I. 2035 LQ GP EIR - Water Supply StudyTerra Nova/La Quinta General Plan EIR
Technical Appendices
APPENDIX I
Water Supply Study for the proposed
La Quinta General Plan Update 2010
Prepared by
Terra Nova Planning and Research, Inc.
42635 Melanie Place, Suite 101
Palm Desert, CA 92211
June 21, 2011
1-1
WATER SUPPLY STUDY
for the proposed:
LA QUINTA
GENERAL PLAN UPDATE 2010
prepared for:
City of La Quinta
P.O. BOX 1504
La Quinta, CA 92253
prepared by:
I
L J TERRA NOVA°
PLANNING & RESEARCH,
INC.
42635 Melanie Place, Ste 101
Palm Desert, CA 92211
June 21, 2011
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
TABLE OF CONTENTS
1.0 EXECUTIVE SUMMARY.................................................................................................... 1
2.0 INTRODUCTION................................................................................................................... 2
2.0.1 Purpose of Document................................................................................................. 2
2.1 PROJECT DESCRIPTION......................................................................................................... 3
2.2 PUBLIC WATER SUPPLY....................................................................................................... 7
2.2.1 Historical Context...................................................................................................... 7
2.3 CVWD WATER PLANNING DOCUMENTS............................................................................. 8
2.3.1 Coachella Valley Water Management Plan............................................................... 8
2.3.2 Urban Water Management Plan................................................................................. 9
2.3.3 Additional Coachella Valley Water District Documentation .................................... 9
3.0 WATER DEMANDS............................................................................................................ 10
3.1 LA QUINTA GENERAL PLAN WATER DEMAND ESTIMATES .................................................. 10
3.1.1 Business As Usual................................................................................................ 11
3.1.2 Existing BAU & New Development Water Efficiency ....................................... 12
3.1.3 Retrofit Existing and New Development Water Efficiency ................................ 14
3.1.4 Summary of La Quinta General Plan Water Demand Scenarios ......................... 15
3.2 REGIONAL WATER DEMANDS.......................................................................................... 17
3.2.1 CVWD Historical Water Use................................................................................... 18
3.2.2 CVWD Projected Water Use................................................................................... 18
3.3 LA QUINTA GP CONSISTENCY DETERMINATION WITH CVWD UWMP ............................. 19
4.0 WATER SUPPLY SOURCES.............................................................................................
25
4.1 GROUNDWATER SUPPLIES..................................................................................................
25
4.1.1 Groundwater............................................................................................................
25
4.1.2 Status of the Aquifer................................................................................................
27
4.1.3 Overdraft Mitigation Efforts....................................................................................
28
4.1.3.1 Coachella Valley Water Management Plan ..............................................
28
4.1.3.2 CVWD Landscape Ordinance...................................................................
29
4.1.3.3 Source Substitution...................................................................................
29
4.1.3.4 Conservation Programs.............................................................................
30
4.2 ADDITIONAL WATER SOURCES..........................................................................................
31
4.2.1 Surface Water...........................................................................................................
31
4.2.2 Recycled Water........................................................................................................
31
4.2.3 Desalinated Water....................................................................................................
32
4.3 IMPORTED WATER SUPPLIES..............................................................................................
32
4.3.1 Colorado River Water..............................................................................................
32
4.3.2 State Water Project (SWP) Water............................................................................
33
4.4 SUMMARY OF WATER RESOURCES....................................................................................
36
4.4.1 Water Supply For La Quinta General Plan..............................................................
37
4.5 WATER SUPPLY RESOURCES PROJECTED...........................................................................
37
4.5.1 Water Supply Reliability..........................................................................................
37
4.5.2 Water Quality...........................................................................................................
39
IV
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
TOC CONTINUED
5.0 SUMMARY AND CONCLUSIONS................................................................................ 41
5.1 COACHELLA VALLEY WATER DISTRICT SERVICE AREA .................................................... 41
5.2 LA QUINTA GENERAL PLAN WATER USE........................................................................... 42
5.2.1 General Water Use Principals.................................................................................. 43
5.2.2 Recommended Mitigation..................................................................................... 44
LIST OF TABLES
TABLE I LA QUINTA GENERAL PLAN UPDATE LAND USES............................................................. 4
TABLE 2 ESTIMATE OF WATER SERVICE DEMANDS FOR CITY LIMITS BAU..................................
I I
TABLE 3 ESTIMATE OF WATER SERVICE DEMANDS FOR SDI BAU...............................................
I I
TABLE 4 ESTIMATE OF WATER SERVICE DEMANDS OVERALL PLANNING AREA BAU ..................
12
TABLE 5 ESTIMATE OF WATER SERVICE DEMANDS FOR CITY LIMITS BAU&NDE.......................
12
TABLE 6 ESTIMATE OF WATER SERVICE DEMANDS FOR SOI BAU&NDE....................................
13
TABLE % ESTIMATE OF WATER SERVICE DEMANDS OVERALL PLANNING AREA BAU&NDE.......
13
TABLE 8 ESTIMATE OF WATER SERVICE DEMANDS FOR CITY LIMITS RE&NDE ..........................
14
TABLE 9 ESTIMATE OF WATER SERVICE DEMANDS FOR SOI RE&NDE.......................................
14
TABLE 10 ESTIMATE OF WATER SERVICE DEMANDS OVERALL PLANNING AREA RE&NDE ........
15
TABLE I I WATER DEMAND SCENARIOS 2035 SUMMARY..............................................................
15
TABLE 12 REGIONAL GROUNDWATER PRODUCTION ACRE-FEET ................................................
17
TABLE 13 CVWD HISTORIC WATER DEMANDS............................................................................
18
TABLE 14 CVWD UWMP PROJECTED WATER DEMANDS............................................................
19
TABLE 15 PROJECTED GROUNDWATER PRODUCTION CVWD ACRE-FEET .................................
19
TABLE 16 POPULATION FORECASTS...............................................................................................
21
TABLE 17 RELATIVE WATER DEMANDS 20 10 ................................................................................
23
TABLE 18 RELATIVE WATER DEMANDS 2035................................................................................
23
TABLE 19 CVWD DELIVERIES UNDER THE QUANTIFICATION SETTLEMENT AGREEMENT ...........
33
TABLE 20 COACHELLA VALLEY STATE WATER PROJECT WATER TABLE A ALLOCATION ............
34
TABLE 21 DWR TABLE A WATER ALLOCATIONS.........................................................................
35
TABLE 22 TOTAL PROJECTED WATER USE CVWD SERVICE AREA (AcRE-FEET .........................
36
TABLE 23 CVWD WATER SUPPLIES..............................................................................................
36
TABLE 24 PROJECTED URBAN WATER SOURCES CVWD ACRE-FEET ........................................
37
TABLE 25 CVWD PROJECTED SUPPLY RELIABILITY BY SOURCE ..................................................
37
LIST OF EXHIBITS
EXHIBIT I CITY LOCATIONS AND GROUNDWATER SUBBASINS..................................................... 5
EXHIBIT 2 LAND USE PLAN.......................................................................................................... 6
EXHIBIT 3 COACHELLA VALLEY GROWTH PROJECTIONS........................................................... 22
LIST OF FIGURES
FIGURE I AND 2: WATER DEMANDS WITHIN CITY LIMITS AND SOI.............................................. 10
FIGURE 3: WATER DEMAND SCENARIOS........................................................................................ 16
m
La
LIST OF APPENDICES
Water Supply Study/Terra Nova
General Plan Update/ June 21, 2011
Appendix A: Water Demand Projections for the La Quinta General Plan ........................ A-1
Appendix B: Water Resources Litigation and Other Actions: Water Reliability ..................B-1
LIST OF ACRONYMS
AC -FT Acre -Feet
AC-FT/YR Acre -Feet per Year
AWWA American Water Works Association
BAU
Business As Usual
CEQA
California Environmental Quality Act
CCF
Centum Cubic Feet
CFS
Cubic Feet per Second
CVAG
Coachella Valley Association of Governments
CVSC
Coachella Valley Stormwater Channel
CVWD
Coachella Valley Water District
CVWMP
Coachella Valley Water Management Plan
DWA
Desert Water Agency
DWR
California Department of Water Resources
ID-1
CVWD's Improvement District No. 1
ID-11
CVWD's Improvement District No. 11
IID
Imperial Irrigation District
LQ
La Quinta
MGD
Million Gallons per Day
MWD
Metropolitan Water District of Southern California
QSA
Quantification Settlement Agreement
SDCWA
San Diego County Water Authority
SOI
Sphere of Influence
SWSC
Supplemental Water Supply Charge
SWP
State Water Project
UWMP
Urban Water Management Plan
WSS
Water Supply Study
WRP
Water Reclamation Plant
ILIA
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
1.0 EXECUTIVE SUMMARY
This Water Supply Study has been prepared to inform the proposed 2010 General Plan Update
for the City of La Quinta. For analysis purposes, the Project is defined as all proposed
development set forth in the La Quinta 2010 General Plan Update. The General Plan Update
provides a variety of land uses, such as residential, commercial, and open space.
This Study examines past, current, and future conditions and reliability of SWP supplies,
Colorado River water, groundwater, and other water supply resources, and evaluates water
supply availability through 2035. The analysis concludes that there are and will continue to be
sufficient water supplies available to meet projected demand for all existing and planned future
development including new development proposed in the General Plan Update from 2010
through 2035. Although water supplies are available, infrastructure will need to be expanded
over the next several years in order to provide a reliable and efficient water treatment and
delivery system throughout the Planning Area.
Sufficient infrastructure and services are currently in place or planned for development within La
Quinta City limits. Infrastructure and services will need to be installed and expanded to serve the
Sphere of Influence. Development within the Sphere of Influence will be phased to assure that
water demands generated are within the service range of the system. The forthcoming Master
Plan of Development for the Sphere of Influence will assure that water demands increase
incrementally in accordance with available supplies.
A comprehensive description of the methodology used to conduct water demand calculations can
be found in Appendix A. The Project -specific model estimates that, at buildout, water demands
generated by the City of La Quinta will increase to 37,783 acre-feet per year, and 16,684 acre-
feet per year for the Sphere of Influence. Water demand projections are based on the maximum
water allowance requirements set forth in CVWD Landscape Ordinance 1302.1, AWWA potable
demand estimates, and new state requirements limiting the per capita water demand.
Water resources in the Coachella Valley are managed regionally through several participating
water purveyors. The Coachella Valley Water District coordinates and jointly plans for water
resources management with purveyors that utilize shared resources. The 2010 CVWMP is the
latest regional water planning document that addresses long term water management planning for
all water resources. The CVWD 2010 Draft UWMP focuses on the urban water supply, including
the water demands generated by the City of La Quinta and the Sphere of Influence, and considers
the reliability of water supplies during drought conditions. Both planning documents project
future water demands that will be generated by new development and the proposed population
growth.
The public water supplier, the Coachella Valley Water District (CVWD), uses surface,
groundwater, imported Colorado River water, recycled water, and various other water supplies to
meet water demands throughout its service area. According to the 2010 CVWMP and the
UWMP, the projected water supplies are sufficient to meet the water demands generated by
existing and planned future development through 2035 under normal, single, and multiple dry
year conditions, including water demands generated by manufacturing, industrial, and
agricultural water users.
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
2.0 INTRODUCTION
This Water Supply Study quantifies the total potential water demand that is projected to be
generated from implementation of the proposed General Plan Update. The entire City of La
Quinta and the Sphere of Influence are served by the Coachella Valley Water District (CVWD or
the District). Water supplies in the District's service area are primarily from imported Colorado
River water, including SWP Exchange water and groundwater, which is extracted locally from
the Whitewater River Subbasin. Deliveries of potable water throughout a majority of the
District's service area are provided via a system of domestic water lines, wells, and elevated
storage facilities. Irrigation water is provided via the Coachella Branch of the All American
Canal and a series of pipes, reservoirs, and laterals that provide water for agricultural uses
throughout the service area.
City Limits
The City of La Quinta has an established water delivery system that is maintained and operated
by the CVWD. Currently in the City of La Quinta, CVWD has the following domestic water
facilities: 21 active wells; 6 booster stations; and 10 existing reservoirs, with capacities ranging
from 250,000 to 12 million gallons and a total storage capacity of 44.6 million gallons. Domestic
water distribution and transmission lines range from 4 inches to 36 inches in diameter.
Sphere of Influence
The Sphere of Influence for the City of La Quinta is located in an unincorporated area of
Riverside County, California and encompasses a total of 8,101.4 acres. Currently only 928.4
acres within the Sphere of Influence are developed, with the remaining 7,173 acres vacant.
Development proposed as part of the General Plan Update will expand residential and
commercial land uses in the Sphere of Influence and result in a substantial increase in water
demand compared to the existing condition.
A Master Plan of Development for the City's Sphere of Influence will be developed by the City
of La Quinta that regulates growth and expansion within the Sphere and assures consistency with
Vista Santa Rosa Land Use Concept.
2.0.1 PURPOSE OF DOCUMENT
The La Quinta General Plan Update is subject to the California Environmental Quality Act
process (CEQA). As the lead agency under CEQA, the City of La Quinta has requested that a
Water Supply Study be prepared to analyze the availability and reliability of water resources.
The Coachella Valley Water District (CVWD), as the Public Water Supplier (PWS), has recently
updated the Urban Water Management Plan. The Draft 2010 UWMP has been prepared pursuant
to Senate Bill 610 requirements and assesses the sufficiency of the water supplies relative to
projected demands under normal, single, and multiple dry year conditions through 2035. This
Water Supply Study is intended to evaluate the water supply and demand conditions for the City
of La Quinta's proposed General Plan Update relative to the UWMP.
This Study has been prepared to inform the City of projected water demands, identify water
supplies, and assess water supply reliability.
2
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
2.1 PROJECT DESCRIPTION
The Planning Area for the City of La Quinta General Plan Update encompasses approximately
48.3 square miles situated in the south central portion of the Coachella Valley, in central
Riverside County, California. The Planning Area is generally bounded on the north by lands
south of Hovley Lane East, on the south by Avenue 64, on the west and southwest by the Santa
Rosa Mountains, and on the east by Harrison Street. (see Exhibit 1, Location Map)
The General Plan Update Planning Area is comprised of 35.7± square miles within the City's
corporate limits, which are largely developed for a range of residential, resort and resort
residential, commercial and open space uses, and 12.6± square miles within the City's Sphere -of -
Influence. There are two Sphere -of -Influence areas in the Planning Area; these occur to the north
and east of the City's corporate limits. The northern SOI area is located generally north of Fred
Waring Drive and east of Washington Street to Adams Street and includes residential
development. The eastern SOI is generally east of Monroe Street to the planning area's eastern
boundary (Harrison Street), extending south of Avenue 52 to Avenue 62. These lands are
primarily comprised of lower density residential uses with limited commercial development.
Residential Land Uses
Under the Preferred Alternative, a total of 7,481.4 acres of land are allocated to residential uses
in the City's corporate limits, and 7,402.7 acres in the SOI areas, for a total of 14,884.1 acres
throughout the Planning Area. There are currently 23,489 dwelling units in the incorporated City
and 801 in the SOL The estimate of future build out units in the Planning Area is based on an
assumption that 75% of the maximum densities permitted will be developed. Thus, the Planning
Area would accommodate an additional 28,880 dwelling units, with 8,180 units in City limits,
and 20,699 within the SOL At build out, the Planning Area is expected to generate a total of
approximately 53,170 dwelling units, including both existing and proposed units.
Commercial Land Uses
Under the Preferred Alternative, approximately 1,292 acres are designated for commercial
development, including General, Tourist and Village Commercial uses in the City and SOI.
There is currently, 6,683,963 square feet of commercial development within the Planning Area.
To estimate future build out square footage of commercial units in the General Plan Update
Planning area, it is assumed that Commercial lands will build out with 22 percent lot coverage,
including buildings and other ancillary structures. Thus, an additional 5,696,960 square feet of
commercial uses could be developed throughout the Planning Area, consisting of 3,238,163
square feet within City limits, and 2,458,797 square feet within the SOI.
Industrial/Light Manufacturing
The General Plan Update allocates 63.8 acres to lands designated Industrial/Light
Manufacturing, which occur entirely within the eastern SOI. As with commercial, a 22 percent
lot coverage for industrial uses is assumed, which provides for 611,408 square feet of
Industrial/Light Manufacturing uses at build out.
3
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
Major Community Facilities
The General Plan Update provides for 398 acres of lands designated "Major Community
Facilities", which includes public service facilities, as well as other public and quasi -public
facilities.
Open Space Natural
Approximately 7,476 acres of Open Space Natural land uses are proposed under the General
Plan Update. This land use designation includes watercourses, floodways and mountainous areas.
Open Space Recreational
Under the General Plan Update, a total of 4,559.5 acres of Open Space Recreational land uses
are proposed. This land use designation includes parks, golf courses, and lands to be developed
for recreational purposes.
Street Rights -of -Way
The proposed General Plan allocates 2,254 acres lands for Street Rights -of -Way to ensure
adequate provision for build out of a circulation network adequate to serve future development.
Table 1 shows the designated land uses, acreages, and units planned for each land use, as well as
the percentage of the total site occupied by each land use category for the La Quinta Planning
Area. Exhibit 2 illustrates the proposed land uses in the Planning Area.
Table 1
La Quinta General Plan Update Land Uses
Existing Development
Proposed Development
Acres
Units
Square
AcresAcres
Units
Square
Land Use Designation
Feet
City Limits
Low Density Residential
4,171.2
20,834
1,675.9
5,028
Medium/High Residential
1,284.0
6,655
350.3
3,153
Commercial
668.9
6,410,202
337.9
3,238,163
Major Community Facilities
238.0
160.0
Open Space (Natural)
2,242.7
5,233.3
Open Space (Recreational)
4,272.0
287.5
Street Right of Ways
1,676.1
257.6
Subtotal
14,552.9
23,489
6,410,202
8,302.5
8,181
3,238,163
Sphere of Influence
Low Density Residential
551.5
801
6,826.60
20,480
Medium/High Residential
0.2
0
24.40
219
Commercial
28.6
273,760
256.6
2,458,797
Industrial/Lgt Mfg.
0.0
63.8
611,408
Major Community Facilities
28.17
1.61
Street Right of Ways
319.93
0.0
Subtotal
928.4
801
273,760
7,173.0
20,699
3,070,205
Project Total
15,481.3
24,290
6,683,936
15,475.5
28,880
6,308,368
Source: La Quinta General Plan Update Land Use Plan, December 27, 2010.
4
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Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
2.2 PUBLIC WATER SUPPLY
CVWD provides services for domestic water, irrigation water, sanitation sewerage collection,
wastewater reclamation and recycling, imported water, stormwater protection, and agricultural
drainage. CVWD currently has approximately 107,000 domestic water connections and has a
groundwater production capacity of 243 million gallons per day (mgd). The CVWD service area
encompasses roughly 640,000 acres, mostly within Riverside County, but also extends into
northern Imperial and San Diego Counties. Areas served with domestic water by CVWD include
a portion of lands near Desert Hot Springs, the Indio Hills area, and a portion of Cathedral City.
CVWD also serves all of Rancho Mirage, Thousand Palms, Palm Desert, Indian Wells, La
Quinta, and portions of Indio and Coachella. The District also serves rural communities,
including Thermal, Mecca, Desert Shores, Salton Sea Beach, Salton City, North Shore, Bombay
Beach, Hot Mineral Springs, and other unincorporated areas of Riverside and Imperial Counties.
The CVWD service area is bordered on the west and north by mountains, which provide an
effective barrier against coastal influences and greatly reduce the amount of rainfall in the
Valley. Thus, natural recharge to the groundwater basin is limited. The majority of natural
recharge occurring within the CVWD service area originates as runoff from the Santa Rosa, San
Jacinto, and Little San Bernardino Mountains.
Development throughout the Coachella Valley has been dependent upon groundwater as a source
of supply. The demand for groundwater has annually exceeded the limited natural recharge of
the groundwater basin. Imported water is used to recharge the aquifer and reduce groundwater
overdraft by providing an alternative water source that can be directly applied to agricultural
lands, golf courses, developed open space, or treated for consumption.
2.2.1 HISTORICAL CONTEXT
The need to enhance the public water supply in the Coachella Valley has been recognized for
many years. The formation of CVWD in 1918 was a direct result of the concern of local
residents about a plan to export water from the Whitewater River to Imperial County. Early on,
Valley residents also recognized that action was needed to stem the decline of the water table,
which was occurring as a result of local pumping in the east Valley. As a result, CVWD entered
into an agreement for the construction of the Coachella Branch of the All American Canal in
order to bring Colorado River water into the Coachella Valley. Since 1949, the Coachella Branch
has been providing water for irrigation to the area that generally encompasses Indio and La
Quinta southerly to the Salton Sea. Colorado River water is delivered by an underground
irrigation distribution piping system from the approximately 120-mile canal to farms and a
growing number of golf courses in the Coachella Valley. In recent years, CVWD has also been
using this water source to recharge the Aquifer in the Lower Valley.
To acquire additional water supplies in order to the meet the increased water demand from
continued growth and development in the Coachella Valley, CVWD and Desert Water Agency
(DWA) entered into separate contracts in 1963 with the State of California to procure water
deliveries from the State Water Project (SWP). Because a direct pipeline from the SWP system
to the Coachella Valley did not and to this day does not exist, CVWD and DWA entered into an
exchange agreement with Metropolitan Water District (MWD).
7
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
The agreement allows for the exchange of like quantities of CVWD and DWA SWP allocations
for MWD allocations of Colorado River water. The water exchange is possible since MWD
receives CVWD and DWA SWP deliveries directly, and CVWD and DWA receive MWD
Colorado River Water via the Colorado River Aqueduct, which crosses the upper portion of the
Coachella Valley near Whitewater. Since 1973, CVWD and DWA have been receiving Colorado
River water from MWD's Colorado River Aqueduct turnout located at Whitewater Canyon to
replenish groundwater in the Valley and reduce groundwater extraction by providing an alternate
water supply.
In order to further limit the use of groundwater, CVWD has been recycling reclaimed wastewater
since 1967 and operates six water reclamation plants, three of which currently recycle water.
Recycled water is used for golf course and greenbelt irrigation throughout CVWD's service area.
CVWD and DWA have historically utilized imported SWP Exchange water to replenish
groundwater supplies. Recharge to the West Valley has been underway since 1973 at the
Whitewater River Spreading Facility, which is estimated to have a recharge capacity of over
300,000 acre-feet per year. Between 1973 and 2009 over 2 million acre-feet of SWP exchange
water have been recharged to the West Valley.
There are currently two recharge facilities in the East Valley, one near Lake Cahuilla (Levy), and
one on the Martinez Canyon alluvial fan. The Thomas E. Levy (Levy) Facility was completed in
2009 and has a recharge capacity of 40,000 acre-feet per year. The Martinez Canyon Facility is
expected to recharge 20,000 to 40,000 acre-feet annually upon completion, which is expected by
2018. Combined these facilities have recharged approximately 97,222 acre feet of Colorado
River water from 1997 through 2010.1
2.3 CVWD WATER PLANNING DOCUMENTS
The Coachella Valley Water District released the draft 2010 UWMP in March of 2011. In
addition to the UWMP, CVWD has several other water planning documents, including the
Regional Water Management Plan and the annual Engineers' Reports. Each of these documents
is described below.
2.3.1 COACHELLA VALLEY WATER MANAGEMENT PLAN
CVWD initiated a water management planning process in the early 1990s to address the
overdraft conditions in the Aquifer and to ensure that there would be adequate water supplies in
the future. The Coachella Valley Water Management Plan (CVWMP) is the product of this
planning process. The Board of Directors approved the CVWMP on October 8, 2002. As part of
the CVWMP planning process, a Program Environmental Impact Report (PEIR) was prepared in
accordance with CEQA guidelines. The PEIR was circulated through the State Clearinghouse
and to the public for extensive review. A Final PEIR was certified for the CVWMP in September
2002.
"Engineer's Report on Water Supply and Replenishment Assessment- Lower Whitewater River Subbasin Area
of Benefit 2011-2012," prepared by the Coachella Valley Water District, May 2011.
