planning proposals that integrate a mix
of land uses, optimizes nearby interactions, reduce the need for travel outside the
neighborhood, and shorten trips to work, shopping, public services and public park
facilities.
Responsible Parties: Planning Department, Redevelopment Agency
H. The City shall monitor the effectiveness of its master plan of bicycle-ways, golf cart/NEV
routes and multi-use paths, including secure bicycle and golf cart/NEV storage facilities,
and other support facilities which increase bicycle and golf cart use.
Responsible Parties: Planning Department, Public Works Department
I. The City shall periodically review roadway design specifications, design standards and
guidelines for public and private streets, and their effectiveness at meeting existing and
anticipated demand, reducing traffic speeds in neighborhoods, and facilitating safe and
efficient use of bicycles and other alternative modes of transportation.
Responsible Parties: Planning Department, Public Works Department, Planning
Commission, City Council
Water Resources & Quality P.
Introduction
The existing water supply and water quality conditions for the General Plan Planning Area are
discussed in this section. This section describes existing and future water demand to determine
potential impacts on water supplies and water quality from the implementation of the proposed
General Plan. Also considered is the current and projected availability and reliability of water
supplies, including those associated with imported Colorado River and State Water Project
water, as well from other water sources that have been identified.
The Coachella Valley Water District (CVWD) is responsible for managing water resources in the
region, including the General Plan area. CVWD delivers domestic and irrigation water to La
Quinta and its Sphere. Therefore, this section also discusses CVWD’s ability to provide water
supplies over the course of General Plan build out.
The Coachella Valley Urban Water Management Plan (CVWD UWMP), the CVWD Draft
Water Management Plan and other CVWD reports, as well as materials from the California
Department of Water Resources and other entities, have been consulted in the preparation of this
discussion.
Thresholds of Significance/Criteria For Determining Significance
The following standards and criteria have been drawn from Appendix G: Environmental
Checklist Form of the CEQA Guidelines. The following factors have been considered to ensure
that the General Plan EIR adequately addresses potential impacts to water resources that may
result from the adoption and implementation development of the General Plan. Implementation
of the La Quinta General Plan will have a significant impact on water resources and quality if it
would:
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a.) Violate any water quality standards or waste discharge requirements.
b.) Substantially deplete groundwater supplies or interfere substantially with groundwater
recharge such that there would be a net deficit in aquifer volume or a lowering of the
local groundwater table level (e.g., the production rate of pre-existing nearby wells would
drop to a level which would not support existing land uses or planned uses for which
permits have been granted).
c.) Substantially alter the existing drainage pattern of the site or area, including through the
alteration of the course of a stream or river, in a manner that would result in substantial
erosion or siltation on- or off-site.
d.) Substantially alter the existing drainage pattern of the site or area, including through the
alteration of the course of a stream or river, or substantially increase the rate or amount of
surface runoff in a manner that would result in flooding on- or off-site.
e.) Create or contribute runoff water that would exceed the capacity of existing or planned
stormwater drainage systems or provide substantial additional sources of polluted runoff.
f.) Otherwise substantially degrade water quality.
It should be noted that items c through e above are addressed Section H: Hydrology of this EIR.
1. Existing Conditions
The Coachella Valley and the Planning Area are within the Colorado River Watershed, which
drains into the Salton Trough. The desert climate is characteristically dry, with an average of less
than 4 inches of annual rainfall. Therefore, water is an especially limited and valuable resource.
To satisfy the demand for water from residential, commercial and agricultural users, the
Coachella Valley supplements local groundwater supplies with water from Northern California
and the Colorado River.
Northern California water is conveyed to Southern California via the California aqueduct. Over
23 million people and 755,000 acres of agricultural lands are served.106 Supplies to southern
California vary annually based on weather. Water supplies are more available in wet years and
decrease during dry years.
California is entitled to 4.4 million acre feet of Colorado River water per year, as set forth in a
1964 Supreme Court ruling. Although Colorado River water is one of the Coachella Valley’s
main sources of water, it has elevated levels of salinity. This water has been cited as contributing
to the elevated salinity levels found in the Valley. These issues are further discussed below under
Water Quality.
106 Department of Water Resources and Public Affairs, www.publicaffairs.water.ca.gov/swp/.
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Whitewater River Subbasin107
The Coachella Valley is underlain by a substantial subsurface groundwater basin. Over millions
of years, conditions created by the Valley’s geology and water runoff from surrounding
mountains have resulted in water collecting in the aquifer, which generally extends from the
Whitewater River in the northwest to the Salton Sea in the southeast. The aquifer is naturally
divided by fault barriers into subbasins, which are further divided into subareas. The Whitewater
River Subbasin (also known as the “Indio Subbasin”) encompasses approximately 400 square
miles and underlies most of the Coachella Valley. It is bounded on the north by Garnet Hill
Fault, on the east by the San Andreas Fault, and on the south by the San Jacinto and Santa Rosa
Mountains. It is estimated that the Subbasin contains approximately 28.9 acre-feet of
groundwater within the first 1,000 feet below the ground surface.
There are five subareas within the Whitewater River Subbasin: the Palm Springs subarea, the
Garnet Hill subarea, the Thermal subarea, the Thousand Palms subarea, and the Oasis subarea.
The City and Sphere are underlain by the Thermal subarea, which is part of the Lower
Whitewater River Subbasin.
Thermal Subarea
The division between the upper and lower portions of the Whitewater River subbasin is located
in the Thermal subarea. The juncture of the Thermal Subarea with the Palm Springs Subarea,
which lies to the west, occurs near Cathedral City. Based on measurement data for the Palm
Springs and Thermal subareas, there appears to be no distinction between the water tables of the
upper and lower subarea, except for the “hinge effect” of the Thermal subarea at Point Happy.
Groundwater levels have generally remained stable, although more recently, increased pumpage
has lowered groundwater levels in the lower portion of the Whitewater River subbasin.
Conditions in most of the Thermal Subarea are confined or semi-confined, with movement
caused by differences in piezometric (pressure) levels. Although unconfined or free water
conditions occur within alluvial fans such as those that at the base of the Santa Rosa Mountains,
an area of reduced permeability, or “aquitard” occurs between the two aquifers. Reduced
permeability is created where fine grained materials such as sand and gravel lenses occur. This
aquitard forms the boundary between the upper and lower aquifers in the Thermal subarea.
The upper and lower aquifer zones of the Thermal subarea have similar lithology108, although the
lower aquifer is thought to be thicker and to receive more subsurface inflow than the upper
aquifer. The lower aquifer is considered the most important source of groundwater in the
Coachella Valley Groundwater basin. It serves the area easterly of Washington Street, which
includes the La Quinta Planning Area. In this portion of the subarea, the top of the water table
ranges from 300 to 600 feet below the surface. Although undetermined, the aquifer is believed to
be at least 500 feet thick and some estimates suggest that it may be over 1000 feet thick. While
the aquifer contains vast water supplies, water table levels vary based on demand. Underlying the
107 “Engineer’s Report on Water Supply and Replenishment Assessment: Lower Whitewater River Subbasin Area
of Benefit, 2011-2012,” prepared by Coachella Valley Water District, May 2011. 108 A rock or rock formation’s gross physical character.
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lower subarea is an aquitard that is generally 100 to 200 feet thick, and up to as much as 500 feet
thick in some areas along the edge of the Salton Sea.
Regional Water Supply and Demand
The Coachella Valley’s principal domestic water source is groundwater. The subbasins
underlying the Coachella Valley contain approximately 39.2 million acre-feet of water, of which
about 28.8 million are within the Whitewater River subbasin. Natural recharge from precipitation
and mountain runoff, supplemented with artificial recharge from imported Colorado River and
State Water Project water, and recycled water from wastewater treatment plants also provide
water to the Coachella Valley.
