01 Air Quality & Noise Impact Study (1999)At to Ot4imia
Technical Appendices
Addendum Environmental Impact Report #232
Prepared for:
County of Riverside Planning Department
Developed by:
Coral Mountain Development, LLC
AE1•CASC=
AIR QUALITY
AND NOISE
IMPACT STUDY
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Prepared by: Endo Engineering March 1999
Endo Engineering Traffic Engineering Air Quality Studies Noise Assessments
March 29, 1999
Mr. Ric Stephens
The AEI-CASC Companies
937 South Via Lata, Suite 500
Colton, CA 92324
SUBJECT: Coral Mountain Specific Plan No. 218
Amendment No. 1 - Air Quality and Noise Impact Study
Dear Mr. Stephens;
Endo Engineering is pleased to submit this analysis of the air quality and noise impacts
associated with the Coral Mountain Specific Plan No. 218, Amendment No. 1 in
unincorporated Riverside County, south and east of the City of La Quinta. The Coral
Mountain Specific Plan is located on either side of Madison Street and Monroe Street,
between Avenue 58 and Avenue 62. The proposed project includes a maximum
development of 3,500 dwelling units and 9.2 acres of commercial uses. It also includes
6.8 acres of community facilities, 41 acres of parks and trails, two championship golf
courses with clubhouses and maintenance facilities and a 10 -acre school. The golf courses
will include recreational amenities such as swimming pools, tennis courts and exercise
facilities in a "country club" atmosphere. The previously approved Specific Plan 218
(previously named Rancho La Quinta Specific Plan) included the development of 4,262
homes, 35 acres of commercial uses, and 2 golf courses on-site
The pages which follow briefly summarize: (1) existing conditions in the project vicinity;
(2) year 2004 conditions with and without the proposed project; (3) year 2010 conditions
with and without the proposed project; and (3) specific mitigation measures designed to
reduce any significant impacts identified to acceptable levels. The methodology employed
to assess these impacts is consistent with the requirements of the County of Riverside and
the South Coast Air Quality Management District.
Should questions or comments arise regarding the findings and recommendations within
this report, please do not hesitate to contact our offices at (949) 362-0020. We look
forward to discussing our findings and recommendations with you.
Q9,pfESS/ON
Cordially, A�
ENDO ENGINEERING LEE fryd� y�,Z
Vicki Lee Endo
Registered Professional
Traffic Engineer TR 1161
TR 1161
* 1& /31 ,9002. *
<�1-F OFCAIIF�`?'o
28811 Woodcock Drive, Laguna Niguel, CA 92677-1330
(949) 362-0020 FAX: (949) 362-0015
AIR QUALITY AND NOISE IMPACT STUDY
CORAL MOUNTAIN AT LA QUINTA
SPECIFIC PLAN NO. 218
AMENDMENT NO. 1
NORTH OF AVENUE 62 AND SOUTH OF AVENUE 58
ON EITHER SIDE OF MADISON ST. AND MONROE ST.
RIVERSIDE COUNTY
March 29, 1999
Prepared For:
AEI CASC COMPANIES
937 South Via Lata, Suite 500
Colton, CA 92324
(909) 783-0101
Prepared By:
ENDO ENGINEERING
28811 Woodcock Drive
Laguna Niguel, CA 92677
(949) 362-0020
Table of Contents
Section Title Page
1.0 EXECUTIVE SUMMARY .............................................
1-1
- Air Quality Summary
- Noise Summary
2.0 PROJECT LOCATION AND DESCRIPTION .....................
2-1
- Project Location
- Project Description
3.0 AIR QUALITY ANALYSIS ..........................................
3-1
3.1 Existing Air Quality ................................................
3-1
- Air Quality Fundamentals
- Regional Air Quality
- Local Air Quality
- Existing Sensitive Receptors
- Local Sources of Air Contaminants
- Regulatory Setting
3.2 Air Quality Impact Analysis .....................................
3-17
- Impact Significance Threshold Criteria
- Short -Term Construction -Related Impacts
- Long -Term Operational Impacts
- Relevant Planning Programs
- Cumulative and Growth Inducing Effects
3.3 Air Quality Mitigation Measures ............................
3-32
- Measures to Minimize Construction Emissions
- Measures to Minimize Operational Emissions
4.0 NOISE ANALYSIS ....................................................
4-1
4.1 Existing Noise Environment .....................................
4-1
- Fundamentals of Noise
- Harmful Effects of Noise
- Community Responses To Sound
- Land Use Compatibility With Noise
- Current Noise Exposure
4.2 Noise Impact Analysis .............................................
4-8
- Short -Term Construction Noise Impacts
- Long -Term Operational Noise Impacts
4.3 Noise Mitigation Measures .......................................
4-17
- General Methods to Reduce Noise Impacts
- Specific Recommendations
APPENDIX
A. Air Quality Appendix
B. Noise Appendix
i
List of Figures
Number Title Following Page
2-1 Vicinity Map.............................................................. 2-1
2-2 Site Development Plan ................................................... 2-1
3-1 Ambient Air Monitoring Stations Operating
During 1995-1997 (Salton Sea Air Basin) ............................ 3-4
3-2 Annual Surface Wind Rose Summary ................................. 3-7
3-3 Coachella Valley Ozone Data ............................................ 3-8
3-4 Coachella Valley PM10 Data ............................................ 3-8
4-1 Typical Noise Levels of Familar Sources ............................. 4-1
4-2 Speech Communication As A Function of
Background Noise Level ................................................ 4-3
4-3 Land Use Compatibility Chart For Community Noise .............. 4-5
4-4 Construction Noise ...................................................... 4-8
ii
List of Tables
Number Title Page
2-1 Proposed Coral Mountain Land Uses
By Planning Area ......................................................... 7_-
2-2 Approved Versus Proposed On -Site Land Uses ..................... 2-3
3-1 Health Effects of Air Pollutants ........................................ 3-6
3-2
Existing Carbon Monoxide Concentrations ...........................
3-10
3-3
SCAQMD Significance Threshold Criteria ...........................
3-18
3-4
"Worst Case" Construction -Related Emissions .......................
3-20
3-5
Future Operational Air Pollutant Emissions
By Development Scenario ...............................................
3-24
3-6
Significance of Operational
Emissions Reductions ...................................................
3-25
3-7
Projected Future Carbon Monoxide Concentrations ..................
3-26
3-8
Approved Cumulative Developments ..................................
3-30
3-9
Future Cumulative Operational Air Pollutant Emissions , ...........
3-31
4-1
Harmful Effects of Noise ...............................................
4-3
4-2 Existing Exterior Noise Exposure
Adjacent to Nearby Roadways ......................................... 4-6
4-3 Year 2004+Project Exterior Noise Exposure
Adjacent to Area Roadways ......... ................................... 4-9
4-4 Project -Related Increase In Year 2004 Traffic Noise ................. 4-11
4-5 Year 2010+Project Exterior Noise Exposure
Adjacent to Nearby Roadways ......................................... 4-13
4-6 Project -Related Increase In Year 2010 Traffic Noise ................ 4-15
ui
1.0 EXECUTIVE SUMMARY
1.1 AIR QUALITY
1.1.1 AIR QUALITY SETTING
1. The project site is located within the Salton Sea Air Basin, which has been designated
a "severe -17" ozone nonattainment area because of violations of the federal ambient air
quality standards for ozone primarily due to pollutant transport from the South Coast
Air Basin.1
2. Ozone levels exceeded the state one-hour standard (0.09 ppm) on 15 percent of the
days monitored in the Coachella Valley. The maximum one-hour ozone concentration
measured was 0.16 parts per million (ppm), which exceeds the federal standard by
more than 33 percent and exceeds the state standard by more than 77 percent.
3. The 1997 Air Quality Management Plan indicates that attainment of the 1 -hour federal
ozone standard will be possible by November 15, 2007 (as required by the Federal
Clean Air Act) with the proposed control strategy for the South Coast Air Basin and
control of locally generated emissions via state and federal regulations.
4. The Coachella Valley was reclassified in February 1993 by the Environmental
Protection Agency (EPA) as a "serious" nonattainment area for PMio, which means
that the valley had violated federal health -based standards for particulate matter.
5. PMlo concentrations in the Coachella Valley exceeded the California 24-hour standard
during 46 percent of the monitoring periods during the three years from 1995 through
1997. The maximum 24-hour PMio concentration monitored was 199 micrograms per
cubic meter (nearly four times the state standard of 50 micrograms per cubic meter).
6. The project site is located outside of the Blowsand Hazard Zone and the Active
Blowsand Zone established by the Coachella Valley Association of Governments
(CVAG) in the `Blowsand Control and Protection Plan" (June 1977).
1.1.2 AIR QUALITY IMPACTS
1. On a daily and a quarterly basis, the proposed project will generate essentially the same
short-term impacts on air quality as the adopted Specific Plan (which represents the No
Project Alternative). "Worst case" daily construction -related emissions associated with
either development scenario are expected to exceed the SCAQMD significance
threshold for PMlo. Quarterly construction -related emissions associated with either
development scenario are expected to exceed the SCAQMD significance thresholds for
PMlo and NOx.
2. Since no appreciable difference in the daily or quarterly construction impacts on air
quality can be established between the these two development scenarios, it could be
argued that the proposed project will have an insignificant short-term impact on air
quality. However, the currently proposed Coral Mountain Specific Plan Amendment
1. This designation indicates that the attainment date for the federal ozone standards is November 15, 2007
(17 years from the date of enactment of the federal Clean Air Act).
1-1
Number 1 represents a substantial reduction in residential (18%) and commercial
(74%) development intensity. Consequently, the air quality impacts generated as a
result of the actual building construction activities required to implement the proposed
project will be lower than those of the approved Specific Plan 218.
3. Project -related long-term emissions are projected to exceed the SCAQMD significance
thresholds for CO, VOC and NOx in the initial development phase (year 2004) and
thereafter.
4. However, the proposed Specific Plan 218 Amendment #1 would generate significantly
lower operational air pollutant emissions of CO, ROC and NOx than the currently
approved Specific Plan 218. It would reduce long-term CO, ROC, and PM i o
emissions by 35%, NOx emissions by 34%, and SOx emissions by 26%.
Consequently, the proposed Specific Plan Amendment #1 would have a significant
long-term beneficial impact on air quality in the study area.
5. The CALINE 4 modeling indicates that the one-hour and eight-hour carbon monoxide
contributions from project -related traffic will not be measurable. Year 2004 and 2010
carbon monoxide levels are not projected to exceed the state or federal CO standards at
the key intersections modeled with or without project -related traffic.
6. Since the project does not involve a General Plan Amendment and is projected to result
in an air pollutant emission burden that is smaller than the adopted Specific Plan 218
on-site, it appears to be consistent with the Air Quality Management Plan and goals.
7. Since the proposed project will generate similar short-term emissions to those of the
approved Specific Plan on-site, cumulative short-term air quality impacts associated
with the proposed project will be comparable to those of the approved Specific Plan.
The proposed project would have a significant long-term beneficial impact on air
quality in the study area by reducing daily cumulative operational emissions by 18
percent.
1.1.3 AIR QUALITY MITIGATION MEASURES
The following measures have been or will be incorporated in the project.
1. Construction equipment shall be properly maintained and serviced to minimize
exhaust emissions.
2. Any construction equipment using diesel drive internal combustion engines should
use a diesel fuel with a maximum of 0.05% sulfur and a four degree retard per the
Riverside County Air Quality Element, Particulate Matter Program.
3. Existing power sources should be utilized where feasible via temporary power poles
to avoid on-site power generation.
4. Construction personnel shall be informed of ride sharing and transit opportunities.
5. Construction parking shall be configured to minimize traffic interference.
6. Construction operations affecting off-site roadways shall be scheduled for off-peak
traffic hours and shall minimize obstruction of through -traffic lanes.
1-2
7 . Cut and fill quantities will be balanced on-site.
8. The proposed project will comply with the provisions of the Riverside County
Zoning Code which establishes minimum requirements for construction activities to
reduce fugitive dust and PMio emissions. A plan to control fugitive dust through
implementation of reasonably available dust control measures shall be prepared and
submitted to Riverside County for approval prior to the issuance of any grading
permits associated with the project. The plan shall specify the fugitive dust control
measures to be employed.
9. SCAQMD Rule 403 shall be adhered to, insuring the clean up of construction -related
dirt on approach routes to the site. Rule 403 prohibits the release of fugitive dust
emissions from any active operation, open storage pile, or disturbed surface area
beyond the property line of the emission source. Particulate matter deposits on public
roadways are also prohibited.
10. Adequate watering techniques shall be employed to partially mitigate the impact of
construction -generated dust particulates. Portions of the project site that are under-
going earth moving operations shall be watered such that a crust will be formed on
the ground surface and then watered again at the end of the day.
11. Any construction access roads (other than temporary access roads) shall be paved as
soon as possible and cleaned after each work day. The maximum vehicle speed limit
on unpaved roads shall be 15 mph.
12. Grading operations shall be suspended during first and second stage ozone episodes
or when winds exceed 25 mph, per the PMio SIP.
13. Any vegetative ground cover to be utilized on-site shall be planted as soon as possible
to reduce the amount of open space subject to wind erosion. Irrigation systems
needed to water these plants shall be installed as soon as possible to maintain the
ground cover and minimize wind erosion of the soil.
14. Landscaping should be accomplished with native drought -resistant species to reduce
water consumption and provide passive solar benefits.
The proposed project shall reduce long-term operational emissions by incorporating
facilities for alternative transportation modes, implementing energy conservation measures
and by reducing VMT in the following manner.
1. Building construction shall comply with the energy use guidelines in Title 24 of the
California Administrative Code.
2. The project will internalize trips and reduce dependency on the private automobile by
providing non -motorized transportation facilities and implementing all feasible
measures to encourage the use of alternate transportation modes.
3. The vehicular circulation system within the project site will be supplemented with a
user friendly walking, bicycling and transit environment.
4. The project will reduce vehicle miles traveled and internalize trips by offering
recreational activities and retail shopping opportunities in a centralized location within
the proposed community.
1-3
5 . Parking areas for the commercial portion of the site should incorporate bicycle spaces
and/or other mandated alternative transportation provisions in conformance with
current County ordinances.
6. The use of energy efficient street lighting and parking lot lighting (low pressure
sodium vapor lights) should be considered on-site to reduce emissions at the power
plant serving the site.
7. The project proponent shall comply with applicable SCAQMD Rules and
Regulations.
1.2 NOISE
1.2.1 NOISE SETTING
1. Ambient sound levels in the project vicinity are primarily affected by motor vehicle
noise, and the roadways with the highest existing traffic volumes are Jefferson
Street, Monroe Street, and Avenue 52.
2. Ambient noise levels emanating from area roadways currently range from a low of
57.3 CNEL (at 50 feet from the centerline of Madison Street) to a high of 74.6
CNEL (at 50 feet from the centerline of Jefferson Street).
3. The 70 dBA contour presently falls within the right-of-way along 12 of the 21
roadway links analyzed.
4. The 65 CNEL contour is located within the right-of-way along 7 of the roadway
links analyzed.
5. The project vicinity is lightly developed (except for PGA West), and the roadways
generally carry traffic volumes that represent only a fraction of their master planned
capacities.
1.2.2 NOISE IMPACTS
By definition, the impact of the Coral Mountain Specific Plan 218 Amendment #1 is the
difference between the proposed project and the impacts of the approved Specific Plan.
Since future traffic volumes will decrease, the proposed project will have a beneficial
impact when compared to the approved project. However, there will be increases in noise
levels if the project is compared with "No Development".
1. Construction activities required on-site to implement the proposed project will
generate short-term increases in noise levels adjacent to site access routes and the on-
site areas under construction that are similar to those with the approved Specific Plan.
2. Motor vehicle noise resulting from the proposed project will constitute a long-term
incremental acoustic impact in the vicinity but will be lower than noise levels with the
approved Specific Plan.
3. The initial phase of the proposed project will generate an audible noise increase
(greater than 3.0 dBA) along Monroe Street (3 links ranging from 3.0 to 3.2 dBA)
and Avenue 60 (2 links ranging from 5.5 to 7.4 dBA) on and adjacent to the project
site.
1-4
4. Potentially audible noise increases (between 1.0 and 3.0 dBA) are projected to occur
with the proposed project in the year 2004 along eleven of the roadway links
evaluated, with noise increases along these links ranging from 1.0 to 2.5 decibels.
5. Upon buildout on-site, the proposed project will generate an audible noise increase
(greater than 3.0 dBA) along Monroe Street (3 links ranging from 3.0 to 3.2 dBA)
and Avenue 60 (2 links ranging from 5.5 to 7.4 dBA) within or adjacent to the project
site.
6. Given the low traffic volumes throughout the study area at present, future
development has the potential to substantially increase traffic volumes. However,
there are relatively few existing sensitive noise receptors, and future sensitive noise
receptors will be shielded from ultimate noise levels generated by adjacent master
planned roadways. Future projected traffic volumes are consistent with master
planned roadway capacities.
7. The year 2010 traffic volumes along master planned roadways have the potential to
generate noise levels that exceed 65 CNEL in areas planned for residential uses on-
site. Prior to the issuance of building permits, the applicant shall be required to
submit an acoustical analysis of the residential lots adjacent to the master planned
roadways that details the specific mitigation proposed to achieve the Riverside County
exterior noise standards.
1.2.3 NOISE MITIGATION
The following specific mitigation measures are recommended for incorporation in the
Mitigation Monitoring Program associated with the proposed project to minimize noise
impacts and insure compliance with applicable noise standards.
1. Construction activities on-site should take place only during the days and hours
specified by the Riverside County Noise Ordinance to reduce noise impacts during
more sensitive time periods.
2. All construction equipment, fixed or mobile, should be equipped with properly
operating and maintained mufflers.
3. Stationary equipment should be placed such that emitted noise is directed away from
noise sensitive receivers.
4. Stockpiling and vehicle staging areas should be located as far as practical from noise
sensitive receptors.
5. Every effort should be made to create the greatest distance between noise sources and
sensitive receptors during construction activities.
6. Residential development located adjacent to master planned streets on-site (Madison
Street, Monroe Street, Avenue 58, Avenue 60, and Avenue 62) shall be carefully
designed and evaluated at more detailed levels of planning to ensure that adequate
noise mitigation is incorporated to meet the Riverside County noise standard of 65
CNEL in outside living areas. Buildings with exterior noise exposures up to 70 dBA
can achieve 45 dBA interior noise levels with standard construction techniques.
7. Building setbacks and pad elevations shall be used in conjunction with acoustic berm
or berm and barrier combinations to reduce intrusive noise to acceptable levels (65
1-5
CNEL or less) in outdoor living areas of all residential units located within the
ultimate 65 CNEL contours adjacent to Madison Street, Monroe Street, Avenue 58,
Avenue 60, and Avenue 62. With exterior noise levels of 65 dBA, standard
construction practices will be adequate to ensure that interior noise levels for
residential units shall not exceed 45 dBA.
8. The architectural details of the commercial/retail buildings and their location and
orientation shall be reviewed prior to submittal of the building permit application to
ensure that interior noise levels will not exceed 50 CNEL.
9. Prior to the issuance of building permits, the final lot layout, pad elevations, building
design, and acoustic berm or berm and barrier combinations shall be evaluated by a
qualified acoustical consultant to verify that proper noise mitigation has been provided
to ensure consistency with the standards and policies in the Noise Element of the
Riverside County General Plan. The resulting acoustical study shall be subn-fitted for
approval to Riverside County.
10. If a perimeter wall is to be constructed between the commercial development on-site
and adjacent noise sensitive areas, it should be a solid barrier constructed as early in
the construction process as feasible so that it will shield sensitive areas from intrusive
construction -related noise.