8
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
In December of 2010, a draft update to the CVWMP was released for review and comment. The
2010 Draft CVWMP is the most up-to-date regional water management document for the
Coachella Valley. The CVWMP utilizes a conjunctive management approach incorporating local
and regional water resource conservation, all available sources of water supply, and water
demand use efficiencies in an effort to guide CVWD in assuring a long-term reliable supply of
water resources throughout the Coachella Valley.
2.3.2 URBAN WATER MANAGEMENT PLAN
CVWD completed a draft update of the Urban Water Management Plan (UWMP) in December
2010, as required under California Water Code, Division 6, Part 2.6. Data used in the UWMP
was based on information in the updated 2010 CVWMP. Domestic water demand projections
and State Water Project (SWP) purchases and reliability were updated in the draft 2010 UWMP
to reflect changes in long-term delivery and reliability of SWP supplies consistent with the 2009
SWP Delivery Reliability Report. The most recently adopted UWMP is the 2005 version, which
was adopted by the CVWD Board on December 13, 2005. The 2010 draft Update UWMP is
expected to be adopted by the board in July 2011. Both the 2010 draft UWMP and the CVWMP
are included in this WSS by reference.
2.3.3 ADDITIONAL COACHELLA VALLEY WATER DISTRICT DOCUMENTATION
Additional documentation used for this WSS include the CVWD Engineer's Reports on Water
Supply and Replenishment Assessments. These yearly reports are completed for the three
groundwater Subbasins within CVWD's service area; Lower Whitewater River Subbasin, Upper
Whitewater River Subbasin; and Mission Creek Subbasin. These reports are required by the State
Water Code before CVWD can levy and collect groundwater replenishment assessments. The
Engineer's Reports describe the condition of groundwater supplies, need for groundwater
replenishment, identification of the area of benefit, water production within the area, and
replenishment assessments to be levied upon water producers.
The CVWD Water System Backup Facilities Charge Study is also referenced in this WSS. The
Study is updated about every two years and provides the most up-to-date water demand factors
by development type. This study assesses all new development and redevelopment projects
within the CVWD service area and identifies water demand by development type, calculates
facility costs, and establishes charges to ensure domestic water availability for future
development.
Another reference document used in this WSS is CVWD's Landscape Ordinance 1302.1, which
puts a limit on the type of plant materials, plant density, and the maximum water allowed per
acre of landscaped area.
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Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
3.0 WATER DEMANDS
3.1 LA QUINTA GENERAL PLAN WATER DEMAND ESTIMATES
The methodology utilized to estimate the existing water demand within the Planning Area and to
project future water demand at build out of the proposed La Quinta General Plan Update is
described in detail in Appendix A. Briefly, water demand estimates for existing and proposed
development are calculated separately and summed for the total estimated water demand at build
out. Water demand estimates are provided for the Planning Area as a whole, and individually for
City Limits and the Sphere of Influence. Water demands for landscaping are shown separate
from potable water demands for each land use.
The following figures show the relative portion of the water demand that will be generated by
existing and proposed development within City limits and the Sphere of Influence. Figure 1
shows that 83% of the 2035 water demand within City Limits will be generated by existing
development and 17% by new development. Figure 2 shows that 92% of the water demand
within the Sphere of Influence will be generated by proposed development and 8% will be
generated by existing development.
City Limits
17% ■ Existing
Development
■ Proposed
Development
Sphere of Influence
8%
0 Existing
Development
■ Proposed
92% Development
Figure 1: Water Demands within City Limits Figure 2: Water Demand within SOI
Several assumptions are made in order to calculate existing and future water demands of the
Planning Area. It should be noted that water demand estimates herein are intended to provide a
sense of scale for the various land uses proposed, rather than predict actual water consumption.
Water use and consumption rates are variable depending on consumer behavior, cost, climate,
and other factors. The approach utilized herein relies upon population, as well as land uses, to
estimate water demands.
Water demand projections at build out of the proposed La Quinta General Plan Update are
provided for the following scenarios: a) the business as usual scenario, which assumes that all
new development will generate water demands at the same rate as existing development; b) the
water efficiency scenario, which assumes that new development adheres to water efficient
principals and existing development continues to generate the same level of water demand; and
c) the retrofit plus efficiency scenario, which assumes that new development adheres to water
efficient principals and existing development is retrofitted to reduce water demands.
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3.1.1 BUSINESS AS USUAL
The Business As Usual Scenario assumes that all new development generates similar water
demands for each land use that is consistent with the existing water demands generated by each
land use. That is, existing rates of water consumption observed for current development continue
and are applied to all new development. This scenario assumes that no additional water
conservation is achieved. Thus, the following tables show the projected water demands at build
out of the proposed La Quinta General Plan under business as usual conditions. Tables 2, 3, and
4 below provide the estimated water demands from all existing and planned future land uses
within City Limits, the Sphere of Influence, and the entire Planning Area, respectively.
As seen in Table 2 the water demand generated within City limits at build out under business as
usual conditions (BAU) is estimated to be approximately 34.5 million gallons per day (mgd) or
about 38,675 acre-feet per year.
Table 2
Estimate of Water Service Demands for City Limits BAU
Landscaping
Potable
Total Demand
Daily Demand
Land Use Designation
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
9,538.70
5,079.13
14,617.83
13.05
Medium/High Density Residential
1,527.90
1,140.65
2,668.55
2.38
Commercial
496.72
1,516.61
2,013.33
1.80
Major Community Facilities
500.14
187.28
687.43
0.61
Open Space - Natural
N/A
N/A
N/A
N/A
Open Space- Recreation
17,765.65
N/A
17,765.65
15.86
Streets, Sidewalks, Medians
922.39
N/A
922.39
0.82
Total
30,751.51
7,923.67
38,675.18
34.53
Source: "La Quinta General Plan Water Resources Projections," Appendix A to Water Supply Assessment, prepared by Terra Nova
Planning & Research Inc., January 2011.
It is estimated that, at build out, all existing and planned future development within the Sphere of
Influence, under BAU conditions, will generate a water demand of approximately 16.6 million
gallons per day (mgd) or about 18,644 acre-feet per year, as shown in Table 3.
Table 3
Estimate of Water Service Demands for SOI BAU
Landscaping
Potable
Total Demand
Daily Demand
Land Use Designation
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
13,305.62
4,179.45
17,485.07
15.61
Medium/High Density Residential
25.99
43.01
69.00
0.06
Commercial
192.99
525.63
718.62
0.64
Major Community Facilities
32.70
14.01
46.72
0.04
Streets, Sidewalks, Medians
324.17
N/A
324.17
0.29
Total
13,881.47
4,762.10
18,643.57
16.64
Source: "La Quinta General Plan Water Resources Projections," Appendix A to Water Supply Assessment, prepared by Terra Nova
Planning & Research Inc., January 2011.
11
Water Supply Study/Terra Nova
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The entire Planning Area for the City of La Quinta is projected to generate a water demand of
approximately 51 million gallons per day (mgd) or about 57,319 acre-feet per year at build out,
under BAU, as shown in Table 4.
Table 4
Estimate of Water Service Demands Overall Planning Area BAU
Landscaping
Potable
Total Demand
Daily Demand
Land Use Designation
(ac-ft/ r)
(ac-ft/ r)
(ac-ft/ r)
(mgd)
Low Density Residential
22,844.32
9,258.58
32,102.89
28.66
Medium/High Density Residential
1,553.88
1,183.66
2,737.55
2.44
Commercial/Industrial
689.71
2,042.24
2,731.95
2.44
Major Community Facilities
532.85
201.29
734.14
0.66
Open Space - Natural
N/A
N/A
-
-
Open Space- Recreation
17,765.65
N/A
17,765.65
15.86
Streets, Sidewalks, Medians
1,246.56
N/A
1,246.56
1.11
Total
44,632.97
12,685.77
57,318.75
51.17
Source: "La Quinta General Plan Water Resources Projections," Appendix A to Water Supply Assessment, prepared by Terra Nova
Planning & Research Inc., January 2011.
3.1.2 EXISTING BAU & NEW DEVELOPMENT WATER EFFICIENCY
The Existing BAU and New Development Water Efficiency Scenario (BAU&NDE) assumes
that all new development achieves greater levels of water conservation compared to existing
water demands. Under this scenario water demand generated by all new development is more
water efficient due to the installation of low water demanding appliances, faucets, and water
efficient irrigation systems and low water demanding landscaping. Existing land uses that are
currently developed are assumed to continue generating the same level of water demand through
build out under this scenario. Thus, existing rates of water consumption observed for current
development continue, and new development achieves reduced water demands. The following
tables show the projected water demands at build out of the proposed La Quinta General Plan
under the new development water efficiency conditions. Tables 5, 6, and 7 below provide the
estimated water demands from all existing and planned future land uses within City Limits, the
Sphere of Influence, and the entire Planning Area, respectively.
As seen in Table 5, the water demand generated within City limits at build out is estimated to be
approximately 33.7 million gallons per day (mgd) or about 37,783 acre-feet per year.
Table 5
Estimate of Water Service Demands for City Limits BAU&NDE
Landscaping
Potable
Total Demand
Daily Demand
Land Use Designation
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
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
Source: "La Quinta General Plan Water Resources Projections," Appendix A to Water Supply Assessment, prepared by Terra Nova
Planning & Research Inc., January 2011.
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Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
It is estimated that, at build out, all existing and planned future development within the Sphere of
Influence, as set forth in the proposed General Plan, under the new development water efficiency
scenario, will generate a water demand of approximately 14.89 million gallons per day (mgd) or
about 16,684 acre-feet per year, as shown in Table 6.
Table 6
Estimate of Water Service Demands for SOI BAU&NDE
Landscaping
Potable
Total Demand
Daily Demand
Land Use Designation
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
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
Source: "La Quinta General Plan Water Resources Projections," Appendix A to Water Supply Assessment, prepared by Terra Nova
Planning & Research Inc., January 2011.
The entire Planning Area for the City of La Quinta is projected to generate a water demand of
approximately 48.62 million gallons per day (mgd) or about 54,467 acre-feet per year at build
out, as shown in Table 4.
Table 7
Estimate of Water Service Demands Overall Planning Area BAU&NDE
Landscaping
Potable
Total Demand
Daily Demand
Land Use Designation
(ac-ft/ r)
(ac-ft/ r)
(ac-ft/ r)
(mgd)
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.
Under this scenario, water conservation is realized for all new development relative to existing
development with comparable land uses. This is accomplished, in part, through implementation
of the CVWD Landscape Ordinance 1302.1, and Title 24 building codes, which require the use
of modern water -efficient appliances. The Landscape Ordinance establishes guidelines and sets
limits for plant materials, plant density, and the maximum water allowed per acre of landscaping.
Title 24 requires the use of appliances and devices that have been certified by their manufacturer
to meet or exceed minimum specification or efficiencies set forth by the California Energy
Commission. The use of modern development standards will limit indoor water consumption
through the use of water conserving appliances, such as low flush toilets, and water efficient
dishwashers, washing machines, faucets, and fixtures.
13
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
3.1.3 RETROFIT EXISTING AND NEW DEVELOPMENT WATER EFFICIENCY
The Retrofit Existing and New Development Water Efficiency Scenario assumes that all new
development achieves water conservation and existing development is retrofitted to achieve the
same level of water conservation realized by new development. Under this scenario, all existing
and new development utilizes the most water efficient appliances, faucets, and irrigation systems
and landscaping is primarily desert or drought tolerant species with limited turf. Thus, existing
rates of water consumption observed for current development are reduced through retrofitting
programs such as turf buyback, incentives to upgrade appliances, and tiered water rates. The
following tables show the projected water demands at build out of the proposed La Quinta
General Plan under the retrofit existing and new development water efficiency scenario
(RE&NDE).
Tables 8, 9, and 10 below provide the estimated water demands from all existing and planned
future land uses within City Limits, the Sphere of Influence, and the entire Planning Area,
respectively. As seen in Table 8, under this scenario, the water demand generated within City
limits at build out is estimated to be approximately 31 million gallons per day (mgd) or about
34,768 acre-feet per year.
Table 8
Estimate of Water Service Demands for City Limits RE&NDE
Landscaping
Potable
Total Demand
Daily Demand
Land Use Designation
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
8,775.60
4,063.30
12,838.91
11.46
Medium/High Density Residential
1,422.52
912.52
2,335.05
2.08
Commercial
496.72
1,051.14
1,547.87
1.38
Major Community Facilities
410.22
93.64
503.86
0.45
Open Space - Natural
N/A
N/A
N/A
N/A
Open Space- Recreation
16,619.48
N/A
16,619.48
14.84
Streets, Sidewalks, Medians
922.39
N/A
922.39
0.82
Total
28,646.95
6,120.61
34,767.56
31.04
Source: "La Quinta General Plan Water Resources Projections," Appendix A to Water Supply Assessment, prepared by Terra Nova
Planning & Research Inc., January 2011.
It is estimated that, at build out, all existing and planned future development within the Sphere of
Influence, under the retrofit existing and new development water efficiency scenario, will
generate a water demand of approximately 14.78 million gallons per day (mgd) or about 16,556
acre-feet per year, as shown in Table 9.
Table 9
Estimate of Water Service Demands for SOI RE&NDE
Landscaping
Potable
Total Demand
Daily Demand
Land Use Designation
(ac-ft/ r)
(ac-ft/ r)
(ac-ft/ r)
(mgd)
Low Density Residential
12,241.17
3,343.47
15,584.64
13.91
Medium/High Density Residential
24.19
34.41
58.60
0.05
Commercial
197.37
364.31
561.68
0.50
Major Community Facilities
20.21
7.01
27.22
0.02
Streets, Sidewalks, Medians
324.17
N/A
324.17
0.29
Total
12,807.11
3,749.19
16,556.30
14.78
Source: "La Quinta General Plan Water Resources Projections," Appendix A to Water Supply Assessment, prepared by Terra Nova
Planning & Research Inc., January 2011.
14
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
The entire Planning Area for the City of La Quinta is projected to generate a water demand of
approximately 45.82 million gallons per day (mgd) or about 51,324 acre-feet per year at build
out, as shown in Table 10.
Table 10
Estimate of Water Service Demands Overall Planning Area RE&NDE
Landscaping
Potable
Total Demand
Daily Demand
Land Use Designation
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
21,016.77
7,406.77
28,423.54
25.37
Medium/High Density Residential
1,446.72
946.93
2,393.65
2.14
Commercial/Industrial
694.09
1,415.45
2,109.54
1.88
Major Community Facilities
430.43
100.65
531.08
0.47
Open Space - Natural
N/A
N/A
-
-
Open Space- Recreation
16,619.48
N/A
16,619.48
14.84
Streets, Sidewalks, Medians
1,246.56
N/A
1,246.56
1.11
Total
41,454.06
9,869.80
51,323.86
45.82
Source: "La Quinta General Plan Water Resources Projections," Appendix A to Water Supply Assessment, prepared by Terra Nova
Planning & Research Inc., January 2011.
The La Quinta General Plan Update is in compliance with the objectives of the UWMP in that
substantial water conservation is realized for all new development relative to existing
development with comparable land uses. This is accomplished, in part, through implementation
of the CVWD Landscape Ordinance 1302.1, and Title 24 building codes, which require the use
of modern water -efficient appliances. The Landscape Ordinance establishes guidelines and sets
limits for plant materials, plant density, and the maximum water allowed per acre of landscaping.
Title 24 requires the use of appliances and devices that have been certified by their manufacturer
to meet or exceed minimum specification or efficiencies set forth by the California Energy
Commission. The use of modern development standards will limit indoor water consumption
through the use of water conserving appliances, such as low flush toilets, and water efficient
dishwashers, washing machines, faucets, and fixtures.
3.1.4 SUMMARY OF LA QUINTA GENERAL PLAN WATER DEMAND SCENARIOS
The following table and figure show the relative water demand for each scenario described
above. The BAU scenario generates the greatest water demand since no further water
conservation is pursued. The BAU & NDE scenario achieves some water conservation since all
new development is water efficient. The retrofit & NDE scenario realizes the greatest water
savings since new development is water efficient and existing development is retrofitted to be
water efficient.
Table 11
Water Demand Scenarios 2035 Summary
(Acre -Feet)
BAU
BAU & NDE
Retrofit &
NDE
Landscaping
44,633
43,258
41,454
Potable
12,686
11,209
9,870
Total
57,319
54,467
51,324
Source: Appendix A
15
70,000
60,000
50,000
40,000
w
a�
s,
Q 30,000
20,000
10,000
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
Water Demand Scenarios
• Landscaping Potable
BAU BAU&NDE Retrofit&NDE
Figure 3: Water Demand Scenarios
As seen in the above tables and figures, landscaping is the greatest water demanding component.
Water demand from landscaping represents approximately 80% of all water demands. The
largest landscaping demands are generated by low density residential and open space recreation.
Combined, these land uses account for approximately 87% of the total projected water demand
generated by irrigation of landscaped areas within the Planning Area.
16
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
3.2 REGIONAL WATER DEMANDS
Groundwater supplies from the Whitewater Subbasin are utilized by a variety of public water
suppliers, including CVWD, DWA, MSWD, the City of Coachella, Indio Water Authority
(IWA), and the Myoma Dunes Mutual Water Company. Other groundwater users include tribes,
individual residents, farmers, golf courses, businesses and commercial facilities. As discussed in
the 2010 WMP, the Whitewater River Subbasin is divided into two management areas,
consisting of the Upper Whitewater River Subbasin Area of Benefit (AOB), and the Lower
Whitewater River Subbasin AOB.
Both the 2002 Coachella Valley Water Management Plan (CVWMP) and CVWD's annual
Engineering Reports provide the historical use of groundwater in the Whitewater River
Subbasin. Groundwater use increased steadily from 92,400 acre-feet per year in 1936 to about
376,100 acre-feet per year in 1999.2 In 2010 the estimated groundwater production was 181,233
acre-feet and 150,000 acre-feet within the upper and lower portions of the Whitewater River
Subbasin respectively, for a combined total groundwater production of approximately 331,233
acre-feet. This includes groundwater produced from all water purveyors in the Whitewater
Subbasin, including CVWD, DWA, IWA, and other individual private users. The decline in
groundwater production between 1999 and 2010 is a result of groundwater conservation efforts,
source substitution projects, and effects of the recent economic recession.
Table 12 below shows the historic groundwater production from regional groundwater resources
including the Whitewater River Subbasin and Mission Creek.
Table 12
Regional Groundwater Production
(Acre -Feet)
2005
2006
2007
2008
2009
2010
Mission Creek
16,315
17,751
17,007
16,270
15,156
14,303
Lower Whitewater River
172,000
172,000
172,000
172,000
160,000
150,000
Upper Whitewater River
203,912
213,037
209,503
210,530
198,713
181,233
Total Pumped
3929227
4029788
398,510
3989800
373,869
345,536
Source: CVWD UWMP Table 4-5 Total Historical Groundwater Production
As a regional water supplier, CVWD coordinates with other water agencies that share common
groundwater resources to establish goals, policies, and programs that assure long term viability
and reliability of groundwater reserves. The CVWMP and UWMP address these shared
groundwater resources and describe conservation programs, recharge activities, and source
substitution programs that facilitate regional groundwater management.
The following discussion focuses on CVWD's service area of benefit.
Z ,CVWD Water Management Plan," Table 3-2: Summary of Historic water Supplies, prepared by CVWD,
December 2002.
17
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
3.2.1 CVWD HISTORICAL WATER USE
The following table shows the historic groundwater use within the CVWD service area from
1995 through 2010.3 All of CVWD's urban water demands are currently met through
groundwater production from the region's Subbasins. In 2010 CVWD's groundwater demands
constituted 31.6% of the regional groundwater demands.
Table 13
CVWD Historic Water Demands
Year
Population
Gross
Water Use
(AFY)
Per Capita
Water Use
(gpcd)
1995
145,329
91,826
564
1996
150,333
96,192
571
1997
152,350
94,114
551
1998
159,051
98,472
553
1999
165,160
106,805
577
2000
171,289
117,547
613
2001
175,616
116,916
594
2002
184,629
123,219
596
2003
180,305
121,231
600
2004
188,358
124,139
588
2005
193,536
121,737
562
2006
195,570
134,988
616
2007
198,363
129,871
584
2008
198,976
129,273
580
2009
201,568
123,825
548
2010
202,660
109,488
482
Source: CVWD 2010 UWMP Table 3-1 and 4-6.
City of La Quinta
Although it is difficult to precisely estimate the City of La Quinta's share of the CVWD service
area demands, a relative per capita comparison is used to estimate the City's share. In 2010, the
City of La Quinta's population was estimated to be 37,467. Assuming a per capita water use of
482 gallon per day, the City of La Quinta is estimated to generate an annual water demand of
20,223 acre-feet for 2010 or 18% of the 2010 CVWD service area's urban water demand.
3.2.2 CVWD PROJECTED WATER USE
Table 14 below shows the projected urban water demands expected to be generated within
CVWD's service area in the year 2035. The service area population for 2035 is estimated to be
512,200 for a total per capita water demand of 423 gallons per day.
3 "CVWD Urban Water Management Plan Update," Table 3-1, prepared for CVWD, December 2010.
18
Water Supply Study/Terra Nova
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Table 14
CVWD UWMP Projected Water Demands
2035
# of
Accounts
Volume
AFY
Single Family
223,900
134,800
Multi -family
10,000
19,400
Commercial
8,400
10,900
Institutional/governmental
830
2,300
Landscape
12,100
65,300
Construction
440
2,100
System Losses
N/A
7,900
Total
255,670
242,700
Source" CVWD 2010 UWMP: Tables 3-12 and 3-18.
As mentioned above, CVWD's urban water demands are currently met through 100%
groundwater supplies. The table below shows that by the year 2035, 53% of urban water
demands will be met through supplies other than groundwater.
Table 15
Projected Groundwater Production CVWD
(Acre -Feet)
2015
2020
2025
2030
2035
Mission Creek
5,000
6,000
6,900
7,100
7,700
Lower Whitewater River
33,200
31,100
30,100
28,400
19,500
Upper Whitewater River
80,500
88,500
92,900
98,000
101,500
Total Groundwater
118,700
125,600
129,900
133,500
128,700
Total Urban Water Use
125,800
156,100
187,700
212,00
242,700
% of Groundwater
94%
81%
69%
63%
53%
Source: CVWD UWMP Table 3-19 Urban Water Use and Table 4-7 CVWD Future Groundwater
Production.
Water supplies within the CVWD service area are further described in detail in Section 4 below.
3.3 LA QUINTA GP CONSISTENCY DETERMINATION WITH CVWD UWMP
Water use is dependent on a number of variables and changes with climate, economic conditions,
new technologies, and education. The water demand projections set forth for the CVWD service
and the La Quinta General Plan are indented to provide a rough approximation of the major
water demanding land uses and the relative water demands that will be generated by various land
use development scenarios and population densities. Such data and modeling allow for informed
policies to encourage growth and development in a manner that maximizes use of available water
resources while assuring that water demands are met and water supply resources are sustained.
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Water Supply Study/Terra Nova
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The CVWMP and the CVWD UWMP utilize population forecasts that were set forth by the
Riverside County Center for Demographic Research (RCCDR) in the 2006 Riverside County
Projections (RCP-06). These forecasts were partially based on 2000 census data, which excluded
second homes and seasonal residents. Thus, population projections set forth in the CVWD WMP
and used as the basis for water demand projections in the UWMP are somewhat understated in
that they do not capture seasonal residents. Furthermore, population projections set forth under
the UWMP assume that build out occurs by 2050.
Latest census data from 2010 has resulted in modified population projections relative to the
previous population forecasts. Growth rate projections utilized in the CVWD UWMP are
somewhat different than the growth rate projections as they are understood today. Current
forecasts predict a reduced population compared to previous predictions. The CVWMP notes
that Riverside County is currently updating its General Plan, which may affect projected
population growth for the Vista Santa Rosa region and the other unincorporated areas of
Riverside County. The same holds true for incorporated jurisdictions within the County,
including those within the CVWD service area such, as the City of La Quinta.
The General Plan for the City of La Quinta has based population projections on land uses,
allowable densities, and the 2010 census data. The La Quinta General Plan estimates existing and
future population based on the number of existing and planned future residential dwelling units
and a household population size of 2.53 for City limits and the Sphere of Influence. Furthermore,
for analysis purposes and to show the greatest potential water demand that may be generated
under the proposed land use scenario, it is assumed that build out of the General Plan will occur
by 2035. As such, population forecasts and associated water demands projected for 2035
analyzed herein are conservative relative to regional forecasts since population densities are not
expected to be realized until 2050 or beyond. Nonetheless, for analysis purposes, build out
conditions are analyzed, and build out is assumed to occur by 2035.