During the twentieth century the Coachella Valley experienced a rapid depletion of its
groundwater in storage. CVWD data shows that significant increases in total water demand in
the Coachella Water Valley occurred during over the decades from 1936 (92,400 acre feet/year
(AFY) to 376,000 AFY in 1999. The increase in water demand reflects both municipal water and
agricultural irrigation. This is consistent with the growth of two primary economic activities in
the Coachella Valley: agriculture and tourism. Agriculture began to develop as a viable industry
in the Coachella Valley in the early 1900’s, especially in the eastern Valley. More recently, the
region has emerged as a leading destination resort area, characterized by lushly landscaped golf
courses and residential communities. In 2009 groundwater use decreased to approximately
358,700 AFY, through the implementation of conservation measures, source substitution projects
and the impacts of the economic downturn.
Regional Water Supply
Domestic water is provided in the City and most of the Sphere by CVWD. Groundwater is the
primary source for this water supply, which CVWD extracts from the Whitewater River
Subbasin by means of a system of deep wells within the region.
Total outflows exceed inflows in the Lower Whitewater River Subbasin Area of Benefit,
resulting in a condition known as overdraft. This condition has resulted in a decline in
groundwater levels in many portions of the eastern Valley from La Quinta to the Salton Sea.
Concerns related to these conditions include potential degradation of water quality and land
subsidence. Water quality concerns are addressed herein; for further discussion of land
subsidence, please see Section III-F, Geology and Soils.
CVWD estimates the annual overdraft balance based on outflows and inflows. It considers
outflows due to production, subsurface drainage, including the agricultural tile drain system, and
evapotranspiration from vegetation. Sources of inflow include natural inflow, non-consumptive
return from groundwater and imported water use, and groundwater replenishment efforts. Based
on these factors, the annual balance in the Area of Benefit through 2010 was estimated to be -
7,457 acre-feet. The cumulative overdraft for the Area of Benefit through 2010 is estimated to be
4,497,609 acre-feet.109
109 Table 3, “Engineer’s Report on Water Supply and Replenishment Assessment: Lower Whitewater River
Subbasin Area of Benefit, 2011-2012,” prepared by Coachella Valley Water District, May 2011.
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Historic and Current Consumption
As shown in Table III-50, below, water withdrawals, or groundwater production, in the Lower
Whitewater Subbasin Area of Benefit have remained generally stable since 1999.
Table III-50
Coachella Valley Water District Annual Water
Production Within the Lower Whitewater River
Subbasin Area of Benefit
1999 – 2010
Year Acre-Feet Million Gallons
19991 168,300 54,866
20002 166,700 54,344
2001 199,800 65,135
2002 172,300 56,170
2003 170,000 55,420
2004 170,000 55,420
2005 170,000 55,420
2006 170,000 55,420
2007 170,000 55,420
2008 170,000 55,420
20093 160,000 52,160
2010 150,000 48,878
1From the “Coachella Valley Water Management Plan, Table 3-2,
Summary of Historical Water Supplies in 1936 and 1999” prepared
by Montgomery Watson Harza.
22002-2008 from the “Engineer’s Report on Water Supply and
Replenishment Assessment: Lower Whitewater River Subbasin Area
of Benefit, 2010-2011, Table 2” prepared by Coachella Valley Water
District, April 2010. 3Assessable groundwater production estimated from reported and
projected unreported groundwater production.
Source: “Engineer’s Report on Water Supply and Replenishment
Assessment: Lower Whitewater River Subbasin Area of Benefit,
2011-2012, Table 2” prepared by Coachella Valley Water District,
May 2011.
Domestic Water Facilities110,111
The CVWD domestic water system is comprised of a system of 30 pressure zones in which water
supplies are drawn from 102 active wells. CVWD uses pressure booster pump and regulating
valve stations to transfer water between pressures zones. 112 The Planning Area is served by the
110 http://www.cvwd.org/about/waterandcv.php 111 Written communication, Mark Johnson, Coachella Valley Water District, December 28, 2010. 112 “Coachella Valley Water District Development Design Manual,” prepared by Coachella Valley Water District,
2010.
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following pressure zones: Valley, Upper, Middle and Lower La Quinta, and Lake Cahuilla.113
The District has 59 storage reservoirs. Domestic water is distributed via a system of pipelines
ranging in size from 4-inches to 36-inches in diameter, located in public street rights of way. In
2011, CVWD delivered 102,805 acre-feet of water to a population of 286,240 in its service area.
Currently CVWD has 21 active wells in the General Plan Area. In addition, there are 6 booster
stations and 10 planned or existing reservoirs in the Planning Area. Each reservoir has between
250,000 and 12 million gallons of capacity, with a total storage capacity of all reservoirs of 44.6
million gallons.114 CVWD has no plans to construct additional reservoirs in La Quinta at this
time.
Imported Water
Imported State Water Project exchange water and Colorado River water provide additional water
resources to the Valley. These sources are further discussed below. CVWD utilizes imported
water to supply its recharge basins behind Dike 4 and its pilot facility in Martinez Canyon, as
well as in the western portion of the Coachella Valley.
Colorado River Water
Colorado River Water is one of Coachella Valley’s main sources of water. It is delivered via the
Coachella branch of the All-American Canal, which extends throughout the Valley and
terminates at Lake Cahuilla in southern La Quinta. Based on the Quantification Settlement
Agreement (QSA), which quantifies Colorado River water allocations to agricultural water
contractors and provides for water transfers between agencies, CVWD is entitled to 368,000
acre-feet per year in 2010. Total deliveries, once reduced by conveyance and distribution losses,
are 337,000 acre-feet per year.115 Future allocations will increase by year 2026 through the end
of the 75-year QSA term. The amount of Colorado River water that the Coachella Valley
actually receives each year varies based on the amount of precipitation that occurs in the
Colorado River watershed.
Issues affecting the long-term reliability of the Valley’s Colorado River supply include an
extended drought in the Colorado River Basin, the Colorado River shortage sharing agreement,
issues related to protection of endangered species and habitat, climate change and legal
challenges to the validity of the QSA. Although the state and CVWD have high priority status
for the allocations provided for under the QSA and these supplies are expected to be reasonably
reliable, state court decisions regarding lawsuits are pending until at least 2011.116
113 La Quinta Pressure Zones Map, prepared by Coachella Valley Water District, December 28, 2010. 114 “Technical Background Report to the Safety Element Update, City of La Quinta, CA” prepared by Earth
Consultants International, September 2010. 115 Table 4-2, “Draft Coachella Valley Water District Water Management Plan” prepared by Montgomery Watson
Harza, December 2010. 116 “Draft Coachella Valley Water District Water Management Plan” prepared by Montgomery Watson Harza,
December 2010.
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State Water Project
CVWD, along with Desert Water Agency (DWA), contracts with the Metropolitan Water
District (MWD) for access to State Water Project (SWP) water in the Coachella Valley. Since no
physical SWP water delivery facilities exist in the Valley, CVWD and DWA access SWP water
through an exchange of Colorado River water from MWD’s Colorado River Aqueduct, which
extends through the Coachella Valley.
In addition to the original “Table A” allocation contracts begun in 1962 and 1963, CVWD and
DWA have contracted for additional SWP water from MWD through agreements reached in
2003, 2004 and 2007. Currently, all CVWD SWP sources, including the original and subsequent
agreements, total 138,350 acre-feet per year. Based on the SWP Delivery Reliability Report
issued by DWR, the average reliability of SWP Table A allocations through 2029 is 60%, which
accounts for climate change. This represents a decrease in published reliability from previous
DRR estimates.117 Accounting for all factors affecting the overall reliability of SWP supplies,
CVWD assumes a long-term reliability of 50%.
CVWD uses SWP exchange water to recharge the Upper Whitewater River and the Mission
Creek Subbasin Areas of Benefit at recharge facilities located near Palm Springs.