11. Truck access, parking area design and air conditioning refrigeration units proposed in
the commercial area on-site shall be carefully designed and evaluated at more detailed
levels of planning to minimize the potential for acoustic impacts to adjacent noise
sensitive development.
1-6
2.0 PROJECT LOCATION AND DESCRIPTION
2.1 PROJECT LOCATION
The project site is located in unincorporated Riverside County, in the Coachella Valley,
south and east of the City of La Quinta. Regional access is provided by Interstate 10 and
State Route 111. The project site is located partially within the Sphere of Influence of the
City of La Quinta.
The Coral Mountain Specific Plan area includes approximately 1,280 acres within
unincorporated Riverside County, on either side of Madison Street and Monroe Street,
between Avenue 58 (to the north) and Avenue 62 (to the south). The northern and western
site boundaries abut the City of La Quinta. Figure 2-1 depicts the location of the project
site and the study area.
2.2 PROJECT DESCRIPTION
2.2.1 PROJECT LAND USE AND CIRCULATION PLAN
The proposed project is the Coral Mountain Specific Plan 218 Amendment No. 1, an
amendment to the Rancho La Quinta Specific Plan 218 approved in 1988 (see Figure 2-2).
It includes a maximum development of 3,500 dwelling units and 9.2 acres of commercial
uses. It also includes 6.8 acres of community facilities, 41 acres of parks and trails, two
championship golf courses with clubhouses and maintenance facilities and a 10 -acre
school. The golf courses will include recreational amenities such as swimming pools,
tennis courts and exercise facilities in a "country club" atmosphere. Table 2-1 details the
land uses proposed on-site by community.
The previously approved Specific Plan 218 included the development of 4,262 homes, 35
acres of commercial uses, and 2 golf courses on-site, as shown in Table 2-2. The currently
proposed Coral Mountain Specific Plan Amendment Number 1 represents a substantial
reduction in residential (18%) and commercial (74%) development intensity. The currently
proposed project includes a maximum development of 762 fewer dwellings and 25.8 fewer
acres of commercial uses.
The proposed project consists of three master planned communities with a variety of
housing products and densities designed for specific lifestyles. Links will be provided
between the community parks and existing trails along the Westside Flood Levy (which
traverses the western boundary of the site). Links on-site will also be provided as shown
in the ECVP Coachella Valley Trails Plan.
The proposed circulation system for Coral Mountain includes improvements to Riverside
County Circulation Element standards along Madison Street, Monroe Street, Avenue 58,
Avenue 60 and Avenue 62. These roads will be dedicated to and maintained by Riverside
County. The internal loop collector system proposed to serve the residential and
recreational areas on-site will consist primarily of private streets. A grade separated
pedestrian crossing is proposed across Madison Street, just north of 60th Avenue.
2-1
Figure 2-1
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Table 2-1
Proposed Coral Mountain
Land Uses By Planning Area
Land Use Type
Acres
Dwelling Units
Resort Village
Single Family Residential
274.1
782
Golf Course
182.0
--
- Clubhouse (10,000 S.F.)
- Maintenance (4,000 S.F.)
Community Facilities (10,000 S.F.)
6.8
--
Arroyo Trail System
28.7
--
R.O.W./Easements
45.8
--
Subtotal
537.4
782
Active Adult Village
Single Family Residential
285.0
1,375
Golf Course
188.8
--
- Clubhouse (10,000 S.F.)
- Maintenance (4,0000 S.F.)
R.O.W./Easements
52.9
--
Subtotal
526.7
1,375,
Primary Housing Village
Residential
- Single Family
142.8
779
- Multi -Family
17.1
397
Park
8.0
--
School (80,000S.F.)
10.0
--
R.O.W.
12.1
--
Subtotal
190.0
1,176
Village Commons
Multi -Family Residential
12.0
167
Commercial/Retail (100,000 S.F.)
9.2
--
Recreation Facilities/Park
4.0
--
Subtotal
25.2
167
Total
1279.3
3,500
2-2
Table 2-2
Approved Versus Proposed
On -Site Land Uses
Land Use Type
Approved Rancho La Quinta
Specific Plan 218
Proposed Coral Mountain
SP 218 Amendment No. l
Residential
- Single Family
4,262 Dwellings
2,936 Dwellings
- Multi -Family
--
564 Dwellings
Total
4,262 Dwellings
3,500 Dwellings
Commercial/Retail
35 Acres
9.2 Acres
Community Facilities
--
6.8 Acres
Golf Courses (2)
380 Acres
371 Acres
Parks/Trails
40 Acres
41 Acres
School
--
10 Acres
Madison Street, Monroe Street, and Avenue 60 will be improved to arterial standards with
86 feet of pavement within 110 -foot rights-of-way. Avenue 58 (west of Madison Street)
will be improved to major standards (76 feet of pavement with an 100 -foot right-of-way).
Avenue 62 (west of Monroe Street) will be improved to secondary standards (64 feet of
pavement with an 88 -foot right-of-way).
A variety of intersection improvements will be provided in conjunction with Specific Plan
implementation. Traffic signals will be installed at the intersections of Monroe Street with
Avenue 58 and Avenue 60. The legs of the intersection of Monroe Street and Avenue 58
will all be widened to provide two lanes in each direction.
2.2.2 ZONING AND LAND USE CATEGORY
The proposed project is generally consistent with the current General Plan and Zoning
designations on-site. The proposed project is the Coral Mountain Specific Plan 218
Amendment No. 1, an amendment to the Rancho La Quinta Specific Plan 218 approved in
1988. The currently proposed Coral Mountain Specific Plan Amendment No. 1 represents
a substantial reduction in residential (18%) and commercial (74%) development intensity.
The currently proposed project includes a maximum development of 762 fewer dwellings
and 25.8 fewer acres of commercial uses.
2.2.3 PROJECT PHASING
The project will be constructed in five phases. The initial phase will include the golf course
construction and some of the adjacent residential planning areas. The remaining phases
will include primarily residential and commercial development.
The initial development phase will begin grading in the year 2000 and be completed by the
year 2004. It will include 873 single family dwellings and two golf courses with a total of
36 holes. Ultimate development of the site could occur by the year 2010.
2-3
73.0—AIR QUALITY ANALYSIS
3.1 EXISTING AIR QUALITY
Various air quality fundamentals are discussed below including: criteria pollutants, ambient
air quality standards, episode criteria, and demonstrated effects of air pollutants on sensi-
tive receptors. This basic information is followed by a discussion of: (1) regional air qual-
ity; (2) local ambient air quality; (3) existing sensitive receptor locations in the project
vicinity; (4) local sources of air contaminants; and (5) the regulatory setting. Appendix A
includes a glossary of technical terms used throughout the air quality analysis.
3.1.1 AIR POLLUTION FUNDAMENTALS
Air pollution is comprised of many substances generated from a variety of sources, both
man-made and natural. Since the rapid industrialization of the twentieth century, almost
every human endeavor, especially those relying on the burning of fossil fuels, creates air
pollution. Most contaminants are actually wasted energy in the form of unburned fuels or
by-products of the combustion process.
Motor vehicles are by far the most significant source of air pollutants in urban areas, emit-
ting photochemically reactive hydrocarbons (unburned fuel), carbon monoxide, and oxides
of nitrogen. These primary pollutants chemically react in the atmosphere with sunlight and
the passage of time to form secondary pollutants such as ozone.
Although significant air quality improvements have been made in California over the past
twenty years, Southern California still experiences severe air pollution problems.
Oxidants and PMio (suspended particulate matter with a mean aerodynamic diameter of less
than 10 micrometers) represent the major air quality problems in the desert regions of
Southern California.
The air quality of the Coachella Valley is determined by the primary pollutant emissions
added daily, and by the primary and secondary pollutants already present in the air mass.
Primary pollutants are those emitted directly from a source and include: carbon monoxide
(CO), nitric oxide (NO), sulfur dioxide (SO2), particulates, and various hydrocarbons and
other volatile organic compounds (VOC). Secondary pollutants are created with the
passage of time in the air mass and include: photochemical oxidants (90% of which are
ozone), photochemical aerosols, peroxyacetylnitrate (PAN), and nitrogen dioxide (NO2).
Criteria Air Pollutants
Criteria air pollutants are those air contaminants for which air quality standards currently
exist. Currently, state and federal air quality standards exist for ozone, nitrogen dioxide
(NO2), sulfur dioxide (SO2), carbon monoxide (CO), fine suspended particulates (PMio),
and lead. California has also set standards for visibility and sulfate. Emissions of criteria
air contaminants or their precursors typically also include total organic gases (TOG),
volatile organic compounds (VOC), oxides of nitrogen (NOx), oxides of sulfur (SOx), and
particulate matter (PM).
3-1
Carbon Monoxide
Carbon monoxide (CO) is a colorless, odorless, toxic gas formed by incomplete combus-
tion of fossil fuels. Carbon monoxide concentrations are generally higher in the winter,
when meteorological conditions favor the build-up of directly emitted contaminants.
Carbon monoxide health warnings and emergency episodes occur almost entirely during
the winter. The most significant source of carbon monoxide is gasoline powered automo-
biles, as a result of inefficient fuel usage in internal combustion engines. Various industrial
processes also emit carbon monoxide.
Oxides of Nitrogen
Oxides of nitrogen (NOx) are the primary receptors of ultraviolet light initiating the photo-
chemical reactions that produce smog. Nitric oxide combines with oxygen in the presence
of reactive hydrocarbons and sunlight to form nitrogen dioxide and ozone. Oxides of
nitrogen are contributors to other air pollution problems including: high levels of fine
particulate matter, poor visibility and acid deposition.
Seven oxides of nitrogen and two hydrated oxides can theoretically exist in the atmosphere,
but only four are present in noticeable amounts. Two of these are classified as pollutants.
These are nitric oxide (NO), a colorless, odorless gas and nitrogen dioxide (NO2), a
reddish -brown gas formed by the combination of nitric oxide with oxygen. Nitric oxide is
far less toxic than nitrogen dioxide in humans.
The primary sources of nitrogen oxides in the basin are incomplete combustion in motor
vehicle engines, power plants, refineries and other industrial operations. Ships, railroads
and aircraft are other significant emission sources.
Sulfur Dioxide and Sulfate
Sulfur dioxide (S02) results from the combustion of high sulfur content fuels. Fuel com-
bustion is the major source of SO2, while chemical plants, sulfur recovery plants, and
metal processing are minor contributors. Sulfates result from a reaction of sulfur dioxide
and oxygen in the presence of sunlight. SO2 levels are generally higher in the winter than
in the summer (when sunlight is plentiful and sulfate is formed more readily).
Recent reductions in sulfur dioxide levels reflect the use of natural gas in power plants and
boilers (since natural gas is very low in sulfur). Low sulfur fuel oil is also utilized within
this air basin.
Volatile Organic Compounds
Hydrocarbon and other volatile organic compounds (VOC) are formed from combustion of
fuels and the evaporation of organic solvents. Many hydrocarbon compounds are major air
pollutants, and those classified as aromatics are highly photochemically reactive with NOx,
forming photochemical smog. Hydrocarbon concentrations are generally higher in winter
when sunlight is limited and photochemical reactions occur more slowly. During the
winter, meteorological conditions are more favorable to their accumulating in the atmos-
phere before producing photochemical oxidants. Motor vehicles are the major source of
organic gases in this basin.
3-2
Particulate Matter
Particulate matter consists of particles in the atmosphere as a by-product of fuel combus-
tion, through abrasion such as tire wear, and through soil erosion by the wind. Particulates
can also be formed through photochemical reactions in the atmosphere. PMio refers to
finely divided solids or liquids such as soot, dust, and aerosols which are 10 microns or
less in diameter and can enter the lungs.
About 90% of total particulates are less than 5 microns in diameter, while the aerosols
formed in the atmosphere (primarily sulfate and nitrate) are usually smaller than 1 micron.
Particulate concentrations are generally higher in the winter near major sources, when more
fuel is burned and meteorological conditions favor the build-up of directly -emitted contami-
nants.
Photochemical Oxidant
Photochemical oxidant (03) can include several different pollutants, but consists primarily
of ozone (90%) and a group of chemicals called organic peroxynitrates. Ozone is a
pungent, colorless toxic gas which is produced by the photochemical process. Photo-
chemical oxidant is created by complex atmospheric reactions involving oxides of nitrogen
and volatile organic compounds, in the presence of ultraviolet energy from sunlight.
Motor vehicles are the major source of ozone precursors (oxides of nitrogen and volatile
organic compounds) in the air basin. Ozone is formed through chemical reactions of
VOCs, oxides of nitrogen and oxygen in the presence of sunlight. Peak ozone concentra-
tions tend to occur in the South Coast Air Basin near the middle of the day in summer and
early fall, when the solar radiation exposure of the air mass is the greatest, because the
reactions that form ozone begin at sunrise and require sunlight to proceed.
The prevailing marine air currents throughout the South Coast Air Basin (SCAB) typically
carry polluted air inland as ozone -forming photochemical reactions proceed. That is why
peak ozone concentrations in the SCAB are found in the inland valleys and adjacent
mountains (between the San Fernando Valley and the Riverside -San Bernardino area),
miles downwind of the largest concentrations of sources of precursor emissions.
Just as oxidant precursors from the coastal Los Angeles area aggravate oxidant problems
inland in Riverside, precursor emissions from the central and eastern areas of the SCAB
(including Anaheim) contribute to locally produced oxidant in the Coachella Valley.l A
comprehensive study confirmed the transport pathways to the Coachella Valley in 1983.2
Although the extent to which the intrusion of ozone contributes to Coachella Valley ozone
exceedances has not been quantified, "...it is ARB's judgment that oxidant problems in the
Southeast Desert would be minimal.if oxidants and oxidant precursors were effectively
controlled in the South Coast Air Basin." 3
In the Coachella Valley, air flow is from the northwest much of the time. Peak oxidant
levels occur in the late afternoon and evening, as pollutants are blown through the San
Gorgonio Pass. Oxidant concentrations in the Coachella Valley are highest closest to the
South Coast Air Basin and decrease steadily as the air mass moves easterly.
1. Drivas, P.J. and F.H. Shair; A Tracer Study of Pollutant Transport in the Los Angeles Area; Atmos.
Environ. 8: 1155-1163; 1974
2. Smith, T.B. et at.; The Impact sof Transport from the South Coast Air Basin on 0gone Levers in the
Southeast Desert Air Basin; CARB Research Library Report No. ARB -R-83-183.
3. SCAQMD and SCAG; AQMP - Southeast Desert Air Basin, Riverside County; October 1979.
3-3
The role of local emissions in the formation of oxidants in the Coachella Valley is difficult
to quantify. Locally produced oxidant undoubtedly accounts for some standard ex-
ceedances. However, tracer studies and other recent studies of ozone levels by location,
hour of day, day of week, etc. indicate that an oxidant cloud caused directly by transport
from the SCAB causes exceedances in Palm Springs as late as 8 pm, when local photo-
chemical activity has slowed. In addition, transported NOx and VOC left over from the
previous day have been identified as major contributors to ozone concentrations at down-
wind desert locations.4
Ambient Air Quality Standards
Ambient air quality is determined from data collected at air quality monitoring stations
located throughout the Salton Sea Air Basin, as shown in Figure 3-1. The ambient air
quality data is given in terms of state and federal standards. These standards represent air
pollutant concentrations which are considered safe (with a reasonable margin of safety) to
protect the public health and welfare.
Both California and the federal government have set air quality standards for ozone, carbon
monoxide, nitrogen dioxide, sulfur dioxide, PM10 and lead. The state and federal ambient
air quality standards are detailed in Appendix A. The California standards are more
stringent than the federal standards (particularly with regard to PMio and sulfur dioxide).
California has also set standards for sulfate, visibility, hydrogen sulfide, and vinyl
chloride.
Two types of national standards have been established. Primary standards were designed
to safeguard the health of people considered to be sensitive receptors while outdoors were
adopted. Secondary standards, designed to safeguard human welfare (by minimizing
damage to plants, and the oxidation of rubber and paint etc.), were also established by the
federal government.
Ambient air quality standards are designed to protect that segment of the population that is
most susceptible to respiratory distress or infection such as: asthmatics, the very young,
the elderly, people weak with illness or disease, or persons engaged in heavy work or
exercise (i.e. sensitive receptors). Healthy adults can tolerate periodic exposures to air
pollutant levels well above these standards before adverse health effects are observed.
California has adopted health advisory levels called episode criteria for ozone, carbon
monoxide, sulfur dioxide, and ozone in combination with sulfates. Episode criteria repre-
sent short-term exposures at concentrations which actually threaten public health (refer to
Appendix A for additional details).
Under the Clean Air Act, the United States Environmental Protection Agency (EPA) is
required to set clean air standards and update them based upon scientific studies without
consideration of the economic impact. The American Lung Association sued the EPA in
1993 to force it to establish new stricter health -based standards.
In November of 1996, the EPA proposed tougher ozone and particulate standards intended
to reduce the number of deaths, illnesses and lost work days linked to air pollution. After
seven months of debate, President Clinton imposed the strict new 8 -hour average ozone
standard and the new standard for particulate matter less than 2.5 microns nationwide on
June 25, 1997. This action will force American cities and states to mount agressive and
4. SCAQMD and SCAG; AQMP - Southeast Desert Air Basin, Riverside County; October 1979.
3-4
Figure 3-1
Ambient Air Monitoring Stations Operating During 1995-1997
Salton Sea Air Basin
r--------
i • Palm Springs
m • Indio
Riverside
r.� County
{
Salton • Niland
j Cz
Sea \ o
Imperial Q
E) Westmorland County
E) Brawley
Winterhaven
i • EI Centro
• Calexico (3) .----_ J•�-r-
Mexico
• Gaseous monitoring and particulate
sampling
e Particulate sampling only
iV,,1d0 Engineering Scale: 1" = 19.25 Miles
costly efforts to clean up the air over the next 15 years or face harsh federal sanctions (such
as a freeze on federal highway funds). Each of southern California's eight counties, where
a total of 17 million people currently live, would exceed one or both of the new standards.
The new PM2.5 standards address particles roughly one twenty-eighth the diameter of a
human hair that can become lodged far into the lungs. An annual average of 15 ug/m3 and
a 24-hour average of 65 ug/m3 have been set as the new PM2.5 standards. To allow for
occasional atmospheric anomalies, communities would be allowed to exceed the 24-hour
standard several times before being designated nonattainment.
The new ozone standard is 0.08 ppm over an 8 -hour period. Communities would be
allowed to disregard the three highest concentartions during each year in determining
compliance. This would focus attention on long-term ozone exposures which pose a
greater health risk than short-term abnormally high concentrations.
Episode Criteria
The South Coast Air Quality Management District monitors contaminant levels and meteo-
rological factors on a daily basis in order to forecast high pollutant levels in stable atmo-
spheric conditions. Such conditions are known as "episodes". Criteria for episodes are
available for photochemical oxidants, carbon monoxide, sulfur dioxide, nitrogen dioxide,
particulate matter and combinations of sulfur dioxide and particulate matter (as shown in the
Appendix A). Episodes are divided into three stages, depending upon the concentration of
the pollutant that is predicted or reached.
Effects of Pollutants on Sensitive Receptors
The California Air Resources Board (GARB) has identified the following groups of indi-
viduals as the most likely to be affected by air pollution: the elderly over 65; children under
14; athletes; and people with cardiovascular and chronic respiratory diseases such as
asthma, emphysema, and bronchitis. These sensitive groups represent over 50% of the
total California population.5 Demonstrated effects of specific air contaminants on health
and vegetation are discussed in Appendix A and summarized in Table 3-1.
The elderly are most sensitive, since the loss of lung tissue is a natural process of aging.
Inhalation of air pollution accelerates this loss by reducing lung volume, and functional
lung tissue. Damaged and irritated lung tissue becomes susceptible to bacterial infection.