Population forecasts set forth in the CVWD UWMP and the census data do not account for the
seasonal population associated with second home owners. As such, it is appropriate to consider
the 27.5% vacancy rate for seasonal residents in order to compare the population projections set
forth by CVWD relative to what is proposed in the La Quinta General Plan Update. With the
consideration of the vacancy rate from seasonal residents, the population projections between the
City's General Plan and CVWD's UWMP and WMP are more or less consistent.
4 2010 Census
20
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
Table 16 below shows the 2010 and 2035 population estimates as set forth in the CVWMP and
the population estimates generated by the land uses proposed under the La Quinta General Plan
Update. It should be noted that Riverside County population estimates for unincorporated areas,
including the proposed La Quinta Sphere of Influence, are provided as an overall total. Thus, the
SOI population forecast below is from the proposed General Plan estimates.
Table 16
Population Forecasts
2010
2035
CVWD Service Area
202,660
512,200
La Quinta City Limits (RCP-06)
45,272
57,937
La Quinta City Limits 2010 Census)'
37,467
46,297
LQ GP City Limits Full Occupancyz
59,427
80,124
LQ GP City Limits 27.5% Vacancy3
43,085
58,090
La Quinta SOI LQGP
2,027
54,396
1. SCAG data using 2010 census, May 2011.
2. Assumes full occupancy of all residential development set forth under the
proposed General Plan Update. Build out is assumed to occur by 2035.
3. Assumes a 27.5% vacancy rate consistent with the 2010 Census.
Assuming buildout in 2035 and full time occupancy of all existing and proposed dwelling units,
the La Quinta General Plan Update proposes a population growth that is 28% greater than the
population growth that was considered in the CVWD UWMP. This difference accounts for
seasonal residence, which, as reported in the 2010 Census account for 27.5% of the vacancy rate.
Given that the City of La Quinta is a seasonal community with a highly fluctuating population on
an annual basis, the 27.5% vacancy rate was applied to the La Quinta General Plan population
forecasts to assess consistency with the CVWD projections. With the consideration of the
vacancy rate, the existing and projected population as set forth in the 2010 General Plan for City
Limits differs by 0.003% of what was projected in the CVWD UWMP.
As mentioned above, for analysis purposes the full occupancy population of 80,124 for City
limits and 54,396 for the Sphere of Influence is utilized to estimate water demands for the
Planning Area at build out in 2035.
Both CVWD and the La Quinta General Plan population projections show that substantial
growth will occur within the Sphere of Influence. Exhibit 3 below shows the relative growth
projections expected to occur throughout the Valley and identifies the La Quinta Planning Area.
21
bonceAuoumy
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— La Quinta Cityhuumary
-.._ La Qam(a Sphere of lMamra Boundary
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Location of Population Growth
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Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
Growth projections for the La Quinta Planning Area and the associated water demands vary
depending on the methodology utilized for projections. Associated water demands based on
CVWD's per capita water usage rates are provided below in Tables 17 and 18.
As mentioned above and described in the CVWD UWMP, water demand projections are
estimated based on population as well as land uses. For analysis purposes, full occupancy is
assumed in order to capture all potential water demand that may be generated by existing and
future residents within the La Quinta Planning Area.
Tables 17 and 18 provide comparisons of projected water demands for the City of La Quinta in
2010 and 2035 based on the CVWD UWMP and population projections and land use
development set forth in the proposed La Quinta General Plan Update. Project specific water use
estimates are consistent with the per capita estimates.
Table 17
Relative Water Demands 2010
Project-
Specific
(AFY)1
Per Capita
Water Use
(gpcd)
Per Capita
Water Use
(AFY)Z
Per Capita
Water Use
(gpcd)
CVWD Service Area
N/A
N/A
109,488
482
La Quinta City Limits
31,227
469
32,085
482
La Quinta SOI
1,268
555
1,095
482
LQ Planning Area
32,945
473
33,180
482
LQ City % of CVWD Demand
29%
N/A
29%
N/A
1 LQ GP Specific Water Demand Estimates, Appendix A.
2 Based 482 gpcd as set forth in Table 3-1 of the UWMP, and LQ GP proposed residential development.
3. Table 3-20 of the 2010 UWMP.
In 2035, project specific estimates for the Sphere of Influence are substantially less than what is
estimated on a per capita basis. This is due to the limited landscaping and outdoor water use
proposed for the SOI under the La Quinta General Plan Update. The per capita water demand for
City Limits, as shown in Table 18 below, includes water demands generated by irrigation of golf
courses, and are consistent with per capita estimates. Assuming that all irrigation of golf courses
is met through non -potable supplies by 2035, the total project -specific water demand for City
limits would be 20,100 acre-feet for a per capita water demand of 133 gallons per day.
Table 18
Relative Water Demands 2035
Project-
Per Capita
Water Use
Per Capita
Specific
Water Use
(AFY)z
Water Use
AFY 1(gpcd)
(gpcd)
CVWD Service Area
N/A
242,700
423
La Quinta City Limits
37,783
421
37,966
423
La Quinta SOI
16,684
256
27,525
423
LQ Planning Area
549467
361
65,491
423
LQ City % of CVWD Demand
16%
16%
1 LQ GP Specific Water Demand Estimates, Appendix A.
2 Based 482 gpcd as set forth in Table 3-1 of the UWMP, and LQ GP proposed residential
development.
3 CVWD 2010 UWMP Table 3-20.
23
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
Consistency Determination for Policy
In order to be consistent with the draft 2010 UWMP under the land use densities proposed, the
City of La Quinta must reduce its per capita water demands to below 423 gallon per capita per
day, assure that all new development achieves water efficient standards, and implement
retrofitting programs to reduce water demands associated with existing development. Retrofitting
programs for the La Quinta City Limits are especially important given that 80% of the land uses
are currently developed. Programs that specifically address water use for open space recreation
and single family residential land uses will be the most effective since these constitute the
greatest water demanding land uses.
The Sphere of Influence on the other hand is mostly undeveloped, and therefore policies and
programs should be focused on limiting water demands generated by new development. Under
the proposed General Plan, the greatest water demanding land use is single family residential. As
such, policies and regulation that focus on reducing water demands associated with residential
landscaping will achieve the greatest water savings in the Sphere of Influence.
In addition to the use of technology, such as smart irrigation meters and low water using
appliances, education and outreach can be effective tools in changing consumer behavior and
achieving water conservation. As such, policies and programs that address consumer awareness,
distribution of water use efficiency information, and incentives should be extended to water
customers.
See Section 5.2.2 for suggested mitigation to reduce the La Quinta General Plan water use
demands to levels that are consistent with the 2010 UWMP Update.
24
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
4.0 WATER SUPPLY SOURCES
CVWD has prepared a water management plan for the Coachella Valley, the Coachella Valley
Water Management Plan (WMP) 2010 Update, that identifies all existing and planned future
water supplies. The following discussion identifies water supplies, water rights, and water
service contracts such as groundwater, imported water, including Colorado River water and State
Water Project (SWP) exchange water, recycled water, desalinated water, and a limited amount of
surface water. A description of the quantities of water received in prior years by CVWD, as well
as future availability, is also provided.
4.1 GROUNDWATER SUPPLIES
The following discussion provides a description of the groundwater supplies, CVWD's rights to
use the basin, the overdraft status of the basin, existing and planned overdraft mitigation efforts,
as well as the historical and projected use of the basin.
4.1.1 GROUNDWATER
Groundwater supplies throughout the Coachella Valley are provided through the Coachella
Valley Groundwater Basin. The Coachella Valley Groundwater Basin extends from Whitewater,
in the San Gorgonio Pass, southeastward to the Salton Sea, and underlies the cities of Palm
Springs, Cathedral City, Rancho Mirage, Palm Desert, Indian Wells, La Quinta, Indio,
Coachella, and the unincorporated communities of Thousand Palms, Thermal, Bermuda Dunes,
Oasis, and Mecca. The Basin is bounded by non -water bearing crystalline rocks of the San
Bernardino and Little San Bernardino Mountains in the north, the Santa Rosa and San Jacinto
Mountains on the west and southwest, the Mecca Hills to the east, and the northwest shoreline of
the Salton Sea to the southeast. 5
Groundwater flow throughout the Basin is limited by fault barriers, constrictions in the basin,
and areas of low permeability. As a result, the Coachella Valley Groundwater Basin is divided
into four subbasins, including the Desert Hot Springs Subbasin, Garnet Hill Subbasin, Mission
Creek Subbasin, and the Whitewater Subbasin. In 1964, DWR estimated that these four
subbasins contained a total of approximately 39.2 million acre-feet of water in the first 1,000 feet
below the ground surface, much of which originated from runoff from adjacent mountains.6
Aquifer Adjudication?
The Coachella Valley Groundwater Basin is not an adjudicated basin, and there are no legal
agreements limiting CVWD's pumping from the Basin. CVWD shares a common groundwater
source with other PWSs, including Desert Water Agency (DWA), the Mission Springs Water
District (MSWD), the City of Coachella, the City of Indio, and the Myoma Dunes Mutual Water
Company. Other groundwater users include some individual residents, farmers, golf courses,
businesses, and commercial facilities.
5 "Coachella Valley Groundwater Basin, Indio Subbasin; California's Groundwater Bulletin 118", prepared by
DWR, February 27, 2004.
6 CVWD 2010 Draft UWMP
7 "Coachella Valley Groundwater Basin, Indio Subbasin; California's Groundwater Bulletin 118", prepared by
DWR, February 27, 2004.
25
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
Although the Coachella Valley Groundwater Basin is not adjudicated, the Whitewater Subbasin
has been divided into two management areas, including the Upper Whitewater River Subbasin
Area of Benefit (AOB) and the Lower Whitewater River Subbasin AOB. The dividing line
separating these two areas is an irregular line trending northeast from Point Happy in La Quinta
to the Indio Hills, located north of Indio. The Upper Whitewater River Subbasin AOB is jointly
managed by CVWD and DWA under the terms of the 1976 Water Management Agreement. The
Lower Whitewater River Subbasin AOB is managed by CVWD. DWA and CVWD jointly
operate a groundwater replenishment program whereby qualifying groundwater pumpers within
each service area pay a per acre-foot fee that is used to pay the cost of importing water and
recharging the aquifer.
Whitewater Subbasin
The Whitewater Subbasin, also known as the Indio Subbasin in Bulletin 118, encompasses
approximately 400 square miles in the Coachella Valley. The Subbasin begins at the junction of
I-10 and Highway I I I in the north, and extends seventy miles southeastward to the Salton Sea.
The Subbasin is bordered on the southwest by the Santa Rosa and San Jacinto Mountains, on the
north by the Garnet Hill, Mission Creek, and Desert Hot Springs Subbasins, and on the east by
the Garnet Hill and San Andreas faults. Groundwater flow between the Whitewater Subbasin and
surrounding subbasins is impeded by these faults. The Whitewater River is the main surface
water feature in the Whitewater Subbasin, and provides natural recharge to the Basin. The
Whitewater River flows southeastward from the western portion of the Subbasin, near the San
Gorgonio Pass, to the Salton Sea. Groundwater flows also move from northwest to southeast.
The Whitewater Subbasin is made up of water -bearing materials, including unconsolidated late
Pleistocene and Holocene alluvial deposits. These deposits make up what is known as the
Ocotillo Conglomerate Formation, which are primary water -bearing units of poorly bedded
coarse sand and gravel. Ocotillo Conglomerate Formation is greater than 1,000 feet think in
many portions of the Subbasin.
Natural recharge in the Whitewater Subbasin is estimated at 49,000 acre-feet per year, and can
range from 187,000 acre-feet per year during wet years, and 10,000 acre-feet per year in dry
years. According to the CVWD UWMP, natural recharge in the Upper Whitewater River portion
of the Whitewater Subbasin was 49,000 acre-feet in 2009, and natural recharge in the Lower
Whitewater River was 33,700 acre-feet. Total inflows are estimated at 392,000 acre-feet per
year, and outflows are estimated at 465,800 acre-feet per year. Outflows from water production
alone in 2009 were 358,713 acre-feet.'o
Thermal Subarea''
The Whitewater Subbasin is further divided into four subareas, including Palm Springs Subarea,
Thousand Palms Subarea, Oasis Subarea, and Thermal Subarea. The City of La Quinta overlies
the Thermal Subarea. The Whitewater Subbasin has a total of approximately 28.8 million acre-
feet of groundwater storage capacity. Approximately 67%, or 19,400,000 acre feet of storage
capacity exists within the Thermal Subarea.
8 Pumpers that are not considered minimal pumpers per CVWD and DWA.
9 "Coachella Valley Groundwater Basin, Indio Subbasin; California's Groundwater Bulletin 118", prepared by
DWR, February 27, 2004.
io "CVWD Water Management Plan Update: Draft Report", prepared for CVWD, December 2010.
11 "CVWD Water Management Plan Update: Draft Report", prepared for CVWD, December 2010.
26
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
The Thermal Subarea is divided into two parts, including the upper and lower portions of the
Whitewater Subbasin. The upper part of the basin underlies the cities of Palm Desert and Rancho
Mirage, and is unconfined due to unconsolidated alluvial deposits, which allow for greater
percolation into the groundwater basin. The lower portion of the subbasin, which begins near
Point Happy, is mostly confined due to silt and clay layers from ancient lake beds. Percolation
rates, therefore, are lower in the southeastern portion of the Thermal Subarea.
Groundwater Summary
The City of La Quinta overlies the lower portion of the Whitewater Subbasin and receives water
from wells within the Whitewater Subbasin. DWR's 1964 estimate showed approximately 73%,
or 28.8 million acre-feet of groundwater was stored in the Whitewater Subbasin. However, the
amount of water in the aquifer has decreased over the years due to the extraction of groundwater
supplies used to serve urban, rural, and agricultural development in the Coachella Valley, which
has resulted in the rate of extraction exceeding the natural rate of recharge, a condition known as
overdraft.12
4.1.2 STATUS OF THE AQUIFER
The Coachella Valley has historically been dependent on groundwater as a source of water
supply. Inflows of groundwater are produced from natural runoff from precipitation and returns
from groundwater use, as well as artificial recharge from imported SWP and Colorado River
water. Groundwater outflows result from pumping, flows to the agricultural drainage system,
evapotranspiration by vegetation, and subsurface outflows to the Salton Sea. Demand for
groundwater in the Whitewater Subbasin continues to exceed natural recharge of the
groundwater basin leading to overdraft. As stated in DWR's Bulletin 118-80, overdraft is "the
condition of a groundwater basin where the amount of water extracted exceeds the amount of
groundwater recharging the basin over a period of time." 13
California Department of Water Resources (DWR) Bulletin 108 published in 1964 and Bulletin
118 (2003) are DWR's most current bulletins that characterize the condition of the Whitewater
Subbasin aquifer as a whole. According to Bulletin 108, the amount of usable supply in the
overdrafted aquifer is decreasing. Bulletin 118 estimated an annual decrease of 33,000 acre-feet
of groundwater storage in the Coachella Valley Groundwater Basin between 1953 and 1967.
More recent estimates show a decrease of 136,700 acre-feet for the entire basin.14
Within the Whitewater Subbasin, CVWD estimates the annual change in storage annually in its
Engineer's Reports on Water Supply and Replenishment Assessment. The recent 2010 CVWD
WMP also reported on storage loss. The annual loss in storage for the entire Whitewater
Subbasin in 2009, as reported in the CVWD WMP, was estimated to be 72,051 acre-feet. This
includes a 23,912 acre-feet loss in storage for the Lower Whitewater River Subbasin and 48,139
acre-feet loss in the Upper Whitewater River Subbasin. The 2009 loss in storage was lower than
historical loss due to increased SWP Exchange water deliveries at Whitewater River Recharge
Facility and increased Canal water recharge at the Thomas E. Levy Groundwater Replenishment
Facility (Levy facility)15 in the East Valley beginning in 2009.
12 "CVWD Water Management Plan Update: Draft Report", prepared for CVWD, December 2010.
13 CVWD UWMP, 2010
14 "Coachella Valley Groundwater Basin, Indio Subbasin; California's Groundwater Bulletin 118", prepared by
DWR, February 27, 2004.
15 Previously known as the Dike-4 facility.
27
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
The cumulative overdraft of the Upper and Lower Whitewater River Groundwater Basin is
estimated to be 5.42 million acre-feet from 1973 through 2009, with the Lower Whitewater
Subbasin making up the majority at 4,490,152 acre-feet of overdraft. The Upper Whitewater
Subbasin has a cumulative overdraft of approximately 928,860 acre-feet. The overdraft condition
of the Aquifer has caused groundwater levels to decrease in portions of the Lower Valley (from
La Quinta to the Salton Sea) and has raised concerns about water quality and land subsidence.
Groundwater levels in the basin have decreased substantially, except in areas where artificial
recharge has successfully raised water levels (i.e., adjacent to and down gradient of the
Whitewater Spreading Facility). Areas near the edges of the Valley where the aquitard is absent
allows for direct recharge to the lower aquifer (located below the clay layers that create the semi -
perched groundwater zone) as demonstrated by the Levy Facility and Martinez Canyon Recharge
Programs. The Martinez Canyon recharge facility is a pilot project and has been underway since
2005. Upon completion of a full-scale facility, the facility is expected to recharge 20,000 to
40,000 AFY on average. The Martinez Canyon facility is projected to start initial operation in
2016 and is expected to reach full capacity by 2018.16
4.1.3 OVERDRAFT MITIGATION EFFORTS
CVWD takes a proactive role in addressing overdraft conditions through region wide planning
efforts and the development and implementation of specific programs, policies and incentives.
The following discussion provides an overview of CVWD's overdraft mitigation efforts as
presented in the WMP and landscaping ordinance, and examples of successful programs that
have been implemented to date.
4.1.3.1 Coachella Valley Water Management Plan
As outlined in Section 2.3, CVWD has developed the CVWMP to comprehensively protect and
augment the groundwater supply. The previous 2002 CVWMP developed water management
plan strategies to address increasing demands within the Coachella Valley and eliminate
overdraft. Water management strategies called out in the 2002 Plan included water conservation,
development of additional water sources, source substitution and groundwater recharge. Since
the 2002 Plan was adopted, increasing demands coupled with reduced reliability of imported
water supplies have increased the potential for future groundwater supply deficits. These new
issues are addressed in the 2010 WMP Update. The goal of the 2010 WMP remains the same as
the 2002 Plan, but has been modified to reflect a more holistic approach: "to reliably meet
current and future water demands in a cost-effective and sustainable manner."
The 2010 WMP Update incorporates a more flexible and adaptive approach to water resources
management. In addition to the elements considered in the 2002 WMP, the 2010 WMP Update
considers and evaluates additional management options, as well as potential water quality
improvements. There have been ongoing concerns regarding the salinity of Colorado River
water. Water management elements that have been considered in the development of the 2010
WMP Update include water conservation, additional water supplies, source substitution,
groundwater recharge, water quality protection and other water management activities. Many of
these elements can be implemented to varying degrees in response to future needs.
16 "CVWD Water Management Plan Update: Draft Report", prepared for CVWD, December 2010.
28
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
A major component of the 2010 WMP water management efforts is water conservation. The
2010 CVWMP abides by the new SB 7x7 legislation passed in 2009, which calls for a 10%
reduction in water use by 2015 and 20% reduction by 2020. In addition, the Plan also provides
examples of more stringent conservation levels that could be used in the Coachella Valley. The
Plan highlights conservation levels used by other desert cities, such as Phoenix and Tucson,
which have even higher conservation levels. Tucson's per capita water use is 177 gallons per
capita day, which is a 50% demand reduction over SB 7x7 regulations. These higher
conservation levels could lead to additional urban water conservation savings between 43,000
AFY to 266,000 AFY by 2045.
4.1.3.2 CV" Landscape Ordinance
In 2003, CV" adopted Landscape Ordinance No. 1320 requiring a 25 percent reduction in
outdoor water use over DWR's model ordinance. Amendments to the ordinance occurred in
2007, requiring new developments to install weather -based irrigation controllers that
automatically adjust water allocation, setbacks of spray emitters from impervious surfaces, use of
porous rock and gravel buffers between grass and curbs to eliminate run-off onto streets, and
requiring all landscaping, with the exception of turf, to be irrigated with a drip system. The 2007
Ordinance also called for an additional 17 percent reduction in outdoor use for new development
(CVWD Ordinance No. 1302-1, 2007). In 2009, Coachella Valley cities, water districts,
Riverside County and CVAG developed a single model landscape ordinance to promote
maximum landscape water use efficiency (CVWD Ordinance No. 1302-2, 2009). The 2009
Ordinance is similar to the 2007 Ordinance, but provides uniform landscaping standards
throughout the Coachella Valley. The La Quinta Landscape Ordinance is modeled off of
CVWD's 2009 Ordinance.
The 2009 Ordinance is one of the most stringent in the State. One of the new features of the
ordinance is turf limitations for new golf courses. New golf courses turf limitations include
limiting turf to 4 acres per hole, plus 10 acres for associated practice areas, such as driving
ranges and putting greens. Therefore, golf courses would be limited to 82 acres of turf for an 18
hole course. A typical 18-hole golf course could achieve an average annual water savings of 200
acre-feet for new golf course development or any rehabilitation of existing golf courses.
4.1.3.3 Source Substitution
Source substitution is the use of an alternate source of water in place of groundwater. The use of
an alternate water source reduces groundwater extraction and allows the groundwater to remain
in storage, thus reducing overdraft. Alternative sources of water include municipal recycled
water, Colorado River water, desalinated agricultural drain water, and re -use of aquaculture
water.
Source substitution projects described in the 2010 WMP include the following:
• Conversion of existing and future golf courses from groundwater to recycled water or
Colorado River water;
• Conversion of urban use from groundwater to treated Colorado River water in the East
Valley
• Conversion of outdoor urban use to Colorado River water or recycled water in the East
Valley; and
• Conversion of agricultural irrigation from groundwater to Colorado River water,
primarily in the Oasis area.
29
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
Examples of effective alternative source substitute efforts include the following:
• CVWD has a recycled water system that treats water from three water reclamation plants
and delivers to golf courses, schools, and open spaces for irrigation. It is estimated that
8,200 acre-feet of recycled water per year is available.
• An additional recycled water use in the East Valley is indirect potable reuse (IPR). IPR is
the planned use of highly treated wastewater to directly augment water supplies.
• CVWD has constructed the Mid -Valley Pipeline (MVP) to deliver Colorado River water
to the Mid -Valley area for use with CVWD's recycled water for golf course and open
space irrigation. Construction of the first phase, from the Coachella Canal to WRP-10,
was completed in 2009, and later phases will expand the MVP to 50 golf courses in the
Rancho Mirage -Palm Desert -Indian Wells area.
• CVWD has secured rights to the Colorado River water and participated in the
construction of the All -American Canal and the Coachella Branch of the All -American
Canal. As of 2010, CVWD receives 368,000 acre-feet per year of Colorado River
deliveries under the QSA.
• CVWD operates the Levy Groundwater Replenishment Facility, which has an estimated
average recharge capacity of 40,000 acre-feet per year. The Martinez Canyon Recharge
Facility is a second recharge facility currently in the trial phase. Once completed, the
Martinez Facility is expected to recharge 20,000 to 40,000 acre-feet per year.
• CVWD has secured rights to SWP Water and negotiated exchange and advanced delivery
agreements with the Metropolitan Water District of Southern California (MWD) to
exchange CVWD's SWP Water for MWD's Colorado River Water source. The SWP
exchange water is used to recharge the Aquifer in the Upper Valley. This recharge
program was started in 1972 and has replenished the Aquifer with over two million acre-
feet of water. CVWD receives 88,100 AFY of Metropolitan's SWP Table A water.
• CVWD plans to utilize treated agricultural drainage water for irrigation purposes. A
desalination pilot study was completed in 2008. A full-scale desalination facility will
have a 10 MGD capacity that will produce approximately 11,000 acre-feet per year (7.5
MGD) of product water.