Groundwater Recharge118
CVWD has implemented a groundwater replenishment program to prevent adverse impacts from
the depletion of groundwater reserves. As noted above, imported water supplies from the
Colorado River and State Water Project are used to artificially recharge the Upper and Lower
Whitewater River and Mission Creek Subbasin Areas of Benefit at CVWD recharge facilities in
the Valley. CVWD has operated the Whitewater River Spreading Facility near Palm Springs
since 1973, utilizing over 2 million acre-feet of SWP water. It has a recharge capacity of 300,000
acre-feet per year, and an annual recharge goal of 100,000 AFY.
The Thomas E. Levy Groundwater Replenishment Facility, located within the impoundment area
of Dike 4 in the southern portion of the La Quinta General Plan Area. The Levy facility was
operated as a pilot program beginning in 1997, with full-scale operations completed in 2009. It
has an average recharge capacity of 40,000 AFY, which is limited by hydraulic and water
delivery constraints associated with the Canal water distribution system. Therefore, the long-
term average capacity is estimated of 32,000 AFY. In future, an additional pipeline and pumping
station from Lake Cahuilla may be constructed.
CVWD has conducted a pilot recharge program at the second east Valley recharge facility in
Martinez Canyon, south of the Planning Area, since 2005. When full-scale operations come on-
line, the Martinez Canyon facility is expected to have an average annual recharge capacity of
between 20,000 and 40,000 AFY. CVWD estimates that this project will begin initial full-scale
operation in 2016, and reach capacity by 2018.
117 Table 4-4, “Draft Coachella Valley Water District Water Management Plan” prepared by Montgomery Watson
Harza, December 2010. 118 “Draft Coachella Valley Water District Water Management Plan” prepared by Montgomery Watson Harza,
December 2010.
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Additional Water Sources
Recycled Water/Tertiary Treated Water
Reclaimed or tertiary treated water can be used for landscape irrigation, thus reducing the
amount of domestic water required for such uses. There are six CVWD water reclamation plants,
of which two have facilities to treat wastewater to tertiary levels, which is non-potable but
suitable for irrigation. A third CVWD water reclamation plant produces secondary treated water
suitable for irrigation where uses are restricted. WRP-7, located in north Indio, serves the
Planning Area, and has capacity to tertiary treat 2.5 million gallons of wastewater daily, with
potential to expand up to 7.5 mgd. A second plant, WRP-4, located in Thermal, also serves the
Planning Area but does not currently recycle wastewater. CVWD plans for this use in future as
demand increases.119
CVWD is the regional stormwater agency and maintains regional drainage facilities in La
Quinta, including agricultural drainage facilities. A system of CVWD laterals connected to the
Coachella Canal currently deliver irrigation water to golf course and agricultural development in
La Quinta. As agricultural uses are converted to residential and other urban development,
particularly in the Sphere, these systems may continue to be used to deliver non-potable water to
irrigate landscaping associated with future development.120
Water Conservation
CVWD and the City of La Quinta implement a variety of water conservation efforts that are
responsive to local conditions and compliant with state legislative requirements. Through its
Draft Water Management Plan, CVWD had developed a system of policies and programs
designed to reduce domestic water use and increase the efficiency of that use to the greatest
extent feasible. The following briefly describes the major water conservation initiatives,
including applicable legislation.
Senate Bill x7-7
Senate Bill (SB) x7-7 (2009) includes several requirements to reduce water consumption and
increase water use efficiency statewide over the next decade. It mandates a 10% reduction in per
capita urban water use by year 2015, and a 20% reduction by year 2020. It further requires that
agricultural water suppliers prepare agricultural water management plans and develop efficient
water management practices. Finally, it requires that sustainable water supplies be expanded at
the regional level through the provision of incentives and alternative water supply sources, such
as desalination and stormwater recovery. 121
119 “Draft Coachella Valley Water District Water Management Plan”, prepared by Montgomery Watson Harza,
December 2010. 120 Personal communication, Mark Johnson, CVWD, December 20, 2010. 121 “SBX7 7 (Steinberg) – November 2, 2009 Fact Sheet”,
http://senweb03.senate.ca.gov/focus/outreach/sd23/200911enews/SBX77FactSheet.pdf California Senate Bill
(SB) x7-7, accessed via Google search, December 14, 2010.
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Water Efficient Landscaping
The California Water Conservation in Landscaping Act122 requires local jurisdictions to
implement a water efficient landscape ordinance, either through adoption of the jurisdiction’s
own or through implementation of the state ordinance, by January 1, 1993. Amendments enacted
in 2006 set forth more stringent requirements than those of the original legislation, with cities
and counties required to meet or exceed the new standards. The CVWD ordinance, adopted in
2003 and updated in 2007, requires that outdoor water use by new development be reduced by
25% beyond state requirements. In 2009, CVWD and other water districts in the Coachella
Valley, along with all Coachella Valley cities, Riverside County and the Coachella Valley
Association of Governments (CVAG), developed a single landscape ordinance for adoption by
each of these entities. The ordinance would encourage maximum efficiency for landscape water
use, establish uniform landscape standards throughout the Valley, and limit turf on new golf
courses. As such, it represents one of the most stringent such ordinances in the state.
The City has adopted the Water Efficient Landscape ordinance (No. 220, Chapter 8.13 in the
City Municipal Code), which implements the requirements of the state’s Model Efficient
Landscaping Ordinance123 and Water Conservation in Landscaping Act, including the more
stringent requirements of the ordinance developed in conjunction with CVWD. The City
ordinance is intended to establish effective water efficient landscape requirements for newly
installed and rehabilitated landscaping. It requires that new and rehabilitated landscape plans for
most residential, commercial and governmental projects are subject to City review, and must
include a water conservation concept statement and verification that the plan provides for water
efficient landscaping. Irrigation systems for existing landscaping may be subject to water audits
when water supply allowances are exceeded; it prohibits the overflow of waste water from
inefficient irrigation systems onto adjoining properties, and requires timely repair of broken or
malfunctioning sprinkler heads or pipes.
Conversion of Uses
The Draft WMP prepared by CVWD establishes goals to reduce groundwater demand for
agriculture and golf courses by converting portions of those uses to recycled or canal water. The
Draft WMP projects a decrease in groundwater demand by agricultural uses by 2045 of 89%
from 2009 levels. As of 2010, CVWD requires golf courses with access to recycled or canal
water to utilize these sources for at least 90% of their irrigation demand by 2015.
Other Water Supplies
CVWD’s Draft WMP describes other water supply sources that have been available in the past
or may be available in the future. These include recycled water from fish farm operations
(aquaculture), water transfer opportunities, desalinated drain and ocean water, and stormwater
capture. The Draft WMP discusses the relative feasibility of each of these options, some of
which may provide additional water supplies in future.
122 California Government Code, Sections 65591, 65593, 65596. 123 California Code of Regulations Title 23, Waters Division 2, Department of Water Resources Chapter 2.7,
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Integrated Regional Water Management Plan124
The Integrated Regional Water Management (IRWM) Planning Act, enacted in 2002,125
encourages the development of integrated regional strategies by local agencies to manage and
improve the quality, quantity and reliability of water supplies. IRWM plans are reviewed by the
California Department of Water Resources (DWR), which also funds water management
projects. The Coachella Valley Regional Water Management Group (CVRWMG) was formed in
2008 through a Memorandum of Understanding between CVWD and four other regional water
management agencies to develop a an Integrated Regional Water Management Plan. Through
the Plan, the Management Group will be eligible for DWR grants. The Plan has completed
public review and was adopted by the CVWD Board in December 2010.126
Urban Water Management Plan
California Water Code California Water Code mandates that CVWD prepare an Urban Water
Management Plan (UWMP) to analyze current and future water supplies and ensure sufficient
supply to serve land uses within its service area. CVWD’s previous UWMP was adopted in
2005127 and has subsequently been updated. The 2010 UWMP has been completed.