This increases the likelihood of chronic respiratory disease by reducing the ability of the
immune system to fight infection and resist disease.
3.1.2 REGIONAL AIR QUALITY
Southern California, with the lowest summertime mean mixing height, the lowest average
wind speed and emissions from the second largest urban area in the U.S., has the worst air
pollution problem in the nation. Although past programs have been effective at improving
the air quality of the SCAB, it still exceeds health -based standards for ozone, carbon
monoxide and PMio. Ozone levels have been reduced by 50 percent over the last 30 years,
sulfur dioxide and lead standards have been met, and other criteria pollutant concentrations
have significantly declined. The Basin met the federal annual NO2 standard for the first
time in 1992.
5. California Air Resources Board; Facts About How Air Pollution Damages Health; 1983.
3-5
Table 3-1
Health Effects of Air Pollutantsa
Pollutant
Most Relevant Effects
Short -Term Exposures: Decline in pulmonary function in healthy individuals
including breathing pattern changes, reduction of breathing capacity, increased
susceptibility to infections, inflammation of the lung tissue and immunological
changes. Increased frequency of asthma attacks, cough, chest discomfort and
Ozone
headache.
Long -Term Exposures: Risk to public health implied by altered connective
tissue metabolism and host defense in animals. A correlation has been reported
between elevated ambient ozone levels and increases in daily hospital admission
rates and mortality.
A consistent association between increased ambient CO levels and excess admissions
for heart diseases (such as congestive heart failure) has been observed.
Carbon
Can cause decreased exercise capacity in patients with angina pectoris.
Monoxide
Adversely affects conditions with an increased demand for oxygen supply (fetal
development, chronic hypoxemia, anemia, and diseases involving the heart and blood
vessels).
Can cause impairment of time interval estimation and visual function.
Sensory responses may be elicited or altered.
Nitrogen
May cause some impairment of pulmonary function and increased incidence of acute
Dioxide
respiratory disease including infections and respiratory symptoms in children.
Can cause difficulty in breathing in healthy as well as bronchitic groups.
Increase in blood lead levels which may impair or decrease hemoglobin synthesis.
Lead
Adversely affects the development and function of the central nervous system, leading
to learning disorders, distractibility, lower I.Q. and increased blood pressure. Lead
poisoning can cause anemia, lethargy, seizures and death.
May cause higher frequencies of acute respiratory symptoms (including airway
Sulfur
constriction in some asthmatics and reduction in breathing capacity leading to severe
Dioxide
difficulties) and diminished ventilatory function in children.
Very high levels of exposure can cause lung edema (fluid accumulation), lung tissue
damage, and sloughing off of cells lining the respiratory tract.
May cause higher frequencies of acute respiratory symptoms and diminished
ventilatory function in children.
A consistent correlation between elevated ambient PM 10 levels and an increase in
Particulates
mortality rates, respiratory infections, number and severity of asthma attacks and the
number of hospital admissions has been observed.
Some recent studies have reported an association between long-term exposure to air
pollution dominated by fine particles and increased mortality, reduction in life -span,
and the possibility of an increased incidence of cancer.
a. SCAQMD, "Draft 1997 Air Quality Management Plan".
3-6
3.1.3 LOCAL AIR QUALITY
Local Climate and Meteorology
The study area is located in the Coachella Valley, an and desert region with a climate
characterized by low annual rainfall, low humidity, hot days and very cool nights. The
climatological station closest to the project site is located in Palm Springs.
The annual precipitation monitored during 1997 in Palm Springs was 4.50 inches, which
was 0.81 inches below the average annual rainfall total normalized over the past 104 years.
The average temperature was 75.5 degrees Fahrenheit during 1997, 2.3 degrees above
normal. Temperature extremes ranged from 37 to 117 degrees Fahrenheit.6
Wind direction and speed (which in turn affect atmospheric stability) are the most important
climatological elements affecting ambient air quality within the planning area. The
prevailing wind direction in Palm Springs is predominantly from the northwest. The
annual mean wind speed is 7.6 miles per hour. Calm conditions occur 13.6 percent of the
time in Palm Springs. In Thermal, the annual mean wind speed is 8.1 miles per hour and
calm conditions occur only 2 percent of the time, as shown in Figure 3-2.
Desert regions are generally windy because minimal friction is generated between the
moving air and the low, sparse vegetation. This allows the wind to maintain its speed
crossing the desert plains. In addition, the rapid daytime heating of the air closest to the
desert surface leads to convective activity and the exchange of surface air for upper air
which accelerates surface winds during the warm part of the day. Rapid cooling at night in
the surface layers during the winter months results in a high frequency of calm winds.?
Since the dominant daytime onshore wind pattern follows the peak travel period (6.00 am -
9:00 am) in the Los Angeles/Orange County area, during periods of low inversions and
low wind speeds, the photochemical smog formed in these areas is transported downwind
into Riverside County, San Bernardino County and the Coachella Valley.
Peak oxidant levels occur in the late afternoon and evening (between 4 pm and 8 pm), as
pollutants are blown through the San Gorgonio Pass. Oxidant concentrations in the 50 -
mile long and 20 -mile wide Coachella Valley are highest, closest to the South Coast Air
Basin, and decrease steadily as the air mass moves east from Banning to Palm Springs and
then Indio.
Surface -based inversions in the Coachella Valley are prevalent at night throughout the year
and usually persist into the day during the winter months. Inversion conditions are associ-
ated with degraded air quality because the surface air is prevented from rising and dissipat-
ing the air pollutants that accumulate throughout the day.
Radiation inversions are prevalent at night throughout the year. They limit the mixing in
the lower atmosphere to a height of 200 to 2,000 feet. They persist through much of the
day in winter but are destroyed early in the day in summer.
Local Ambient Air Quality
The South Coast Air Quality Management District maintains ambient air quality monitoring
stations at numerous locations. The project site is located within the Coachella Valley
6. NOAA; Climatological Data Annual Summary, California, 1997.
7. California Air Resources Board; Climate of the Southeast Desert Air Basin, January, 1990.
3-7
Figure 3-2
Annual Surface Wind Rose Summary
(Thermal)
11.2%
25.7% -� _.. 10.1%
11.5% ! 3.8%
. \
2.7%
0.8°I
t
0.8%
1.0%
2.0% ten. -.•..._ ...._L_ - ....... ......... 8.0%
5.5%
Note: Bar thickness represents percent of predominant wind direction.
Bar length indicates wind speed. Calm = 2.0% of time. Mean Speed = 8.1 mph.
MW
endoEngineering
Sx S
which is Source Receptor Area (SRA) 30. The SRA 30 monitoring stations are located in
the City of Palm Springs and the City of Indio. The 1995 through 1997 ambient air quality
data (which is included in Appendix A) indicates that only ozone and PMio have exceeded
the relevant state and federal standards in the Riverside County portion of the Salton Sea
Air Basin.
Ozone
Ozone air quality trends since 1976 for the South Air Basin and the Coachella -San Jacinto
Planning Area indicate a parallel downward trend in the number of days exceeding the
federal 1 -hour ozone standard. This has occurred despite the fact that population growth in
the Coachella Valley over this period has been dramatic.
The Coachella Valley is currently designated as a "severe -17" ozone nonattainment area.
This designation indicates that the attainment date for the federal ozone standards is
November 15, 2007 (17 years from the date of enactment of the federal Clean Air Act).
Figure 3-3 depicts the number of days from 1995 through 1997 exceeding the one-hour
state ozone standard as well as the maximum hourly ozone concentrations at Coachella
Valley ambient air monitoring stations in Indio or Palm Springs. Ozone levels exceeded the
state one-hour standard (0.09 ppm) on 15 percent of the days monitored. The maximum
one-hour ozone concentration measured was 0.16 parts per million (ppm). This exceeds
the federal standard by more than 33 percent and exceeds the state standard by more than
77 percent. The federal one-hour ozone standard (>.12 ppm) was exceeded on 2 percent of
the days monitored. No ozone episodes were declared at either air monitoring station
during these three years.
Inhalable Particulate Matter (PMio)
The Coachella Valley was reclassified in February 1993 by the Environmental Protection
Agency (EPA) as a "serious" nonattainment area for PMio, which means that the valley had
violated federal health -based standards for particulate matter. PMio in this area comes
mostly from locally generated fugitive dust produced by both human activities (on -road and
off-road vehicles and construction activities) and natural occurrences (wind storms). The
highest concentrations are typically found in the summer, when hot dry weather produces
more dust. A PMio maintenance plan for the Coachella Valley was recently developed as a
separate plan from the 1997 AQMP.
PMio monitoring in the Coachella Valley between 1995 and 1997 indicated that (with the
exception of two measured PMio exceedances due to high wind natural events) the area
attained the federal PMIo standard. The EPA recently released a natural events policy which
exempts certain high wind events causing PMio air quality exceedances as being counted as
a violation. Consequently, the Coachella Valley is eligible for consideration by the EPA as
having attained the federal PMIo standard. A reclassification of the Coachella Valley by the
EPA may not occur, however, before the year 2000.
Figure 3-4 depicts the percentage of PMIo samples exceeding the state 24-hour standard
from 1995 through 1997 as well as the maximum 24-hour PMio concentrations in the
Coachella Valley. As shown therein, PMio concentrations exceeded the California 24-hour
standard during 46 percent of the monitoring periods. The maximum 24-hour PMio
concentration monitored was 199 micrograms per cubic meter (nearly four times the state
standard of 50 micrograms per cubic meter). The PMio annual geometric mean concentra-
tion exceeded the state standard of 30 micrograms per cubic meter during all three years,
and ranged between 46.1 and 47.2 micrograms per cubic meter in the Coachella Valley.
W
Figure 3-3
Coachella Valley Ozone Data
Maximum Hourly Ozone Concentrations
0.20
X0.18_
CL
CL -
0.16
�
o
0.14
c _
0.12
-
Federal Standard
c
.'
.12 rn
0.10;
" '
State Standard
E
0.08
r
(.09 PPm)
0.06
,:
x
2 0.04
y
O 0.02
1
' r
0.00
1995 1996 1997
Year
Days Exceeding State Ozone Standard
80-
0 -c
(D70-
0
O" 60-
0
2rr
m
c 50
O w
cc 40
cis
�, V`
o 0 30
0 c
0 0
in 20
Z 10d,
0
I�Nv1
1995 1996 1997
Year
ndo Engineering
Source: 1995-1997 SCAQMD Air Monitoring Data
Figure 3-4
Coachella Valley PM10 Data
Maximum 24 -Hour Concentrations
200—
M71
E
0 150
Federal Standard
(150 ug/m3)
c
a�
i
U
C
v 100
0
2
N
E 50
State Standard
E
(50 ug/m3)
X
c0
0
d
1995 1996 1997
Year
Percentage of PM10 Samples Exceeding State Standard
100
90
80-
07075
70-
75(D
C X 60
>, w
Co 0 co 50-
0o
-0
T;
)
Q0 ° 40
cTJ
Z^ 30
/r
rnL
a 20-
10
0
-
1995 1996 1997
iv
Year
ndo Engineering
Source: 1995-1997 SCAOMD Air Monitoring Data
The federal 24-hour PMio standard of 150 ug/m3 was exceeded three times between 1995
and 1997. The PMio concentration reached a maximum level of 199 ug/m3. The annual
arithmetic mean ranged between 50.8 and 53.4 micrograms per cubic meter (which
exceeded the federal standard of 50 ug/m3).
The SCAQMD identified the open sources of fugitive dust (PMIo) emissions throughout
Riverside County in 1987 and projected them for the year 2010. Although natural/unspec—
ified sources comprised over 65 percent of the open area source PMio emissions in 1987
(followed by paved roads at 14 percent, and construction at 10 percent), by the year 2010,
this situation was projected to change dramatically and the primary open area source
category was projected to be construction (at more than 59 percent).$
Nitrogen Dioxide
The federal annual average nitrogen dioxide standard was not exceeded at the Coachella
Valley stations between 1995 and 1997. Similarly, the state 1 -hour nitrogen dioxide
standard was not exceeded. The maximum 1 -hour NO2 concentration monitored was 0.09
ppm, which was 36 percent of the standard (0.25 ppm).
Carbon Monoxide
The state and national carbon monoxide (CO) standards were not exceeded in the Coachella
Valley between 1995 and 1997. The highest maximum CO concentration measured during
the last three years was 3.0 ppm (1 -hour average) and 1.6 ppm (8 -hour average).
Other Criteria Pollutants
Sulfur dioxide and lead are not monitored in the Coachella Valley. Lead concentrations
dropped dramatically following the phasing out of leaded gasoline. Federal sulfur dioxide
standards were last exceeded in the 1960's and the state standards were last exceeded in
1990 in Los Angeles County. These pollutants are not of concern to the SCAQMD or the
California Air Resources Board (CARB) in the Coachella Valley.
3.1.4 EXISTING SENSITIVE RECEPTORS
Land uses considered by the SCAQMD to be sensitive receptors include the following:
• residences, • long-term health care facilities,
• schools, • rehabilitation centers,
• playgrounds, • convalescent centers,
• child care centers, • retirement homes, and
• athletic facilities.
If these receptors are located adjacent to a major intersection, carbon monoxide (CO) "hot
spots" may occur during times of peak use. High levels of carbon monoxide are also
associated with traffic congestion, and with idling or slow-moving vehicles, depending on
the background CO concentration. Therefore, projects that could negatively impact levels
of service at major intersections with nearby sensitive receptors must quantify and, if
necessary, mitigate potential impacts.
8. SCAQMD; AQMP Draft Technical Report III -F Inventory of Mo Emission, December 1990.
�:
Existing residential land uses within the study area that are sensitive to air quality are
located primarily north of the project site. Since current traffic volumes in the vicinity of
these sensitive areas are relatively low and the ambient carbon monoxide concentrations in
the Coachella Valley are also quite low, it is unlikely that a CO "hot spot' exists at these
receptors. To verify this conclusion, carbon monoxide levels were modeled at three of the
most heavily utilized intersections in the study area where sensitive receptors are located.
Localized carbon monoxide levels during morning peak hour traffic were assessed with the
CALINE 4 computer model. The intersections selected for modeling met two criteria: (1)
land uses sensitive to air quality currently are located adjacent to the intersection, and (2)
the intersecting roadways were expected to carry the most project -related traffic in the
future. The assumptions and model output sheets are included in Appendix A. A
comparison of the projected carbon monoxide levels to state and federal standards indicates
whether or not carbon monoxide "hot spots" may occur during times of peak use.
As shown in Table 3-2, current carbon monoxide levels within the study area are quite low.
Existing traffic volumes contribute up to 0.5 ppm to the ambient 1 -hour carbon monoxide
concentrations and up to 0.3 ppm to the ambient 8 -hour carbon monoxide concentrations at
50 feet from the intersections modeled.
Table 3-2
Existing Carbon Monoxide Concentrations
a. Receptor distances are measured from the roadway centerline.
b A Persistence Factor of 0.6 was used to determine the 8 -hour CO concentrations from the 1 -hour values.
c. The background CO concentration was the highest 1 -hour and 8 -hour concentration measured between
1995 and 1997 at the Palm Springs ambient air monitoring station.
3-10
1 -Hour Average (ppm)
8 -Hour Average (ppm)
Receptor Distancesa (Feet)
50
100
200
50
100
200
Local Intersection Contributionb
Jefferson Street @
- Avenue 50
0.5
0.3
0.2
0.3
0.2
0.1
Madison Street @
- Airport Boulevard
0.1
0.1
0.1
0.1
0.1
0.1
- Avenue 58
0.1
0.1
0.0
0.1
0.1
0.0
Background CO Concentrationc
3.0
3.0
3.0
1.6
1.6
1.6
Local Contribution+Background
Jefferson Street @
- Avenue 50
3.5
3.3
3.2
1.9
1.8
1.7
Madison Street @
- Airport Boulevard
3.1
3.1
3.1
1.7
1.7
1.7
- Avenue 58
3.1
3.1
3.0
1.7
1.7
1.6
State Standard
20.0
20.0
20.0
9.0
9.0
9.0
Federal Standard
35.0
35.0
35.0
9.0
9.0
9.0
a. Receptor distances are measured from the roadway centerline.
b A Persistence Factor of 0.6 was used to determine the 8 -hour CO concentrations from the 1 -hour values.
c. The background CO concentration was the highest 1 -hour and 8 -hour concentration measured between
1995 and 1997 at the Palm Springs ambient air monitoring station.
3-10
Morning peak hour carbon monoxide concentrations adjacent to the intersections modeled
(including background concentrations) are expected to be as high as 3.5 ppm at a distance
of 50 feet. This represents only 17.5 percent of the 20 ppm state standard and is only 10
percent the 35 ppm federal standard (1 -hour average). Similarly, the state and federal 8 -
hour carbon monoxide standards are not currently being exceeded in the study area. Eight-
hour carbon monoxide concentrations near sensitive receptors located adjacent to the three
intersections modeled are as high as 1.9 ppm at a distance of 50 feet. This represents less
than 21 percent of the 9.0 ppm state standard. Therefore, carbon monoxide (CO) "hot
spots" do not currently occur during peak travel periods.
3.1.5 LOCAL SOURCES OF AIR CONTAMINANTS
The Coachella Valley is sparsely populated, with the largest urban area represented by Palm
Springs. Industrial sources in the Coachella Valley are generally limited and localized.
Blowsand is the most severe form of wind erosion, occurring when barren sand or sandy
loam soils are exposed to high winds, in the absence of moisture. Blowsand can cause
significant property damage and expensive clean-up procedures. It contributes to high
suspended particulate levels and associated respiratory problems for sensitive receptors.
The project site is not located within the area designated by the Coachella Valley
Association of Governments (CVAG) as a "Blowsand Hazard Zone".9 This zone is
defined as ".. all land, by nature of its location or soil characteristics subject to real or
potential sand accumulation and/or abrasion, or land which may cause sand damage to
adjacent property." Within the blowsand hazard zone is an "Active Blowsand Zone".
Blowsand reduction measures are required for projects located within the "Active
Blowsand Zone".
3.1.6 REGULATORY SETTING
Federal Clean Air Act Requirements
Section 110 of the federal Clean Air Act (CAA) requires that each State adopt a plan which
provides for implementation, maintenance and enforcement of the primary and secondary
national air quality standards in that state. That requirement is met by the State
Implementation Plan (SIP).
The November 1990 amendments to the federal Clean Air Act (CAA) were intended to
intensify air pollution control efforts across the nation. The CAA identified specific
emission reduction goals, required both a demonstration of reasonable further progress (an
incremental reduction in emissions of relevant air pollutants needed to ensure attainment of
the national ambient air quality standards or NAAQS by the applicable date) and an attain-
ment demonstration, and incorporates more stringent sanctions for failure to attain or to
meet interim milestones.
As a "severe -17" nonattainment area, the Coachella Valley must demonstrate reasonable
further progress and attainment of the national ozone standards according to the provisions
of the 1990 federal Clean Air Act. The 1990 federal Clean Air Act requires the Coachella
Valley to: (1) identify specific emission reduction goals; (2) demonstrate reasonable further
progress in VOC emissions; (3) demonstrate attainment of the federal ozone standard; and
9. CVAG;Final SIP for PM10 in the Coachella Valley; November 1990-
3-11
(4) provide contingency measures or actions in the event of a failure to attain or to meet
interim milestones. 10
The CAA also requires that each serious ozone nonattainment area achieve actual VOC
emission reductions of at least 3% per year (averaged over each consecutive 3 -year period
beginning November 15, 1997 until November 15, 2007). Milestone years for VOC
emission reductions in the Coachella Valley are 1999, 2002, 2005 and 2007.