• CVWD has worked with an aquaculture farm and developed water efficiency programs
that include water treatment and reuse. Historically, the amount of fish farm effluent
recycled in the East Valley was approximately 2,000 AFY. Recent termination of one of
largest fish farms in the East Valley has occurred, and the facility is now being used to
grow algae for the production of biofuel. This conversion has significantly reduced
groundwater pumping as well as eliminated a source of reusable aquaculture effluent.
4.1.3.4 Conservation Programs
CVWD is working with the cities and counties in its service area to limit the amount of water
that can be used for outdoor landscaping. As discussed earlier, CVWD's 2009 Landscape
Ordinance provides uniform landscaping standards throughout the Coachella Valley.
As a result of the adoption of state-wide indoor water conservation measures requiring low flush
toilets, shower and faucet flow restrictors and other devices, the amount of water used inside
homes has been significantly reduced. With the large number of new homes constructed, these
conservation programs have reduced impacts of new development on the Aquifer. Recent
passage of SB 7x7 legislation in 2009 now requires that public water suppliers achieve a 10%
reduction in water use by 2015 and 20% reduction by 2020.
30
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
These measures include water efficient landscaping and irrigation controls, water efficient
plumbing, tiered or seasonal water pricing, public information and education programs,
alternative water supplies, water restrictive municipal development policies, appointing a CVWD
conservation coordinator, and refining the maximum water allowance budgets for landscaped
and recreational areas.
CVWD's long term plan to conserve groundwater reserves involves water conservation across all
land uses, as well as increased utilization of additional water resources such as more Colorado
River water, SWP water, recycled water, and desalinated agricultural drain water.
4.2 ADDITIONAL WATER SOURCES
4.2.1 SURFACE WATER
Surface water supplies come from several local rivers and streams, including the Waitewater
River, Snow Creek, Falls Creek and Chino Creek. In 2009, surface water supplied less than one
percent of the total water supply to the West Valley for urban and golf course needs. There was
no surface water supplied to the East Valley. Because surface water supplies are affected by
variations in annual precipitation, the annual supply is highly variable. Since 1936, the estimated
historical surface water supply has ranged from approximately 1,400 to 9,000 acre-feet per year,
averaging about 5,800 AFY.17
4.2.2 RECYCLED WATER
Wastewater that has been highly treated and disinfected can be reused for landscape irrigation
and other purposes; treated wastewater is not suitable for potable use. Recycled wastewater has
historically been used for irrigation of golf courses and municipal landscaping.
CVWD operates six water treatment plants, three of which generate recycled irrigation water for
golf courses and large landscaped areas. The water reclamation plant (WRP) used by the City of
La Quinta is WRP-4, which is located approximately 2.0 miles east Mecca. WRP-4 became
operational in 1986 and serves communities from La Quinta to Mecca. WRP-4 currently does
not recycle effluent, however it may provide future recycled supplies when the demand for
recycled water develops and tertiary treatment is constructed.18
Recycled water use is currently limited to irrigation of golf courses and large urban landscapes.
In 2010 approximately 8,380 acre-feet of recycled water was used for these purposes. As
projected in the UWMP, by 2035 31,380 acre-feet of recycled water is expected to be available
for irrigation of crop lands, golf courses, and landscaped area. Shifting the water source from
groundwater to recycled water for irrigation is a central strategy of the UWMP. As such, it is
recommended that the La Quinta General Plan incorporate policies and programs that support the
use of recycled water for irrigation.
17 "CVWD Water Management Plan Update: Draft Report", prepared for CVWD, December 2010.
18 "CVWD Water Management Plan Update: Draft Report", prepared for CVWD, December 2010.
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Water Supply Study/Terra Nova
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4.2.3 DESALINATED WATER
Desalination involves the removal of some amount of salts and other minerals from water. The
removal process converts a high salinity water source to a water source that is suitable for
consumption or non -potable uses, depending on the level of treatment. Desalination requires
specialized equipment and infrastructure, and energy demands for the desalination process are
extremely high. Therefore, the financial requirements associated with desalination are often
prohibitive.
Desalination of Drainage Water
CVWD plans to collect and treat agricultural drainage water from the shallow, semi -perched
groundwater zone for reuse. The underground agricultural drain system consists of nearly 2,500
miles of on -farm drains and pipelines that collect and convey agricultural water runoff. The 2002
WMP recommended that a drain water desalination facility commence operation between 2010
and 2015 with a 4,000 AFY facility. The facility would be expanded to 11,000 AFY capacity by
2025. Product water would be desalted to a quality equivalent to Colorado River and delivered to
the Canal distribution system for non -potable use such as irrigation.
In 2008 the Malcolm-Pirnie pilot study and feasibility study was conducted to assess a variety of
treatment technologies and brine management approaches. The Study found that the reverse
osmosis with dew evaporation technique was the preferred treatment approach and
recommended that brine management be accomplished via conveyance to constructed wetlands
at the north shore of the Salton Sea. The Study estimated that desalination costs could range from
$480 to $740 per acre-foot depending on the capacity of the facility and may be as much as
$1,200 per acre-foot under the zero liquid discharge alternative.
Desalination of Ocean Water
Since the Coachella Valley is located approximately 200 miles from the Pacific Ocean, exchange
of desalinated seawater, rather than direct use, may be feasible. Given the substantial amount of
conveyance infrastructure required for seawater desalination, participation in multiple
desalination projects via exchange programs may be pursued. In the 2010 WMP, CVWD
assumes that up to 100,000 acre-feet per year of desalinated seawater might be available for
exchange. The cost of seawater desalination is estimated to range from $1,000 to $2,000 per
acre-foot.
4.3 IMPORTED WATER SUPPLIES
4.3.1 COLORADO RIVER WATER
The Coachella Canal is a branch of the All -American Canal, which brings Colorado River water
into the Coachella Valley and Imperial County. The service area for Colorado River water
delivery under CVWD contract with the U.S. Bureau of Reclamation is defined as Improvement
District No. 1 (ID-1). Under the 1931 California Seven Party Agreement, CVWD has water
rights to Colorado River water as part of the first 3.85 million acre feet allocated to California.
CVWD is in the third priority position along with the Imperial Irrigation District (IID). This
priority is ahead of the 550,000 acre-feet allocation to the Metropolitan Water District of
Southern California.
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California's Colorado River water supply is protected by the 1968 Colorado River Basin Project
Act, which holds that the Colorado River water supplies to Arizona and Nevada developed after
1968 shall be reduced to zero before California's allocation is reduced below 4.4 million acre
feet in any year. Historically, CVWD has received approximately 330,000 acre-feet annually of
Priority 3a Colorado River water. This source of water is considered reliable through execution
of the 2003 Quantification Settlement Agreement (QSA) among some of the California Colorado
River contractors.
The QSA was entered into and between CVWD, Imperial Irrigation District (IID), and the San
Diego County Water Authority (SDCWA). The QSA quantifies CVWD's Colorado River water
rights for the next 75 years. Under the QSA, CVWD will be allocated up to 459,000 acre-feet per
year of Colorado River water as shown in Table 19.
Table 19
CVWD DELIVERIES UNDER THE QUANTIFICATION SETTLEMENT AGREEMENT
Component
2010 Amount
2026 Amount
(AFY)
(AFY)
Base Allotment
330,000
330,000
1988 MWD/IID Approval Agreement
20,000
20,000
Coachella Canal Lining (to SDCWA)
-26,000
-26,000
To Miscellaneous/Indian PPRs
-3,000
-3,000
IID/CVWD First Transfer
12,000
50,000
IID/CVWD Second Transfer
0
53,000
MWD/SWP Transfer
35,000
35,000
Total Diversion at Imperial Dam
368,000
459,000
Less Conveyance Losses'
-31,000
-31,000
Total Deliveries to CVWD
337,000
428,000
Source: CVWMP Table 4-2 CVWD Deliveries under the QSA, December 2010.
' Assumed losses after completion of canal lining projects.
4.3.2 STATE WATER PROJECT (SWP) WATER
CVWD and DWA are SWP contractors for the Whitewater River Basin. The SWP includes 660
miles of aqueduct and conveyance facilities extending from Lake Oroville in the north to Lake
Perris in the south. The SWP has contracts to deliver water supplies annually to 29 agencies.
CVWD's original SWP water right (Table A amount) was 23,100 acre-feet per year and DWA's
original SWP Table A amount was 38,100 acre-feet per year, for a combined Table A amount of
61,200 acre-feet per year. In 2004, CVWD purchased an additional 9,900 acre-feet per year of
SWP water from the Tulare Lake Basin Water Storage District, which brought CVWD's SWP
allotment to 33,000 acre-feet per year.
In addition, CVWD and DWA have also negotiated an exchange agreement with MWD for
100,000 acre-feet of SWP Table A amount. MWD has permanently transferred 88,100 acre-feet
per year and 11,900 acre-feet per year of its SWP Table A amounts to CVWD and DWA,
respectively. This agreement provides that CV NM and DWA generally receive this water from
the SWP during wet years, which allows the two agencies to recharge the groundwater basin and
operate a conjunctive use program, storing water in wet years and pumping the groundwater
basin in dry years.
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In 2007, CVWD and DWA made a second purchase of SWP water from the Tulare Lake Basin
Water Storage District. CVWD purchased 5,250 acre-feet per year and DWA purchased 1,750
acre-feet per year. Also in 2007, CVWD and DWA completed the transfer of 12,000 acre-feet
per year and 4,000 acre-feet per year, respectively, from the Berrenda Mesa Water District for a
total Table A amount of 16,000 acre-feet annually. Therefore, the total SWP Table A amount for
CVWD and DWA is 194,100 acre-feet per year, with CVWD's portion equal to 138,350 acre-
feet per year. Table 20 summarizes CVWD and DWA total maximum allocations of Table A
SWP water.
Table 20
Coachella Valley State
Water Project
Water Table A Allocation
(ac-ft/ r)
Original
Tulare
Tulare Lake
Metropolitan
Berrenda
SWP
Lake Basin
Basin
Water District
Mesa
Table A
Transfer #1
Transfer #2
Transfer
Transfer'
Total
CVWD 23,100
9,900
5,250
88,100
12,000
138,350
DWA 38,100
-
1,750
11,900
4,000
55,750
Total 61,200
9,900
7,000
100,000
16,000
1949100
Source: CVWD 2010 Draft UWMP.
CVWD purchases Table A amounts from SWP contractors as they become available and meet
CVWD's needs. Additional purchases from the SWP and others with water rights, mainly in the
Central Valley of California, will be evaluated as they become available to determine whether
they meet CVWD's needs. If they do, CVWD may purchase additional SWP water rights.
Water purveyors make annual requests to the DWR for SWP water allocations and the
Department makes an initial SWP Table A allocation for planning purposes, typically in the last
month before the next water delivery year. Throughout the year, as additional information
regarding water supplies becomes available to DWR, its allocation/delivery estimates are
updated.
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The following table outlines the historic reliability of SWP deliveries, including initial and final
allocations for since 1987.
Table 21
DWR Table A Water Allocations
(1987 —2011)
Year
Initial Allocation Final Allocation
1987
100%
100%
1988
100%
100%
1989
100%
100%
1990
100%
100%
1991
85%
30%
1992
20%
45%
1993
10%
100%
1994
50%
50%
1995
40%
100%
1996
40%
100%
1997
70%
100%
1998
40%
100%
1999
55%
100%
2000
50%
90%
2001
40%
39%
2002
20%
70%
2003
20%
90%
2004
35%
65%
2005
40%
90%
2006
55%
100%
2007
60%
60%
2008
25%
35%
2009
15%
40%
2010
5%
50%
2011*
25%
70%
Average
48%
77%
Source: California DWR, Water Contract Branch within the State Water Project
Analysis Office, Notices to State Water Contractors, 1987 — 2010.
* Latest update for 2011 was posted on March 15, 2011.
As noted previously, CVWD and DWA do not directly receive SWP water. Rather, CVWD and
DWA have entered into an exchange agreement with MWD that allows MWD to take delivery of
CVWD's and DWA's SWP Table A water. In exchange, MWD provides an equal amount of
Colorado River water that MWD transports through its Colorado River Aqueduct, which crosses
the Coachella Valley near Whitewater. The exchange agreement allows for advanced delivery
and storage of water, thereby providing better and more efficient water management. As a result,
water is not recharged every year, but is recharged during year when SWP and surplus waters
are available. The large storage capacity of the Aquifer and the large volume of water in storage
allow CVWD and DWA to pump from the Aquifer for a number of years without recharging and
to recharge large amounts of water to refill the Aquifer when surplus water is available.
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Spot Purchases and Permanent Water Purchases
CVWD and DWA also purchase additional water from the SWP as available. Purchase of
additional SWP water may involve purchases on the spot market, Pool A, B, and Interruptible
water, as well as the purchase of additional long-term supplies of Table A water. Since 2002 over
6,100 acre-feet has been purchased from the spot market.19
CVWD purchases Table A amounts from SWP contractors as they become available and meet
CVWD's needs. Additional purchases from the SWP and from others with water rights, mainly
in the Central Valley of California, will be evaluated as they become available to determine
whether they meet CVWD's needs. CVWD may purchase additional SWP water rights should a
suitable opportunity arise.
4.4 SUMMARY OF WATER RESOURCES
In addition to urban water demands, CVWD's service area also generates non -potable water
demands for groundwater recharge and use. Table 22 below shows the total projected water
demands for the CVWD service area through 2035.
Table 22
Total Projected Water Use CVWD Service Area
(Acre -Feet)
2015
2020
2025
2030
2035
Total Urban Water Use
125,800
156,100
187,700
212,000
242,700
Groundwater recharge
131,200
148,500
158,700
159,400
163,100
Non -potable Water Use
339,000
319,400
314,200
299,400
283,600
Total
596,000
624,000
660,600
670,800
689,400
Source: CVWD UWMP Table 4-7 CVWD Future Groundwater Production
Table 23 shows CVWD's existing water supply entitlements, rights, and service contracts.
Table 23
CVWD Water Supplies
(Entitlements, Rights, and Water Service Contracts)
Supplies
Ever
Supply
acre-feet/year
Entitlement
Right
Contract
Other
Utilized
Groundwater
Unspecified 1
X
Yes
Colorado River
459,000 2
X
Yes
SWP Exchange
138,350 s
X
Yes
1. CVWD shares a common groundwater source with DWA that has not been adjudicated.
2. As set forth in the QSA between IID, MWD, and CVWD, October 2003. (See Table 5 above)
3. Includes Original Table A amount, Tulare, Berrenda Mesa and MWD Agreements. (See Table 20 above)
19 CVWD WMP 2010.
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4.4.1 WATER SUPPLY FOR LA QUINTA GENERAL PLAN
As described above, CVWD utilizes a number of water sources to meet water demands for its
service area. For the City of La Quinta and the Sphere of Influence, CVWD provides
groundwater as the primary water supply and, as feasible, uses imported Colorado River water
for irrigation.
4.5 WATER SUPPLY RESOURCES PROJECTED
The UWMP projects that the percentage of water from each of the current water supply sources
will change significantly by 2035 relative to 2005 conditions. Table 24 below shows the
projected water supplies that will be utilized to be meet demands for the CVWD service area
through 2035. Sources other than groundwater constitute 47% of the water supply that will be
utilized to meet urban water demands in 2035.
Table 24
Projected Urban Water Sources CVWD
(Acre -Feet)
Water Use
2015
2020
2025
2030
2035
Groundwater
118,700
125,600
129,900
133,500
128,700
Treated Colorado River
5,700
19,300
31,400
39,500
49,100
Untreated Colorado River
1,300
11,100
26,300
39,000
54,800
Desalinated A. Drain
0
0
0
0
10,000
Total
125,800
156,100
187,700
212,000
2429700
Source: CVWD UWMP Table 4-1 CVWD Future Water
4.5.1 WATER SUPPLY RELIABILITY
Table 25 below, illustrates the assumptions associated with the projected water supply reliability
for each water resources available to the CVWD service area. See Appendix B for information
on recent litigation that may affect delivery of SWP supplies or Colorado River Water.
Table 25
CVWD Projected Supply Reliability by Source
Normal Water
Single Dry
Multiple Dry Years
Year 1
Year 2
Year 3
Supply Sources
Year
Year
Groundwater
100%
100%
100%
100%
100%
Colorado River Water
100%
100%
100%
100%
100%
Recycled Water
100%
100%
100%
100%
100%
SWP Water'
50%
11%
34%
35%
36%
Desalinated Drain Water
100%
100%
100%
100%
100%
1 Consistent with DWR SWP 2009 Delivery Reliability Report for Single and Multiple Dry Years. CVWD
assumes that 50% of SWP supplies are available during normal years.
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State Water Project
DWR issues the State Water Project Delivery Reliability Report every two years, with the 2009
version being the most recent. The 2009 Report accounts for variability in water delivery
reliability from climate change and federal litigation regarding listed fish species. The Final
DWR 2009 Reliability Report, projects that future SWP Table A deliveries through 2029 will
average 60% of Table A Allocation under normal year conditions, 11 % under single dry year
conditions, and 34-36% under multiple dry year conditions.20 This percentage of allocations is
based on computer modeling of the state's watersheds, past hydrology adjusted for climate
change, recent federal litigation, and conditions of the State's river and reservoir systems.
The CVWD UWMP accounted for uncertainty in modeling restriction, risk of levee failure in the
delta, additional pumping restriction, ongoing litigation, and potential impacts of climate change.
As such, the CVWD UWMP assumes a more conservative long-term delivery reliability average
of 50% in the absence of a successful Bay Delta Conservation Plan.
Colorado River Water
Reliability of the Colorado River water supply is dependent upon the availability of this source,
which may be affected by precipitation levels and recent litigation challenging the QSA. See
Appendix B.
In January 2010, the QSA was rendered invalid in a state court decision (Superior Court of
California, 2010), and was subsequently issued a temporary stay from the California Court of
Appeals (Case Number C064293; to be heard on February 14, 2011). 21
As described above, the use of Colorado River water for domestic purposes is projected to
increase substantially by 2035. Determining the best way to treat this water in order to substitute
for and decrease the area's dependency on groundwater is an important objective of the CVWD
UWMP. A study of surface water treatment options was conducted by CVWD in order to
determine historic and projected Colorado River water quality, establish water quality treatment
goals, identify feasible treatment technologies, and assess the compatibility of blending treated
surface water with groundwater and the resultant potential for corrosion. In 2008 CVWD
finalized the Phase 2 Draft Surface Water Treatment Process Evaluation Report, which
investigated treatment options for producing potable quality water from Colorado River water.
The Report calls for the treatment and distribution of as much as 32,000 acre-feet of Colorado
River water for domestic use annually,22 and may be ramped up to as much as 92,000 acre-feet
per year.23,24
20 "The State Water Project Delivery Reliability Report 2009," prepared by the California Department of Water
Resources, Bay -Delta Office, August 2010.
21 "CVWD Water Management Plan Update: Draft Report", prepared for CVWD, December 2010.
22 "CVWD Water Management Plan Update: Draft Report", prepared for CVWD, December 2010.
23 Personal communication with Mark Johnson, CVWD Director of Engineering, September 9, 2008.
24 "Coachella Valley Water District (CVWD) Domestic Water System (Surface Water) Treatment Plant Design
Development Report," prepared by Malcolm Pirnie, Inc., September 2008.
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4.5.2 WATER QUALITY
The quality of the groundwater within the Whitewater River Subbasin is dependent on a number
of factors, including the source of the water, the type of water -bearing materials in which it
occurs, depth, proximity to faults and recharge basins, presence of surface contaminants, well
maintenance, and other hydrogeological or cultural factors. The California Regional Water
Quality Control Board (CRWQCB), Lahontan Region, implements federal and state laws to
assure that water quality standards are met for domestic water systems under the authority of the
federal and state Safe Drinking Act.
Planning, management, and enforcement of these laws assure that all urban water served by
CVWD meets state and federal water quality standards. The quality of water within the
Whitewater River Subbasin and both treated and untreated Colorado River water is described as
good in Table 5-13 of the CVWD UWMP. The 2011 Water Quality Report prepared by CVWD
shows domestic water quality by service area. Monitoring for certain contaminants has been
conducted, and no established thresholds for water quality standards have been exceeded within
the CVWD service area.25
Emerging groundwater quality issues consist of salinity, arsenic, perchlorate, chromium-6
uranium, nitrate, carcinogens, and endocrine disrupting compounds. Each of these is discussed in
detail below.
Colorado River water is used for direct recharge to groundwater reserves and is relatively high in
salinity, containing more than one ton of salt (600 o 700 ppm) in every acre-foot of water
delivered. Salinity levels at the Whitewater River Recharge Facility range from 530 to 750 mg/L,
averaging 636 mg/L since 1973. Colorado River water delivered via the Coachella Canal ranges
from 625 to 975 mg/L, with an average concentration of 790 mg/L over the last 60 years. 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. Another option is to treat
Colorado River water through a desalination process before recharge. As mentioned above,
desalination is currently expensive and may be cost prohibitive. CVWD will continue to
monitory concentrations in recharge supplies and groundwater. With implementation of the
CVWMP, salinity will not affect groundwater supply reliability.
The Water Quality Report notes that, due to the erosion of natural deposits, some low levels of
arsenic are periodically detected in the domestic water system. For the City of La Quinta the
range of arsenic was not detected to a maximum of 5.7 ug/L. The average arsenic concentration
was not detectable. The US EPA researches the effects of arsenic and has found that exposure
can cause cancer in humans at high concentrations and is linked to skin damage and circulatory
problems. To protect against these potential effects, the Maximum Contaminant Level (MCL) for
arsenic has been set 10 ug/L. All domestic water delivered by CVWD was well below this
threshold. CVWD will continue to monitor arsenic levels and as needed may relocate, blend or
treat groundwater supplies to minimize arsenic concentrations.
25 "CVWD 2011 Domestic Water Quality Table," prepared by CVWD, 2011.
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Perchlorate was detected in imported Colorado River water in the 1990s. The perchlorate source
was determined to be from the Kerr-McGee plan in Nevada, upstream from Lake Mead.
Treatment of perchlorate in 1999 at three different locations in Nevada led to steadily declining
perchlorate concentrations in Colorado River water. Treatment has been effective in significantly
reducing the concentration of perchlorate to levels below the state reporting level of 2 pg/L.
Although perchlorate is no longer a major concern in Colorado River water, CVWD continues to
monitor for this contaminant.
In California, chromium-6 is regulated under the 50 pg/L maximum contaminant level for total
chromium. The California State's Office of Environmental Health Hazard Assessment (OEHHA)
has set forth a Public Health Goal (PHG) of 0.06 µg/L for chromium-6, which is currently being
considered by the EPA. The EPA will review latest information and data on chromium-6 as part
of its 2011 human health assessment and determine if new standards need to be set. At this time,
EPA recommends increased monitoring of chromium-6. Monitoring in the Coachella Valley to
date has identified over 100 wells with detectable levels of chromium-6. CVWD will continue to
monitor for chromium-6 and blend or treat groundwater to achieve required MCL.
Radon, a byproduct of uranium, is another potential water contaminant that has been detected in
low level in CVWD's water supply due to the erosion of naturally occurring deposits. For the
City of La Quinta, the range of uranium was not detected to a maximum of 12 picocuries per liter
(pCi/L). The average uranium concentration was 4.5 pCi/L within the La Quinta service area.
The MCL for uranium has been set 20 pCi/L. All domestic water delivered by CVWD was well
below this threshold.
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, the range of nitrate concentration was 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 systems and removing on -lot septic may further limit nitrate accumulation
in groundwater reserves.
CVWD also monitors for carcinogens and endocrine disrupting compounds. The EPA is
considering a new strategy for addressing such compounds including new water treatment
technologies. CVWD will continue to monitor domestic water supplies for carcinogens and
endocrine disrupting compounds and incorporate new management strategies as required.
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Water Supply Study/Terra Nova
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5.0 SUMMARY AND CONCLUSIONS
The Coachella Valley has a vast groundwater reservoir with a total storage capacity of 28.8
million acre-feet of water within the Whitewater River Subbasin. CVWD receives Colorado
River water supplies, produces recycled water, and is pursuing additional water resources such as
desalinated water supplies. Water demands within the region are generated by urban water users,
golf courses, and agriculture. Urban water supplies are met through groundwater production,
whereas golf courses and agricultural water demands are largely met through imported Colorado
River water via the Coachella Canal and a limited amount of recycled water and groundwater.