Water Quality
In the Coachella Valley, groundwater quality is affected by depth, hydrogeologic or cultural
features, such as proximity to faults or recharge basins, and the presence of contaminants. In
general, the Valley has generally good to excellent water quality. Exceptions occur in portions of
the Subbasin where perched or semi-perched water tables occur, where groundwater contains
high concentrations of dissolved solids. In some areas in the Planning Area, long-term discharge
associated septic systems may also affect groundwater quality. Importation of Colorado River
water has also impacted groundwater quality in some areas. These issues are further discussed
below.
The CVWD Draft WMP addresses existing and emerging issues associated with water quality in
the Coachella Valley. These include salinity and the presence of a variety of contaminants,
including total dissolved solids and nitrates. CVWD regularly monitors wells, and testing data
provided in the most recent Water Quality Report shows water supplies meet all state and federal
standards for drinking water. In some areas, low levels of naturally occurring arsenic have been
found. CVWD has three ion treatment facilities for arsenic removal; these are located in the
Mecca and Thermal areas. For the most part, water treatment in wells is limited to chlorination
to assure disinfection.128
124 “Draft Coachella Valley Water District Water Management Plan”, prepared by Montgomery Watson Harza,
December 2010. 125 California Water Code, Division 6 Part 2.2, §10530 et seq., as amended. 126 Personal communication, Mark Johnson, CVWD, December 20, 2010. 127 “Final Coachella Valley Water District Water Management Plan”, prepared by Mongomery Watson Harza,
December 2005. 128 “Coachella Valley Water District Development Design Manual,” prepared by Coachella Valley Water District,
2010.
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Nitrates and total dissolved solids are briefly discussed below.
Total Dissolved Solids
Total Dissolved Solids (TDS) naturally leach into groundwater from soils. The secondary MCL
for TDS includes an upper level of 1,000 milligrams per liter (mg/L) and a short-term level of
1,500 mg/L. Based on CVWD domestic well monitoring data for 2009, TDS levels ranged from
150 to 980 mg/L.
Nitrates
The most closely monitored chemical in drinking water is nitrate. Nitrate is a nitrogen
compound, and the most common sources in groundwater include leaching of nitrogen-based
fertilizers, animal waste and natural deposits such as mesquite hummocks or alluvial fan
formations. Nitrates may also result from septic tank discharges. These compounds are often
found in shallower aquifer zones and may result from activities such as recharge, pumping, and
overdraft reduction.129
In drinking water, nitrate levels over 45 mg/L pose a health risk for infants younger than six
months old, as well as pregnant women and certain other specific conditions. Nitrate levels do
not demonstrate rapid change, given well depths. Should nitrate levels show an increase, CVWD
increases frequency of monitoring and is prepared to remove wells from service where indicated.
Data from CVWD 2009 well monitoring shows that average nitrate levels ranged from 2.1 to 7.1
mg/L.130 Concentrations as high as 39 mg/L were detected in samples taken from wells serving
the Cove Communities, which includes portions of La Quinta.
Impacts of Septic Systems on Groundwater Quality
Impacts on groundwater quality from long-term discharge from septic systems are more recent
and generally less extensive as compared with other water quality issues. However, CVWD, the
Regional Water Quality Control Board, and the Riverside County Department of Health
acknowledge that groundwater quality may be impacted by these discharges. There are a variety
of factors that influence impacts to groundwater from septic systems. These include population,
relative density, wastewater volume, soil conditions and septic system maintenance. Where large
populations at high densities are present, and where septic systems are poorly maintained,
impacts are generally greater. The removal of wastewater through community sewer systems
provides safeguards to protect groundwater resources from nitrate contamination. The majority
of residential development in the Planning Area is served by existing sanitary sewer facilities.
However, some areas, especially in the Sphere of Influence, still utilize septic systems. As future
development builds out, sewer systems will be extended to serve these areas and septic systems
will be abandoned.
129 “Draft Coachella Valley Water District Water Management Plan”, prepared by Montgomery Watson Harza,
December 2010. 130 “Coachella Valley Water District 2011 Domestic Water Quality Summary, in the CVWD 2011 Domestic Water
Quality Report.”
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Water Quality Regulation
There are a variety of federal and state laws and regulations that are intended to assure the
adequate planning, implementation and enforcement of water quality control effort. On a federal
level, the primary pieces of legislation are the Clean Water Act and the National Environmental
Policy Act (NEPA). Water quality statutes and administrative laws enacted by the State of
California include the California Water Code, California Environmental Quality Act (CEQA)
and California Code of Regulations. Health and Safety Code, Fish and Game Code and Public
Resources Code also include applications to water quality.
California Water Code (Section 13260), states that “any person discharging waste or proposing
to discharge waste that may affect waters of the State, except to a community sewer system” is
required “to file a report of waste discharge with the regional board of that region” where
densities exceed two (2) dwelling units/acre. For commercial and industrial wastewater
generators where discharge volumes exceed certain thresholds, these requirements also apply.
The California Regional Water Quality Control Board (CRWQCB), Colorado River Basin
Region, implements federal and state laws and regulations pertaining to water quality. The
CRWQCB has prepared a Water Quality Control Plan for the Colorado River Basin, which was
adopted in 1993. The plan is subject to periodic review by the State Water Quality Control Board
and the US Environmental Protection Agency, and the Regional Board updates it as needed. In
compliance with the federal Clean Water Act, the CRWQCB is also required to list water bodies
that exceed or are expected to exceed water quality standards even with implementation of water
quality control standards. Those affecting the Coachella Valley in the most current listing
include the Coachella Valley Stormwater Channel and the Salton Sea. The Board sets specified
time limits by which it will develop total maximum daily loads (TMDL) to limit the discharge of
pollutants and thereby remedy water quality impairment for specified pollutants. TMDL
completion dates for the Stormwater Channel range from 2014 to 2021.
The primary water quality issues in the Coachella Valley are salinity and nitrates. In addition to
addressing issues regarding septic and sewer systems, the CRWQCB oversees concerns about
the Whitewater River and other sources of surface water. CRWQCB monitors illegal discharges
of human or animal waste, leaking fuel storage tanks, and unauthorized hazardous and toxic
materials dumping sites.
National Pollutant Discharge Elimination System
The National Pollutant Discharge Elimination System (NPDES) was adopted in 1990 to
implement the federal Clean Water Act. NPDES requires that local jurisdictions adopt and
implement storm water management plans and programs to “effectively prohibit non-storm water
discharge into the storm drain and require controls to reduce the discharge of pollutants from
storm water systems to waters of the United States to the maximum extent possible.” CEQA
analysis is not required for pollutant control measures. The La Quinta Department of Public
Works manages the NPDES program for the City.
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2. Project Impacts
At build out, the proposed General Plan will result in 53,103 dwelling units. As compared with
the previous General Plan, which planned for 78,952 units, this represents a decrease of
approximately 25,849 units, or 32.7%. As a result of new residential development in the
Planning Area, it is expected that a population of approximately 134,352 will be generated at
build out. New commercial, industrial, public facilities and other types of development will also
occur as a result of implementation of the proposed General Plan. The proposed Land Use Plan
for the General Plan would result in less overall development as compared with the previous
General Plan. Build out of the new residential and other types of development will result in an
increase in water consumption compared to existing conditions, which has the potential to
impacts water resources.
Water Demand Analysis
A Water Supply Study (WSS)131 has been prepared for the La Quinta General Plan and is
included in Appendix I of this EIR. The WSS estimates current water demands generated within
the Planning Area and projects future water demands that will be generated at build out of the
proposed General Plan. It should be noted that the WSS prepared for the General Plan is
programmatic, and qualifying individual development projects within the Planning Area may be
subject to preparation of project-level Water Supply Assessments as warranted.