This requirement appears to be extremely difficult to meet in the Coachella Valley because
of the limited local emissions in the area in 1990 and the rapid population growth projected
for this area. All increases in VOC emissions caused by growth will need to be fully offset
in order to meet both the federal Clean Air Act and the California Clean Air Act require-
ments. For example, the CAA requires 3% VOC emission reductions beginning in 1997.
If an area experiences population growth such that VOC emissions increase by 15% over
1990 levels, then the area must develop regulations that achieve VOC reductions of at least
18% (the 3% rate -of -progress requirement plus the 15% increase from population growth).
According to the Southern California Association of Governments, by the year 2020,
population in the Coachella Valley is projected to more than double (from 267,000 in 1990
to 389,000 in the year 2010 and 475,000 in the year 2020). In view of the population
growth projected for the Coachella Valley, the rate -of -progress requirements of the CAA
cannot be met unless further local controls are implemented. ll
In view of strong evidence that pollutant transport from the SCAB to the Coachella Valley
is the primary cause of the ozone nonattainment status of the Coachella Valley, the 1997
AQMP states that aggressive control of the SCAB emissions is an effective strategy to
substantially improve air quality in the Coachella Valley.
The Coachella -Valley is currently designated as a "severe -17" ozone nonattainment area.
This designation indicates that the attainment date for the federal ozone standards is
November 15, 2007 (17 years from the date of enactment of the federal Clean Air Act).
The 1994 AQMP indicated that attainment of the standard would be possible with the
proposed control strategy for the SCAB and control of locally generated emissions via state
and federal regulations. The 1997 AQMP photochemical grid modeling carries forward the
1994 AQMP conclusions and control approach for the Coachella Valley.
The 1997 AQMP demonstrates that the VOC and NOx emission reductions from existing
SCAQMD and CARB rules are sufficient to meet the CAA post -1996 rate -of -progress
requirements for the Coachella Valley. 12 The rate -of -progress requirements for all mile-
stone years are met by a combination of VOC and NOx reduction from existing SCAQMD
and ARB rules. The control strategy provides additional VOC and NOx reductions for all
the years beginning with 1999 which can be used as a contingency in the event of a mile-
stone failure.
The CAA requires the SCAQMD to develop: a Federal Attainment Plan for Ozone; a post -
1996 rate -of -progress demonstration; an ozone attainment demonstration; a PMIo SIP
which incorporates best available control measures (BACM) for fugitive sources; near-term
(<year 2000) and long-term (>year 2000) transportation control measures and contingency
measures (i.e. additional control measures which would be implemented in the event of a
milestone or attainment failure).
10. The 1997 AQMP revision addresses these requirements and satisfies the SIP requirements under Title I
of the Clean Air Act.
11. SCAQMD; Draft 1997AQMP; August 1996; Table 8-1.
12. SCAQMD; Draft 1997 AQMP; August 1996; Table 8-4.
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The California Clean Air Act
The California Clean Air Act (CCAA), which is generally more stringent than the federal
CAA, was signed into law in 1988 and amended in 1992. The CCAA divides nonattain-
ment areas into categories with progressively more stringent requirements, based on
pollutant levels monitored therein.
The CCAA establishes a legal mandate to achieve health -based state air quality standards at
the earliest practicable date that is generally more stringent than the federal CAA. Serious
and above nonattainment areas are required to revise their AQMP to include specified
emission reduction strategies and to meet milestones in implementing emission controls and
achieving better air quality.
The study area is located in the Coachella Valley, which is an extreme nonattainment area
for ozone (based upon the state 1 -hour ozone standard). The ozone standard exceedance is
attributed to pollutant transport from the South Coast Air Basin (SCAB). Since the SCAB
is a non -attainment area for carbon monoxide, nitrogen dioxide, ozone and PMio, the
Coachella Valley may only be able to attain the ozone standard after the SCAB reduces
emissions of ozone precursors (VOCs and NOx).
The CCAA requires the establishment of indirect and area source controls to reduce vehicle
miles traveled (VMT) and increase average vehicle ridership (AVR). It specifies the use of
best available retrofit control technology for existing sources. The CCAA requires new
source review to mitigate all emissions from new and modified permitted sources. It also
requires consideration of transportation control measures (TCM's) and significant use of
low -emission vehicles by fleet operators.
CCAA requirements for control strategy development that are addressed in the 1997 AQMP
(Revised October 1996) include:
• Rate -of -progress requirements (reducing pollutants contributing to nonattain-
ment by 5% per year or the maximum feasible);
• Reduce per -capita population exposure to severe nonattainment pollutants
(Ozone, CO and NO2 for the SCAB) according to a prescribed schedule;
• Rank control measures by cost-effectiveness and implementation priority.
Air Quality Management Plan
It is the responsibility of the South Coast Air Quality Management District (SCAQMD) to
lead the regional effort to attain the state and national AAQS. The SCAQMD is charged
with developing and implementing the Air Quality Management Plan and reducing
emissions from industries, some mobile sources, and consumer products. The state Clean
Air Act requires that the AQMP be updated every 3 years.
The Air Quality Management Plan (AQMP) for the SCAB was originally adopted in 1979.
Subsequent revisions, as required by both state and federal Clean Air Acts, have occurred
since that time. The purpose of the 1994 AQMP was to set forth a comprehensive program
to lead the SCAB and Southeast Desert Air Basin portions of Los Angeles and Riverside
Counties into compliance with all national and state air quality standards.
3-13
The 1994 AQMP addressed the following federal Clean Air Act requirements for all non -
attainment areas within the SCAQMD's jurisdiction: 13
• updated 1990 emission inventories for CO, VOC, NOx, SOx and PMio;
• revised demonstration of 15% reduction in VOC emissions by 1996 to meet
rate -of -progress requirements;
• post -1996 VOC rate -of -progress requirements;
• an overall control strategy that met federal Reasonably Available Control
Measures (RACM) and Reasonably Available Control Technology (RACT)
requirements;
• Transportation Control Measures;
• attainment demonstration for ozone including contingency measures;
• revised attainment demonstrations for CO and NO2 including contingency
measures; and
• Best Available Control Measures for PMio.
The 1994 AQMP demonstrated attainment of the federal and state ambient air quality
standards. It proposed to achieve the federal ozone and PMio standards through long-term
measures that emphasized a greater reduction of nitrogen oxides emissions from on -road
and off-road sources than previous versions of the AQMP.
The 1994 AQMP addressed the State Implementation Plan requirements under Title I of the
federal Clean Air Act while acknowledging that attainment of the national ozone standard in
the Coachella -San Jacinto Planning Area would only be possible with substantial emission
reductions in the South Coast Air Basin. The 1994 AQMP concluded that: (1) a control
strategy that concentrates on South Coast Air Basin sources is sufficient to demonstrate
attainment in the Coachella -San Jacinto Planning Area; and (2) control of local VOC and
NOx emissions will have little effect on ozone exceedances in the planning area.
Aggressive control of VOC and NOx emissions within the South Coast Air Basin is the
most effective control strategy for ozone attainment in the Coachella Valley because locally
generated emissions are overwhelmed by upwind emissions generated within the SCAB.
The SCAB emissions of VOC and NOx are up to 50 times those in the Coachella Valley.
Improved air quality in the Coachella Valley clearly depends on reduced emissions in the
South Coast Air Basin.
Photochemical modeling undertaken by the SCAQMD for the 1994 AQMP has demon-
strated that the federal one-hour ozone standard will be met by November 15, 2007 in the
Coachella -San Jacinto Planning Area, as required by the federal Clean Air Act. The AQMP
control strategy provides sufficient VOC and NOx emission reductions from existing
SCAQMD and ARB rules to meet the CAA rate -of -progress requirements for the Coachella
Valley.
Because local government provides the primary focus of land use and growth management
decisions, no air quality management plan can succeed without the active participation of
local government. Most of the control measures relating to local government are in the
areas of trip reduction, energy conservation, and dust control.
13. The SCAB and those portions of the Southeast Desert Nonattainment Area (Antelope Valley and
Coachella -San Jacinto Planning Area) are nonattainment areas within the SCAQMD's jurisdiction.
3-14
Compliance with the provisions of the federal CAA and CCAA is the primary focus of the
latest Air Quality Management Plan developed by SCAQMD and SCAG. The latest
version adopted by the SCAQMD in November, 1996, is entitled the 1997AQMP. It was
adopted by the CARB in February of 1997, and was included in the State Implementation
Plan (SIP) and sent to the EPA for its review and approval. The EPA rejected the 1997
AQMP, therefore, pending its revision and resubmittal, the provisions of the 1994 AQMP
currently apply.
According to the 1997 AQMP, attainment of all federal health standards is to occur no later
than the year 2000 for carbon monoxide, the year 2006 for PMio and the year 2010 for
ozone. State standards would be attained no later than the year 2000 for carbon monoxide.
State standards for ozone and PMio would not be achieved until after the year 2010. Both
the federal and State standards for nitrogen dioxide have been met.
The 1997 AQMP includes short-term, intermediate, and long-term control measures, and
market based incentive strategies to meet targets for emission reduction. The short-term
measures identify specific control measures under existing technology. The control
measures consist mainly of: (1) stationary source controls that will be the subject of the
SCAQMD rule making, (2) CARB adopted motor vehicle emissions standards and fuel
specifications, and (3) federally adopted programs to reduce emissions from sources under
federal jurisdiction. Intermediate term measures are composed primarily of the extension or
more stringent application of short-term control measures. Long-term measures depend on
substantial technological advancements and breakthroughs that are expected to occur over
the next 20 years.
Control measures focus on adoption of new regulations or the enhancement of existing
regulations for stationary sources, as well as implementation/facilitation of advanced
transportation technologies (i.e., telecommunication, zero emission and alternative fuel
vehicles and infrastructure and both capital and non -capital based transportation
improvements). Capital based improvements consist of high occupancy vehicle (HOV)
lanes, transit improvements, traffic flow improvements, park and ride and intermodal
facilities, and urban freeway, bicycle and pedestrian facilities. Non -capital based
improvements consist of rideshare matching and CMP based transportation demand
management activities.
One type of transportation measure eliminated from the 1997 AQMP was indirect source
controls, which would regulate local land use decisions, particularly medium to large-scale
developments. These measures were found too expensive to implement without producing
cost-effective emissions reductions. Rule 2202, the replacement for Regulation XV -
Ridesharing, remains in effect to ensure that emissions reduction levels originally projected
with implementation of Regulation XV and other indirect source control strategies are
achieved. This removal reflects a growing understanding that command and control
measures tied to local land use decisions do not effectively alter travel behavior.
State Implementation Plan for PMio in the Coachella Valley
The SCAQMD's Final November 1990 State Implementation Plan (SIP) for PMio in the
Coachella Valley addresses the EPA's non -attainment particulate designation for the
Coachella Valley and the control measures required to meet state and federal PMio
standards (summarized in Appendix A). Large-scale blowsand events, which can produce
high levels of PMio through natural processes, are not targeted for control. This SIP
focuses on man-made dust producing activities and the reduction of blowsand intrusion
into populated areas.
3-15
The implementation and monitoring program of the SIP is dependent on the SCAQMD,
CVAG and local governments. Local governments are asked to develop ordinances,
monitor progress, and create a County Service Area (CSA) or similar funding mechanism
to implement the SIP.
SCAQMD Rules and Regulations
The SCAQMD is responsible for controlling stationary air pollution sources. Therefore,
its Rules and Regulations address a wide variety of industrial and commercial operations
(e.g. volatile organic compound operations, coating operations, paint and ink manufactur-
ing, etc.) and require operational controls on many processes (e.g. gasoline dispensing,
dry cleaning, incinerator burning, etc.). Rule 403 outlines controls on blowing dust from
construction sites. Rule 1108 specifies the content of cutback asphalt. Rule 1113 details
permitted VOC emissions from architectural coatings.
Rule 2202 went into effect on January 1, 1997. This rule applies to employers with more
than 250 employees and provides options for reducing employee work trips. Regulated
businesses are required to submit an emission reduction program with an emission
reduction target and the means for achieving that target.
The purpose of Rule 2202 - On Road Motor Vehicle Mitigation Options is to reduce mobile
emissions associated with employee commute trips to comply with federal and State Clean
Air Act requirements. As of January 1, 1997, this Rule applies to any employer who
employs 250 or more employees and provides a menu of options for reducing employee
work trips. Regulated businesses are required to submit an emission reduction program
that includes an emission reduction target (ERT) and means for achieving the identified
ERT. Mitigation options include: scrapping of older vehicles, incorporating clean fuel on
or off road vehicles into the company's vehicle fleet, conducting remote sensing of
employee vehicles and repair of gross emitters, utilizing emission reduction credits from
stationary sources, and participating in the Air Quality Investment Program (AQIP), which
requires payment of set fees per employee into a fund used to implement mobile source
emission reduction programs, approved the SCAQMD Governing Board.
Riverside County Comprehensive General Plan Air Quality Element
The Riverside County Air Quality Element contains policies for improving air quality in the
form of programs and land use standards focused on locally produced emissions which
exceed air quality standards. The creation of jobs close to homes is encouraged to lessen
peak hour congestion and air pollutant emissions of commuters. Transportation Demand
Management strategies are outlined to reduce the number of cars and trucks on the
transportation system during peak commute hours.
Policies that increase mobility to improve air quality are outlined, including the construction
of new bike lanes. Particulate emission reduction strategies are identified for construction
activities, unpaved roads, wind erosion, and agricultural activities. The goal of the
Riverside County Air Quality Element is to establish a system of charges that requires
individuals who undertake polluting activities to bear the economic cost of their actions in
an effort to encourage individuals to choose less polluting activities.
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3.2 AIR QUALITY IMPACT ANALYSIS
The South Coast Air Quality Management District is responsible for adopting, implement-
ing and enforcing air quality regulations within the Salton Sea Air Basin. The SCAQMD
reviews and comments on environmental documents for projects that may generate signifi-
cant adverse air quality impacts. The SCAQMD advises the lead agency in addressing and
mitigating the potential adverse air quality impacts caused by projects both during and after
construction. However, the final decision on the significance of the air quality impacts lies
with the judgment of the lead agency, Riverside County. This decision must be based
upon several considerations including the following.
1) What is the intensity and type of project?
2) What is the location of the project (i.e. upwind of sensitive receptors or in
areas with high pollutant concentrations)?
3) Will the project cause an exceedance of any air quality standard?
4) Will the project make a substantial contribution to an existing exceedance of
an air quality standard?
5) Is the project inconsistent with the AQMP?
6) Will the project emit toxic or hazardous air pollutants?
7) Will the mitigation measures that are attached to the project mitigate the air
quality impacts to the maximum extent feasible?
The proposed project is the Coral Mountain Specific Plan 218 Amendment No. 1, an
amendment to the Rancho La Quinta Specific Plan 21.8 approved in 1988. The previously
approved Specific Plan 218 included the development of 4,262 homes, 35 acres of
commercial uses, and 2 golf courses on-site. The currently proposed Coral Mountain
Specific Plan Amendment Number 1 represents a substantial reduction in residential (18%)
and commercial (74%) development intensity. The currently proposed project includes a
maximum development of 3,500 dwelling units, 9.2 acres of commercial uses, 6.8 acres of
community facilities, 41 acres of parks and trails, two championship golf courses with
clubhouses and maintenance facilities and a 10 -acre school. The impact analysis herein
addresses both the approved Specific Plan and the proposed Specific Plan 218 Amendment
#1 to permit a comparison to be made and conclusions to be drawn regarding the
significance of project -related impacts on air quality and the need for mitigation.
Two types of air pollutant sources must be considered with respect to the proposed project:
stationary sources and mobile sources. Stationary source considerations include emissions
from construction activities and natural gas combustion, as well as emissions at the power
plant associated with the electrical requirements of the proposed development. Mobile
source considerations include exhaust emissions resulting from short-term construction
activities and long-term vehicular travel associated with the proposed project.
3.2.1 IMPACT SIGNIFICANCE THRESHOLD CRITERIA
The SCAQMD has established short-term construction -related and long-term operational
thresholds which they recommend for use by lead agencies in making a determination of
significance that considers both primary or direct impacts and secondary or indirect impacts
on air quality. However, the final determination of whether or not a project is significant is
3-17
within the purview of the lead agency pursuant to Section 15064 (b) of the CEQA
Guidelines.)
For construction -related emissions, the SCAQMD has established significance thresholds
on a daily and quarterly basis. Projects with construction -related emissions in a quarterly
period that exceed any of the quarterly emission thresholds shown in Table 3-3 should be
considered to be significant.
Table 3-3
SCAQMD Significance Threshold Criteriaa
(Pounds/Day)
Pollutant
CO
ROC
NOx
Sox
PM10
Operational Emissions
-Pounds/Day
550
75
100
150
150
Construction Emissions
- Pounds/Day
550
75
100
150
150
- Tons/Quarter
24.75
2.5
2.5
6.75
6.75
a. SCAOMD, CEQA Air Qualitv Handbook; November, 1993
Since a project's quarterly emissions are determined by averaging over a 3 -month period
(including only actual working days), it is possible to not exceed the quarterly thresholds
while exceeding the daily thresholds shown in Table 3-3. If emissions on an individual
day exceed any of the daily thresholds, the project impact should be considered significant.
Localized carbon monoxide impacts on sensitive receptors that exist adjacent to roadways
serving project -related traffic must be assessed. Projected 1 -hour and 8 -hour carbon
monoxide concentrations at intersections in the project vicinity must be identified and
compared to the state 1 -hour and 8 -hour carbon monoxide standards to determine the
significance of project -related impacts. Significant impacts occur when carbon monoxide
standard exceedances are projected at sensitive receptor locations.
In cases where the background concentration already exceeds the state carbon monoxide
standards, a significant impact is defined as occurring when there will be a measurable
increase in carbon monoxide levels at the receptor site. A measurable increase is defined by
the SCAQMD as 1.0 ppm for 1 -hour carbon monoxide levels and 0.45 ppm for 8 -hour
carbon monoxide levels.
3.2.2 SHORT-TERM CONSTRUCTION -RELATED IMPACTS
Short-term impacts on air quality will occur during the construction activities required to
implement the proposed project. These adverse impacts will be similar to those of the
approved Specific Plan on a daily and quarterly basis. They will include:
1. SCAQMD, CEQA Air Quality Handbook, April 1993, page 6-2.
3-18
1) air pollutant emissions at the power plant serving the construction site while
temporary power lines are needed to operate construction equipment and
provide lighting;
2) exhaust emissions from the construction equipment used as well as the
vehicles used to transport the off-highway construction equipment required;
3) exhaust emissions from the passenger vehicles of construction workers;
4) particulate emissions (fugitive dust) from excavation, grading and clearing
activities;
5) exhaust emissions from the heavy vehicles used to transport building
materials, sand, and gravel to the site;
6) emissions related to the development of on-site landscaping; and
7) emissions from architectural coating and paving materials used for build-
ings, roads, parking lots etc.
For a "worst case" short-term impact assessment, it was assumed that the project will be
approved and construction will begin in the year 2000 with an average construction crew of
20 people and a "worst case" construction crew of 35. Approximately eight months of
mass grading on-site would be required for the initial development phase, followed by 36
months of fine grading activities. During the grading activities, approximately 20 acres per
day would be disturbed. Building construction for the initial phase would extend over a
30 -month period. Construction of the initial phase could be completed during the year
2004.
Construction equipment on-site will typically operate nine hours per day and five days per
week. The remainder of the site would be mass graded over a period of 6 months,
beginning in the year 2004. Some overlap between construction phases may occur.
Following the initial development phase, fine grading activities would extend for 54
months, and be followed by 60 months of building construction. Buildout of the site is
projected to occur by the year 2010.