The 2010 UWMP and WMP identify potential water conservation savings for urban, agriculture,
and golf courses, describe conjunctive use techniques to maximize available water supplies such
as increase recharge, use of recycled water, and desalinated water. The UWMP concludes that
there are sufficient water supplies available to meet demands throughout the service area in 2035
under normal, single, and multiple dry year scenarios, including municipal, manufacturing,
industrial, and agricultural water users.
The 2035 water supply projections show that there are sufficient resources available to meet
projected demands. However, the long term trend indicates that water demands will continue to
increase with population growth, while new water supply resources become more limited. As
such, it is essential that local and regional planning efforts recognize the immediate need to
conserve water, develop water efficient land use practices, and maintain water demands at a level
that can be met without resulting in overdraft conditions.
With CVWD's management strategy and the ongoing implementation of the CVWMP, the
groundwater supply is sufficient to serve the City of La Quinta's urban water demand through
build out of the proposed General Plan. In order to be consistent with the goal of the CVWD
WMP, the City of La Quinta will need to expand infrastructure and the use of treated and
unfiltered Colorado River as appropriate for landscaping and irrigation, and continue to reduce
its overall per capita water demand.
The projected water demand associated with the General Plan Planning Area represents
approximately 22% of total CVWD water demands in 2035. In CVWD's UWMP and CVWMP,
the District included water demand projections for new growth and development within its
service area, including development within the City of La Quinta and the Sphere of Influence.
Although the level of growth varies depending on the population projections utilized, the
targeted per capita water demand set forth by CVWD for 2035 is achievable under the proposed
La Quinta General Plan update.
5.1 COACHELLA VALLEY WATER DISTRICT SERVICE AREA
Based on the information, analysis, and findings documented in the UWMP and WMP, there is
substantial evidence to support a determination that there will be sufficient water supplies to
meet the demands within CVWD's service area through 2035. This is based on the volume of
water available in the aquifer, CVWD's Colorado River contract supply, SWP Table A amounts,
and rights and contracts to meet future water demand projected to be generated within CVWD's
service area. CVWD has committed resources to further implement the primary elements of the
CVWMP, which include the purchase of additional water supplies, water conservation, and
source substitution.
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Water Supply Study/Terra Nova
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Over the past several years, CVWD has made significant progress in providing private and
public consumers of local water resources with information, technology, training, and incentives
that have resulted in water conservation. The CVWMP identifies several water conservation
measures with the goal of reducing urban water demand by 15% by 2015 and 20% by 2020.
Further water conservation may be realized from 2020 through 2035. These measures include
water efficient landscaping and irrigation, water efficient plumbing and appliances, tiered or
seasonal water pricing, public information and education programs, alternative water supplies,
water restrictive municipal development policies, appointing a CVWD conservation coordinator,
and refining the maximum water allowance for landscaped and recreational areas
A central strategy of the 2010 UWMP is to expand the use of Colorado River water and recycled
water supplies for irrigation in place of groundwater and to incorporate treated Colorado River
water into the domestic water system. As projected, by 2035 Colorado River water will account
for 47% of the domestic water supply.
As described in the 2010 CVWD UWMP (Section 5), groundwater reserves, Colorado River
water supplies, and other water resources such as recycled water and desalinated agricultural
drain water are adequate to meet projected water demands within the CVWD service area
including the City of La Quinta and the Sphere of Influence. This includes normal, single, and
multiple dry year conditions through 2035 without impacting existing or planned future water
users including agricultural, industrial, and manufacturing.
5.2 LA QUINTA GENERAL PLAN WATER USE
As projected herein, assuming Scenario B as described above, the Planning Area will generate an
annual water demand of approximately 54,467 acre-feet per year in 2035. Development within
City Limits will account for 37,783 acre-feet and the Sphere of Influence will account for 16,684
acre-feet of the water demand. The estimated 2010 water demand within City limits is 31,228
acre-feet and 1,268 acre-feet within the Sphere of Influence. New growth as proposed in the
General Plan Update will account for 17% of the build out demand by 2035 within City Limits,
and 92% within the Sphere of Influence.
As mentioned above, the water demand estimates assume full occupancy for all land uses.
However, La Quinta is a seasonal community with a high quantity of second homes and a 28.5
percent vacancy rate. As such, the water demand projections herein are conservative in that they
assume full occupancy year round. Water demand projections for 2035 are also conservative
since this analysis assumes that build out of the La Quinta General Plan will occur by 2035.
Based on current economic conditions and refined population growth rates, actual build out of
the La Quinta General Plan is expected to occur after 2035.
Urban water demands for the Planning Area are currently met through groundwater supplies,
however, by 2035 47% of the domestic water system will be comprised of treated Colorado
River water. CVWD is currently working on designing and implementing an area -wide water
service system, which includes establishing pressure zones for the siting of gravity fed storage
tanks, pipeline conveyance system expansion and extension, and development of a water
treatment facility that treats Colorado River water to potable standards for the East Valley.
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The City of La Quinta has an established water delivery system that is maintained and operated
by the CVWD. New development proposed within City Limits is largely infill development that
will require limited expansion of water conveyance infrastructure. A portion of the water
demands generated by open space recreation within the City limits are currently met through
canal water. By 2035 a majority of the water utilized to irrigate open space recreation land uses
should be derived from sources other than groundwater, such as Canal water, recycled water, or
desalinated drain water. Substituting groundwater for non -potable water sources for irrigation of
large scale landscaping, such as open space recreation land uses, will require installation of
pipelines to distribute Canal water and expansion of recycled water production and conveyance.
The Sphere of Influence currently lacks sufficient water service infrastructure to provide reliable
service to meet projected water demands at build out. In order to assure that water services are
available to La Quinta's Sphere of Influence, new infrastructure including water treatment,
production wells, storage tanks (reservoirs) and pressure zones for the siting of reservoirs, and
transmission mains will need to be developed.
5.2.1 GENERAL WATER USE PRINCIPALS
The City of La Quinta recognizes the importance of water conservation practices and has
incorporated water use efficiency principals into the proposed General Plan. The City will assure
that all future development adhere to policies that govern water use practices such as building
codes, landscaping standards, per capita reduction targets, and fee programs to secure additional
water supplies. The following conditions describe the existing standards that must be met:
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.
The City shall coordinate and cooperate with CVWD to ensure City-wide compliance with State
Senate Bill x7-7 by implementing programs to reduce per capita urban water use by 10% by year
2015, and 20% reduction by year 2020, including the following: landscaping conversion
programs and the smart irrigation control program; and expansion 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.
The City shall require that future development in the General Plan Area that meets the definition
of a "project," as defined under Water Code Section 10912, provide an adopted Water Supply
Assessment in compliance with SB 610 and 221, prior to approval of development plans.
43
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
As the largest water demanding component, water conservation realized for irrigation and
landscaping can have the greatest impact on reducing the overall water demand. The use of
drought tolerant desert plants and efficient irrigation systems can drastically reduce water
demands compared to traditional grass lawns and irrigation techniques.
Therefore, all landscape areas shall be irrigated using an automatic climate -based irrigation
system that relies primarily on point application or bubblers/drip irrigation to minimize water
loss and maximize water application directly to the root zone. Scheduled irrigation of native
plants should be viewed as temporary for the initial period of plant growth establishment. Once
native plant materials have rooted and are surviving on their own, supplemental water should be
minimized. Turf and shrub irrigation will utilize independent delivery systems for optimum
water efficiency.
Water conservation for the Planning Area will be achieved through the widespread use o£ 1)
drip and other efficient irrigation, 2) intelligent irrigation controllers, 3) native and non-native
drought -tolerant planting materials, and 4) the use of low flush toilets, water efficient appliances,
showerheads, and faucets. Furthermore, every effort should be made to substitute groundwater
for other available sources for irrigation demands such as recycled water, Colorado River water,
or desalinated drain water.
All new development will participate via the payment of a Supplemental Water Supply Charge
(SWSC), which will be used to offset costs associated with purchasing new water supplies and
other activities to reduce overdraft conditions in the basin. The SWSC is determined based on the
historical water use by each type of development and the cost of purchasing imported water.
Through this charge and the conservation methods outlined above, potential impacts on the
groundwater basin as a result of the proposed La Quinta General Plan Update are expected to be
less than significant.
5.2.2 RECOMMENDED MITIGATION
An Environmental Impact Report (EIR) is being prepared for the La Quinta General Plan, and a
broad range of mitigation measures have been included in the EIR to minimize potential impacts
on water resources by encouraging water saving designs and water conservation. Development
of land uses set forth within the General Plan Update, as well as existing development shall be
required to implement the following measures in order to assure the most efficient use of water
resources and to meet and maintain the CVWMP goals through 2035:
44
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
1. The City shall 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.
2. Require project developers to pay the Supplemental Water Supply Charge and other
applicable fees for the purpose of buying additional water rights to import water and
replenish the basin.
3. Project proponents shall contribute their fair share towards the construction and operation of
new CVWD facilities, including wells, reservoirs, pipelines, and recycled water treatment
facilities.
4. Project applicants shall be encouraged to utilize onsite grey water systems to fulfill all or a
portion of the onsite water demand requirements.
5. 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.
6. Native plant materials and other drought -tolerant plants shall be used in all non -turf areas of
project landscaping.
7. Large expanses of lawn and other water -intensive landscaped areas shall be kept to the
minimum necessary and consistent with the functional and aesthetic needs of the Project,
while providing soil stability to resist erosion. The use of turf shall be limited to only the
areas necessary to provide play areas for children and other appropriate uses.
8. The installation and maintenance of efficient on -site irrigation systems will minimize runoff
and evaporation and maximize effective watering of plant roots. Drip irrigation, smart
irrigation controllers, and moisture detectors will be used to the greatest extent practicable to
increase irrigation efficiency.
9. The City shall encourage existing development to reduce water consumption over "business
as usual."
10. 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.
11. Golf courses and large expanses of turf shall be irrigated with non -potable water supplies,
such as canal water and recycled water as available.
12. The City, in conjunction with CVWD and golf course developments, shall aggressively
pursue the expansion of non -potable water supplies for irrigation purposes.
45
Water Supply Study/Terra Nova
La Quinta General Plan Update/ June 21, 2011
13. 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.
14. To the greatest extent practicable, the City shall require that all new development connect to
the community sanitary sewer system.
15. 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.
16. 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.
17. For future development and redevelopment, project proponents shall confer with CVWD
engineers to determine locations of existing drains, easements, and rights -of way.
18. The City shall coordinate with CVWD to establish City specific water demands for existing
land uses, that can be used to identify effective water savings programs and target sectors that
can further conservation or benefit from water audits and retrofits.
46
APPENDIX A
Water Demand Projections for the
La Quinta General Plan
Prepared in Support of the
La Quinta General Plan
Water Supply Assessment
Prepared by
r
L -A Terra Nova Planning & Research, Inc.®
42635 Melanie Place, Suite #101
Palm Desert, CA 92211
June 22, 2011
Water Supply Study/ La Quinta General Plan
Technical Appendix A/ June 22, 2011
Water Demand Methodology
The following describes the methodology, techniques, and assumptions that were utilized in
quantifying water demand estimates for all existing and proposed land uses described in the La
Quinta General Plan Update (2010). At build out of the General Plan, water demand will
increase substantially over the existing water demand within the Planning Area. The analysis
considers landscape and potable water demand for all existing and proposed land uses within
City limits, the Sphere of Influence, and the overall Planning Area.
Water demand projections at build out of the proposed La Quinta General Plan Update are
provided for the following scenarios: a) the business as usual scenario, which assumes that all
new development will generate water demands at the same rate as existing development; b) the
water efficiency scenario, which assumes that new development adheres to water efficient
principals and existing development continues to generate the same level of water demand; and
c) the retrofit plus efficiency scenario, which assumes that new development adheres to water
efficient principals and existing development is retrofitted to reduce water demands.
Landscape Water Demand Methodology
Applying an estimated "percentage landscaped area" to the total acres designated for each land
use, as described below, provided the proposed "landscape area" for each land use component,
which excludes impervious surfaces. The total estimated acreage that will require irrigation for
landscaping purposes was then multiplied by the estimated Maximum Applied Water Allowance
(MWA) in order to calculate the total water demand.
The Maximum Water Allowance is determined pursuant to CVWD's Landscape Ordinance No
1302.1 and is dependent upon the localized evapotranspiration (ETo). Several (ET) zones are
defined for the Coachella Valley and account for differences in transpiration rates for plants,
which vary depending on the location. For example, transpiration rates in cove areas adjacent to
hillsides along the Valley's margins have a lower ET rate compared to transpiration rates on the
more exposed valley floor, since the former tend to be better shaded and protected from high
winds. La Quinta contains several ETo Zones within its Planning Area. In order to capture a
reasonable water allowance for existing and new development within in the Planning Area, Zone
3a and 4 ETo rates were utilized, respectively.
A-1
Water Supply Study/ La Quinta General Plan
Technical Appendix A/ June 22, 2011
Potable Water Demand Methodology
Potable water demand for proposed development within the Planning Area was calculated for all
indoor uses based on estimates from the American Water Works Association Research
Foundation (AWWARF). For residential land uses, the number of occupied dwelling units' was
multiplied by the household population size of 2.53 people per dwelling unit for City Limits and
for the Sphere of Influence. The total population was then multiplied by the AWWARF per
capita factor for indoor use: 69.3 gallons per day per person under business as usual conditions,3
or 55.4 gallons per day per person under more efficient water use conditions.4
Indoor potable demand for non-residential land uses was multiplied by the appropriate
AWWARF water demand factor. AWWARF figures for non-residential uses are presented as a
range depending on the level of efficiency. Square footages for commercial land uses are from
the Land Use Table for the General Plan Update and assume 22% area coverage for buildings.
The same coverage assumption was used to estimate the square footage associated with Major
Community Facilities.
Existing BAU and New Development Efficiency (Scenario B)
The following describes the approach utilized to estimate the water demand associate with build
out of the preferred alternative under the conditions that existing land uses maintain current
water demands and new development adhere to the most recent water efficiency standards.
Existing Water Demand
Existing water demand is generated from residential, commercial, and recreational open space
land uses. Existing development within the La Quinta General Plan Planning Area that generate
a water demand include the following:
City Limits
• 20,834 low density residential,
• 2,655 medium/high density residential,
• 6,410,202 square feet of commercial,
• 238 acres of Major Community Facilities,
• 4,272 acres open space recreational uses, and
• 1,676 acres of street rights -of -way
Sphere of Influence
• 801 low density residential,
• 273,760 square feet of commercial,
• 28.6 acres of Major Community Facilities, and
• 320 acres of street rights -of -way
' Although the Department of Finance specifies a 28.5 percent vacancy rate for the City of La Quinta, this
analysis assumes full occupancy.
Z SCAG Demographic data information and U.S. Census data 2010.
3 Project #241A, Residential End Uses of Water, AWWARF, Winter 1999/2000.
4 SB 7x7 requires that the per capita water demand be reduced by 20%.
A-2
Water Supply Study/ La Quinta General Plan
Technical Appendix A/ June 22, 2011
Landscape Water Demand Methodology
Landscape water demand was calculated using the estimated landscape coverage area for
residential, commercial, major community facilities, open space, and street rights -of way land
uses. For low density residential, 40% landscape coverage is assumed, consisting of 15%
moderate desert landscaping and 25% high water demand landscaping. For medium/high density
residential 25% landscape coverage is assumed, consisting of 15% moderate desert landscaping
and 10% high water demand landscaping. For commercial land uses a 15% moderate desert
landscaping coverage is assumed. The major communities facilities land use assumes a total
landscape coverage of 30% consisting of 5% for desert landscaping and 25% for high water
demanding landscape. It is assumed that natural open space does not generate any water demand.
Open space recreation is assumed to generate a water demand for 90% of the total acreage,
consisting of 5% moderate desert landscaping and 85% high water demand landscaping. For
street right-of-ways 15% landscape area coverage is assumed, with all of it being moderate
desert landscaping.
A majority of the existing development within the La Quinta Planning Area is located within
Zone 3A. The total projected water demand associated with landscaping is calculated using the
MWA factor for moderate desert landscaping or high water demand landscaping such as turf, or
water features. The MWA for moderate desert landscaping in Zone 3A is 1,353.97 CCF5 or
3.108 acre-feet per acre annually. The MWA for turf and other water intensive landscaping in
Zone 3A is 1,895.56 CCF or 4.352 acre-feet per acre annually. Existing landscaping within the
Planning Area is dominated by turf, with limited desert landscaping.
As shown in Table A-1 through A-3, a total of 25,495 acre-feet per year is required for irrigation
of landscaped areas for existing development within City limits, and 1,055 acre-feet within the
Sphere of Influence. The total water demand from existing landscaping within the Planning Area
is estimated to be 26,550 acre-feet per year.
Potable Water Demand Methodology
As mentioned above, potable water demand for existing development within the Planning Area
was calculated for all indoor uses based on estimates from the American Water Works
Association Research Foundation (AWWARF). The AWWARF factor for schools of 16 gpd per
square foot is used to estimate the total potable water demand for MC facilities.
For commercial land uses, a factor of 51.22 gallons per day was assumed. This factor is intended
to capture the average water demand for all types of commercial uses including retail, office,
supermarket, hotel, and restaurants. For analysis purposes it was assumed that existing
commercial development within the La Quinta Planning Area consists of 60% retail, 24% office,
8% hotels, and 4% restaurant and supermarkets. Using these percentages and the high range of
AWWA end uses of 30.5 gpd, 35 gpd, 115 gpd, 331 gpd, and 52 gpd for retail, office, hotels,
restaurant, and supermarkets respectively, it was estimated that the average commercial use
factor is 51.22 gpd.6
5 1 CCF = 100 cubic feet
6 Project #24113, Commercial and Industrial End Uses of Water, AWWARF, Summer 2000.
A-3
Water Supply Study/ La Quinta General Plan
Technical Appendix A/ June 22, 2011
Tables A-4 through A-6 show the estimated potable water demand for existing land uses within
the La Quinta General Plan Planning Area, which is estimated to be 5,946 acre-feet per year,
consisting of 5,733 acre-feet within City limits and 214 acre-feet within the Sphere of Influence.
Total Water Demand
As seen in Tables A-7 through A-9, the total existing water demand within the La Quinta
General Plan Planning Area is estimated to be 32,496 acre-feet per year, consisting of 31,228
acre-feet within City limits and 1,268 acre-feet within the Sphere of Influence.
Proposed Water Demand (New Development)
New development will be constructed using water efficient principles and technologies.
Therefore, for all proposed development it is appropriate to utilize demand factors that reflect
greater water efficiency to estimate water demand.
Landscape Water Demand Methodology
Landscape water demand was calculated using the estimated landscape coverage area for
residential, commercial, major community facilities, open space, and street rights -of way land
uses. For low density residential, 40% landscape coverage is assumed with 25% consisting of
moderate desert landscaping and 15% consisting of high water demand landscaping. For
medium/high density residential 25% landscape coverage is assumed with 20% consisting of
moderate desert landscaping and 5% consisting of high water demand landscaping. For
commercial land uses a 15% moderate desert landscaping coverage is assumed. The major
communities facilities land use assumes a total landscape coverage of 25% consisting of 10% for
desert landscaping and 15% for high water demanding landscape. It is assumed that natural open
space does not generate any water demand. Open space recreation is assumed to generate a water
demand for 90% of the total acreage, consisting of 25% moderate desert landscaping and 65%
high water demand landscaping. For street right-of-ways 15% landscape area coverage is
assumed, with all of it being moderate desert landscaping.
A majority of the proposed development within the La Quinta Planning Area will occur within
Zone 4. The total projected water demand associated with landscaping is calculated using the
MWA factor for moderate desert landscaping or high water demand landscaping such as turf, or
water features. The MWA for moderate desert landscaping in Zone 4 is 1,588.66 CCF7 or 3.647
acre feet per acre annually. The MWA for turf and other water intensive landscaping in Zone 4 is
2,224.12 CCF or 5.106 acre feet per acre annually. New landscaping within the Planning Area
will be predominantly moderate desert landscaping with limited turf areas.
As shown in Tables A-10 through A-12, a total of 4,880 acre-feet per year would be required for
irrigation of landscaped areas for proposed developed within City limits, and 11,829 acre-feet
within the Sphere of Influence. The total water demand from landscaping activities due to
proposed development within the Planning Area is projected to be 16,708 acre-feet per year at
build out.
7 1 CCF = 100 cubic feet
A-4
Water Supply Study/ La Quinta General Plan
Technical Appendix A/ June 22, 2011
Potable Water Demand Methodology
As mentioned above, indoor uses are based on estimates from the American Water Works
Association Research Foundation (AWWARF). A per capita water demand of 55.44 gallons per
day is assumed since it is 20% less than the 69.0 gallon per day considered in the BAU scenario.
Square footages for commercial and Major Community (MC) Facilities land uses assume 22%
area coverage for buildings. The low range of 8 gpd per square foot for schools is used to
estimate the total potable water demand for MC facilities at build out.
For commercial land uses, a factor of 35.5 gallons per day was assumed. This factor is intended
to capture the average water demand for all types of commercial uses including retail, office,
supermarket, hotel, and restaurants. For analysis purposes it was assumed that existing
commercial development within the La Quinta Planning Area consists of 60% retail, 24% office,
8% hotels, and 4% restaurant and supermarkets. Using these percentages and the low range of
AWWA end uses of 30.5 gpd, 26 gpd, 60 gpd, 130 gpd, and 24 gpd for retail, office, hotels,
restaurant, and supermarkets respectively, it was estimated that the average commercial use
factor is 35.5 gpd.
Tables A-13 through A-15 show the estimated potable water demand for new development
within the La Quinta General Plan Planning Area, which is estimated to be 5,263 acre-feet per
year, consisting of 1,676 acre-feet within City limits and 3,587 acre-feet within the Sphere of
Influence.
Total Projected Water Demand
The combined water demand for proposed development set forth in the La Quinta General Plan
Update considers the use of water for outdoor irrigation of landscaped areas and domestic or
indoor water use. Tables A-16 through A-18 summarize the estimated water demand for City
limits, the Sphere of Influence, and the overall Planning Area, respectively. Based on the
methodology described above, new development within the Planning Area will generate a water
demand of 6,555 acre-feet per year for City limits, 15,416 acre-feet per year for the Sphere of
Influence, and a combined new water demand of 21,971 acre-feet per year throughout the
Planning Area.
Build Out Water Demand
It is assumed that build out will occur by 2035 and that water demand will increase incrementally
over the 25-year build out horizon. Assuming average annual growth, it is estimated that the
annual increase in water demand will be approximately 300 acre-feet per year from new growth
and development within City limits and 695 acre-feet per year within the Sphere of Influence.
Tables A-19 through A-21 estimate the projected water demand that will be generated from
implementation of the proposed General Plan Update. Water demand at build out of the General
Plan will come from irrigation of outdoor landscaped areas and indoor water use. Methodologies
used to estimate water demand for the proposed land uses described in the La Quinta General
Plan Update are described in detail above for existing and proposed land uses. The Build Out
Water Demand Tables show the combined total water demand generated by existing and
proposed development.
A-5
Water Supply Study/ La Quinta General Plan
Technical Appendix A/ June 22, 2011
Build Out Landscape Water Demand
At build out, the landscaping demand is projected to be 30,374 acre-feet per year for City limits,
and 12,884 acre-feet per year for the Sphere of Influence. Therefore, the Planning Area is
estimated to generate a total landscaping demand of 43,258 acre-feet per year at build out.
Build Out Potable Water Demand
At build out, the potable water demand is projected to be 7,409 acre-feet per year for City limits,
and 3,801 acre-feet per year for the Sphere of Influence. Therefore, the Planning Area is
estimated to generate a total potable water demand of 11,209 acre-feet per year at build out.
Total Projected Water Demand at Build Out
As shown in Table A-21, the combined (existing and proposed) water demand is projected to be
54,467 acre-feet per year at build out of the La Quinta General Plan Planning Area, consisting of
37,783 acre-feet within City Limits, and 16,684 acre-feet within the Sphere of Influence.