Existing Water Demands
Table III-51 shows the estimated water demands that are currently generated within the Planning
Area. Methodology and assumptions utilized to estimate the existing water demands within the
Planning Area are described in Appendix A of the WSS, which is included in full in Appendix I
of this EIR.
131 “Water Supply Study for the proposed La Quinta General Plan Update 2010,” prepared by Terra Nova Planning
& Research, June 21, 2011.
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Table III-51
Estimate of Existing Water Service Demands
Land Use Designation
Landscaping
(ac-ft/yr)
Potable
(ac-ft/yr)
Total Demand
(ac-ft/yr)
Daily Demand
(mgd)
La Quinta City Limits
Low Density Residential 6,482.65 4,091.66 10,574.31 9.44
Medium/High Density Residential 1,157.40 521.42 1,678.83 1.5
Commercial 311.87 1,007.61 1,319.48 1.18
Major Community Facilities 295.91 111.99 407.9 0.36
Open Space - Natural N/A N/A - -
Open Space- Recreation 16,465.48 N/A 16,465.48 14.7
Streets, Sidewalks, Medians 781.47 N/A 781.47 0.7
Total 25,494.78 5,732.69 31,227.46 27.88
Sphere of Influence
Low Density Residential 857.11 157.31 1,014.42 0.91
Medium/High Density Residential 0.18 - 0.18 0
Commercial 17.71 43.03 60.74 0.05
Major Community Facilities 30.65 13.26 43.9 0.04
Streets, Sidewalks, Medians 149.17 N/A 149.17 0.13
Total 1,054.82 213.6 1,268.42 1.13
Planning Area Summary
Low Density Residential 7,339.76 4,248.97 11,588.73 10.35
Medium/High Density Residential 1,157.58 521.42 1,679.01 1.5
Commercial/Industrial 329.58 1,050.64 1,380.22 1.23
Major Community Facilities 326.56 125.25 451.81 0.4
Open Space - Natural N/A N/A - -
Open Space- Recreation 16,465.48 N/A 16,465.48 14.7
Streets, Sidewalks, Medians 930.64 N/A 930.64 0.83
Total 26,549.59 5,946.28 32,495.88 29.01
Source: "La Quinta General Plan Water Resources Projections," Appendix A to Water Supply Assessment, prepared by Terra Nova
Planning & Research Inc., January 2011.
As seen in the Table above, the existing water demands for the La Quinta Planning Area are
estimated to be 32,496 acre-feet per year, consisting of 31,227 acre-feet within City limits and
1,268 acre-feet within the Sphere of Influence. Existing water demands in the Planning Area are
comprised of 3.9% within the Sphere and 96.1% within City limits.
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Water Demands at Build Out (2035)
The following table shows the projected water demand for land uses in the City, Sphere and the
entire planning area at build out, assuming that new development adheres to water efficiency
building standards and existing development continues to generate business as usual water
demands.
Table III-52
Estimate of Water Service Demands at Build Out
Land Use Designation
Landscaping
(ac-ft/yr)
Potable
(ac-ft/yr)
Total Demand
(ac-ft/yr)
Daily Demand
(mgd)
La Quinta City Limits
Low Density Residential 9,294.22 4,881.63 14,175.85 12.66
Medium/High Density Residential 1,502.34 1,016.81 2,519.15 2.25
Commercial 496.72 1,360.39 1,857.11 1.66
Major Community Facilities 476.80 149.64 626.44 0.56
Open Space - Natural N/A N/A N/A N/A
Open Space- Recreation 17,681.77 N/A 17,681.77 15.79
Streets, Sidewalks, Medians 922.39 N/A 922.39 0.82
Total 30,374.25 7,408.47 37,782.72 33.73
Sphere of Influence
Low Density Residential 12,309.74 3,375.02 15,684.76 14.00
Medium/High Density Residential 24.21 34.41 58.62 0.05
Commercial 192.99 377.52 570.51 0.51
Major Community Facilities 32.47 13.63 46.10 0.04
Streets, Sidewalks, Medians 324.17 N/A 324.17 0.29
Total 12,883.57 3,800.58 16,684.15 14.89
Planning Area Summary
Low Density Residential 21,603.95 8,256.66 29,860.61 26.66
Medium/High Density Residential 1,526.55 1,051.22 2,577.77 2.30
Commercial/Industrial 689.71 1,737.91 2,427.62 2.17
Major Community Facilities 509.27 163.27 672.54 0.60
Open Space - Natural N/A N/A - -
Open Space- Recreation 17,681.77 N/A 17,681.77 15.79
Streets, Sidewalks, Medians 1,246.56 N/A 1,246.56 1.11
Total 43,257.82 11,209.05 54,466.87 48.62
Source: "La Quinta General Plan Water Resources Projections," Appendix A to Water Supply Assessment, prepared by Terra Nova
Planning & Research Inc., January 2011.
As seen in the Table above, the build out water demands for the La Quinta Planning Area are
estimated to be 54,467 acre-feet per year, consisting of 37,783 acre-feet within City limits and
16,684 acre-feet within the Sphere of Influence. Build out water demands in the Planning Area
are comprised of 30.6% within the Sphere and 69.3% within City limits.
Proposed Development
At build out development within the La Quinta Planning Area is expected to consume 54,467
acre-feet of water per year, which represents an increase in water demand of approximately
21,971 acre-feet compared to water demands generated by existing development. The Table
below shows the projected water demand that will be generated from new development set forth
in the proposed General Plan Update.
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Table III-53
Estimate of Water Service Demands from New Development
La Quinta
Landscaping
(ac-ft/yr)
Potable
(ac-ft/yr)
Total Demand
(ac-ft/yr)
Daily Demand
(mgd)
City Limits 4,879.47 1,675.78 6,555.26 5.85
Sphere of Influence 11,828.75 3,586.98 15,415.73 13.76
Planning Area Summary 16,708.23 5,262.77 21,970.99 19.61
As seen in the Table above, 70% of the new water demand will be generated by new developed
within the Sphere, and 30% will be generated by new development within City Limits.
Water Demand Consistency
CVWD’s 2010 UWMP accounts for new growth and development that is expected to occur
within the region including the Planning Area. Section 3.3 of the WSS describes the water
demand projections for the La Quinta General Plan Update relative to the water demand
projections set forth in the CVWD UWMP. The average per capita water demand for the CVWD
Service Area is approximately 482 gallons per capita per day (gpcd) for 2010 and is projected to
be 423 gpcd for 2035. The 2010 per capita water demand for the La Quinta Planning Area is
approximately 473 gallons per day and is projected to be 361 gpcd in 2035. The water demand
estimates for the La Quinta Planning Area for 2010 and 2035 are 2% and 15% more efficient
compared to the CVWD estimates. As such, water demands generated by the La Quinta Planning
Area are fully captured and accounted for within the CVWD UWMP projections. Therefore,
water demand projections proposed by the La Quinta General Plan Update are consistent with
the water demand estimates utilized by CVWD.
Impacts to Water Supply Resources
As described above, CVWD serves as the water provider for the City of La Quinta and the
Sphere. Water supplies that serve the existing La Quinta Planning Area are derived from
groundwater in storage and imported Colorado River water and SWP exchange water. All urban
water demands are currently met through groundwater supplies. New water demands generated
by proposed development set forth in the La Quinta General Plan Update will be met through a
combination of groundwater, imported supplies, and recycled water.
CVWD expects to have sufficient water supplies to serve development in the Planning Area
through 2035 and beyond by utilizing a combination of water supply sources and treating surface
water supplies to potable quality standards. CVWD projects that, in 2035, the urban water
demand will be supplied by a total of 242,700 acre-feet per year consisting of 53% groundwater,
20% treated Colorado River Water, 22% Untreated Colorado River Water, and 4% desalinated
agricultural drain water.