Field Office Stationary Source Emissions
Typically a field office is located at a construction site. Operation of a field office during
construction activities would result in air pollutant emissions at the power plant supplying
its electricity or from the use of gasoline -powered portable generators at the construction
site. Appendix A includes air pollutant emission factors associated with the generation of
electricity at the power plant. In general, a 500 square foot field office would generate
negligible amounts of air pollution (.0052 pounds of CO, .0003 pounds of ROC, .0298
pounds of NOx, .0031 pounds of SOx, and .0010 pounds of Mo per day).
Construction Period Exhaust Emissions
Localized exhaust emissions will result from the use of construction equipment to
implement the project. Exhaust emissions over a broader area will result from the transport
of off-highway equipment and the construction crew to and from the construction site.
Table 3-4 provides the "worst case" daily and quarterly emissions associated with the
proposed construction activities. Daily emissions for construction of the initial phase were
found to exceed those of subsequent phases (since on -road motor vehicle emission rates are
decreasing each year). The quarterly emissions projections represent an average of the
construction -related emissions over a 3 -month period that includes emissions only on actual
working days.
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Table 3-4
"Worst Case" Construction -Related Emissionsa
Emissions Source
CO
ROC
NOx
Sox
PM10
Daily Emissions
(Pounds/Day)
- Construction Equip.
22.29
4.80
65.08
7.33
5.90
- Maximum Crew of 35
24.14
4.35
4.39
0.37
0.75
- Materials Delivery
17.76
2.96
9.51
0.58
1.34
- Graded Surfacesd
-
-
-
-
348.48
Total
64.19
12.11
78.98
8.28
356.47
Daily Thresholda
550
75
100
150
150
(Pounds/Day)
Threshold Exceeded
No
No
No
No
Yes
Quarterly Emissions
(Tons/Quarter)
- Construction Equip.
5.81
1.18
15.00
1.62
1.51
- Average Crew of 20b
0.45
0.08
0.08
0.01
0.01
- Materials Deliveryc
0.58
0.10
0.31
0.02
0.04
- Graded Surfacesd
-
-
-
-
11.33
Total
6.84
1.36
15.39
1.65
12.89
Quarterly Thresholda
24.75
2.50
2.50
6.75
6.75
(Tons/Quarter)
Threshold Exceeded
No
No
Yes
No
Yes
a. Refer to the worksheets in Appendix A for assumptions, emission factors and calculations.
b. Assumes an average crew of 20 and 65 working days/quarter.
c. Assumes construction equipment and building materials delivery trips occur on 65 days during the
"worst case" quarter.
b. Assumes 20 acres are disturbed on-site per day and twice daily watering occurs.
Grading PMio Emissions
The primary sources of construction -related PMio emissions on-site will include: grading
activities and heavy-duty equipment on paved and unpaved areas. Cut and fill quantities
will be balanced on-site but may not be balanced within the initial phase. An average PMio
emission factor for construction activities is 26.4 pounds of PMio per day per acre
disturbed.2 This factor can be reduced by 34% through twice daily watering.
Without watering to control dust, daily PMio emissions from 20 acres would total 528.0
pounds. Regular watering would reduce the PMio emissions to 348.48 pounds per day.
Assuming 65 working days per quarter, Mo emissions from 20 acres would total 17.16
tons without watering or 11.33 tons with regular watering. Refer to Appendix A for the
spreadsheet used to make this determination.
2. Source: SCAQMD, CEQA Air Quality Handbook; 11/93; Table A9-9; pg A9-93. Refer to the
fugitive dust grading emissions worksheets in Appendix A for assumptions and calculations.
3-20
It can be seen from Table 3-4 that "worst case" daily construction -related emissions
associated with the proposed project are expected to exceed the SCAQMD significance
threshold for PM1o. If 20 acres are disturbed on-site on a daily basis as expected, the
resulting PMio emissions will be significant (more than twice the SCAQMD threshold of
significance). No more than 8 acres per day could be disturbed to reduce the grading on-
site to the point that daily PMio emissions would not be significant.
As shown in Table 3-4, project -related quarterly construction emissions are projected to
exceed the SCAQMD quarterly thresholds of significance for NOx and PMio. Without
mitigation other than regular watering during grading activities, the project will have a
significant short-term impact on local NOx and PMio concentrations. If no more than 8
acres per day were disturbed on-site during grading activities, quarterly PMio emissions
would not exceed the quarterly threshold.
Scrapers are projected to generate 75 percent of the NOx emissions during the construction
period. To avoid exceeding the quarterly NOx threshold of significance, only one scraper
could be active on-site for the 65 days in a quarter. A restriction of this magnitude would
not be feasible, as it would increase the length of the grading activities on-site by a factor of
nine and the initial phase would require 33 years of grading rather than 3.7 years. An
alternative approach would be to restrict the number of days each quarter that grading could
occur on-site. If nine scrapers were used on-site for only 9 days per quarter, the quarterly
threshold for NOx would not be exceeded. This approach would not be feasible as it
would extend the grading period to the point that development on-site would not be
completed for 62 years.
Clearly, other measures are required to minimize short-term emissions, since essentially
any development would generate a significant short-term impact and it is virtually impossi-
ble to mitigate short-term construction impacts to a level of insignificance. The SCAQMD
recommends a series of measures that can assist in reducing construction emissions (see
Section 3.3). These measures rely on the use of diesel rather than gasoline -powered
equipment (90% of all heavy construction equipment is currently diesel powered), keeping
the construction equipment well -tuned, and employing activity management techniques (re-
scheduling for use in off-peak hours or using fewer pieces of equipment at once when
feasible and extending the construction period when feasible to reduce daily emissions).
Future tracts within the project site will comply with SCAQMD Rule 403 which prohibits
the release of fugitive dust emissions from any active operation, open storage pile, or
disturbed surface area beyond the property line of the emission source. Particulate matter
deposits on public roadways are also prohibited. Future tracts will be required to comply
with all reasonably available control measures, as part of the development review process.
Even with these mitigation measures, it will be difficult to develop a parcel within the
project site without exceeding the SCAQMD PMio and NOx significance threshold criteria.
While restricting the size of the disturbed area during grading may be an effective way to
reduce PMio emissions below the SCAQMD threshold of significance, it is not feasible.
Restricting the size of the disturbed area or the number of scrapers in use on-site would
force the construction equipment and crew to remain at each site for a much longer period
to complete the grading activities. Since the cost of the grading is related to the number of
days that the crew and the equipment will be needed at the construction site, the increase in
grading costs associated with this mitigation strategy would more than offset the benefits
achieved. Increasing the time required to grade each development site would also increase
the motor vehicle emissions generated by the construction crew commuting to and from the
job site and the construction -related noise impacts on adjacent land uses.
3-21
Paving Material and Architectural Coating Emissions
Reactive organic compound (ROC) emissions will occur as a result of surface coating and
paving materials used during future construction activities. SCAQMD Rule 11083
prohibits the use of rapid and medium cure cutback asphalts in the air basin (asphalt can
contain no more than 0.5% by volume organic compounds). Rule 1108.1 also prohibits
any organic compounds in emulsified asphalts. Therefore, it is expected that ROC
emissions, as a result of paving activities, will be minor.
The reactive organic compound content of architectural coating materials (paint, varnish,
lacquer, primer, etc.) will not be permitted to exceed the SCAQMD's Rule 1113 architec-
tural coating threshold of 2.08 pounds of ROC per gallon. Most, if not all, of the ROCs
will evaporate during the surface coating application and drying process. To minimize
ROC emissions during future surface coating operations, the use of water-based enamels
should be encouraged to the extent feasible and the use of lacquers should be discouraged.
Significance of Short -Term Impacts
On a daily and a quarterly basis, the proposed project will generate essentially the same
short-term impacts on air quality as the adopted Specific Plan (which represents the No
Project Alternative). "Worst case" daily construction -related emissions associated with
either development scenario are expected to exceed the SCAQMD significance threshold for
PMio. Quarterly construction -related emissions associated with either development
scenario are expected to exceed the SCAQMD significance thresholds for PMio and NOx.
By definition, the impact of Amendment #1 to Specific Plan 218 is the difference between
it's impacts and those associated with the No Project Alternative (the approved Specific
Plan 218). Since no appreciable difference in the daily or quarterly construction impacts on
air quality can be established between the these two development alternatives, it could be
concluded that the proposed project will have an insignificant short-term impact on air
quality.
The currently proposed Coral Mountain Specific Plan Amendment Number 1 represents a
substantial reduction in residential (18%) and commercial (74%) development intensity.
Consequently, the air quality impacts generated as a result of the actual building
construction activities required to implement the proposed project will be lower than those
of the approved Specific Plan 218 by a corresponding amount.
Since air quality impacts resulting from construction activities could exceed the PM]o and
NOx thresholds of significance, mitigation measures are required to reduce these impacts.
Potential mitigation measures for use as conditions of approval on future tentative maps are
provided in Section 3.3. All feasible mitigation measures should be incorporated to reduce
construction -related air quality impacts to the maximum extent feasible.
3.2.3 LONG-TERM OPERATIONAL IMPACTS
Air Pollutant Emission Projections
During the life of the proposed development, a variety of emissions will be produced by its
day-to-day operations. Only a small fraction of the project -related emissions would be
emitted at a fixed location by stationary sources. Nearly all of the emissions would be
emitted over a broad area by motor vehicles.
3. Telephone communication with Ms. Linda Basilio, SCAQMD, on 4/30/93.
3-22
Emission projections can be made for the initial development phase (year 2004) and the
project buildout year (2010) by multiplying anticipated motor vehicle, natural gas, and
electrical usage rates for each development scenario by the appropriate emission factors, as
specified by the SCAQMD in the CEQA Air Quality Handbook (11/93 Update). The usage
rate assumptions and emission factors utilized are detailed in Appendix A and the results are
summarized in Table 3-5.
If the proposed project changes operational emissions (compared to the adopted Specific
Plan 218) by an amount that exceeds the SCAQMD operational emission significance
threshold criteria, a significant long-term impact on air quality will occur. Table 3-5
provides the daily air pollutant emissions expected upon project buildout with and without
the proposed project.
As shown therein, following buildout of the project site, the proposed Specific Plan 218
Amendment #1 would generate significantly lower operational air pollutant emissions of
CO, ROC and NOx than the currently approved Specific Plan 218. The projected reduction
in PMio would be approximately one-half of the SCAQMD significance threshold and
therefore would not be considered significant. When compared to the approved Specific
Plan 218, the proposed project would reduce long-term CO, ROC, and PMio emissions by
35%, NOx emissions by 34%, and SOx emissions by 26%.
Table 3-6 includes the SCAQMD operational thresholds for the Coachella Valley and the
change in operational emissions associated with the proposed project for comparison. It
can be seen from Table 3-6 that the projected year 2010 decrease in operational emissions
associated with the proposed Specific Plan 218 Amendment No. 1 would exceed three of
the five SCAQMD significance threshold criteria (CO, ROC and NOx). Therefore, the
proposed project would cause a significant long-term decrease in operational CO, ROC and
NOx emissions.
Project -related reductions in operational emissions of SOx and PMio, while less than
significant (based upon the SCAQMD threshold criteria), would represent 35 percent of the
SP 218 operational emissions of these criteria pollutants. Consequently, the proposed
Specific Plan Amendment #1 would have a significant long-term beneficial impact on air
quality in the study area.
Air Quality Projections
Background carbon monoxide concentrations in the vicinity in 1995, 1996 and 1997 were
measured as 3 ppm (1 -hour average) and 1.5 or 1.6 ppm (8 -hour average). This represents
a small fraction of the 20 ppm (1 -hour average) and 9 ppm (8 -hour average) state carbon
monoxide standards. Future year 2010 carbon monoxide levels in the project vicinity
during morning peak hour traffic were assessed with the CALINE4 computer model at the
three most heavily used intersections with sensitive receptors located nearby.
The SCAQMD CEQA Air Quality Handbook (Table 9-9 pg. 9-28) provides future year CO
adjustment factors that can be applied to data monitored in the project vicinity to estimate
future year "No Project" CO background concentrations. For data measured at the Palm
Springs monitoring station, the future year CO adjustment factor shown for all years is
1.00. An adjustment factor of 1.0 indicates that the SCAQMD expects current and future
background CO concentrations to be the same. Based upon this fact (and the consistency
of CO data for 1995, 1996 and 1997 from the Palm Springs ambient air monitoring station)
Table 3-7 includes future year 2004 and year 2010 background CO concentrations of 3.0
ppm (1 -hour average) and 1.6 ppm (8 -hour average).
3-23
Table 3-5
Future Operational Air Pollutant Emissionsa
By Development Scenario
(Pounds/Day)
Scenario
Natural Gas
Electricity
Mobile
Total
Pollutant
Emissions
Emissions
Emissions
Emissions
Initial Phase On -Site
(Year 2004)
CO
0.06
2.88
1,384.03
1,386.97
ROC
0.01
0.14
190.13
190.29
NOx
15.63
16.58
237.26
269.47
Sox
Negligible
1.73
19.76
21.49
PM10
Negligible
0.58
42.07
42.65
Buildout On -Site
(Year 2010)
CO
0.36
12.05
3,784.38
3,796.79
ROC
0.10
0.60
407.27
407.97
NOx
59.57
69.28
710.80
839.65
Sox
Negligible
7.23
67.32
74.55
PM10
Negligible
2.41
136.44
138.85
Approved SP 218
(Year 2010)
CO
1.21
17.83
5,837.11
5,856.15
ROC
0.32
0.89
628.19
629.40
NOx
81.93
102.52
1,096.36
1,280.81
Sox
Negligible
10.70
103.84
114.54
PM10
0.01
3.57
210.45
214.03
Project -Related
Change (2010)
CO
-0.85
-5.78
-2,052.73
-2,059.36
ROC
-0.22
-0.29
-220.92
-221.43
NOx
-22.36
-33.24
-385.56
-441.16
Sox
Negligible
-3.47
-36.52
-39.99
PM10
-0.01
-1.16
-74.01
-75.17
a. See Appendix A for assumptions as well as stationary and mobile source emissions worksheets.
3-24
Table 3-6
Significance of Operational Emissions Reductionsa
Criteria
Pollutant
SP 218 Amend. #1
Emissions
(Pounds/Day)
Approved SP 218
Emissions
(Pounds/Day)
Project -Related
Change
(Pounds/Day)
Thresholda
(Pounds/Day)
[Exceeded]
CO
3,796.79
5,856.15
-2,059.36
550 [Yes]
ROC
407.97
629.40
-221.43
75 [Yes]
NOx
839.65
1,280.81
-441.16
100 [Yes]
Sox
74.55
114.54
-39.99
150 [No]
PM10
138.85
214.03
-75.17
150 [No]
a. Format is SCAQMD threshold [project -related change in emissions exceeds threshold or not].
As shown in Table 3-7, year 2010 peak hour traffic will contribute 1.4 ppm (over a 1 -hour
period) and 0.8 ppm (over an 8 -hour period) to the carbon monoxide concentrations at 50
feet from the "worst case" intersection of Madison Street and Airport Boulevard. The
highest carbon monoxide concentration expected at 50 feet from this intersection under year
2010 conditions is projected to be 4.4 ppm over a 1 -hour averaging period and 2.4 ppm
over an 8 -hour averaging period. Project -related traffic volumes would increase carbon
monoxide levels by up to 0.4 ppm at 50 feet from this intersection. Changes in CO
concentrations of this magnitude are insignificant.
A significant impact is defined as occurring when there will be a measurable increase in
carbon monoxide levels at a sensitive receptor site. There are no sensitive receptors in the
project vicinity located close enough to the key intersections to be exposed to an increase in
carbon monoxide levels of this magnitude.
A project has a significant impact if it interferes with the attainment of the state 1 -hour or 8 -
hour carbon monoxide standards by either exceeding them or contributing to an existing or
projected violation. The proposed project will not interfere with the attainment of the state
1 -hour or 8 -hour carbon monoxide standards by either exceeding them or contributing to an
existing or projected violation at sensitive receptor locations. Future carbon monoxide
concentrations adjacent to the three "worst case" intersections modeled will be below the 20
ppm state standard and 35 ppm federal standard (1 -hour average) with all development
scenarios analyzed. Similarly, the state and federal 8 -hour carbon monoxide standards will
not be exceeded with any development scenario.
Significance of Long -Term Impacts
Projects with daily operational emissions that exceed any of the long-term operational
significance thresholds established by the SCAQMD should be considered to be significant.
The impact of the proposed Specific Plan 218 Amendment No. l has been identified as the
change in emissions between the approved Specific Plan 218 and the proposed SP 218
Amendment No. 1. Consequently, the proposed project would have a significant long-
term beneficial impact on air quality in the study area.
3-25
Table 3-7
Projected Carbon Monoxide Concentrationsa
(Parts Per Million)
a. Receptor distances are measured from the roadway centerline.
b. Refer to Appendix A for the assumptions CALINE 4 output sheets.
3-26
1 -Hour Average (ppm)
8 -Hour Average (ppm)
Receptor Distancesb (Feet)
50
100
200
50
100
200
Year 2004 Ambient
Jefferson Street @
- Avenue 50
0.7
0.4
0.3
0.4
0.2
0.2
Madison Street @
- Airport Boulevard
0.3
0.2
0.1
0.2
0.1
0.1
- Avenue 58
0.3
0.2
0.1
0.2
0.1
0.1
Year 2004+Initial Phase
Jefferson Street @
- Avenue 50
0.7
0.4
0.3
0.4
0.2
0.2
Madison Street @
- Airport Boulevard
0.4
0.3
0.2
0.2
0.2
0.1
- Avenue 58
0.4
0.3
0.2
0.2
0.2
0.1
Year 2010 Ambient
Jefferson Street @
- Avenue 50
0.9
0.5
0.3
0.5
0.3
0.2
Madison Street @
- Airport Boulevard
1.0
0.5
0.3
0.6
0.3
0.2
- Avenue 58
0.5
0.3
0.2
0.3
0.2
0.1
Year 2010+Buildout On -Site
Jefferson Street @
- Avenue 50
1.0
0.5
0.3
0.6
0.3
0.2
Madison Street @
- Airport Boulevard
1.4
0.6
0.4
0.8
0.4
0.2
- Avenue 58
0.8
0.4
0.2
0.5
0.2
0.1
2004 Background CO (ppm)
3.0
3.0
3.0
1.6
1.6
1.6
2010 Background CO (ppm)
3.0
3.0
3.0
1.6
1.6
1.6
State Standard
20.0
20.0
20.0
9.0
9.0
9.0
Federal Standard
35.0
35.0
35.0
9.0
9.0
9.0
a. Receptor distances are measured from the roadway centerline.
b. Refer to Appendix A for the assumptions CALINE 4 output sheets.
3-26
3.2.4 RELEVANT PLANNING PROGRAMS
Air Quality Management Plan
The purpose of a consistency finding is to determine whether or not a project is consistent
with the assumptions and objectives of regional air quality plans. Based on this determina-
tion, conclusions can be drawn regarding whether or not a specific project will interfere
with the region's ability to comply with federal and state air quality standards. The
consistency determination fulfills the CEQA goal of fully informing local agency decision
makers of the environmental costs of projects under consideration early enough to ensure
that air quality concerns are fully addressed. This allows decision makers to contribute to
the clean air goals in the AQMP and the PMio SIP.
When a project is inconsistent, local governments can consider project modifications or
mitigation measures to eliminate the inconsistency. Under CEQA, even if a project is
found consistent, it can still have a significant impact on air quality by exceeding the
SCAQMD significance thresholds.4
Since the Riverside County Comprehensive Plan is the basis for the AQMP emissions
inventories, it appears that Specific Plan 218, which was approved in 1988 is consistent
with all of the key underlying assumptions associated with the AQMP. The previously
approved Specific Plan 218 included the development of 4,262 homes, 35 acres of
commercial uses, and 2 golf courses on-site. By comparison, the currently proposed Coral
Mountain Specific Plan Amendment Number 1 represents a substantial reduction in
residential (18%) and commercial (74%) development intensity. The currently proposed
project includes a maximum development of 762 fewer dwellings and 25.8 fewer acres of
commercial uses.