Business As Usual (Scenario A)
This water demand scenario uses assumptions that are consistent with the Existing Water
Demands as described above under Scenario B and applies these same assumptions to proposed
development. Therefore, unlike Scenario B described above, this scenario assumes that new
development will not achieve any water conservation compared to existing development. This
scenario is provided in order to show the projected water demands that would be realized from
all proposed development, should all new development generate the same water demands as
existing land uses within the planning area. See the Scenario A tables included herein.
Total Projected Water Demand at Build Out
The combined (existing and proposed) water demand under the business as usual scenario is
projected to be 57,318 acre-feet per year at build out of the La Quinta General Plan Planning
Area, consisting of 38,675 acre-feet within City Limits, and 18,644 acre-feet within the Sphere
of Influence.
Retrofit and Water Efficiency Scenario C
This scenario uses assumptions that are consistent with the Proposed Water Demands as
described above under Scenario B for new development and applies the same water conservation
principals to existing development. Retrofitting activities have the potential to result in
substantial water savings within the City of La Quinta and will have minimal effects to the
Sphere of Influence. This Scenario assumes that existing development is retrofitted to achieve
the same level of water use as new development adhering to water conservation principals. See
the Scenario C tables included herein.
Total Projected Water Demand at Build Out
The combined (existing and proposed) water demand under the retrofit scenario is projected to
be 51,324 acre-feet per year at build out of the La Quinta General Plan Planning Area, consisting
of 34,768 acre-feet within City Limits, and 16,556 acre-feet within the Sphere of Influence.
A-6
APPENDIX A
SCENARIO B: Business As Usual + New Development Efficiency
Water Demand Projections for the
La Quinta General Plan
Prepared in Support of the
La Quinta General Plan
Water Supply Assessment
Prepared by
r
L -A Terra Nova Planning & Research, Inc.®
42635 Melanie Place, Suite #101
Palm Desert, CA 92211
June 22, 2011
Scenario B
La Quinta General Plan Update - Landscape Water Demand Existing Development City Limits
Table A-1
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre'
Total Demand
(AF/Y)
Low Density Residential (MDL)
4,171.20
15%
625.68
3.108
1,944.79
Low Density Residential (HWD)
4,171.20
25%
1,042.80
4.352
4,537.85
Medium/High Density Residential (MDL)
1,284.00
15%
192.60
3.108
598.66
Medium/High Density Residential (HWD)
1,284.00
10%
128.40
4.352
558.75
Subtotal
5,455.20
1,989.48
7,640.05
Commercial (MDL)
668.90
15%
100.34
3.108
311.87
Major Community Facilities (MDL)
238.00
5%
11.90
3.108
36.99
Major Community Facilities (HWD)
238.00
25%
59.50
4.352
258.92
Open Space- Natural
2,242.70
0%
N/A
N/A
N/A
Open Space- Recreation (MDL)
4,272.00
5%
213.60
3.108
663.93
Open Space- Recreation (HWD)
4,272.00
85%
3,631.20
4.352
15,801.55
Streets, Sidewalks, Medians (MDL)
1,676.10
15%
251.42
3.108
781.47
Subtotal
9,097.70
49267.95
17,854.73
Total Landscaping Demand
1 14,552.90
1 6457.43
1 25,494.78
Source: Total acreages are from developed lands under the General Plan Update Land Use Tables, prepared December 27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning Area. In order
to capture a reasonable water allowance it was assumed that Zone 3A is representative of the MWA average for all Zones.
Moderate Desert Landscaping (MDL) Zone 3A 3.108
Turf and High Water Demand (HWD) Zone 3A 4.352
ac-ft/ac/yr 1,353.97 CCF
ac-ft/ac/yr 1,895.56 CCF
A-7
Scenario B
La Quinta General Plan Update - Landscape Water Demand Existing Development Sphere of Influence
Table A-2
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AVY)
per Acre'
Total Demand
(AF/Y)
Low Density Residential (MDL)
551.50
15%
82.73
3.108
257.13
Low Density Residential (HWD)
551.50
25%
137.88
4.352
599.98
Medium/High Density Residential (MDL)
0.20
15%
0.03
3.108
0.09
Medium/High Density Residential (HWD)
0.20
10%
0.02
4.352
0.09
Subtotal
551.70
220.65
857.29
Commercial (MDL)
28.60
15%
4.29
3.108
13.33
Major Community Facilities (MDL)
28.17
5%
1.41
3.108
4.38
Major Community Facilities (HWD)
28.17
25%
7.04
4.352
30.65
Streets, Sidewalks, Medians (MDL)
319.93
15%
47.99
3.108
149.17
Subtotal
376.27
60.73
197.53
Total Landscaping Demand
927.97
281.38
1,054.82
Source: Total acreages are from developed lands under the General Plan Update Land Use Tables, prepared December 27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning Area. In order
to capture a reasonable water allowance it was assumed that Zone 3A is representative of the MWA average for all Zones.
Moderate Desert Landscaping (MDL)
Zone 3A 3.108 ac-ft/ac/yr
Turf and High Water Demand (HWD) Zone 3A 4.352 ac-ft/ac/yr
La Quinta General Plan Update - Landscape Water Demand Overall Planning Area
1,353.97 CCF
1,895.56 CCF
Table A-3
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre
Total Demand
(AF/Y)
City Limits
14,552.90
-
6,257.43
-
25,494.78
Sphere of Influence
927.97
-
281.38
-
1,054.82
Planning Area Total
15,480.87
-
6,538.81
-
26,549.59
A-8
Scenario B
La Quinta General Plan - Potable Water Demand for City Limits
Table A-4
Potable Water Demand for
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day
Total
AF/Year
Low Density Residential
2.53
20,834
69.3
4,091.66
Medium/High Density Residential
2.53
2,6551
69.3
521.42
Subtotal
23,489
4,613.09
Non -Residential Land Use
Square
Feet
Gallons Per Day
Total
AF/Year
Commercial
6,410,202
51.22
1,007.61
Major Community Facilities
2,280,802
16
111.99
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A
N/A
N/A
Streets, Sidewalks, Medians
N/A
N/A
N/A
Subtotal
6,410,202
51.22
1,119.60
Potable Water Demand Total
5,732.7
La Quinta General Plan - Potable Water Demand for Sphere of Influence
Table A-5
Potable Water Demand for
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day
Total
AF/Year
Low Density Residential
2.53
801
69.3
157.31
Medium/High Density Residential
2.53
69.3
-
Subtotal
801
157.31
Non -Residential Land Use
Square
Feet
Gallons Per Day
Total
AF/Year
Commercial
273,760
51.22
43.03
Major Community Facilities
269,959
16
13.26
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A
N/A
N/A
Streets, Sidewalks, Medians
N/A
N/A
N/A
Subtotal
273,760
51.22
56.29
Potable Water Demand Total
213.6
La Quinta General Plan Update - Potable Water Demand Overall Planning Area
Table A-6
Potable Water Demand
Demand
(AF/Y)
City Limits
5,732.69
Sphere of Influence
213.60
Planning Area Total
5,946.28
A-9
Scenario B
Table A-7
La Quinta General Plan
Existing Water Demands for City Limits
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
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
1.50
Commercial
311.87
1,007.61
1,319.48
1.18
Major Community Facilities
295.91
111.99
407.90
0.36
Open Space - Natural
N/A
N/A
-
-
Open Space- Recreation
16,465.48
N/A
16,465.48
14.70
Streets, Sidewalks, Medians
781.47
N/A
781.47
0.70
City Limits Total
25,494.78
5,732.69
31,227.46
27.88
Table A-8
La Quinta General Plan
Existing Water Demands for Sphere of Influence
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
857.11
157.31
1,014.42
0.91
Medium/High Density Residential
0.18
-
0.18
0.00
Commercial
17.71
43.03
60.74
0.05
Major Community Facilities
30.65
13.26
43.90
0.04
Streets, Sidewalks, Medians
1 149.17
N/A
1 149.17
0.13
City Limits Total
1 1,054.821
213.601
1,268.421
1.13
Table A-9
La Quinta General Plan
Existing Water Demands for Planning Area
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
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
1.50
Commercial
329.58
1,050.64
1,380.22
1.23
Major Community Facilities
326.56
125.25
451.81
0.40
Open Space - Natural
N/A
N/
-
-
Open Space- Recreation
16,465.48
N/A
16,465.48
14.70
Streets, Sidewalks, Medians
1 930.64
N/A
930.641
0.83
City Limits Total
1 26,549.591
5,946.28
32,495.88
29.01
A-10
Scenario B
La Quinta General Plan Update - Landscape Water Demand Proposed Development City Limits
Table A-10
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre
Total Demand
(AF/Y)
Low Density Residential (MDL)
1,675.90
25%
418.98
3.647
1,528.03
Low Density Residential (HWD)
1,675.90
15%
251.39
5.106
1,283.54
Medium/High Residential (MDL)
350.30
20%
70.06
3.647
255.51
Medium/High Residential (HWD)
350.30
5%
17.52
5.106
89.43
Subtotal
2,026.20
757.94
3,156.51
Commercial (MDL)
337.90
15%
50.69
3.647
184.85
Major Community Facilities (MDL)
160.00
10%
16.00
3.647
58.35
Major Community Facilities (HWD)
160.00
15%
24.00
5.106
122.54
Open Space- Natural
5,233.30
0%
N/A
N/A
N/A
Open Space- Recreation (MDL)
287.50
25%
71.88
3.647
262.13
Open Space- Recreation (HWD)
287.50
65%
186.88
5.106
954.16
Streets, Sidewalks, Medians (MDL)
1 257.60
15%
1 38.64
3.647
140.92
Subtotal
1 6,276.30
1 388.08
1,722.96
Total Landscaping Demand
1 8,302.50
1 1,146.01
1 4,879.47
Source: Acreages are from the vacant land proposed for development under the General Plan Update Land Use Tables, prepared December
27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning
Area. In order to capture a reasonable water allowance it was assumed that Zone 4 is representative of the MWA average since most of the
new developement proposed in the General Plan Update will occur within this Zone.
Moderate Desert Landscaping (MDL) Zone 4 3.647 ac-ft/ac/yr 1,588.66 CCF
Turf and High Water Demand (HWD) Zone 4 5.106 ac-ft/ac/yr 2,224.12 CCF
A-11
Scenario B
La Quinta General Plan Update - Landscape Water Demand Proposed Development Sphere of Influence
Table A-11
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AFC
per Acre
Total Demand
(AF/Y)
Low Density Residential (MDL)
6,826.60
25%
1,706.65
3.647
6,224.25
Low Density Residential (HWD)
6,826.60
15%
1,023.99
5.106
5,228.37
Medium/High Residential (MDL)
24.40
20%
4.88
3.647
17.80
Medium/High Residential (HWD)
24.40
5%
1.22
5.106
6.23
Subtotal
6,851.00
2,736.74
11,476.65
Commercial (MDL)
320.40
15%
48.06
3.647
175.28
Major Community Facilities (MDL)
1.61
10%
0.16
3.647
0.59
Major Community Facilities (HWD)
1.61
15%
0.24
5.1061
1.23
Streets, Sidewalks, Medians (MDL)
1 319.90
15%
1 47.99
3.6471
175.00
Subtotal
I 322.01
196.45
1352.10
Total Landscaping Demand
1 7,173.011
1 2,833.191
1 11,828.75
Source: Acreages are from the vacant land proposed for development under the General Plan Update Land Use Tables, prepared December
27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning
Area. In order to capture a reasonable water allowance it was assumed that Zone 4 is representative of the MWA average since most of the
new developement proposed in the General Plan Update will occur within this Zone.
Moderate Desert Landscaping (MDL) Zone 4 3.647 ac-ft/ac/yr 1,588.66 CCF
Turf and High Water Demand (HWD) Zone 4 5.106 ac-ft/ac/yr 2,224.12 CCF
La Quinta General Plan Update - Landscape Water Demand Overall Planning Area
Table A-12
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre2
Total Demand
(AF/Y)
City Limits
8,302.50
14%
1,146.01
4.26
4,879.47
Sphere of Influence
7,173.01
1 39%
1 2,833.19
1 4.18
1 11,828.75
Planning Area Total
15,475.51
53%
3,979.20
8.43
16,708.23
A-12
Scenario B
La Quinta General Plan - Potable Water Demand for City Limits
Table A-13
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day'
Total
AF/Year
Low Density Residential
2.53
5,028
55.44
789.97
Medium/High Density Residential
2.53
3,153
55.44
495.38
Subtotal
8,1811
1,285.36
Non -Residential Land Use
Sq.Ft.
Gallons Per Day'
AF/Year
Commercial
3,238,163
35.5
352.78
Major Community Facilities
1,533,312
8.0
37.64
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A_N/A
N/A
Streets, Sidewalks, Medians
I N/A
N/A
N/A
Subtotal
1 3,238,163
35.5
390.43
Potable Water Demand Total
1
1,675.8
1 Water use factors are from the American Water Works Association Research Foundation Commercial and
Industrial and Residential End Uses of Water, 2000. Assumes water efficient appliances and design and a 20% per
capita reduction.
La Quinta General Plan - Potable Water Demand for Sphere of Influence
Table A-14
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day'
Total
AF/Year
Low Density Residential
2.53
20,480
55.44
3,217.71
Medium/High Density Residential
2.53
219
55.44
34.41
Subtotal
20,699
1
3,252.12
Non -Residential Land Use
Sq.Ft.
Gallons Per Day'
AF/Year
Commercial
3,070,205
35.5
334.48
Major Community Facilities
15,429
8.0
0.38
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A
N/A
N/A
Streets, Sidewalks, Medians
N/A
N/A
N/A
Subtotal
334.86
Potable Water Demand Total
3,587.0
1 Water use factors are from the American Water Works Association Research Foundation Commercial and
Industrial and Residential End Uses of Water, 2000. Assumes water efficient appliances and design and a 20% per
capita reduction.
La Quinta General Plan Update - Potable Water Demand Overall Planning Area
Table A-15: Potable Water Demand
Demand (AF/Y)
City Limits
1,675.78
Sphere of Influence
3,586.98
Planning Area Total
5,262.76
A-13
Scenario B
Table A-16
La Quinta General Plan
Proposed Water Demands for City Limits
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
2,811.57
789.97
3,601.54
3.22
Medium/High Density Residential
344.94
495.38
840.33
0.75
Commercial
184.85
352.78
537.63
0.48
Major Community Facilities
180.89
37.64
218.54
0.20
Open Space - Natural
N/A
N/A
N/A
N/A
Open Space- Recreation
1,216.29
N/A
1,216.29
1.09
Streets, Sidewalks, Medians
140.92
N/A
140.92
0.13
City Limits Total
4,879.47
1,675.78
6,555.26
5.85
Table A-17
La Quinta General Plan
Proposed Water Demands for Sphere of Influence
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
11,452.63
3,217.71
14,670.34
13.10
Medium/High Density Residential
24.03
34.41
58.43
0.05
Commercial/Industrial
175.28
334.48
509.76
0.46
Major Community Facilities
1.82
0.38
2.20
0.00
Streets, Sidewalks, Medians
1 175.00
N/A
1 175.00
0.16
SOI Total
1 11,828.751
3,586.981
15,415.741
13.76
Table A-18
La Quinta General Plan
Proposed Water Demands for Planning Area
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
14,264.19
4,007.68
18,271.88
16.31
Medium/High Density Residential
368.97
529.79
898.76
0.80
Commercial/Industrial
360.13
687.27
1,047.40
0.94
Major Community Facilities
182.71
38.02
220.74
0.20
Open Space - Natural
N/A
N/A
N/A
N/A
Open Space- Recreation
1,216.29
N/A
1,216.29
1.09
Streets, Sidewalks, Medians
315.93
N/A
315.93
0.28
City Limits Total
1 16,708.231
5,262.76
21,970.99
19.61
F_dE11
Scenario B
Table A-19
La Quinta General Plan
Build Out Water Demands for City Limits
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
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/
N/A
Open Space- Recreation
17,681.77
N/A
17,681.77
15.79
Streets, Sidewalks, Medians
922.39
N/Al
922.39
0.82
City Limits Total
1 30,374.251
7,408.471
37,782.72
33.73
Table A-20
La Quinta General Plan
Build Out Water Demands for Sphere of Influence
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
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/Industrial
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
SOI Limits Total
1 12,883.571
3,800.581
16,684.151
14.89
Table A-21
La Quinta General Plan
Build Out Water Demands for Planning Area
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
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
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
11246.56
N/Al
1,246.56
1.11
Planning Area Total
43,257.821
11,209.051
54,466.87
48.62
A-15
APPENDIX A
SCENARIO A: Business As Usual
Water Demand Projections for the
La Quinta General Plan
Prepared in Support of the
La Quinta General Plan
Water Supply Assessment
Prepared by
r 7
L -A Terra Nova Planning & Research, Inc.®
42635 Melanie Place, Suite #101
Palm Desert, CA 92211
June 22, 2011
Scenario A
La Quinta General Plan Update - Landscape Water Demand Existing Development City Limits
Table A-1
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre'
Total Demand
(AF/Y)
Low Density Residential (MDL)
4,171.20
15%
625.68
3.108
1,944.79
Low Density Residential (HWD)
4,171.20
25%
1,042.80
4.352
4,537.85
Medium/High Density Residential (MDL)
1,284.00
15%
192.60
3.108
598.66
Medium/High Density Residential (HWD)
1,284.00
10%
128.40
4.352
558.75
Subtotal
5,455.20
1,989.48
7,640.05
Commercial (MDL)
668.90
15%
100.34
3.108
311.87
Major Community Facilities (MDL)
238.00
5%
11.90
3.108
36.99
Major Community Facilities (HWD)
238.00
25%
59.50
4.352
258.92
Open Space- Natural
2,242.70
0%
N/A
N/A
N/A
Open Space- Recreation (MDL)
4,272.00
5%
213.60
3.108
663.93
Open Space- Recreation (HWD)
4,272.00
85%
3,631.20
4.352
15,801.55
Streets, Sidewalks, Medians (MDL)
1,676.10
15%
251.42
3.108
781.47
Subtotal
9,097.70
49267.95
17,854.73
Total Landscaping Demand
1 14,552.90
1 6457.43
1 25,494.78
Source: Total acreages are from developed lands under the General Plan Update Land Use Tables, prepared December 27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning Area. In order
to capture a reasonable water allowance it was assumed that Zone 3A is representative of the MWA average for all Zones.
Moderate Desert Landscaping (MDL) Zone 3A 3.108
Turf and High Water Demand (HWD) Zone 3A 4.352
ac-ft/ac/yr 1,353.97 CCF
ac-ft/ac/yr 1,895.56 CCF
A-16
Scenario A
La Quinta General Plan Update - Landscape Water Demand Existing Development Sphere of Influence
Table A-2
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AVY)
per Acre'
Total Demand
(AF/Y)
Low Density Residential (MDL)
551.50
15%
82.73
3.108
257.13
Low Density Residential (HWD)
551.50
25%
137.88
4.352
599.98
Medium/High Density Residential (MDL)
0.20
15%
0.03
3.108
0.09
Medium/High Density Residential (HWD)
0.20
10%
0.02
4.352
0.09
Subtotal
551.70
220.65
857.29
Commercial (MDL)
28.60
15%
4.29
3.108
13.33
Major Community Facilities (MDL)
28.17
5%
1.41
3.108
4.38
Major Community Facilities (HWD)
28.17
25%
7.04
4.352
30.65
Streets, Sidewalks, Medians (MDL)
319.93
15%
47.99
3.108
149.17
Subtotal
376.27
60.73
197.53
Total Landscaping Demand
927.97
281.38
1,054.82
Source: Total acreages are from developed lands under the General Plan Update Land Use Tables, prepared December 27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning Area. In order
to capture a reasonable water allowance it was assumed that Zone 3A is representative of the MWA average for all Zones.
Moderate Desert Landscaping (MDL)
Zone 3A 3.108 ac-ft/ac/yr
Turf and High Water Demand (HWD) Zone 3A 4.352 ac-ft/ac/yr
La Quinta General Plan Update - Landscape Water Demand Overall Planning Area
1,353.97 CCF
1,895.56 CCF
Table A-3
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre
Total Demand
(AF/Y)
City Limits
14,552.90
-
6,257.43
-
25,494.78
Sphere of Influence
927.97
-
281.38
-
1,054.82
Planning Area Total
15,480.87
-
6,538.81
-
26,549.59
A-17
Scenario A
La Quinta General Plan - Potable Water Demand for City Limits
Table A-4
Potable Water Demand for
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day
Total
AF/Year
Low Density Residential
2.53
20,834
69.3
4,091.66
Medium/High Density Residential
2.53
2,6551
69.3
521.42
Subtotal
23,489
4,613.09
Non -Residential Land Use
Square
Feet
Gallons Per Day
Total
AF/Year
Commercial
6,410,202
51.22
1,007.61
Major Community Facilities
2,280,802
16
111.99
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A
N/A
N/A
Streets, Sidewalks, Medians
N/A
N/A
N/A
Subtotal
6,410,202
51.22
1,119.60
Potable Water Demand Total
5,732.7
La Quinta General Plan - Potable Water Demand for Sphere of Influence
Table A-5
Potable Water Demand for
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day
Total
AF/Year
Low Density Residential
2.53
801
69.3
157.31
Medium/High Density Residential
2.53
69.3
-
Subtotal
801
157.31
Non -Residential Land Use
Square
Feet
Gallons Per Day
Total
AF/Year
Commercial
273,760
51.22
43.03
Major Community Facilities
269,959
16
13.26
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A
N/A
N/A
Streets, Sidewalks, Medians
N/A
N/A
N/A
Subtotal
273,760
51.22
56.29
Potable Water Demand Total
213.6
La Quinta General Plan Update - Potable Water Demand Overall Planning Area
Table A-6
Potable Water Demand
Demand
(AF/Y)
City Limits
5,732.69
Sphere of Influence
213.60
Planning Area Total
5,946.28
F.M.,
Scenario A
Table A-7
La Quinta General Plan
Existing Water Demands for City Limits
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
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
1.50
Commercial
311.87
1,007.61
1,319.48
1.18
Major Community Facilities
295.91
111.99
407.90
0.36
Open Space - Natural
N/A
N/A
-
-
Open Space- Recreation
16,465.48
N/A
16,465.48
14.70
Streets, Sidewalks, Medians
781.47
N/A
781.47
0.70
City Limits Total
25,494.78
5,732.69
31,227.46
27.88
Table A-8
La Quinta General Plan
Existing Water Demands for Sphere of Influence
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
857.11
157.31
1,014.42
0.91
Medium/High Density Residential
0.18
-
0.18
0.00
Commercial
17.71
43.03
60.74
0.05
Major Community Facilities
30.65
13.26
43.90
0.04
Streets, Sidewalks, Medians
1 149.17
N/A
1 149.17
0.13
City Limits Total
1 1,054.821
213.601
1,268.421
1.13
Table A-9
La Quinta General Plan
Existing Water Demands for Planning Area
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
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
1.50
Commercial
329.58
1,050.64
1,380.22
1.23
Major Community Facilities
326.56
125.25
451.81
0.40
Open Space - Natural
N/A
N/
-
-
Open Space- Recreation
16,465.48
N/A
16,465.48
14.70
Streets, Sidewalks, Medians
1 930.64
N/A
930.641
0.83
City Limits Total
1 26,549.591
5,946.28
32,495.881
29.01
Scenario A
La Quinta General Plan Update - Landscape Water Demand Proposed Development City Limits
Table A-10
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre2
Total Demand
(AF/Y)
Low Density Residential (MDL)
1,675.90
15%
251.39
3.647
916.82
Low Density Residential (HWD)
1,675.90
25%
418.98
5.106
2,139.24
Medium/High Residential (MDL)
350.30
15%
52.55
3.647
191.63
Medium/High Residential (HWD)
350.30
10%
35.03
5.106
178.86
Subtotal
2,026.20
757.94
3,426.55
Commercial (MDL)
337.90
15%
50.69
3.647
184.85
Major Community Facilities (MDL)
160.00
5%
8.00
3.647
29.18
Major Community Facilities (HWD)
160.00
25%
40.00
5.106
204.24
Open Space- Natural
5,233.30
0%
N/A
N/
N/
Open Space- Recreation (MDL)
287.50
5%
14.38
3.647
52.43
Open Space- Recreation (HWD)
287.50
85%
244.38
5.106
1,247.75
Streets, Sidewalks, Medians (MDL)
257.60
15%
38.64
3.647
140.92
Subtotal
6,276.30
396.08
1,859.36
Total Landscaping Demand
1 8,302.50
1 1,154.01
1 5,285.91
Source: Acreages are from the vacant land proposed for development under the General Plan Update Land Use Tables, prepared December
27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning
Area. In order to capture a reasonable water allowance it was assumed that Zone 4 is representative of the MWA average since most of the
new developement proposed in the General Plan Update will occur within this Zone.