CVWD’s UWMP and the WMP provide long term water supply/demand planning in an effort to
protect water resources, preserve water quality, and assure that water supplies are available to
meet demands. CVWD’s UWMP evaluates water demands relative to supplies for the period
between 2010 and 2035 under normal, single, and multiple dry year conditions. The UWMP
finds that with groundwater supplies, imported water supplies, water conservation programs, and
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recharge activities water supplies are sufficient to meet demands during normal, single, and
multiple dry year conditions through 2035.
Implementation of new growth and development set forth under the proposed General Plan will
result in an increase in the demand for water of approximately 6,555 acre-feet within City Limits
and 15,416 acre-feet within the Sphere of Influence by 2035. This new demand will be met by
groundwater, imported Colorado River water, desalinated agricultural drain water, or a
combination thereof. As described above, CVWD has accounted for this increased water demand
in conjunction with all other projected water demands within the service area and has determined
that through the utilization of a combination of water supply sources sufficient water supplies
will be available to meet demands in 2035. As such, the level of additional water supplies needed
to meet demands generated by development within City Limits and the Sphere at build out of the
General Plan will not substantially deplete groundwater reserves or interfere with groundwater
recharge.
The City of La Quinta relies on CVWD to manage and supply water resources. Nonetheless, the
City is committed to promoting water conservation and achieving water savings, protecting
groundwater reserves, and preserving groundwater quality. In the La Quinta Planning Area water
conservation can be achieved through retrofitting existing development, installing water efficient
appliances, the use of new technology, and advanced irrigation control for outdoor landscaping.
Source Substitution
At build out, 20% (11,209 acre-feet) of the water demands within the Planning Area will be
generated by potable demands whereas 80% (43,258 acre-feet) will be generated by non-potable
demands, such as landscaping. The use of non-potable water supplies for the irrigation of
recreational open space, especially golf course development, as well as other landscaped area
protects groundwater reserves by utilizing an alternative water supply source.
Water Resources and Climate Change
The region’s water supply consists of both surface and groundwater supplies, which have
varying susceptibility to climate change. Surface water supplies are especially susceptible to
increasing temperatures that are associated with changing climatic conditions. Groundwater
reserves tend to be somewhat protected from climate change since they are underground and are
not susceptible to increased evaporation due to elevated temperatures. As such, CVWD’s long
term water management strategy relies on conjunctive use thereby maximizing the use of surface
flows when they are available including use of surface water to recharge the groundwater basin,
and the use of banked groundwater supplies when surface flows are limited or unavailable.
Given the substantial amount of uncertainty associated with predicting the affect that climate
change will have on water resources, CVWD continuously monitors inflows and outflows in the
basin, implements programs to conserve water, recharge the basin, and protect water resources,
and routinely updates planning and management strategies to incorporate the latest available
information and technologies.
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Water Quality
The quality of water within the Whitewater River Subbasin and both treated and untreated
Colorado River water is described as good in the CVWD UWMP (Table 5-13). The 2011 Water
Quality Report prepared by CVWD shows the domestic water quality by service area.
Monitoring for certain contaminants has been conducted and no established thresholds for
domestic water quality standards have been exceeded within the CVWD service area. The
primary groundwater quality concerns in the Whitewater River Subbasin are salinity and
nitrate.132 Arsenic, perchlorate, chromium-6, uranium, carcinogens, and endocrine disrupting
compounds have been identified as emerging issues and are monitored by CVWD. 133
Salinity
Colorado River water is used for direct recharge to groundwater reserves and is relatively high in
salinity. Salinity levels of surface water supplies within the service area range from an average of
636 mg/L to of 790 mg/L. CVWD is evaluating and pursuing several options to limit the
concentration of salt in recharge supplies. One option is to directly import SWP supplies via
construction of a SWP extension pipeline that would connect to the Whitewater and Mission
Creek spreading facilities. SWP supplies typically have an average total dissolved solids
concentration of 245 mg/L. Other option is to treat Colorado River water through a desalination
process before recharge, although this option may be cost prohibitive. CVWD will continue to
monitory TDS in recharge supplies and groundwater. With implementation of the CVWMP
salinity will not affect groundwater supply reliability.
Nitrates
Groundwater quality may also be adversely impacted by long-term discharge from on-lot septic
systems. These impacts to groundwater quality are expected to be greatest where septic systems
serve large populations in high densities, such as the La Quinta cove community. For the City of
La Quinta, nitrate concentrations in domestic water provided by CVWD range from “not
detected” to a maximum of 40 mg/L. The average nitrate concentration was 7 mg/L within the
La Quinta service area. The MCL for nitrate has been set at 45 mg/L. Although domestic water
delivered by CVWD was below this threshold, the maximum concentration was approaching the
threshold. Nitrates in the groundwater supply are attributed to leaching of fertilizers, animal
waste, and natural deposits. Expanding the sewer system and removing on-lot septic may further
limit nitrate accumulation in groundwater reserves.
Water Quality Impacts
Impacts to water quality are expected to be comparable to or slightly less than those associated
with the 2002 General Plan. The proposed General Plan provides for fewer residential units and
overall less commercial and industrial square footage than does the 2002 General Plan.
A majority of the new development in the Planning Area will be required to connect to
community sewer facilities and, over time, it is expected that lots currently using septic systems
132 “CVWD 2011 Domestic Water Quality Table,” prepared by CVWD, 2011. 133 Refer to section 4.5.2 of the Water Supply Study for additional information on emerging pollutants of concern.
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will be provided with the opportunity to connect to sanitary sewer facilities, thereby reducing the
potential for nitrate leaching.
The proposed General Plan is not expected to impact water quality from project implementation.
However, to further limit potential impacts to water resources and reduce impacts to less than
significant levels the following mitigation measures are proposed. Further, implementation of the
proposed General Plan will ensure the continued implementation of federal, state, local and all
other applicable pollution control standards.
3. Mitigation
Water Conservation
Increasing demands on water supplies in the General Plan Area require the implementation of
short and long-term water conservation efforts to ensure the continued availability of this
resource. Reduction in per capita consumption as well as water-efficient landscaping design and
management are among the best conservation opportunities. The City’s Water efficient landscape
ordinance prohibits washing driveways and walkways with water, excessive runoff of landscape
irrigation water, and other wasteful water practices. It establishes penalties when these
requirements are violated. There are a variety of state and regional mandates in place intended to
reduce urban water consumption over the next several decades. As previously noted, new state
requirements mandate a 10% reduction in per capita urban water use by year 2015, and 20%
reduction by year 2020. The CVWD water efficient landscape ordinance, on which the City
ordinance is based, requires that outdoor water use by new development be reduced by 25% over
mandated state levels. Further, the CVWD Draft WMP requires that golf course users with
access to canal or recycled water convert at least 90% of their irrigation water use to those
sources by 2015.
General Mitigation Measures
Groundwater subareas are not defined by jurisdictional boundaries. The issues of groundwater
depletion and contamination addressed herein are regional and local issues. Therefore, in
Southern California, the efficient use and increased conservation of water will continue to be
critical issues to be considered in community planning and development. The City and CVWD
must continue to collaborate to protect and manage water resources.
There are a variety of goals, policies, and programs included in the proposed City General Plan
update that are intended to ensure the continued availability of a dependable supply of safe, high-
quality domestic water for all community segments. The following mitigation measures shall be
implemented to reduce the potential impacts to water resources associated with implementation
of the proposed General Plan to less than significant levels:
1. The City shall coordinate and cooperate with CVWD to ensure City-wide compliance
with State Senate Bill x7-7 by implementing policies to reduce per capita urban water use
by 10% by year 2015, and 20% reduction by year 2020, including landscaping
conversion programs and the smart irrigation control program; expanding the availability
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of sustainable water supplies such as tertiary treated water, and encouraging its use for
landscape irrigation purposes, especially for irrigating golf courses and other large
landscaped areas.
2. The City should review and amend its Development Standards to require that all new
development demonstrate a reduction of domestic water consumption equivalent to the
CalGreen Tier One standards in effect at the time of development.