By decreasing the commercial development within the project site, the proposed
development would generate fewer jobs than the previously approved Specific Plan. By
decreasing the number of dwellings built on-site, the proposed project would reduce the
demand for employment in the vicinity. By providing a mix of residential product types,
the project would permit more affordable housing opportunities for future residents who
relocate on-site to work within the commercial development proposed. This could reduce
the length of work trips and the number of regional vehicle miles traveled (VMT).
Applicable control measures contained in the AQMP should be considered as future regula-
tions which are currently in the development stage. The inclusion of feasible control
measures and mitigation measures in the project will minimize to the greatest extent feasible
the potential air quality impacts attributable to the proposed project.
The proposed project incorporates support commercial uses on-site that will be centrally
located to serve the Coral Mountain residential development. Recreational amenities will be
provided on-site to reduce the need to travel off-site by motor vehicle for these activities.
By incorporating facilities that encourage the use of alternative transportation modes, the
proposed Specific Plan would reduce the number of automobile trips generated by future
development on-site. The proposed project would reduce operational emissions associated
with development of the site over the long term. The proposed project will not interfere
with the attainment of the state 1 -hour or 8 -hour carbon monoxide standards by either
exceeding them or contributing to an existing or projected violation at sensitive receptor
locations. In these ways the proposed project would achieve the air quality goals set forth
in the AQMP.
4. SCAQMD, CEQA Air Quality Handbook, April 1993, page 12-1.
3-27
State Implementation Plan for Mo in the Coachella Valley
The proposed project will adhere to applicable Riverside County ordinances regarding
fugitive dust and construction activities. Both are control measures outlined in the PMio
SIP. Project proponents will also implement feasible PMio guidelines such as discontin-
uing grading when winds exceed 25 miles per hour. It appears, therefore, that the
proposed project is consistent with the PMio SIP.
SCAQMD Rules and Regulations
The project proponent will comply with all applicable SCAQMD "Rules and Regulations".
Riverside County Air Quality Element
One primary air quality goal of the Riverside Air Quality Element is to improve air quality
on a long-term basis by reducing vehicle trips and vehicle miles traveled. The proposed
project is consistent with that goal in that it will provide fewer dwellings and more jobs in a
"housing rich," "job poor" area, thereby improving the jobs/housing balance (which will
reduce vehicle miles traveled). It will also provide recreational opportunities in the vicinity
or existing residential development that are attractive and thereby reduce vehicle miles
traveled associated with trips to more distant recreational destinations.
The proposed project will establish minimum requirements for construction activities to
reduce fugitive dust and PMio emissions. A plan to control fugitive dust through
implementation of reasonably available dust control measures shall be prepared and
submitted to Riverside County for approval prior to the issuance of any grading permits
associated with future on-site tracts.
The proposed project will also comply with the provisions of the Riverside County Zoning
Code which establish minimum requirements for erosion control associated with grading
projects. This will ensure that no debris is washed, blown by wind, or otherwise
deposited onto streets or adjacent property. Special measures that may be required in
addition to an on-site watering system are outlined therein.
3.2.5 CUMULATIVE AND GROWTH INDUCING EFFECTS
There are currently numerous known cumulative projects that have been approved and will
be constructed in the study area prior to the year 2010. Therefore, project -related
cumulative impacts on air quality could be significant and must be evaluated.
The proposed project will induce growth within the study area and within the Coachella
Valley. By providing a destination resort that is attractive to millions of people, the
proposed project will expose tourists to the opportunities and amenities offered by the City
of La Quinta and surrounding communities. Some of these visitors will elect to annually
visit or even relocate in the Coachella Valley.
The demand for housing to accommodate these new residents will cause the number of
housing starts to increase. New residents will seek jobs in the commercial/entertainment
and resort facilities within and surrounding the project site. They will frequent local and
regional commercial developments. As the demand for employment and retail opportunities
grows, it will be met by future development. In this manner, growth within the project site
will induce growth within the study area and the surrounding communities.
3-28
Development of the project site is in response to previous growth inducements within the
study area. In addition to Specific Plan 218, eight other Specific Plans have been approved
for development within the study area, as shown in Figure 3-5. Table 3-8 details the land
uses associated with these approved cumulative developments. For a "worst case"
analysis, all of these cumulative projects were assumed to be completed and fully occupied
by the year 2010. A linear interpolation was used to estimate the cumulative development
that could be expected by the year 2004.
By the year 2004, cumulative development is expected to include: 352 multi -family
residential dwellings, 1,910 single family dwellings, 955 hotel rooms, and 241,000 square
feet of commercial development. Upon project buildout in the year 2010, cumulative
development is projected to include: 774 multi -family residential dwellings, 5,053 single
family dwellings, 2,100 hotel rooms, and 530,000 square feet of commercial development.
As shown in Table 3-9, cumulative development within the study area will generate
operational emissions that exceed all of the SCAQMD significance threshold criteria except
one (the SOx threshold). Daily operational emissions associated with the initial
development phase on-site will increase cumulative emissions in the study area by 23
percent. Even with this increase, the SCAQMD operational SOx threshold of significance
will not be exceeded. Since details regarding the initial development phase of the approved
Specific Plan 218 are unknown, it is not clear whether or not the proposed project will
result in a less intense or more intense initial development scenario for the project site.
Although the operational emissions from the initial development phase could be greater
with the proposed project, it is unlikely, given the overall reduction in development
intensity proposed on-site.
The year 2010 decrease in operational emissions associated with the proposed Specific Plan
218 Amendment No. 1 will exceed three of the five SCAQMD significance threshold
criteria (CO, ROC and NOx). Therefore, the proposed project would cause a significant
long-term decrease in cumulative CO, ROC and NOx emissions. Project -related reductions
in cumulative emissions of SOx and PMio, while less than significant (based upon the
SCAQMD threshold criteria), would represent 18% of the cumulative emissions of these
criteria pollutants. The proposed project would have a significant long-term beneficial
impact on air quality in the study area by reducing daily cumulative operational emissions
by 18 percent.
3-29
Table 3-8
Approved Cumulative Developments
Development/Land Use Type
Hotel
Dwelling
Bldg. Area
Rooms
Units
(Square Feet)
The Ranch Specific Plan
Commercial/Retail
--
--
120,000
Hotel
600
--
--
Subtotal
600
120,000
PGA West Specific Plan
Single Family Residential
--
400
--
Hotel
1,000
--
--
Commercial/Retail
--
--
100,000
Subtotal
1,000
400
100,000
Foster Turf (SP 015)
Single Family Residential
--
200
--
The Grove (SP 016)
Single Family Residential
--
820
--
Commercial/Retail
--
--
210,000
Subtotal
820
210,000
PGA Weiskopf (SP 017)
Single Family Residential
--
400
--
Vista Santa Rosa Specific Plan
Single Family Residential
--
850
The Quarry
Single Family Residential
--
580
--
Green Specific Plan
Single Family Residential
--
277
--
Travertine Specific Plan
Single Family Residential
--
1,526
--
Multiple Family Residential
--
774
--
Hotel
500
--
--
Commercial/Retail
--
--
100,000
Subtotal
500
2,300
100,000
Total
2,100
5,827
530,000
3-30
Table 3-9
Future Cumulative Operational Air Pollutant EmissionSa
Scenario
Emissions
Proposed Project
Emissions (Lbs./Day)b
Cumulative Project
Emissions (Lbs./Day)
Project+Cumulative
Emissions (Lbs./Day)
Year 2004
CO
1,386.97
6,149.86
7,536.83
ROC
190.29
844.08
1,034.37
NOx
269.47
1,166.24
1,43 5.71
Sox
21.49
94.42
115.91
PM10
42.65
188.81
231.46
Year 2010
CO
-2,059.36
11,661.46
9,602.10
ROC
-221.43
1,254.09
1,032.66
NOx
-441.16
2,465.66
2,024.50
Sox
-39.99
223.44
183.45
PM10
-75.17
424.85
349.68
a. See Appendix A for assumptions as well as stationary and mobile source emissions worksheets.
b. Year 2004 emissions are positive numbers as they represent the initial development phase proposed on-
site and could not be subtracted form the initial phase of the approved SP 218, since land use data is not
available. Year 2010 values are negative as they represent a reduction in operational emissions
associated with the proposed project when compared to the currently approved Specific Plan on-site.
3-31
3.3 AIR QUALITY MITIGATION MEASURES
As indicated in the impact analysis, SCAQMD significance thresholds for NOx and PMIo
are expected to be exceeded during the construction phase, with or without the proposed
project. However, by reducing the development intensity on-site, the air quality impacts
generated as a result of the actual building construction activities required to implement the
proposed project will be lower than those of the approved Specific Plan 218. Mitigation
measures cannot be incorporated in the project that reduce construction -related NOx and
PM10 emissions to a level of insignificance.
The long-term operational air pollutant emission levels associated with the proposed project
will exceed the SCAQMD significance threshold criteria for all pollutants. However, the
proposed project would generate much lower emissions over the long term than the
previously approved SP 218. Therefore, the proposed project would have a significant
long-term beneficial impact on air quality in the study area.
Although it may not be possible to mitigate construction -related air quality impacts to a level
of insignificance, implementation of the following mitigation measures, where feasible,
would reduce the magnitude of the impacts substantially.
3.3.1 MEASURES TO MINIMIZE CONSTRUCTION -RELATED EMISSIONS
The following measures have been or will be incorporated in the project.
1. Construction equipment shall be properly maintained and serviced to minimize
exhaust emissions.
2. Any construction equipment using diesel drive internal combustion engines should
use a diesel fuel with a maximum of 0.05% sulfur and a four degree retard per the
Riverside County Air Quality Element, Particulate Matter Program.
3. Existing power sources should be utilized where feasible via temporary power poles
to avoid on-site power generation.
4. Construction personnel shall be informed of ride sharing and transit opportunities.
5. Construction parking shall be configured to minimize traffic interference.
6. Construction operations affecting off-site roadways shall be scheduled for off-peak
traffic hours and shall minimize obstruction of through -traffic lanes.
7. Cut and fill quantities will be balanced on-site.
8. The proposed project will comply with the provisions of the Riverside County
Zoning Code which establishes minimum requirements for construction activities to
reduce fugitive dust and PMio emissions. A plan to control fugitive dust through
implementation of reasonably available dust control measures shall be prepared and
submitted to Riverside County for approval prior to the issuance of any grading
permits associated with the project. The plan shall specify the fugitive dust control
measures to be employed.
9. SCAQMD Rule 403 shall be adhered to, insuring the clean up of construction -related
dirt on approach routes to the site. Rule 403 prohibits the release of fugitive dust
emissions from any active operation, open storage pile, or disturbed surface area
3-32
beyond the property line of the emission source. Particulate matter deposits on public
roadways are also prohibited.
10. Adequate watering techniques shall be employed to partially mitigate the impact of
construction -generated dust particulates. Portions of the project site that are under-
going earth moving operations shall be watered such that a crust will be formed on
the ground surface and then watered again at the end of the day.
11. Any construction access roads (other than temporary access roads) shall be paved as
soon as possible and cleaned after each work day. The maximum vehicle ;speed limit
on unpaved roads shall be 15 mph.
12. Grading operations shall be suspended during first and second stage ozone episodes
or when winds exceed 25 mph, per the PM to SIP.
13. Any vegetative ground cover to be utilized on-site shall be planted as soon as possible
to reduce the amount of open space subject to wind erosion. Irrigation systems
needed to water these plants shall be installed as soon as possible to maintain the
ground cover and minimize wind erosion of the soil.
14. Landscaping should be accomplished with native drought -resistant species to reduce
water consumption and provide passive solar benefits.
3.3.2 MEASURES TO MINIMIZE OPERATIONAL EMISSIONS
The proposed project shall reduce long-term operational emissions by incorporating
facilities for alternative transportation modes, implementing energy conservation measures
and by reducing VMT in the following manner.
1. Building construction shall comply with the energy use guidelines in Title 24 of the
California Administrative Code.
2. The project will internalize trips and reduce dependency on the private automobile by
providing non -motorized transportation facilities and implementing all feasible
measures to encourage the use of alternate transportation modes.
3. The vehicular circulation system within the project site will be supplemented with a
user friendly walking, bicycling and transit environment.
4. The project will reduce vehicle miles traveled and internalize trips by offering
recreational activities and retail shopping opportunities in a centralized location within
the proposed community.
5. Parking areas for the commercial portion of the site should incorporate bicycle spaces
and/or other mandated alternative transportation provisions in conformance with
current County ordinances.
6. The use of energy efficient street lighting and parking lot lighting (low pressure
sodium vapor lights) should be considered on-site to reduce emissions at the power
plant serving the site.
7. The project proponent shall comply with applicable SCAQMD Rules and
Regulations.
3-33
4.0 NOISE ANALYSIS
4.1 EXISTING NOISE ENVIRONMENT
Noise fundamentals are introduced below such as: noise rating schemes, typical noise
levels of familiar noise sources, sound propagation, and various factors which affect motor
vehicle noise levels. This information is followed by a discussion of: (1) the harmful
effects of noise, (2) community responses to sound, (3) guidelines for achieving land use
compatibility with noise, and (4) the current noise environment in the project vicinity.
4.1.1 FUNDAMENTALS OF NOISE
Noise levels are measured on a logarithmic scale in decibels which are then weighted and
added over a 24-hour period to reflect not only the magnitude of the sound, but also its
duration, frequency, and time of occurrence. In this manner, various acoustical scales and
units of measurement have been developed such as: equivalent sound levels (Leq), day -
night average sound levels (Ldn) and community noise equivalent levels (CNEL's).
A -weighted decibels (dBA) approximate the subjective response of the human ear to a
broad frequency noise source by discriminating against the very low and very high
frequencies of the audible spectrum. They are adjusted to reflect only those frequencies
which are audible to the human ear. The decibel scale has a value of 1.0 dBA at the
threshold of hearing and 140 dBA at the threshold of pain. Each interval of 10 decibels
indicates a sound energy ten times greater than before, which is perceived by the human ear
as being roughly twice as loud. Therefore, a 1.0 decibel increase is just audible whereas a
10 decibel increase means the sound is perceived as being twice as loud as before.
Examples of the decibel level of various noise sources are shown in Figure 4-1. They
include: the quiet rustle of leaves (10 dBA), a motion picture studio (20 dBA), a library
(35 dBA), ambient noise outdoors (50 dBA), normal conversation at 5 feet (55 dBA), or a
busy street at 50 feet (75 dBA).
Noise Rating Schemes
Equivalent sound levels are not measured directly but rather calculated from sound pressure
levels typically measured in A -weighted decibels (dBA). The equivalent sound level (Leq)
is the constant level that, over a given time period, transmits the same amount of acoustic
energy as the actual time -varying sound. Equivalent sound levels are the basis for both the
Ldn and CNEL scales.
Day -night average sound levels (Ldn) are a measure of the cumulative noise exposure of
the community. The Ldn value results from a summation of hourly Leq's over a 24-hour
time period with an increased weighting factor applied to the nighttime period between
10:00 PM and 7:00 AM. This noise rating scheme takes into account those subjectively
more annoying noise events which occur during the normal sleeping hours.
Community noise equivalent levels (CNEL) also carry a weighting penalty for noises that
occur during the nighttime hours. In addition, CNEL levels include a penalty for noise
events that occur during the evening hours between 7:00 PM and 10:00 PM. Because of
the weighting factors applied, CNEL values at a given location will always be larger than
4-1
Figure
4-1
Typical Noise
Levels of Familiar Sources
dBA
145
Physically Painful
140
Sonic Boom
Extremely Loud
135
130
125
Jet Takeoff at 200'
Discomforting
120
Oxygen Torch
115
Discotheque
110
Construction Noise at 3 meters
105
Power Mower at 3'
Very Loud
100
Newspaper Press, Subway Train
95
Freight Train at 50'
90
Food Blender
85
Electric Mixer, Alarm Clock
80
Heavy Truck at 50', Average Factory
75
Busy Street Traffic at 50'
70
;;:;:';
Average Traffic at 100', Vacuum Cleaner at 10'
Loud
65
Electric Typewriter at 10'
60
Dishwasher at 10', Air Conditioning Unit at 15'
55
Normal Conversation at 5'
Quiet
50
Typical Daytime Suburban Background, Quiet Office
45
Refrigerator at 10'
40
Bird Calls
35
Library
Very Quiet
30
Soft Whisper at 5 meters
25
20
Motion Picture Studio
15
Barely Audible
.:
10
Leaves Rustling
5
Threshold of Hearing
0
MMW
IMF
VV
Endo Engineering
Source:
Tipler, Paul A. "Physics", New York: Worth Publishers 1976.
Y ,
Ldn values, which in turn will exceed Leq values. However, CNEL values are typically
within one decibel of the Ldn value.
Sound Propagation
For a "line source" of noise such as a heavily traveled roadway, the noise level drops off
by a nominal value of 3.0 decibels for each doubling of distance between the noise source
and the noise receiver. Environmental factors such as wind conditions, temperature
gradients, characteristics of the ground (hard or soft) and the air (relative humidity), and the
presence of vegetation combine to increase the attenuation achieved outside laboratory
conditions to 4.5 decibels per doubling of distance in many cases.
The increase in noise attenuation in exterior environments is particularly true: (1) for
freeways where an elevated or depressed profile, higher truck mix, or the presence of
intervening buildings or topography come into play; (2) where the view of a roadway is
interrupted by isolated buildings, clumps of bushes, scattered trees; (3) when the
intervening ground is soft or covered with vegetation; or (4) where the source or receiver is
located more than three meters above the ground. The nominal value of 3.0 dBA with
doubling applies to sound propagation from a "line source": (1) over the top of a barrier
greater than 3 meters in height; or (2) where there is a clear unobstructed view of the
highway, the ground is hard, no intervening structures exist and the line -of -sight between
the noise source and receiver averages more than 3 meters above the ground. ]
In an area which is relatively flat and free of barriers, the sound level resulting from a
single. "point source" of noise drops by 6 decibels for each doubling of distance or 20
decibels for each factor of ten in distance. This applies to fixed noise sources and mobile
noise sources which are temporarily stationary such as an idling truck or other heavy duty
equipment operating within a confined area (such as industrial processes or construction).
Sound propagation from a train resembles a "line source" near the railroad tracks and a
"point source" at distances beyond three -tenths of the train length.
Factors Affecting Motor Vehicle Noise
The noise levels adjacent to "line sources" such as roadways increase by 3.0 dBA with
each doubling in the traffic volume (provided that the speed and truck mix do not change).
From the mathematical expression relating increases in the number of noise sources (motor
vehicles) to the increase in the adjacent sound level, it can be shown that a 26 percent
increase in the traffic volume will cause a 1.0 dBA increase in adjacent noise levels.
Doubling the number of vehicles on a given route increases the adjacent noise levels by 3.0
dBA, but changing the vehicle speed has an even more dramatic effect.
Increasing the vehicle speed from 35 to 45 mph raises the adjacent noise levels by
approximately 2.7 dBA. Raising the speed from 45 to 50 mph increases adjacent noise
levels by 1.0 dBA. A speed increase from 50 to 55 mph increases adjacent noise levels by
0.9 dBA. Consequently, lower motor vehicle speeds can have a significant positive impact
in terms of reducing adjacent noise levels.2
1. State of California, Department of Transportation, Noise Manual, 1980.
2. Endo Engineering conclusions based upon computer runs of RD -77-108 with all variables held constant
except vehicle speed.