Moderate Desert Landscaping (MDL) Zone 4 3.647 ac-ft/ac/yr 1,588.66 CCF
Turf and High Water Demand (HWD) Zone 4 5.106 ac-ft/ac/yr 2,224.12 CCF
A-20
Scenario A
La Quinta General Plan Update - Landscape Water Demand Proposed Development Sphere of Influence
Table A-11
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre
Total Demand
(AF/Y)
Low Density Residential (MDL)
6,826.60
15%
1,023.99
3.647
3,734.55
Low Density Residential (HWD)
6,826.60
25%
1,706.65
5.106
8,713.95
Medium/High Residential (MDL)
24.40
15%
3.66
3.647
13.35
Medium/High Residential (HWD)
24.40
10%
2.44
5.106
12.46
Subtotal
6,851.00
2,736.74
12,474.31
Commercial (MDL)
320.40
15%
48.06
3.647
175.28
Major Community Facilities (MDL)
1.61
5%
0.08
3.647
0.29
Major Community Facilities (HWD)
1.61
25%
0.40
5.106
2.06
Streets, Sidewalks, Medians (MDL)
319.90
15%
47.99
3.6471
175.00
Subtotal
322.011
1 96.531
1 352.63
Total Landscaping Demand
1 7,173.011
1 2,833.27
1 12,826.94
Source: Acreages are from the vacant land proposed for development under the General Plan Update Land Use Tables, prepared December
27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning
Area. In order to capture a reasonable water allowance it was assumed that Zone 4 is representative of the MWA average since most of the
new developement proposed in the General Plan Update will occur within this Zone.
Moderate Desert Landscaping (MDL) Zone 4 3.647 ac-ft/ac/yr 1,588.66 CCF
Turf and High Water Demand (HWD) Zone 4 5.106 ac-ft/ac/yr 2,224.12 CCF
La Quinta General Plan Update - Landscape Water Demand Overall Planning Area
Table A-12
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre
Total Demand
(AF/Y)
City Limits
8,302.50
14%
1,154.01
4.58
5,285.91
Sphere of Influence
1 7,173.01
1 39%
1 2,833.27
1 4.53
1 12,826.94
Planning Area Total
1 15,475.51
1 53%
1 3,987.28
1 9.11
1 18,112.85
A-21
Scenario A
La Quinta General Plan - Potable Water Demand for City Limits
Table A-13
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day'
Total
AF/Year
Low Density Residential
2.53
5,028
69.30
987.47
Medium/High Density Residential
2.53
3,153
69.30
619.23
Subtotal
8,181
1
1,606.69
Non -Residential Land Use
Sq.Ft.
Gallons Per Day'
AF/Year
Commercial
3,238,163
51.22
509.00
Major Community Facilities
1,533,312
16.0
75.29
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A
N/A
N/A
Streets, Sidewalks, Medians
N/A
N/A
N/A
Subtotal
3,238,163
51.22
584.29
Potable Water Demand Total
2,191.0
1 Water use factors are from the American Water Works Association Research Foundation Commercial and
Industrial and Residential End Uses of Water, 2000. Assumes water efficient appliances and design and a 20% per
capita reduction.
La Quinta General Plan - Potable Water Demand for Sphere of Influence
Table A-14
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day'
Total
AF/Year
Low Density Residential
2.53
20,480
69.30
4,022.14
Medium/High Density Residential
2.53
219
69.30
43.01
Subtotal
20,699
4,065.15
Non -Residential Land Use
Sq.Ft.
Gallons Per Day'
AF/Year
Commercial
3,070,205
51.2
482.60
Major Community Facilities
15,429
16.0
0.76
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A
N/A
N/A
Streets, Sidewalks, Medians
N/A
N/A
N/A
Subtotal
483.36
Potable Water Demand Total
4,548.5
1 Water use factors are from the American Water Works Association Research Foundation Commercial and
Industrial and Residential End Uses of Water, 2000. Assumes water efficient appliances and design and a 20% per
capita reduction.
La Quinta General Plan Update - Potable Water Demand Overall Planning Area
Table A-15: Potable Water Demand
Demand (AF/Y)
City Limits
2,190.98
Sphere of Influence
4,548.51
Planning Area Total
6,739.49
A-22
Scenario A
Table A-16
La Quinta General Plan
Proposed Water Demands for City Limits
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
3,056.05
987.47
4,043.52
3.61
Medium/High Density Residential
370.49
619.23
989.72
0.88
Commercial
184.85
509.00
693.85
0.62
Major Community Facilities
204.24
75.29
279.52
0.25
Open Space - Natural
N/A
N/A
N/A
N/A
Open Space- Recreation
1,300.18
N/A
1,300.18
1.16
Streets, Sidewalks, Medians
140.92
N/A
140.92
0.13
City Limits Total
5,256.73
21190.98
7,447.72
6.65
Table A-17
La Quinta General Plan
Proposed Water Demands for Sphere of Influence
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
12,448.51
4,022.14
16,470.64
14.70
Medium/High Density Residential
25.81
43.01
68.82
0.06
Commercial/Industrial
175.28
482.60
657.88
0.59
Major Community Facilities
2.06
0.76
2.81
0.00
Streets, Sidewalks, Medians
1 175.00
N/A
1 175.001
0.16
SOI Total
1 12,826.651
4,548.511
17,375.151
15.51
Table A-18
La Quinta General Plan
Proposed Water Demands for Planning Area
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
15,504.56
5,009.60
20,514.16
18.31
Medium/High Density Residential
396.30
662.24
1,058.54
0.95
Commercial/Industrial
360.13
991.60
1,351.73
1.21
Major Community Facilities
206.29
76.05
282.34
0.25
Open Space - Natural
N/A
N/A
N/A
N/A
Open Space- Recreation
1,300.18
N/A
1,300.18
1.16
Streets, Sidewalks, Medians
1 315.93
1 N/Al
315.931
0.28
City Limits Total
1 18,083.381
6,739.491
24,822.87
22.16
A-23
Scenario A
Table A-19
La Quinta General Plan
Build Out Water Demands for City Limits
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
9,538.70
5,079.13
14,617.83
13.05
Medium/High Density Residential
1,527.90
1,140.65
2,668.55
2.38
Commercial
496.72
1,516.61
2,013.33
1.80
Major Community Facilities
500.14
187.28
687.43
0.61
Open Space - Natural
N/A
N/A
N/
N/A
Open Space- Recreation
17,765.65
N/A
17,765.65
15.86
Streets, Sidewalks, Medians
922.39
N/A
922.39
0.82
City Limits Total
30,751.511
7,923.671
38,675.18
34.53
Table A-20
La Quinta General Plan
Build Out Water Demands for Sphere of Influence
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
13,305.62
4,179.45
17,485.07
15.61
Medium/High Density Residential
25.99
43.01
69.00
0.06
Commercial/Industrial
192.99
525.63
718.62
0.64
Major Community Facilities
32.70
14.01
46.72
0.04
Streets, Sidewalks, Medians
324.17
N/A
324.171
0.29
SOI Limits Total
1 13,881.471
4,762.101
18,643.571
16.64
Table A-21
La Quinta General Plan
Build Out Water Demands for Planning Area
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
22,844.32
9,258.58
32,102.89
28.66
Medium/High Density Residential
1,553.88
1,183.66
2,737.55
2.44
Commercial
689.71
2,042.24
2,731.95
2.44
Major Community Facilities
532.85
201.29
734.14
0.66
Open Space - Natural
N/A
N/A
-
-
Open Space- Recreation
17,765.65
N/A
17,765.65
15.86
Streets, Sidewalks, Medians
11246.56
N/Al
1,246.56
1.11
Planning Area Total
44,632.971
12,685.771
57,318.75
51.17
A-24
APPENDIX C
SCENARIO C: Retrofit Existing + New Development Efficiency
Water Demand Projections for the
La Quinta General Plan
Prepared in Support of the
La Quinta General Plan
Water Supply Assessment
Prepared by
r 7
L -A Terra Nova Planning & Research, Inc.®
42635 Melanie Place, Suite #101
Palm Desert, CA 92211
June 22, 2011
Scenario C
La Quinta General Plan Update - Landscape Water Demand Existing Development City Limits
Table A-1
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre'
Total Demand
(AF/Y)
Low Density Residential (MDL)
4,171.20
25%
1,042.80
3.108
3,241.32
Low Density Residential (HWD)
4,171.20
15%
625.68
4.352
2,722.71
Medium/High Density Residential (MDL)
1,284.00
20%
256.80
3.108
798.21
Medium/High Density Residential (HWD)
1,284.00
5%
64.20
4.352
279.37
Subtotal
5,455.20
1,989.48
7,041.62
Commercial (MDL)
668.90
15%
100.34
3.108
311.87
Major Community Facilities (MDL)
238.00
10%
23.80
3.108
73.98
Major Community Facilities (HWD)
238.00
15%
35.70
4.352
155.35
Open Space- Natural
2,242.70
0%
N/A
N/A
N/A
Open Space- Recreation (MDL)
4,272.00
25%
1,068.00
3.108
3,319.65
Open Space- Recreation (HWD)
4,272.00
65%
2,776.80
4.352
12,083.53
Streets, Sidewalks, Medians (MDL)
1,676.10
15%
251.42
3.108
781.47
Subtotal
9,097.70
49256.05
16,725.86
Total Landscaping Demand
1 14,552.90
1 6,245.53
1 23,767.47
Source: Total acreages are from developed lands under the General Plan Update Land Use Tables, prepared December 27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning Area. In order
to capture a reasonable water allowance it was assumed that Zone 3A is representative of the MWA average for all Zones.
Moderate Desert Landscaping (MDL)
Turf and High Water Demand (HWD)
Zone 3A 3.108
Zone 3A 4.352
ac-ft/ac/yr 1,353.97 CCF
ac-ft/ac/yr 1,895.56 CCF
A-25
Scenario C
La Quinta General Plan Update - Landscape Water Demand Existing Development Sphere of Influence
Table A-2
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AFIY)
per Acre'
Total Demand
(AF/Y)
Low Density Residential (MDL)
551.50
25%
137.88
3.108
428.56
Low Density Residential (HWD)
551.50
15%
82.73
4.352
359.99
Medium/High Density Residential (MDL)
0.20
20%
0.04
3.108
0.12
Medium/High Density Residential (HWD)
0.20
5%
0.01
4.352
0.04
Subtotal
551.70
220.65
788.71
Commercial (MDL)
28.60
15%
4.29
3.108
13.33
Major Community Facilities (MDL)
28.17
10%
2.82
3.108
8.76
Major Community Facilities (HWD)
28.17
15%
4.23
4.352
18.39
Streets, Sidewalks, Medians (MDL)
319.93
15%
47.99
3.108
149.17
Subtotal
376.27
59.32
189.64
Total Landscaping Demand
1 927.971
1 279.971
1 978.35
Source: Total acreages are from developed lands under the General Plan Update Land Use Tables, prepared December 27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning Area. In order
to capture a reasonable water allowance it was assumed that Zone 3A is representative of the MWA average for all Zones.
Moderate Desert Landscaping (MDL)
Zone 3A 3.108 ac-ft/ac/yr
Turf and High Water Demand (HWD) Zone 3A 4.352 ac-ft/ac/yr
La Quinta General Plan Update - Landscape Water Demand Overall Planning Area
1,353.97 CCF
1,895.56 CCF
Table A-3
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre
Total Demand
(AF/Y)
City Limits
14,552.90
-
6,245.53
-
23,767.47
Sphere of Influence
927.97
-
279.97
-
978.35
Planning Area Total
15,480.87
-
6,525.50
-
24,745.83
A-26
Scenario C
La Quinta General Plan - Potable Water Demand for City Limits
Table A-4
Potable Water Demand for
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day
Total
AF/Year
Low Density Residential
2.53
20,834
55.4
3,273.33
Medium/High Density Residential
2.53
2,6551
55.4
417.14
Subtotal
23,489
3,690.47
Non -Residential Land Use
Square
Feet
Gallons Per Day
Total
AF/Year
Commercial
6,410,202
35.5
698.36
Major Community Facilities
2,280,802
8
56.00
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A
N/A
N/A
Streets, Sidewalks, Medians
N/A
N/A
N/A
Subtotal
6,410,202
35.5
754.36
Potable Water Demand Total
4,444.8
La Quinta General Plan - Potable Water Demand for Sphere of Influence
Table A-5
Potable Water Demand for
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day
Total
AF/Year
Low Density Residential
2.53
801
55.4
125.76
Medium/High Density Residential
2.53
55.4
-
Subtotal
801
125.76
Non -Residential Land Use
Square
Feet
Gallons Per Day
Total
AF/Year
Commercial
273,760
35.5
29.82
Major Community Facilities
269,959
8
6.63
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A
N/A
N/A
Streets, Sidewalks, Medians
N/A
N/A
N/A
Subtotal
273,760
35.5
36.45
Potable Water Demand Total
162.2
La Quinta General Plan Update - Potable Water Demand Overall Planning Area
Table A-6
Potable Water Demand
Demand
(AF/Y)
City Limits
4,444.83
Sphere of Influence
162.21
Planning Area Total
4,607.04
A-27
Scenario C
Table A-7
La Quinta General Plan
Existing Water Demands for City Limits
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
5,964.04
3,273.33
9,237.36
8.25
Medium/High Density Residential
1,077.58
417.14
1,494.72
1.33
Commercial
311.87
698.36
1,010.23
0.90
Major Community Facilities
229.33
56.00
285.33
0.25
Open Space - Natural
N/A
N/A
-
-
Open Space- Recreation
15,403.19
N/A
15,403.19
13.75
Streets, Sidewalks, Medians
781.47
N/A
781.47
0.70
City Limits Total
23,767.47
4,444.83
289212.30
25.19
Table A-8
La Quinta General Plan
Existing Water Demands for Sphere of Influence
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
788.54
125.76
914.30
0.82
Medium/High Density Residential
0.17
-
0.17
0.00
Commercial
22.09
29.82
51.91
0.05
Major Community Facilities
18.39
6.63
25.02
0.02
Streets, Sidewalks, Medians
1 149.17
N/A
1 149.17
0.13
City Limits Total
1 978.351
162.211
1,140.561
1.02
Table A-9
La Quinta General Plan
Existing Water Demands for Planning Area
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
6,752.58
3,399.09
10,151.66
9.06
Medium/High Density Residential
1,077.75
417.14
1,494.89
1.33
Commercial
333.96
728.19
1,062.15
0.95
Major Community Facilities
247.72
62.62
310.34
0.28
Open Space - Natural
N/A
N/A
-
-
Open Space- Recreation
15,403.19
N/A
15,403.19
13.75
Streets, Sidewalks, Medians
1 930.64
N/A
930.64
0.83
City Limits Total
1 24,745.831
4,607.04
29,352.87
26.20
A-28
Scenario C
La Quinta General Plan Update - Landscape Water Demand Proposed Development City Limits
Table A-10
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre
Total Demand
(AF/Y)
Low Density Residential (MDL)
1,675.90
25%
418.98
3.647
1,528.03
Low Density Residential (HWD)
1,675.90
15%
251.39
5.106
1,283.54
Medium/High Residential (MDL)
350.30
20%
70.06
3.647
255.51
Medium/High Residential (HWD)
350.30
5%
17.52
5.106
89.43
Subtotal
2,026.20
757.94
3,156.51
Commercial (MDL)
337.90
15%
50.69
3.647
184.85
Major Community Facilities (MDL)
160.00
10%
16.00
3.647
58.35
Major Community Facilities (HWD)
160.00
15%
24.00
5.106
122.54
Open Space- Natural
5,233.30
0%
N/A
N/A
N/A
Open Space- Recreation (MDL)
287.50
25%
71.88
3.647
262.13
Open Space- Recreation (HWD)
287.50
65%
186.88
5.106
954.16
Streets, Sidewalks, Medians (MDL)
1 257.60
15%
1 38.64
3.647
140.92
Subtotal
1 6,276.30
1 388.08
1,722.96
Total Landscaping Demand
1 8,302.50
1 1,146.01
1 4,879.47
Source: Acreages are from the vacant land proposed for development under the General Plan Update Land Use Tables, prepared December
27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning
Area. In order to capture a reasonable water allowance it was assumed that Zone 4 is representative of the MWA average since most of the
new developement proposed in the General Plan Update will occur within this Zone.
Moderate Desert Landscaping (MDL) Zone 4 3.647 ac-ft/ac/yr 1,588.66 CCF
Turf and High Water Demand (HWD) Zone 4 5.106 ac-ft/ac/yr 2,224.12 CCF
A-29
Scenario C
La Quinta General Plan Update - Landscape Water Demand Proposed Development Sphere of Influence
Table A-11
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AFC
per Acre
Total Demand
(AF/Y)
Low Density Residential (MDL)
6,826.60
25%
1,706.65
3.647
6,224.25
Low Density Residential (HWD)
6,826.60
15%
1,023.99
5.106
5,228.37
Medium/High Residential (MDL)
24.40
20%
4.88
3.647
17.80
Medium/High Residential (HWD)
24.40
5%
1.22
5.106
6.23
Subtotal
6,851.00
2,736.74
11,476.65
Commercial (MDL)
320.40
15%
48.06
3.647
175.28
Major Community Facilities (MDL)
1.61
10%
0.16
3.647
0.59
Major Community Facilities (HWD)
1.61
15%
0.24
5.1061
1.23
Streets, Sidewalks, Medians (MDL)
1 319.90
15%
1 47.99
3.6471
175.00
Subtotal
I 322.01
196.45
1352.10
Total Landscaping Demand
1 7,173.011
1 2,833.191
1 11,828.75
Source: Acreages are from the vacant land proposed for development under the General Plan Update Land Use Tables, prepared December
27, 2010.
1 Maximum Water Allowance (MWA) per CVWD's Landscape Ordinance No 1302.1. La Quinta contains all ETo Zones within its Planning
Area. In order to capture a reasonable water allowance it was assumed that Zone 4 is representative of the MWA average since most of the
new developement proposed in the General Plan Update will occur within this Zone.
Moderate Desert Landscaping (MDL) Zone 4 3.647 ac-ft/ac/yr 1,588.66 CCF
Turf and High Water Demand (HWD) Zone 4 5.106 ac-ft/ac/yr 2,224.12 CCF
La Quinta General Plan Update - Landscape Water Demand Overall Planning Area
Table A-12
Landscape Water Demand
Total Acres
Landscaped
Area
Landscaped
Acres
MWA (AF/Y)
per Acre2
Total Demand
(AF/Y)
City Limits
8,302.50
14%
1,146.01
4.26
4,879.47
Sphere of Influence
7,173.01
1 39%
1 2,833.19
1 4.18
1 11,828.75
Planning Area Total
15,475.51
53%
3,979.20
8.43
16,708.23
A-30
Scenario C
La Quinta General Plan - Potable Water Demand for City Limits
Table A-13
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day'
Total
AF/Year
Low Density Residential
2.53
5,028
55.44
789.97
Medium/High Density Residential
2.53
3,153
55.44
495.38
Subtotal
8,1811
1,285.36
Non -Residential Land Use
Sq.Ft.
Gallons Per Day'
AF/Year
Commercial
3,238,163
35.5
352.78
Major Community Facilities
1,533,312
8.0
37.64
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A_N/A
N/A
Streets, Sidewalks, Medians
I N/A
N/A
N/A
Subtotal
1 3,238,163
35.5
390.43
Potable Water Demand Total
1
1,675.8
1 Water use factors are from the American Water Works Association Research Foundation Commercial and
Industrial and Residential End Uses of Water, 2000. Assumes water efficient appliances and design and a 20% per
capita reduction.
La Quinta General Plan - Potable Water Demand for Sphere of Influence
Table A-14
Land Uses
Population
/Unit
Number of
Units
Gallons Per
Day'
Total
AF/Year
Low Density Residential
2.53
20,480
55.44
3,217.71
Medium/High Density Residential
2.53
219
55.44
34.41
Subtotal
20,699
1
3,252.12
Non -Residential Land Use
Sq.Ft.
Gallons Per Day'
AF/Year
Commercial
3,070,205
35.5
334.48
Major Community Facilities
15,429
8.0
0.38
Open Space - Natural
N/A
N/A
N/A
Open Space- Recreation
N/A
N/A
N/A
Streets, Sidewalks, Medians
N/A
N/A
N/A
Subtotal
334.86
Potable Water Demand Total
3,587.0
1 Water use factors are from the American Water Works Association Research Foundation Commercial and
Industrial and Residential End Uses of Water, 2000. Assumes water efficient appliances and design and a 20% per
capita reduction.
La Quinta General Plan Update - Potable Water Demand Overall Planning Area
Table A-15: Potable Water Demand
Demand (AF/Y)
City Limits
1,675.78
Sphere of Influence
3,586.98
Planning Area Total
5,262.76
A-31
Scenario C
Table A-16
La Quinta General Plan
Proposed Water Demands for City Limits
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
2,811.57
789.97
3,601.54
3.22
Medium/High Density Residential
344.94
495.38
840.33
0.75
Commercial
184.85
352.78
537.63
0.48
Major Community Facilities
180.89
37.64
218.54
0.20
Open Space - Natural
N/A
N/A
N/A
N/A
Open Space- Recreation
1,216.29
N/A
1,216.29
1.09
Streets, Sidewalks, Medians
140.92
N/A
140.92
0.13
City Limits Total
4,879.47
1,675.78
6,555.26
5.85
Table A-17
La Quinta General Plan
Proposed Water Demands for Sphere of Influence
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
11,452.63
3,217.71
14,670.34
13.10
Medium/High Density Residential
24.03
34.41
58.43
0.05
Commercial/Industrial
175.28
334.48
509.76
0.46
Major Community Facilities
1.82
0.38
2.20
0.00
Streets, Sidewalks, Medians
1 175.00
N/A
1 175.00
0.16
SOI Total
1 11,828.751
3,586.981
15,415.741
13.76
Table A-18
La Quinta General Plan
Proposed Water Demands for Planning Area
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
14,264.19
4,007.68
18,271.88
16.31
Medium/High Density Residential
368.97
529.79
898.76
0.80
Commercial/Industrial
360.13
687.27
1,047.40
0.94
Major Community Facilities
182.71
38.02
220.74
0.20
Open Space - Natural
N/A
N/A
N/A
N/A
Open Space- Recreation
1,216.29
N/A
1,216.29
1.09
Streets, Sidewalks, Medians
315.93
N/A
315.93
0.28
City Limits Total
1 16,708.231
5,262.76
21,970.99
19.61
A-32
Scenario C
Table A-19
La Quinta General Plan
Build Out Water Demands for City Limits
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
8,775.60
4,063.30
12,838.91
11.46
Medium/High Density Residential
1,422.52
912.52
2,335.05
2.08
Commercial
496.72
1,051.14
1,547.87
1.38
Major Community Facilities
410.22
93.64
503.86
0.45
Open Space - Natural
N/A
N/A
N/
N/A
Open Space- Recreation
16,619.48
N/A
16,619.48
14.84
Streets, Sidewalks, Medians
1 922.39
N/A
922.39
0.82
City Limits Total
1 28,646.951
6,120.611
34,767.56
31.04
Table A-20
La Quinta General Plan
Build Out Water Demands for Sphere of Influence
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
12,241.17
3,343.47
15,584.64
13.91
Medium/High Density Residential
24.19
34.41
58.60
0.05
Commercial/Industrial
197.37
364.31
561.68
0.50
Major Community Facilities
20.21
7.01
27.22
0.02
Streets, Sidewalks, Medians
324.17
N/A
324.17
0.29
SOI Limits Total
1 12,807.111
3,749.191
16,556.301
14.78
Table A-21
La Quinta General Plan
Build Out Water Demands for Planning Area
Total Annual
Landscaping
Potable
Demand
Daily Demand
GP Land Use Designations
(ac-ft/yr)
(ac-ft/yr)
(ac-ft/yr)
(mgd)
Low Density Residential
21,016.77
7,406.77
28,423.54
25.37
Medium/High Density Residential
1,446.72
946.93
2,393.65
2.14
Commercial
694.09
1,415.45
2,109.54
1.88
Major Community Facilities
430.43
100.65
531.08
0.47
Open Space - Natural
N/A
N/A
-
-
Open Space- Recreation
16,619.48
N/A
16,619.48
14.84
Streets, Sidewalks, Medians
11246.56
N/Al
1,246.561
1.11
Planning Area Total
1 41,454.061
9,869.801
51,323.86
45.82
A-33
APPENDIX B
Water Resources Litigation and Other Actions: Water Reliability
La Quinta General Plan
r
Prepared in Support of the
La Quinta General Plan
Water Supply Assessment
Prepared by
Terra Nova Planning & Research, Inc.®
42635 Melanie Place, Suite #101
Palm Desert, CA 92211
June 22, 2011
Water Supply Study: Appendix B/Terra Nova
La Quinta General Plan Update/ June 21, 2011
Water Resource Litigation and Other Actions
The following is a summary of pertinent legal actions and other actions that may impact the
reliability of water resources from State Water Project.