3. The City shall continue to implement its Water Efficient Landscape ordinance by
requiring that City and private sector development projects implement water efficient
landscaping plans to meet or exceed current water efficiency standards.
4. The City shall require that new development reduce its projected water consumption over
“business as usual” consumption rates.
5. In conjunction with the Coachella Valley Water District as well as independently, the
City shall develop programs to allow and encourage the retrofitting of existing water-
intensive appliances and irrigation systems in existing development.
6. The City and Coachella Valley Water District shall review future development proposals
that propose to convert agricultural uses to urban development to ensure that non-potable
water is used for irrigation purposes, and that new irrigation systems utilize existing
agricultural drainage and irrigation water delivery facilities to the greatest extent feasible.
7. The City shall continue to require that all new developments use water conserving
appliances and fixtures, including low-flush toilets and low-flow showerheads and
faucets, as well as the application of water-conserving technologies in conformance with
Section 17921.3 of the Health and Safety Code, Title 20, California Administrative Code
Section 1601(b), and applicable sections of Title 24 of the State Code.
8. The City shall continue to encourage that new development use faucets, showerheads and
appliances in new development that exceed Title 20 and Title 24 water efficiency
requirements.
9. The City shall, prior to approval of development plans, require that qualifying future
development in the General Plan Area have an adopted Water Supply Assessment in
compliance with AB 610 and 221.
10. To the greatest extent practicable, the City shall require new development to connect to
the community sanitary sewer system.
11. The City shall review and amend its Development Standards and Review Procedures to
ensure coordination with the Coachella Valley Water District and to assure that existing
sewer service along with the extension of sewer service is capable of meeting the needs
of current and future development.
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12. To the greatest extent feasible, the City shall coordinate with the Coachella Valley Water
District to encourage the elimination of septic systems where they occur within the City.
Mitigation Monitoring and Reporting
A. The Planning Department and the City Engineer shall review all development proposals to
evaluate their potential for adverse impacts on water quality and quantity, and shall require
all development to mitigate any significant adverse impacts.
Responsible Parties: Planning Department, City Engineer, Coachella Valley Water
District, project developer.
B. The City shall continue to coordinate and cooperate with the Coachella Valley Water
District to ensure that the groundwater aquifer is protected from excessive extraction.
Responsible Parties: Planning Department, City Engineer, Coachella Valley Water District.
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III-1
III.
EXISTING ENVIRONMENTAL CONCERNS, PROJECT IMPACTS AND MITIGATION
MEASURES ........................................................................................................................................................... III-1
AESTHETICS ................................................................................................................................................. III-1
A.
1.
Existing Conditions ................................................................................................................................. III-2
2.
Project Impacts ........................................................................................................................................ III-4
3.
Mitigation Measures ................................................................................................................................ III-6
AGRICULTURAL RESOURCES ........................................................................................................................ III-7
B.
1.
Existing Conditions ................................................................................................................................ III-7
2.
Project Impacts ..................................................................................................................................... III-10
3.
Mitigation Measures ............................................................................................................................. III-12
AIR QUALITY AND GREENHOUSE GASES .................................................................................................... III-13
C.
1.
Existing Conditions ............................................................................................................................... III-15
2.
Project Impacts ...................................................................................................................................... III-25
3.
Mitigation Measures .............................................................................................................................. III-33
BIOLOGICAL RESOURCES ........................................................................................................................... III-36
D.
1.
Existing Conditions ............................................................................................................................... III-37
2.
Project Impacts ...................................................................................................................................... III-51
3.
Mitigation .............................................................................................................................................. III-53
CULTURAL RESOURCES .............................................................................................................................. III-55
E.
1.
Existing Conditions ............................................................................................................................... III-57
2.
Project Impacts ...................................................................................................................................... III-65
3.
Mitigation Measures .............................................................................................................................. III-66
GEOLOGY AND SOILS .................................................................................................................................. III-67
F.
1.
Existing Conditions ............................................................................................................................... III-68
2.
Project Impacts ...................................................................................................................................... III-88
3.
Mitigation Measures .............................................................................................................................. III-90
HAZARDS AND HAZARDOUS MATERIALS ................................................................................................... III-91
G.
1.
Existing Conditions ............................................................................................................................... III-92
2.
Project Impacts ...................................................................................................................................... III-97
3.
Mitigation Measures ............................................................................................................................ III-100
HYDROLOGY ............................................................................................................................................ III-101
H.
1.
Existing Conditions ............................................................................................................................. III-102
2.
Project Impacts .................................................................................................................................... III-113
3.
Mitigation Measures ............................................................................................................................ III-114
LAND USE AND PLANNING ........................................................................................................................ III-115
I.
1.
Existing Conditions ............................................................................................................................. III-116
2. Project Impacts ....................................................................................................................................... III-121
3.
Mitigation Measures ............................................................................................................................ III-131
MINERAL RESOURCES ............................................................................................................................... III-131
J.
1.
Existing Conditions ............................................................................................................................ III-131
2.
Project Impacts ................................................................................................................................... III-134
3.
Mitigation Measures ........................................................................................................................... III-134
NOISE ....................................................................................................................................................... III-135
K.
1.
Existing Conditions ............................................................................................................................. III-135
2.
Project Impacts .................................................................................................................................... III-152
3.
Mitigation Measures ............................................................................................................................ III-163
POPULATION AND HOUSING ..................................................................................................................... III-165
L.
1.
Existing Conditions ............................................................................................................................. III-165
2.
Project Impacts .................................................................................................................................... III-166
3.
Mitigation Measures ............................................................................................................................ III-169
PUBLIC SERVICES & UTILITIES ................................................................................................................ III-170
M.
RECREATIONAL RESOURCES .................................................................................................................... III-194
N.
1.
Existing Conditions ............................................................................................................................ III-194
2.
Project Impacts ................................................................................................................................... III-197
3.
Mitigation Measures ............................................................................................................................ III-198
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III-2
TRANSPORTATION/TRAFFIC ..................................................................................................................... III-198
O.
1.
Existing Conditions ............................................................................................................................. III-205
2. Project Impacts ....................................................................................................................................... III-221
3. Mitigation Measures ............................................................................................................................... III-229
WATER RESOURCES & QUALITY .............................................................................................................. III-238
P.
1.
Existing Conditions ............................................................................................................................. III-239
2.
Project Impacts .................................................................................................................................... III-250
3.