4-2
The truck mix on a given roadway also has a significant effect on adjacent noise levels. As
the number of trucks increases and becomes a larger percentage of the vehicle volume,
adjacent noise levels increase. This effect is more pronounced if the number of heavy duty
(3+ axle) trucks is large when compared to the number of medium duty (2 axle) trucks.
4.1.2 HARMFUL EFFECTS OF NOISE
Noise can cause temporary physical and psychological responses in humans. Temporary
physical reactions to passing noises range from a startle reflex to constriction in peripheral
blood vessels, the secretion of saliva and gastric juices, and changes in heart rate, breathing
patterns, the chemical composition of the blood and urine, dilation of pupils in the eye,
visual acuity and equilibrium. The chronic recurrence of these physical reactions has been
shown to cause fatigue, digestive disorders, heart disease, circulatory and equilibrium
disorders. Moreover, noise is a causal factor in stress-related ailments such as ulcers, high
blood pressure and anxiety.
Three harmful effects of noise which are commonly of concern include speech interference,
the prevention or interruption of sleep, and hearing loss. Figure 4-2 illustrates how
excessive background noises can reduce the amount and quality of verbal exchange and
thereby impact education, family life-styles, occupational efficiency, and the quality of
recreation and leisure time. Speech interference begins to occur at about 40 to 45 decibels
and becomes severe at about 60 decibels. Background noise levels affect performance and
learning processes through distraction, reduced accuracy, increased fatigue, annoyance and
irritability, and the inability to concentrate (particularly when complex tasks are involved or
in schools where younger children exhibit short concentration spans).
Several factors determine whether or not a particular noise event will interfere with or
prevent sleep. These factors include the noise level and characteristics, the stage of sleep,
the individual's age and motivation to waken. Ill or elderly people are particularly
susceptible to noise -induced sleep interference, which can occur when intruding noise
levels exceed the typical 35-45 decibel background noise level in bedrooms. Sleep
prevention can occur when intruding noise levels exceed 50 dBA.
Hearing loss, which may begin to occur at 75 dBA (as shown in Table 4-1), is one of the
most harmful effects of noise on people. Approximately 20 million people in the United
States currently have some degree of hearing loss. In many of these cases, exposures to
very loud, impulsive, or sustained noises caused damage to the inner ear which was
substantial even before a hearing loss was actually noticed. To prevent the spread of
hearing loss, a desirable goal would be to minimize the number of noise sources which
expose people to sound levels above 70 decibels.
Table 4-1
Harmful Effects Of Noisea
Harmful Effect
Prevention or Interruption of Sleep
Speech Interference
Extra Auditory Physiological Effects
Hearing Loss
Noise Levels at Which
Harmful Effects Occur
35 - 45 dB (A)
50 - 60 dB (A)
65 - 75 dB (A)
75 - 85 dB (A)
a. California Department of Public Health, Report to 1971 Legislature,
4-3
Figure 4-2
Speech Communication as a Function
of Background Noise Level
120
I
53 *fes
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V
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Y
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•/J/J/J/Jf.frJfJrff/fffrJff�fifirifiiififliJfi,/i//ifAif{iffiffiJfiAffiY/JifJJiIf/iJJJiJJJiJrJi/JJif!iJ/ifilfif
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eeeeefYfflfflrff/ ./r.JfffJ
//rrff/fJtf!/Id/C
rf/rrr//rrrr•rr•r//r/{r{/ffftffJ!///d{frffrJr///
ee Communication Possible ""s's,",eeeeeOV/1";s; ;ss.111:11;:`s
/!/rrrrrrrrrrrrrrrYrrrrrrrrrrrrrrrrlrrrrrr/rJffffffJrf/r!/If/JffrfJJ/d//J/
60!t,!!Jr!!r/rrfif/rrrr/rf,rr,Jrfrrl/1✓//rffrrfrfffffrJrr!!/r/tfrrrrrJ/rr
llrrJrffilfffr#JffrfrYAffYJfrJfffrdlJ//YffrJrfffffJ/'/fI✓///{/fI/Jr/////el
!llffrYl/Y//Yffif////fffJffJJlffJli/flA/YYrfffffff/fP/!rlfdJll!/r/J//dI/
fldell//flirAf/fY//ffffJirJf}!f!//AAfrrf/fffifr/!J//r//JJ//!/Jr//////
r frf!lrJYt{rffr/{rJYfff{JrJff}!/f/{f{r{rfffJflJ/r1/!/f/rr!/td/ddd/f//
r/rr/fffiff f/Irf/ff{Yf{Jf!{}}{/{{{rlfrfffff r'rttr/J!J//JJrrr//d//JFI
ff!/f///fifr/ffJ/f{fffffffff/fJ{{ffrfff{ffffrrr///F/JJ///f////J////
//'l ffrfY/{lirJffffffffff/ffrrrfrfffffff f'/rrd/rJfrrJr//f//////I//
ffrffY{{ffrfJfffffiJlf}frflrYfflffffJ/frlrf✓r////////rd//rJ/It/
r/Y/Y//Yff/fffrtffff}1//Yrf{fffr{f{ffrrfflJ///J///r///dJ/!!II
fY ffr/fffffrftrff}{{/f//fff{Jr/tf/f/rr/r//t/J//rf/fJr//I!f!
I/JYtJ{JffJJffff/}/!♦rfff//d/ff/frfflft///JI////d/dd//!fJ
f/tfJrfJJ/lrJ///I/rf//Jrfff/t/rrr/.?//////lXefdlJ/dlfff
�•`'•`'� °lJJrJJJJrlr JJ
JJJf..... Expected Normal ,
Voice Level
0 Area of ell
50—Fff/f/Yr//1J!{/fIJlJJJ/!f/J/ff////JJJJr/f
A/IJJr(rJJJJJJJrr/Ff/JJff/f///J/J/fJl
N early Normal//JrrdddrdrJ/JJdr/J/J/J/t/t,rlfrf
NearlyJrrrlrr/rJJJrrr,rrr/JrrJflfJ
'//lfJJf!!f/fAr/flfff///
Speech Communication-'...-.."-"'-".'-'
0
J
40
0 5 10 15 20 25 30
Talker to Listener Distance in Feet
Source: Miller, "Effects of Noise on People", Journal of Acoustical Society of America, V.56, No.3, 9/74
[K)(Endo
Engineering
4.1.3 COMMUNITY RESPONSES TO SOUND
Approximately 10 percent of the population has a very low tolerance for noise and will
object to any noise not of their own making. Consequently, even in the quietest
environment, some complaints will occur. Another 25 percent of the population will not
complain even in very severe noise environments.3 Thus, a variety of reactions can be
expected from people exposed to any given noise environment.
Despite this variability in behavior on an individual level, the population as a whole can be
expected to exhibit the following responses to changes in noise levels. An increase or
decrease of 1.0 dBA cannot be perceived except in carefully controlled laboratory
experiments. A 3.0 dBA increase is considered just noticeable outside of the laboratory.
An increase of 5.0 dBA is often necessary before any noticeable change in community
response (i.e. complaints) would be expected.4
Community responses to noise may range from registering a complaint by telephone or
letter, to initiating court action, depending upon each individual's susceptibility to noise and
personal attitudes about noise. Several factors are related to the level of community
annoyance including:
• fear associated with noise producing activities;
• socio-economic status and educational level of the receptor;
• noise receptor's perception that they are being unfairly treated;
■ attitudes regarding the usefulness of the noise producing activity; and
• receptor's belief that the noise source can be controlled.5
Recent studies have shown that changes in long-term noise levels measured in units of Ldn
or CNEL, are noticeable and are responded to by people. About 10 percent of the people
exposed to traffic noise of 60 Ldn will report being highly annoyed with the noise, and
each increase of one Ldn is associated with approximately 2 percent more people being
highly annoyed. When traffic noise exceeds 60 Ldn or aircraft noise exceeds 55 Ldn,
people begin complaining.6 Group or legal actions to stop the noise should be expected to
begin at traffic noise levels near 70 Ldn and aircraft noise levels near 65 Ldn.
4.1.4 LAND USE COMPATIBILITY WITH NOISE
Some land uses are more tolerant of noise than others. For example, schools, hospitals,
churches and residences are more sensitive to noise intrusion than commercial or industrial
activities. As ambient noise levels affect the perceived amenity or livability of a
development, so too can the mismanagement of noise impacts impair the economic health
and growth potential of a community by reducing the area's desirability as a place to live,
shop and work. For this reason, land use compatibility with the noise environment is an
important consideration in the planning and design process.
3. Bolt Beranek & Newman, Literature Survey for the FHA Contract on Urban Noise, Report No. 1460,
January 1967.
4. State of California, Department of Transportation, Noise Manual, 1980 and Highway Research Board,
National Cooperative Highway Research Program Report 117, 1971.
5. United States Environmental Protection Agency, Public Health and Welfare Criteria For Noise, July
1973.
6. State of California, Department of Health Services, Dr. Jerome Lukas, Memo dated July 11, 1984.
4-4
Riverside County Policies
As part of its Comprehensive General Plan Environmental Hazards and Resources
Element, Riverside County has established standards and policies regarding land use
compatibility with noise. It has also provided review procedures and diagrams for use in
identifying noise hazards on a site specific basis. All development applications within
unincorporated County territory are reviewed for consistency with the standards and
policies detailed in the Comprehensive General Plan and summarized below.
Figure 4-3 is a "Land Use Compatibility Chart for Community Noise" which has been
reproduced from the Comprehensive General Plan. It identifies normally acceptable,
conditionally acceptable, and generally unacceptable noise levels for various land use types
(including noise levels where various land uses are discouraged).
As shown in Figure 4-3, residential uses, office buildings, and professional service and
business establishments are "normally acceptable" in exterior noise environments up to 60
CNEL (dBA) and "conditionally acceptable" in exterior noise environments up to 70 CNEL
(dBA). Commercial land uses including restaurants, general retail, entertainment and
commercial services are "normally acceptable" in exterior noise environments up to 65
CNEL (dBA) and "conditionally acceptable" between 65 CNEL and 75 CNEL.
A "normally acceptable" designation indicates that standard construction can occur with no
special noise reduction requirements. A "conditionally acceptable" designation implies that
new construction or development should be undertaken only after a detailed analysis of the
noise reduction requirements for each land use type is made and needed noise insulation
features are incorporated in the design.
City of La Quinta Noise Standards
The City of La Quinta has established noise standards by land use type as specified in the
Environmental Hazards Element of the General Plan (refer to Appendix B). Residential
uses are acceptable in noise environments below 60 CNEL (in outdoor living areas).
Commercial, employment and manufacturing uses are allowed in areas with a noise
exposure below 75 CNEL. Golf and tennis uses are restricted to areas with a noise
exposure below 70 CNEL. Hotels and motels are permitted in areas with a noise exposure
below 70 CNEL; however, noise levels below 60 CNEL are desirable in outdoor living
areas.
4.1.5 CURRENT NOISE EXPOSURE
The primary sources of noise in the project area are transportation facilities. Ambient noise
levels in the project vicinity are currently affected primarily by motor vehicle noise
emanating from area roadways. The roadways with the highest existing traffic volume are
Jefferson Street, Monroe Street, and Avenue 52. The project site is far removed from
railroad activity, military, public and private airports, and other significant noise
generators.
Noise from motor vehicles is generated by engine vibrations, the interaction between the
tires and the road, and the exhaust system. Reducing the speed of motor vehicles reduces
the noise exposure of listeners both inside the vehicle and adjacent to the roadway.
The highway traffic noise prediction model developed by the Federal Highway
Administration (RD -77-108) and currently being applied throughout the nation was used to
evaluate existing noise conditions near the project site. This model accepts various
4-5
Figure 4-3
Land Use Compatibility Chart For Community Noise
Explanation of Land Use Consequence
Normally Acceptable, With no special noise reduction re- 0 Generally LDnaccecta & New construction is dis-
quirements assuming standard construction. (Category couraged. If new construction or development does
A) proceed, a detailed analysis of the noise reduction
requirements must be made and needed noise
® Conditionally Acce tap ble. New construction or develop- insulation features included in the design. (Category C)
ment should be undertaken only after a detailed analysis
of the noise reduction requirement is made and needed La�,Discouraged New construction or develop -
noise insulation features included in the design. ndsment should generally not be undertaken. (Category D)
(Category B)
VMW
Endo Engineering Source: County of Riverside Comprehensive General Plan
..�
-r
Lan' 0 .i 75 80 8
Residential Land Uses: Single and Multiple Family
I MN
p Quarters, Mobilehomes
•a
= .01 \\
`\\1�\
Transient... Hotels,
=1IR*
Classrooms, Libraries, Churches, Hospitals,
MEM'S' 100 ON,% N t OR,
NursingSchool
Homes,
Recreational Land Uses: Golf Courses, Open Space
Areas with walking, bicycling or horseback riding trails,
01\000 1\01101
P\ammial
water based recreation areas where motorized boats
and jet-sWCis are prohibited.
Office Buildings, Personal, Business, and Professional
10, WINN 110011 VIN
Services
ink
Sports Arenas, Outdoor Spectator Sports
Recreational Land Uses: Playgrounds, Neighborhood
Ball Parks, Motorcycle Parks, and Water-based
Recreation Areas where motorized boats and jet-skiis
are permitted.
= NO WINE 111 01, i 1111 0100, 1
Commercial Land Uses: Retail Trade, Movie Theaters,�,WNIMM,
Restaurants, Bars, Entertainment Commercial
Activities, Services.
�M ��I01 �"
Com
..
000
.
Explanation of Land Use Consequence
Normally Acceptable, With no special noise reduction re- 0 Generally LDnaccecta & New construction is dis-
quirements assuming standard construction. (Category couraged. If new construction or development does
A) proceed, a detailed analysis of the noise reduction
requirements must be made and needed noise
® Conditionally Acce tap ble. New construction or develop- insulation features included in the design. (Category C)
ment should be undertaken only after a detailed analysis
of the noise reduction requirement is made and needed La�,Discouraged New construction or develop -
noise insulation features included in the design. ndsment should generally not be undertaken. (Category D)
(Category B)
VMW
Endo Engineering Source: County of Riverside Comprehensive General Plan
parameters including the traffic volume, vehicle mix and speed, and roadway geometry, in
computing equivalent noise levels during typical daytime, evening and nighttime hours.
The resultant noise levels are then weighted, summed over 24 hours, and output as the
CNEL value. Various CNEL contours are subsequently located through a series of
computerized iterations designed to isolate the 60, 65, and 70 CNEL contour locations.
Table 4-2 provides the current noise levels adjacent to roadways within the study area. The
distance to various noise contours used for land use compatibility purposes has been
determined by assuming a sound propagation with distance drop off rate of 3.0 dBA with
each doubling.7
As shown in Table 4-2, the ambient noise levels emanating from area roadways currently
range from a low of 57.3 CNEL (at 50 feet from the centerline of Madison Street) to a high
of 74.6 CNEL (at 50 feet from the centerline of Jefferson Street). The 70 dBA contour
presently falls within the right-of-way along 12 of the 21 roadway links analyzed. The 65
CNEL contour is located within the right-of-way along 7 of the roadway links analyzed.
Table 4-2
Existing Exterior Noise Exposure
Adjacent to Nearby Roadways
Roadway
A.D.T.a
(Veh/Day)
CNELb @
50 Feet
Distance to Contours (Ft.)c
70 dBA 65 dBA 60 dBA
Jefferson Street
- N/O Avenue 50
10,900
74.6
143
453
1432
- N/O Avenue 52
7,300
71.8
73
224
706
- N/O Avenue 54
6,600
71.1
64
202
639
PGA Boulevard
- S/O Avenue 54
5,200
64.7
R/W
R/W
130
Madison Street
- N/O Avenue 52
300
59.0
R/W
R/W
R/W
- N/O Airport Boulevard
1,800
67.1
R/W
78
240
- N/O Avenue 58
1,200
65.1
R/W
51
161
- N/O Avenue 60
200
57.3
R/W
R/W
R/W
Monroe Street
- N/O Avenue 50
10,500
73.1
102
321
1014
- N/O Avenue 52
7,500
73.0
99
313
990
- N/O Avenue 54
3,400
69.6
R/W
143
453
- N/O Airport Boulevard
2,800
68.7
R/W
117
368
- N/O Avenue 58
2,200
67.7
R/W
93
292
- S/O Avenue 58
1,100
64.7
R/W
R/W
147
- N/O Avenue 60
1,100
64.7
R/W
R/W
147
- S/O Avenue 60
1,100
64.7
R/W
R/W
147
- N/O Avenue 62
1,100
64.7
R/W
R/W
147
a. A.D.T. means current average daily two-way traffic volume.
b. CNEL values are given at 50 feet from all roadway centerlines (see Appendix B for assumptions).
c. All distances are measured from the centerline. R/W means the contour falls within the right -of -way -
7. Riverside County Department of Health, Memorandum, December 21, 1990.
2
Table 4-2
Existing Exterior Noise Exposure (Cont.)
Adjacent to Nearby Roadways
Roadway
A.D.T.a
(Veh/Day)
CNELb @
50 Feet
Distance to Contours (Ft.)c
70 dBA 65 dBA 60 dBA
Avenue 50
- W/O Jefferson Street
6,300
72.3
85
267
843
- E/O Jefferson Street
7,500
73.0
99
313
990
- E/O Madison Street
6,300
72.3
85
267
843
- E/O Monroe Street
5,800
71.9
77
243
769
Avenue 52
- W/O Jefferson Street
7,500
71.7
74
232
734
- E/O Jefferson Street
4,600
70.9
61
193
611
- E/O Madison Street
4,500
70.8
60
189
597
- E/O Monroe Street
4,300
70.6
57
180
570
Avenue 54
- W/O Jefferson Street
200
57.6
R/W
R/W
R/W
- E/O Jefferson Street
2,800
68.7
R/W
117
368
- E/O Madison Street
1,100
64.7
R/W
R/W
147
- E/O Monroe Street
1,300
65.4
R/W
55
172
Airport Boulevard
- E/O Madison Street
900
63.1
R/W
R/W
102
- E/O Monroe Street
1,900
66.4
R/W
69
217
Avenue 58
- W/O Madison Street
400
60.3
R/W
R/W
54
- E/O Madison Street
800
63.3
R/W
R/W
106
- E/O Monroe Street
1,100
64.7
R/W
R/W
147
Avenue 60
- E/O Madison Street
200
57.3
R/W
R/W
R/W
- W/O Monroe Street
200
57.3
R/W
R/W
R/W
- E/O Monroe Street
300
59.0
R/W
R/W
R/W
Avenue 62
- E/O Monroe Street
1,100
64.7
R/W
R/W
147
a. A.D.T. means current average daily two-way traffic volume.
b. CNEL values are given at 50 feet from all roadway centerlines (see Appendix B for assumptions).
c. All distances are measured from the centerline. R/W means the contour falls within the right-of-way.
4-7
4.2 NOISE IMPACT ANALYSIS
4.2.1 SHORT-TERM CONSTRUCTION -RELATED IMPACTS
Short-term acoustic impacts are those associated with construction activities necessary to
implement the proposed land uses on-site. These noise levels will be higher than the
ambient noise levels in the project area today, but will subside once construction is
completed.
Two types of noise impacts should be considered during the construction phase. First, the
transport of workers and equipment to the construction site will incrementally increase
noise levels along the roadways leading to and from the site. The increase although
temporary in nature, could be audible to noise receptors located along the roadways utilized
for this purpose. Second, the noise generated by the actual on-site construction activities
should be evaluated.
Construction activities are carried out in discrete steps, each of which has its own mix of
equipment, and consequently its own noise characteristics. These various sequential
phases will change the character of the noise levels surrounding the construction site as
work progresses. Despite the variety in the type and size of construction equipment,
similarities in the dominant noise sources and patterns of operation allow noise ranges to be
categorized by work phase. Figure 4-4 illustrates typical construction equipment noise
ranges at a distance of 50 feet.