The availability and reliability of State Water Project (SWP) water from the Sacramento -San
Joaquin Delta (Delta) have been affected by numerous legal and regulatory actions over the last
several years. These matters have resulted in changes to Delta pumping frequency and duration.
Although various legal, regulatory and legislative issues surrounding SWP deliveries have yet to
be resolved and could result in further restrictions to SWP operations, or the relaxation of such
restrictions, the latest DWR SWP Delivery Reliability Report released August 2010, sets forth
delivery projections for short term and long term scenarios including normal, single, multiple
dry -year periods.
Watershed Enforcers v. California Department of Water Resources, et al
In this case, the Department of Water Resources (DWR) was alleged of operating SWP facilities
without "take authorization" as defined under the California Endangered Species Act. The case
was stayed pending appeal. Due to the stay, the judgment is currently not in effect and DWR has
not been required to cease operations of the Banks pumping plant facilities. Moreover, DWR has
taken the position that it has incidental take coverage to operate the SWP pursuant to the state
and federal Endangered Species Acts. The case remains active for purposes of addressing a
discrete legal issue raised by a third parry regarding whether or not DWR is the type of entity
that is subject to the take prohibitions of the California Endangered Species Act. The Watershed
Enforcers case is not expected to result in additional reductions to SWP supplies. Furthermore,
the effects of SWP operations on protected fish species in the Delta are being addressed in the
separate cases discussed below.
Delta Smelt and Related Litigation Matters
The delta smelt is a small fish with a typical adult size of 2-3 inches that is found only in the
Sacramento -San Joaquin Delta Estuary (Delta). The delta smelt was listed as a threatened species
by the U.S. Fish and Wildlife Service (FWS) and by CDFG in 1993. The delta smelt population
is affected by many factors such as toxic discharges, invasive and/or predatory species, in -Delta
diversions, ocean conditions, Delta exports, and various other contributors.
The US. Fish and Wildlife Services (FWS) released a revised Biological Opinion (BiOp), which
addressed the impacts of the SWP and the Central Valley Project (CVP) on delta smelt in 2008.
Subsequently, several lawsuits challenging the 2008 BiOp were filed challenging its validity. In
December 2010, five lawsuits collectively referred to as the Delta Smelt Cases were consolidated
and a decision was issued. The court mandated that the FWS revise the BiOp. The new BiOp is
scheduled for release on June 30th, 2011.
On February 24, 2011 a settlement was reached between FWS, environmental groups, and urban
water users that relaxes pumping restrictions in the Delta as an Interim Remedy through June 30,
I
Water Supply Study: Appendix B/Terra Nova
La Quinta General Plan Update/ June 21, 2011
2011. The Interim Remedy provides for a 14-day running average of Old and Middle River
(OMR) flows between -1,250 cfs and -6,000 cfs, and 5-day running average within 25% of the
14-day average, as adequate flows for protecting the delta smelt. The FWS will set and may
modify OMR flows within this range based upon best available science using real time data
concerning overall delta smelt distribution, turbidity, salvage, incidental take, temperature and
other relevant physical and biological factors. The Stipulation still places pumping restrictions
when delta smelt are located near pumping stations.1,2
The degree to which SWP deliveries may be reduced under the new BiOp for delta smelt remains
difficult to forecast, although DWR and other agencies have estimated potential delivery
reductions and are reflected in DWR's 2009 SWP Delivery Reliability Report.
Longfin Smelt: California Department of Fish and Game Incidental Take Permit and Related
Litigation Matters
On February 29, 2009, CDFG issued an Incidental Take Permit to DWR as the owner and
operator of the SWP. The Permit applies to the ongoing and long-term operation of the SWP's
facilities in the Delta, including Clifton Court Forebay, the John E. Skinner Fish Facility, the
Harvey O. Banks Pumping Plant and the North Bay Aqueduct, and authorizes DWR to
incidentally take longfin smelt in connection with its operation of the SWP, provided the terms
and conditions of the Permit are satisfied. The Permit imposes operating restrictions on the SWP
facilities that are based in large part on the restrictions imposed on the SWP by the new BiOp
issued by FWS for delta smelt (see above).
As with the BiOp for delta smelt, potential water supply restrictions under the Permit are
dependent on various factors that cannot be predicted with a high degree of certainty, including
hydrologic conditions in the Delta region, migratory and reproductive patterns of longfin smelt,
and other factors affecting longfin smelt abundance in the Delta. DWR has not indicated whether
reductions in SWP exports are likely to result from the Permit.
Due to a number of alleged deficiencies in the Permit, an organization of water agencies holding
contracts to receive SWP supplies from DWR has filed a complaint in Sacramento County
Superior Court challenging the Permit. (See, e.g., State Water Contractors v. California Dept. of
Fish and Game, et al., Sac. Sup. Ct. Case No. 34-2009-80000203.) That case has brought
CDFG's ability to enforce the Permit into question. In light of the foregoing factors, potential
reductions in SWP supplies resulting from CDFG's Incidental Take Permit for longfin smelt
remain speculative at this time.
Salmon/Anadromous Species: New National Marine Fisheries Service Biological Opinion and
Related Litigation Matters
"Temporary Settlement Reached in Delta Smelt Case", Association of California Water Agencies, February 25,
2011.
2 "Stipulation and Proposed Order for Interim Remedy through June 30, 2011", US District Court for the Eastern
District of California, February 25, 2011.
Water Supply Study: Appendix B/Terra Nova
La Quinta General Plan Update/ June 21, 2011
An additional factor that has the potential to affect the availability and reliability of SWP
supplies is the ongoing litigation and regulatory actions affecting protected anadromous fish
species in the Delta, including, winter and spring -run salmon, steelhead trout and green sturgeon.
A previous BiOp prepared by the National Marine Fisheries Service (NMFS) was invalidated in
2008,3 and on June 4, 2009, NMFS issued a new BiOp assessing the effects of CV? and SWP
operations on protected salmon, steelhead, green sturgeon, and resident killer whales.
Subsequently, legal challenges were filed against the revised BiOp including allegations that the
water supply restrictions set forth in the BiOp were established in violation of the Federal
Endangered Species Act, the Federal Administrative Procedures Act, and other laws.4 These
cases question whether the water supply restrictions set forth in the BiOp can be imposed against
the SWP.
DWR estimated that average year reductions have the potential to be reduced by 10 percent, in
addition to restrictions imposed under the FWS BiOp for delta smelt.5 As with the FWS BiOp for
delta smelt and the Incidental Take Permit for longfin smelt, potential water supply restrictions
under the NMFS BiOp are dependent on various factors that cannot be predicted with a high
degree of certainty, including hydrologic conditions in the Delta region, migratory and
reproductive patterns of protected anadromous fish, and other factors affecting the abundance of
those species in the Delta. For these reasons, the degree to which SWP deliveries may be reduced
under the new NMFS BiOp species remains difficult to forecast, although DWR and other
agencies have estimated potential delivery reductions, which are reflected in DWR's 2009 SWP
Delivery Reliability Report.
California Drought Conditions
In February of 2009, the Governor declared a state of emergency due to the statewide drought
conditions, evidenced by the extremely low reservoir storage and estimated snowpack water
content at that time. Soon thereafter, a Report to the Governor, prepared in March 2009, set forth
the statewide hydrologic conditions, which were somewhat improved from the time the
declaration was made. As of March 2009 the larger reservoirs had accumulated an overall
average of 82% of their historic average and the statewide snowpack was 87% of average.6
Recent improvements to California's water supply have reduced drought impacts seen
throughout the State in 2007-2009.
On March 16, 2011, DWR increased the 2011 SWP allocation to 70% of contractor's requests.
State Water Project allocation will increase from 2,503,276 acre-feet to 2,920,488 due to high
snowpack in 2011. The statewide snowpack water content is 129% of average as of March 2011.
3 Pacific Coast Federation of Fishermen's Associations, et al. v. Gutierrez, et al., Case No. 1:06-CV-00245-
OWW-GSA).
4 See, e. San Luis & Delta Mendota Water Authorit
y, ty, et al. v. Locke, et al., Case No. 1:09-CV-01053-OWW-
DLB; Stockton East Water District v. United States National Oceanic and Atmospheric Administration, et al.,
Case No. 1:09-CV-01090-OWW-DLB; State Water Contractors v. Locke, Case No. 1:09-CV-01378 OWW
(E.D. Cal); Kern County Water Agency v. Locke, Case No. 1:09-CV-01520-OWW (E.D. Cal); Oakdale
Irrigation District v. U. S. Dept. of Commerce, Case No. 2:09-CV-02452 JAM (E.D. Cal); The Metropolitan
Water District of Southern California v. NMFS, et al., Case No. 1:09-CV-01625 SMS (E.D. Cal).
5 DWR News Release: DWR Responds to New Biological Opinion to Protect Salmon," June 4, 2009.
6 "California's Drought: Water Conditions & Strategies to Reduce Impacts," prepared by the Department of
Water Resources and the Department of Food and Agriculture, Report to the Governor March 30, 2009.
[a,
Water Supply Study: Appendix B/Terra Nova
La Quinta General Plan Update/ June 21, 2011
A majority of the State's Reservoirs are also above normal storage levels. For example, Lake
Oroville in Northern California is at 113% of normal stage as of March 2011. Lake Oroville is
the SWP principal reservoir, and above normal reservoir levels are good news for SWP
contractors.7
2009 SWP Delivery Reliability Report
The Department of Water Resources released the 2009 State Water Project Delivery Reliability
Report, which includes detailed analysis and projections of future SWP deliveries. The revised
report takes into consideration all recent and anticipated changes in pumping restriction as a
result of litigation since 2009. In addition, the report considers potential changes in the
precipitation patter, rise in sea level, and snowpack accumulation/melting period as a result of
global warming. Water delivery impacts to short term and long-term SWP deliveries are
quantified and analyzed in the Report.
As discussed above and in the WSA, the 2009 DWR Report is notable in several other key
respects. First, similar to the Final 2007 Report, when forecasting the short, intermediate and
long-term availability and reliability of SWP exports from the Delta, the 2009 Report expressly
incorporates and accounts for the effects of the 2008 FWS Biological Opinion (BiOp) and NMFS
BiOp to protect listed fish species in the Delta. Second, the delivery forecasts of the 2009 Report
expressly account for the potential effects of global climate change. Third, the 2009 Report
utilizes the most conservative assumption that the regulatory restrictions set forth by assuming
that the new BiOps will remain in place and that no actions to improve Delta governance and
conveyance will occur.
Although DWR utilizes these conservative assumptions, and they are incorporated into the water
supply analyses for the Project, it should be noted that various processes and efforts are currently
underway pursuant to the Bay Delta Conservation Plan, Delta Vision, and new state laws to
improve Delta governance and conveyance systems, all of which are intended to increase the
availability and reliability of SWP supplies beyond the regulatory restrictions that have been
imposed under the revised FWS BiOp and NMFS BiOp. As discussed above, both BiOps have
been legally challenged and require further revisions in order to correct deficiencies and comply
with the National Environmental Policy Act.
Thus, the assumptions set forth by DWR in projecting future SWP delivery reliability, and in
preparing the WSA, utilize the most stringent approach to ensure a thorough and candid
assessment of what may be considered a worst -case scenario for imported SWP supplies.
7 "State Water Project Allocation Increases to 70%", prepared by DWR, March 16, 2011.
Water Supply Study: Appendix B/Terra Nova
La Quinta General Plan Update/ June 21, 2011
Quantification Settlement Agreement Cases and related issues regarding reliability of Colorado
River Water Supplies
The availability and reliability of the Metropolitan Water District's (MWD) Colorado River
water supplies are discussed in great length and detail in several published documents. For
instance, MWD's 2005 Regional Urban Water Management Plan discusses the agency's access
to Colorado River water by noting first that several water agencies in California have rights to
divert water from the River. Through the 1931 Seven Parry Agreement, California's share of
Colorado River were assigned to seven agencies, including MWD. Colorado River water is
delivered to MWD via the Colorado River Aqueduct (CRA), which has a delivery capacity of
1,800 cubic feet per second, or 1.3 million acre-feet per year. The CRA conveys water 242 miles
from the Lake Havasu intake to Lake Mathews, a terminal reservoir near the City of Riverside.
As reported in MWD's Annual Report for the Fiscal Year 2007-2008, MWD has contracts with
the federal Bureau of Reclamation for a basic apportionment of 550,000 acre-feet per year and an
additional 842,000 acre-feet when available, where MWD may receive surplus water or water
unused by Arizona, Nevada or California entities such as the Palo Verde Irrigation District, the
Yuma Project Reservation District, the Imperial Irrigation District and the Coachella Valley
Water District. According to MWD, the agency conveyed 801,009 acre-feet of CRA water
during the fiscal year.
The Annual Report notes that, despite an above -normal spring runoff in 2008, water levels at
Lake Mead at the end of the fiscal year were at the lowest level since 1965. In response to those
conditions, MWD has aggressively pursued additional supplies from storage and acquisition
programs and has instituted other means of stabilizing its Colorado River resources.
As set forth in its Annual Report, MWD took steps to improve water management capability by
signing an agreement with other water agencies in the Lower Colorado River Basin in December
2007 which allows some of those agencies to develop and store new water supplies in Lake
Mead. The agreement allows MWD to store up to 1.5 million acre-feet in Lake Mead at no
additional cost and allows water agencies to cooperate on water conservation projects. In May
2008, MWD also partnered with the Southern Nevada Water Authority and the Central Arizona
Water Conservation District to fund the Drop 2 Reservoir Project, which will help conserve
water currently lost from the system. Under the program, MWD received an additional 100,000
acre-feet of storage credits in Lake Mead, water that was available for recovery by late 2008.
Additional information and analyses regarding MWD's Colorado River water supplies are set
forth in MWD's Appendix A to Preliminary Official Statement dated July 2, 2008, describing
MWD's Water Revenue Refunding Bonds, 2008 Series C. According to MWD, the Colorado
River was MWD's original source of water after MWD's establishment in 1928. According to
MWD, and as indicated above, MWD has a legal entitlement to receive water from the Colorado
River under a permanent service contract with the Secretary of the Interior.
Im
Water Supply Study: Appendix B/Terra Nova
La Quinta General Plan Update/ June 21, 2011
Water from the Colorado River or its tributaries is also available to other users in California, as
well as users in the states of Arizona, Colorado, Nevada, New Mexico, Utah, and Wyoming (the
"Colorado River Basin States"), resulting in both competition and the need for cooperation
among these holders of Colorado River entitlements. California is apportioned the use of 4.4
million acre-feet of water from the Colorado River each year plus one-half of any surplus that
may be available for use collectively in Arizona, California and Nevada. In addition, as
indicated in MWD's Annual Report, California has historically been allowed to use Colorado
River water apportioned to but not used by Arizona and Nevada when such supplies have been
requested for use in California. In recent years, however, Arizona and Nevada have increased
their use of water from the Colorado River, leaving no unused apportionment available for
California.
MWD has taken steps to augment its share of Colorado River water through agreements with
other agencies that have rights to use such water. Under a 1988 water conservation agreement
(the "1988 Conservation Agreement") between MWD and the Imperial Irrigation District (IID),
IID has constructed and is operating a number of conservation projects that are currently
conserving 105,000 acre-feet of water per year. In 2007, the conserved water augmented the
amount of water available to MWD by 85,000 acre-feet and, by prior agreement, to the
Coachella Valley Water District (CVWD) by 20,000 acre-feet.
In 1992, MWD entered into an agreement with the Central Arizona Water Conservation District
(CAWCD) to demonstrate the feasibility of CAWCD storing Colorado River water in central
Arizona for the benefit of an entity outside of the State of Arizona. Pursuant to this agreement,
CAWCD created 80,909 acre-feet of long-term storage credits that may be recovered by
CAWCD for MWD. MWD, the Arizona Water Banking Authority, and CAWCD executed an
amended agreement for recovery of these storage credits in December 2007. In 2007, 16,804
acre-feet were recovered. MWD requested that 25,000 acre-feet be recovered in 2008, and
expects to request the balance of the storage credits over the next several years. Water recovered
by CAWCD under the terms of the 1992 agreement allows CAWCD to reduce its use of
Colorado River water, resulting in Arizona having an unused apportionment. The Secretary of
the Interior is making this unused apportionment available to MWD under its Colorado River
water delivery contract.
As discussed above, in April 2008, MWD's Board authorized the expenditure of $28.7 million to
join the CAWCD and the Southern Nevada Water Authority (SHWA) in funding the
construction of a new 8,000 acre-foot off -stream regulating reservoir near Drop 2 of the All -
American Canal in Imperial County. The reservoir will be constructed by the Bureau of
Reclamation and is anticipated to be completed in late 2010. The Drop 2 Reservoir is expected
to save up to 70,000 acre-feet of water per year by capturing and storing water that would
otherwise be lost. In return for its funding, MWD received 100,000 acre-feet of water that is
stored in Lake Mead until recovered, with annual delivery of up to 65,000 acre-feet of water
from 2011 through 2036. Besides the additional water supply, the new reservoir will add to the
flexibility of Colorado River operations.
Water Supply Study: Appendix B/Terra Nova
La Quinta General Plan Update/ June 21, 2011
The October 2003 Quantification Settlement Agreement (QSA) executed by CVWD, IID and
MWD is also a core component of MWD's Colorado River water supply arrangement. The QSA
establishes Colorado River water use limits for IID, CVWD and MWD, provides for specific
acquisitions of conserved water and water supply arrangements for up to 75 years, and restores
the opportunity for MWD to receive surplus water under the Interim Surplus Guidelines (see
below). The QSA also allows MWD to enter into other cooperative Colorado River supply
programs. Related agreements modify existing conservation and cooperative water supply
agreements consistent with the QSA, and set aside several disputes among California's Colorado
River water agencies.
Specific programs authorized under the QSA include lining portions of the All -American and
Coachella Canals, which is projected to conserve 96,200 acre-feet annually with 80,200 acre-feet
of conserved water to be delivered to SDCWA by exchange with MWD and 16,000 acre-feet to
be delivered to the San Luis Rey Indian tribes by exchange under a water rights settlement; an
amendment to the 1988 Conservation Agreement and the associated 1989 Approval Agreement
extending the term of the 1988 Conservation Agreement and providing for the transfer of up to
105,000 acre-feet of water conserved by IID to MWD less the amount (up to 20,000 acre-feet of
the conserved water) used by CVWD; and the transfer of 200,000 acre-feet of water conserved
annually by IID to SDCWA. With full implementation of the programs identified in the QSA, at
times when California is limited to its basic apportionment of 4.4 million acre-feet per year,
MWD expects to be able to annually divert to its service area 852,000 acre-feet of Colorado
River water plus any unused agricultural water that may be available, as was the case in 2004
and 2005. This is further augmented by the PVID program, which provides up to 118,000 acre-
feet of water per year. Legal issues having the potential to affect the QSA are further discussed
below.
In January 2001, the Secretary of the Interior adopted guidelines (the "Interim Surplus
Guidelines") for use through 2016 in determining if there is surplus Colorado River water
available for use in California, Arizona and Nevada. The purpose of the Interim Surplus
Guidelines is to provide a greater degree of predictability with respect to the availability and
quantity of surplus water through 2016. The Interim Surplus Guidelines were later extended
through 2026.
The Interim Surplus Guidelines contain a series of benchmarks for reductions in agricultural use
of Colorado River water within California by set dates. Under the Interim Surplus Guidelines,
MWD initially expected to divert up to 1.25 million acre-feet of Colorado River water annually
under foreseeable runoff and reservoir storage scenarios from 2004 through 2016. An extended
drought in the Colorado River Basin initially reduced these expectations. From 2000 to 2004,
snow pack and runoff in the Colorado River Basin were below average. Although runoff was
slightly above average in 2005, the runoff in 2006 and 2007 was again below average, making
2000 through 2007 the driest eight -year period on record. Above -average precipitation occurred
in 2008, however, producing April through June inflows into Lake Powell that measured 144
percent of inflows for the same period in 2007.
Water Supply Study: Appendix B/Terra Nova
La Quinta General Plan Update/ June 21, 2011
In February 2007, the Bureau of Reclamation issued a Draft Environmental Impact Statement
(EIS) regarding new federal guidelines concerning the operation of the Colorado River system
reservoirs. These new guidelines provide water release criteria from Lake Powell and water
storage and water release criteria from Lake Mead during shortage and surplus conditions in the
Lower Basin, provide a mechanism for the storage and delivery of conserved system and non -
system water in Lake Mead and extend the Interim Surplus Guidelines through 2026. The
Bureau of Reclamation released the Final EIS in November 2007, and the Secretary of the
Interior issued the final guidelines through a Record of Decision signed in December 2007. The
Record of Decision and accompanying agreement among the Colorado River Basin States
protect reservoir levels by reducing deliveries during drought periods, encourage agencies to
develop conservation programs and allow the states to develop and store new water supplies.
The Colorado River Basin Project Act of 1968 insulates California from shortages in all but the
most extreme hydrologic conditions.
In addition, on May 26, 2006, MWD and the Bureau of Reclamation executed an agreement for a
demonstration program that allows MWD to leave conserved water that MWD would otherwise
use in Lake Mead in 2006 and 2007. Only intentionally -created surplus water (water that has
been conserved through an extraordinary conservation measure, such as land fallowing) was
eligible for storage in Lake Mead under this program. MWD may store additional intentionally -
created surplus water in Lake Mead under the federal guidelines for operation of the Colorado
River system reservoirs described above. The Secretary of the Interior will deliver intentionally
created surplus water to MWD in accordance with the terms of a December 13, 2007 Delivery
Agreement between the United States and MWD.
As indicated above, the QSA has been subject to litigation. In the Coordinated QSA Cases
(Sacramento County Superior Court, Judicial Council Coordination Proceeding No. 4353),
several legal actions were filed after the QSA was adopted in 2003. Those cases were
coordinated and stayed for over two years beginning in 2004 while a procedural issue in two of
the cases was determined by the Court of Appeal. The cases became active again in late 2007.
In January 2010, the Sacramento County Superior Court ruled that the QSA's funding
mechanism for Salton Sea mitigation efforts exceeded the debt limitation requirements under
State law. For several reasons, however, it is not certain that this decision will have any affect
the availability and reliability of MWD's Colorado River supplies. For instance, independent of
the QSA, MWD holds senior rights to the Colorado River and other Colorado River supplies.
Moreover, the U.S. Department of the Interior determines deliveries from the Colorado River
and the Department is not a party to the case and thus not bound by the ruling. Beyond that, it is
possible that action will be taken to correct the funding mechanism such that it comports with
applicable requirements. Finally, the effect of the ruling has been stayed by the Court of Appeal,
allowing the QSA to be implemented unless otherwise directed by the courts. For these and other
reasons, it remains speculative as to whether and to what degree, if any, the QSA litigation will
affect the amount of Colorado River water delivered to MWD by the Department of the Interior.
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