Mitigation ............................................................................................................................................ III-256
TABLE III-1 EMISSIONS THRESHOLDS FOR SCAQMD ............................................................................................ III-14
TABLE III-2 STATE AND FEDERAL AMBIENT AIR QUALITY STANDARDS ................................................................ III-19
TABLE III-3 PM10 MONITORING DATA FOR THE COACHELLA VALLEY ................................................................. III-20
TABLE III-4 PM2.5 MONITORING DATA FOR THE COACHELLA VALLEY .................................................................. III-21
TABLE III-5 OZONE MONITORING DATA ................................................................................................................. III-22
TABLE III-6 CONSTRUCTION EMISSIONS FOR THE PLANNING AREA ........................................................................ III-27
TABLE III-7 PROJECTED DAILY EMISSIONS AT GENERAL PLAN BUILD OUT ........................................................... III-29
TABLE III-8 GHG EMISSIONS FROM CONSTRUCTION OF THE GENERAL PLAN ........................................................ III-31
TABLE III-9 GHG EMISSIONS FROM OPERATION AT GENERAL PLAN BUILD OUT ................................................... III-31
TABLE III-10 AIR QUALITY CONTROL METHODS .................................................................................................... III-34
TABLE III-11 SPECIAL STATUS PLANTS IN THE LA QUINTA GENERAL PLAN AREA AND VICINITY ......................... III-43
TABLE III-12 SPECIAL STATUS REPTILES IN THE LA QUINTA GENERAL PLAN AREA AND VICINITY ...................... III-43
TABLE III-13 SPECIAL STATUS BIRD SPECIES IN THE LA QUINTA GENERAL PLAN AREA AND VICINITY ................ III-43
TABLE III-14 SPECIAL STATUS MAMMAL IN THE LA QUINTA GENERAL PLAN AREA AND VICINITY ...................... III-44
TABLE III-15 HORIZONTAL PEAK GROUND ACCELERATIONS AND SEISMIC INTENSITIES ....................................... III-80
TABLE III-16 EXISTING LAND USE DESIGNATIONS WITHIN CITY LIMITS .............................................................. III-118
TABLE III-17 2002 LAND USE DESIGNATIONS WITHIN SPHERE OF INFLUENCE ..................................................... III-119
TABLE III-18 2002 LAND USE DESIGNATIONS WITHIN PLANNING AREAS ............................................................ III-120
TABLE III-19 EXISTING LAND USE SUMMARY ...................................................................................................... III-121
TABLE III-20 PROPOSED LAND USE FOR CITY LIMITS ........................................................................................... III-123
TABLE III-21 RIVERSIDE COUNTY VISTA SANTA ROSA LAND USE ....................................................................... III-124
TABLE III-22 RIVERSIDE COUNTY LAND USE NORTH SPHERE .............................................................................. III-125
TABLE III-23 RIVERSIDE COUNTY LAND USE SPHERE SUMMARY ........................................................................ III-125
TABLE III-24 GENERAL PLAN UPDATE EAST SPHERE LAND USE .......................................................................... III-126
TABLE III-25 GENERAL PLAN UPDATE LAND USE NORTH SPHERE ....................................................................... III-126
TABLE III-26 GENERAL PLAN UPDATE LAND USE SPHERE SUMMARY ................................................................. III-127
TABLE III-27 PROPOSED LAND USE SUMMARY ..................................................................................................... III-129
TABLE III-28 EXTERIOR NOISE LIMITS .................................................................................................................. III-139
TABLE III-29 EXISTING (AMBIENT) SHORT-TERM NOISE LEVEL MEASUREMENTS ............................................... III-140
TABLE III-30 EXISTING (AMBIENT24-HOUR NOISE LEVEL MEASUREMENTS ........................................................ III-142
TABLE III-31 CITY OF LA QUINTA HOURLY TRAFFIC FLOW DISTRIBUTION ......................................................... III-144
TABLE III-32 EXISTING NOISE EXPOSURE ADJACENT TO GENERAL PLAN UPDATE STUDY AREA ROADWAYS .... III-147
TABLE III-33 YEAR 2035 BUILD OUT CONDITIONS NOISE CONTOURS ................................................................. III-153
TABLE III-34 YEAR 2035 PREFERRED ALTERNATIVE NOISE CONTOUR COMPARISON .......................................... III-157
TABLE III-35 DESERT SANDS UNIFIED SCHOOL DISTRICT ENROLLMENT AND CAPACITY .................................... III-172
TABLE III-36 COACHELLA VALLEY UNIFIED SCHOOL DISTRICT ENROLLMENT AND CAPACITY ........................... III-173
TABLE III-37 POTENTIAL STUDENT GENERATION LA QUINTA CITY LIMITS ......................................................... III-174
TABLE III-38 POTENTIAL STUDENT GENERATION SPHERE OF INFLUENCE ............................................................ III-175
TABLE III-39 POTENTIAL STUDENT GENERATION PLANNING AREA SUMMARY ................................................... III-175
TABLE III-40 ESTIMATED ELECTRICITY USAGE RATES ......................................................................................... III-183
TABLE III-41 NATURAL GAS CONSUMPTION FACTORS ......................................................................................... III-185
TABLE III-42 SOLID WASTE GENERATION AT GENERAL PLAN BUILD OUT ......................................................... III-192
TABLE III-43 LEVEL OF SERVICE DESCRIPTION .................................................................................................... III-201
TABLE III-44 INTERSECTION LEVEL OF SERVICE DESCRIPTIONS .......................................................................... III-202
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TABLE III-45 CITY ROADWAY CLASSIFICATIONS LEVEL OF SERVICE VOLUMES/CAPACITY VALUES (AVERAGE DAILY
TRIPS – ADT) ............................................................................................................................................... III-203
TABLE III-46 EXISTING DAILY VOLUMES AND CAPACITY SUMMARY ................................................................... III-216
TABLE III-47 EXISTING PEAK HOUR INTERSECTION LOS ..................................................................................... III-219
TABLE III-48 GENERAL PLAN BUILD OUT (2035) ROADWAY SEGMENT ANALYSIS .............................................. III-222
TABLE III-49 GENERAL PLAN BUILD OUT (2035) INTERSECTION ANALYSIS ......................................................... III-227
TABLE III-50 COACHELLA VALLEY WATER DISTRICT ANNUAL WATER PRODUCTION WITHIN THE LOWER
WHITEWATER RIVER SUBBASIN AREA OF BENEFIT ..................................................................................... III-242
TABLE III-51 ESTIMATE OF EXISTING WATER SERVICE DEMANDS ....................................................................... III-251
TABLE III-52 ESTIMATE OF WATER SERVICE DEMANDS AT BUILD OUT ............................................................... III-252
TABLE III-53 ESTIMATE OF WATER SERVICE DEMANDS FROM NEW DEVELOPMENT ........................................... III-253
EXHIBIT III-1 VEGETATION COMMUNITIES ............................................................................................................. III-40
EXHIBIT III-2 CNDDB, CRITICAL HABITAT & MODELED HABITAT ....................................................................... III-47
EXHIBIT III-3 LAND OWNERSHIP AND CONSERVATION AREAS ............................................................................... III-49
EXHIBIT III-4 PALEONTOLOGICAL SENSITIVITY MAP .............................................................................................. III-60
EXHIBIT III-5 CULTURAL RESOURCES SURVEY MAP .............................................................................................. III-64
EXHIBIT III-6 GEOLOGIC MAP OF THE PLANNING AREA ......................................................................................... III-72
EXHIBIT III-7 WIND EROSION SUSCEPTIBILITY MAP ............................................................................................... III-78
EXHIBIT III-8 FAULTS AND HISTORICAL SEISMICITY MAP ...................................................................................... III-83
EXHIBIT III-9 SEISMIC HAZARDS ............................................................................................................................. III-87
EXHIBIT III-10 FEMA FLOOD HAZARD ZONES AND FLOOD CONTROL FACILITIES ............................................... III-108
EXHIBIT III-11 MINERAL RESOURCE ZONE MAP ................................................................................................... III-133
EXHIBIT III-12 LAND USE AND NOISE COMPATIBILITY ......................................................................................... III-138
EXHIBIT III-13 NOISE MONITORING LOCATIONS IN THE STUDY AREA .................................................................. III-143
EXHIBIT III-14 EXISTING TRUCK AND BUS ROUTES .............................................................................................. III-146
EXHIBIT III-15 EXISTING AIRPORT NOISE CONTOURS ........................................................................................... III-150
EXHIBIT III-16 FUTURE AIRPORT NOISE CONTOURS (JACQUELINE COCHRAN AIRPORT) ...................................... III-161
EXHIBIT III-17 EXISTING (2010) AVERAGE DAILY TRAFFIC VOLUMES ................................................................ III-212
EXHIBIT III-18 GENERAL PLAN ROADWAY CLASSIFICATIONS .............................................................................. III-214
EXHIBIT III-19 GENERAL PLAN STREET CROSS SECTIONS .................................................................................... III-215
EXHIBIT III-20 GENERAL PLAN BUILD OUT (2035) AVERAGE DAILY TRAFFIC VOLUMES ................................... III-226
EXHIBIT III-21 PRESCRIBED INTERSECTION IMPROVEMENT .................................................................................. III-233