The earth moving equipment category includes excavating machinery (backhoes,
bulldozers, shovels, trenchers, front loaders, etc.) and highway building equipment
(compactors, scrapers, graders, pavers, etc.). Typical operating cycles may involve one or
two minutes of full power operation followed by three to four minutes at lower power
settings. Noise levels at 50 feet from earth moving equipment range from 73 to 96 dBA.
The Environmental Protection Agency has found that the noisiest equipment types
operating at construction sites typically range from 88 to 91 dBA at 50 feet. Although
noise ranges were found to be similar for all construction phases, the erection phase (laying
sub -base and paving) tended to be less noisy. Noise levels varied from 79 dBA to 89 dBA
at 50 feet during the erection phase of construction. The foundation phase of construction
tended to create the highest noise levels, ranging from 88 to 96 dBA at 50 feet.
4.2.2 LONG-TERM OPERATIONAL IMPACTS
Long-term acoustic impacts could occur both on-site and off-site if the proposed project is
approved and implemented. Off-site noise impacts will result primarily from project -related
traffic on site access roads. On-site acoustic impacts could result from motor vehicle noise
generated by ultimate traffic volumes on the master planned roadways adjacent to the
project.
Off -Site Vehicular Noise Impacts
Noise levels on area streets were quantified for two different horizon years. Since the
initial development phase on-site is expected to have an opening year of 2004, year 2004
traffic volumes with and without the project were analyzed to determine the noise levels that
could be expected. In addition, year 2010 (the project buildout year) traffic volumes were
used to project noise levels in the study area and identify the significance of project -related
increases in motor vehicle noise.
W.
Figure 4-4
Construction Noise
Source: EPA, 1971; "Noise from Construction Equipment and Operations, Building Equipment,
and Home Appliances". NTID300.1
WEndo Engineering
Noise Level (dBA) at 50 feet
60 70 80 90 100 110
Front Loader
Dozer
rn
Dragline
0
Backfiller
Lu
Scraper/Grader
Trucks
rn
Concrete Mixers
c
CZ
Concrete Pumps
Cn
CZ
N
(Z
Motor Crane
M.
Pumps
CZ
C
Generators
CZ
U)
Compressors
Source: EPA, 1971; "Noise from Construction Equipment and Operations, Building Equipment,
and Home Appliances". NTID300.1
WEndo Engineering
Year 2004 Noise Impacts
The projected year 2004+project noise levels adjacent to roadways carrying appreciable
volumes of project -related traffic are shown in Table 4-3. As shown therein, noise levels at
50 feet from the centerline of each facility will range from a low of 58.9 CNEL along
Madison Street to a high of 77.9 CNEL along Jefferson Street. The 70 CNEL contour will
remain within the right-of-way along five of the roadway links analyzed.
Table 4-3
Year 2004+Project Exterior Noise Exposure
Adjacent to Area Roadways
Roadway
A.D.T.a
(Veh/Day)
CNEL @
50 Feetb
Distance to Contours (Ft.)c
70 dBA 65 dBA 60 dBA
Jefferson Street
- N/O Avenue 50
23,020
77.9
306
968
3061
- N/O Avenue 52
21,860
76.9
214
671
2121
- N/O Avenue 54
24,150
76.7
232
734
2322
PGA Boulevard
- S/O Avenue 54
12,490
68.5
R/W
100
308
Madison Street
- N/O Avenue 52
290
58.9
R/W
R/W
R/W
- N/O Airport Boulevard
15,970
76.6
214
675
2132
- N/O Avenue 58
15,960
76.3
212
670
2117
- N/O Resort Village Access
13,900
75.7
185
583
1844
- N/O Avenue 60
11,130
74.7
147
463
1465
- S/O Avenue 60
7,840
73.2
104
328
1037
Active Adult Village Access
- S/O Avenue 60
3,620
66.8
R/W
75
238
Monroe Street
- N/O Avenue 50
17,250
75.3
168
532
1682
- N/O Avenue 52
15,050
76.0
198
625
1976
- N/O Avenue 54
10,810
74.6
143
453
1432
- N/O Airport Boulevard
8,310
73.5
111
351
1111
- N/O Avenue 58
7,610
73.1
102
321
1014
- S/O Avenue 58
4,890
71.2
66
207
654
- N/O Avenue 60
4,890
71.2
66
207
654
- S/O Avenue 60
4,300
70.6
57
180
570
- S/O S. Primary Housing Access
2,150
67.6
R/W
91
286
- N/O Avenue 62
2,150
67.6
R/W
91
286
Avenue 50
- W/O Jefferson Street
15,270
76.1
202
639
2022
- E/O Jefferson Street
8,140
73.4
109
343
1086
- E/O Madison Street
7,890
73.2
104
328
1037
- E/O Monroe Street
7,950
73.3
106
336
1061
a. A.D.T. means average daily two-way traffic volume for 2004+project conditions.
b. CNEL values are given at 50 feet from all roadway centerlines (see Appendix B for assumptions).
c. All distances are measured from the centerline. R/W means the contour falls within the right-of-way.
4-9
Table 4-3 (Continued)
Year 2004+Project Exterior Noise Exposure
Adjacent to Area Roadways
Roadway
A.D.T.a
(Veh/Day)
CNEL @
50 Feetb
Distance to Contours (Ft.)c
70 dBA 65 dBA 60 dBA
Avenue 52
- W/O Jefferson Street
12,690
73.9
122
385
1219
- E/O Jefferson Street
6,640
72.5
88
279
883
- E/O Madison Street
6,530
72.4
86
273
863
- E/O Monroe Street
6,040
72.1
81
255
805
Avenue 54
- W/O Jefferson Street
180
57.1
R/W
R/W
R/W
- E/O Jefferson Street
15,690
76.2
207
654
2069
- E/O Madison Street
6,790
72.6
91
286
903
- E/O Monroe Street
2,670
68.5
R/W
111
351
Airport Boulevard
- E/O Madison Street
2,660
67.9
R/W
97
306
- E/O Monroe Street
3,500
69.0
R/W
125
394
Avenue 58
- W/O Madison Street
2,060
67.4
R/W
86
273
- E/O Madison Street
3,600
69.8
R/W
150
474
- E/O Monroe Street
1,920
67.1
R/W
81
255
Resort Village Access
- W/O Madison Street
3,070
66.1
R/W
64
202
Avenue 60
- E/O Madison Street
4,070
70.4
55
172
544
- W/O Monroe Street
2,620
68:5
R/W
111
351
- E/O Monroe Street
830
63.5
R/W
R/W
111
S. Pri. Housing Vil. Access
- E/O Monroe Street
2,150
64.6
R/W
R/W
143
Avenue 62
- W/O Monroe Street
1,610
66.3
R/W
67
212
- E/O Monroe Street
1,520
66.1
R/W
64
202
a. A.D.T. means average daily two-way traffic volume for 2004+project conditions.
b. CNEL values are given at 50 feet from all roadway centerlines (see Appendix B for assumptions).
c. All distances are measured from the centerline. R/W means the contour falls within the right -of -way -
Table 4-4 shows the increase in motor vehicle noise levels associated with project -related
traffic in the initial development phase opening year (2004). As shown therein, in spite of
the low ambient or background traffic volumes, the proposed project will only generate an
audible noise increase (greater than 3.0 dBA) along Monroe Street (3 links ranging from
3.0 to 3.2 dBA) and Avenue 60 (2 links ranging from 5.5 to 7.4 dBA) on or adjacent to the
project site for year 2004 conditions. There are no existing sensitive receptors that will be
impacted by the increased traffic volumes.
Potentially audible noise increases (between 1.0 and 3.0 dBA) are projected to occur with
the proposed project in the year 2004 along eleven of the roadway links evaluated. Project -
related noise increases along these links will range from 1.0 to 2.5 decibels.
4-10
Table 4-4
Project -Related Increase
in Year 2004 Motor Vehicle Noise
Roadway Link
2004 Ambientb
CNEL at 50 Feeta
2004+Project
CNEL at 50 Feeta
Increase
(dBA)
Jefferson Street
- N/O Avenue 50
77.4
77.9
0.5
- N/O Avenue 52
76.3
76.9
0.6
- N/O Avenue 54
75.9
76.7
0.8
PGA Boulevard
- S/O Avenue 54
68.4
68.5
0.1
Madison Street
- N/O Avenue 52
58.9
58.9
0.0
- N/O Airport Boulevard
75.0
76.6
1.6
- N/O Avenue 58
74.6
76.3
1.7
- N/O Resort Village Access
73.2
75.7
2.5
- N/O Avenue 60
73.2
74.7
1.5
- S/O Avenue 60
73.2
73.2
0.0
Monroe Street
- N/O Avenue 50
74.7
75.3
0.6
- N/O Avenue 52
75.2
76.0
0.8
- N/O Avenue 54
73.3
74.6
1.3
- N/O Airport Boulevard
71.8
73.5
1.7
- N/O Avenue 58
70.9
73.1
2.2
- S/O Avenue 58
68.0
71.2
3.2
- N/O Avenue 60
68.0
71.2
3.2
- S/O Avenue 60
67.6
70.6
3.0
- S/O S. Primary Housing Access
67.6
67.6
0.0
- N/O Avenue 62
67.6
67.6
0.0
Avenue 50
- W/O Jefferson Street
75.9
76.1
0.2
- E/O Jefferson Street
73.3
73.4
0.1
- E/O Madison Street
73.2
73.2
0.0
- E/O Monroe Street
73.0
73.3
0.3
Avenue 52
- W/O Jefferson Street
73.5
73.9
0.4
- E/O Jefferson Street
72.5
72.5
0.0
- E/O Madison Street
72.4
72.4
0.0
- E/O Monroe Street
71.8
72.1
0.3
Avenue 54
- W/O Jefferson Street
57.1
57.1
0.0
- E/O Jefferson Street
74.8
76.2
1.4
- E/O Madison Street
71.2
72.6
1.4
- E/O Monroe Street
67.9
68.5
0.6
Airport Boulevard
- E/O Madison Street
66.8
67.9
1.1
- E/O Monroe Street
68.0
69.0
1.0
a. CNEL values are given at 50 feet from all roadway centerlines (see Appendix B for assumptions).
b. Year 2004 ambient roadway noise levels and traffic volumes are provided in Appendix B.
4-11
Table 4-4 (Continued)
Project -Related Increase
in Year 2004 Motor Vehicle Noise
Roadway Link
2004 Ambientb
CNEL at 50 Feeta
2004+Project
CNEL at 50 Feeta
Increase
(dBA)
Avenue 58
- W/O Madison Street
67.4
67.4
0.0
- E/O Madison Street
68.4
69.8
1.4
- E/O Monroe Street
66.3
67.1
0.8
Avenue 60
- E/O Madison Street
63
70.4
7.4
- W/O Monroe Street
63
68.5
5.5
- E/O Monroe Street
62.1
63.5
1.4
Avenue 62
- W/O Monroe Street
66.3
66.3
0.0
- E/O Monroe Street
66.1
66.1
0.0
a. CNEL values are given at 50 feet from all roadway centerlines (see Appendix B Tor assumptions).
b. Year 2000 ambient roadway noise levels and traffic volumes are provided in Appendix B.
Year 2010 Noise Impacts
Table 4-5 presents motor vehicle noise levels in the vicinity in the year 2010 with the
proposed project. As shown therein, noise levels at 50 feet from the centerline of each
facility will range from a low of 57.6 CNEL along Avenue 54 to a high of 80.2 CNEL
along Madison Street.
Table 4-6 shows the increase in motor vehicle noise levels associated with project -related
traffic by the year 2010 (upon buildout of the project site). As shown therein, the proposed
project will generate an audible noise increase (greater than 3.0 dBA) along Monroe Street
(3 links ranging from 3.0 to 3.2 dBA) and Avenue 60 (2 links ranging from 5.5 to 7.4
dBA). These links are located within or adjacent to the project site.
Potentially audible noise increases (between 1.0 and 3.0 dBA) are projected to occur with
the proposed project in the year 2010 along nineteen of the roadway links evaluated.
Project -related noise increases along these links will range from 1.0 to 2.9 decibels.
Inaudible noise increases (less than 1.0 dBA) are expected to occur adjacent to the
remaining roadway links analyzed.
Ultimate On -Site Vehicular Noise Impacts
Ultimate on-site noise levels adjacent to master planned roadways are required to ensure
that appropriate noise mitigation is incorporated in the project design. The Riverside
County Comprehensive Plan Circulation Element includes five roadways within or adjacent
to the project site. These master planned roadways include: Madison Street (arterial),
Monroe Street (arterial), Avenue 58 (major), Avenue 60 (arterial), and Avenue 62
(secondary).
4-12
Table 4-5
Year 2010+Project Exterior Noise Exposure
Adjacent to Nearby Roadways
Roadway
A.D.T.a
(Veh/Day)
CNEL @
50 Feetb
Distance to Contours (Ft.)c
70 dBA 65 dBA 60 dBA
Jefferson Street
- N/O Avenue 50
32,820
80.0
434
1370
4330
- N/O Avenue 52
30,710
78.4
301
948
2996
- N/O Avenue 54
31,160
77.8
299
946
2991
PGA Boulevard
- S/O Avenue 54
20,560
70.6
56
161
504
Madison Street
- N/O Avenue 50
12,870
76.0
174
546
1724
- N/O Avenue 52
20,020
77.9
268
845
2670
- N/O Avenue 54
30,220
79.7
405
1278
4041
- N/O Airport Boulevard
33,750
80.1
444
1401
4431
- N/O Avenue 58
34,320
80.2
454
1434
4534
- N/O Resort Village Access
30,460
79.7
405
1278
4041
- N/O Avenue 60
25,730
78.4
343
1086
3434
- S/0 Avenue 60
17,280
76.6
227
718
2269
Active Adult Village Access
- S/O Avenue 60
7,450
70.0
50
157
496
Village Commons Access
- N/O Avenue 60
2,580
65.4
R/W
55
172
Monroe Street
- N/O Avenue 50
23,560
77.2
229
719
2273
- N/O Avenue 52
21,750
78.2
287
905
2861
- N/O Avenue 54
16,160
76.9
214
671
2121
- N/O Airport Boulevard
18,140
76.9
243
769
2431
- N/O Avenue 58
18,360
76.9
243
769
2431
- S/0 Avenue 58
13,780
75.7
185
583
1844
- N/O Avenue 60
10,040
74.3
134
423
1336
- S/O Avenue 60
7,450
73.0
99
313
990
- S/O S. Primary Housing Access
4,790
71.1
64
202
639
- N/O Avenue 62
3,470
69.7
R/W
147
463
Avenue 50
- W/O Jefferson Street
12,790
75.9
170
533
1685
- E/O Jefferson Street
15,410
76.7
204
641
2026
- E/O Madison Street
11,880
75.6
159
498
1572
- E/O Monroe Street
11,970
75.0
157
496
1570
Avenue 52
- W/O Jefferson Street
21,550
76.8
209
656
2073
- E/O Jefferson Street
15,740
76.8
209
656
2073
- E/O Madison Street
11,130
75.3
149
465
1467
- E/O Monroe Street
9,120
73.9
122
385
1219
a. A.D.T. means average daily two-way traffic volume for year 2010+project conditions.
b. CNEL values are given at 50 feet from all roadway centerlines (see Appendix B for assumptions).
c. All distances are measured from the centerline. R/W means the contour falls within the right-of-way.
4-13
Table 4-5 (Continued)
Year 2010+Project Exterior Noise Exposure
Adjacent to Nearby Roadways
Roadway
A.D.T.a
(Veh/Day)
CNEL @
50 Feetb
Distance to Contours (Ft.)c
70 dBA 65 dBA 60 dBA
Avenue 54
- W/O Jefferson Street
200
57.6
R/W
R/W
R/W
- E/O Jefferson Street
15,580
76.8
209
656
2073
- E/O Madison Street
8,730
74.3
119
369
1166
- E/O Monroe Street
3,600
69.8
R/W
150
474
Airport Boulevard
- E/O Madison Street
4,930
70.5
56
176
557
- E/O Monroe Street
6,440
71.7
74
232
734
Avenue 58
- W/O Madison Street
4,030
70.3
54
168
532
- E/O Madison Street
7,240
72.9
97
306
968
- E/O Monroe Street
3,230
69.4
R/W
137
432
Resort Village Access
- W/O Madison Street
5,250
68.5
R/W
111
351
N. Pri. Housing Vil. Access
- E/O Monroe Street
4,150
67.4
R/W
86
273
Avenue 60
- E/O Madison Street
10,180
74.3
134
423
1336
- W/O Monroe Street
6,420
72.3
85
267
843
- E/O Monroe Street
1,710
66.6
R/W
72
227
S. Pri. Housing Vil. Access
- E/O Monroe Street
2,660
65.5
R/W
56
176
Active Adult Vil. Access
- W/O Monroe Street
1,320
62.5
R/W
R/W
88
Avenue 62
- W/O Monroe Street
3,320
69.5
R/W
140
442
- E/O Monroe Street
2,160
67.6
R/W
91
286
a. A.D.T. means average daily two-way traffic volume for year 2010+project conditions.
b. CNEL values are given at 50 feet from all roadway centerlines (see Appendix B for assumptions).
c. All distances are measured from the centerline. R/W means the contour falls within the right-of-way.
4-14
Table 4-6
Project -Related Increase
in Year 2010 Motor Vehicle Noise
Roadway Link
2010 Ambientb
CNEL at 50 Feeta
2010+Project
CNEL at 50 Feeta
Increase
(dBA)
Jefferson Street
- N/O Avenue 50
79.6
80.0
0.4
- N/O Avenue 52
77.8
78.4
0.6
- N/O Avenue 54
77.2
77.8
0.6
PGA Boulevard
- S/O Avenue 54
70.5
70.6
0.1
Madison Street
- N/O Avenue 50
74.7
76.0
1.3
- N/O Avenue 52
76.6
77.9
1.3
- N/O Avenue 54
78.4
79.7
1.3
- N/O Airport Boulevard
78.5
80.1
1.6
- N/O Avenue 58
78.4
80.2
1.8
- N/O Resort Village Access
77.2
79.7
2.5
- N/O Avenue 60
76.6
78.4
1.8
- S/O Avenue 60
76.6
76.6
0.0
Monroe Street
- N/O Avenue 50
76.3
77.2
0.9
- N/O Avenue 52
77.0
78.2
1.2
- N/O Avenue 54
74.9
76.9
2.0
- N/O Airport Boulevard
74.0
76.9
2.9
- N/O Avenue 58
73.3
76.9
3.6
- S/O Avenue 58
70.5
75.7
5.2
- N/O Avenue 60
70.5
74.3
3.8
- S/O Avenue 60
69.7
73.0
3.3
- S/O S. Primary Housing Access
69.7
71.1
1.4
- N/O Avenue 62
69.7
69.7
0.0
Avenue 50
- W/O Jefferson Street
75.3
75.9
0.6
- E/O Jefferson Street
76.3
76.7
0.4
- E/O Madison Street
75.3
75.6
0.3
- E/O Monroe Street
74.6
75.0
0.4
Avenue 52
- W/O Jefferson Street
76.3
76.8
0.5
- E/O Jefferson Street
76.2
76.8
0.6
- E/O Madison Street
74.9
75.3
0.4
- E/O Monroe Street
73.4
73.9
0.5
Avenue 54
- W/O Jefferson Street
57.6
57.6
0.0
- E/O Jefferson Street
75.3
76.8
1.5
- E/O Madison Street
72.0
74.3
2.3
- E/O Monroe Street
68.5
69.8
1.3
a. CNEL values are given at 50 feet from all roadway centerlines (see Appendix B for assumptions).
b. Year 2010 ambient roadway noise levels and traffic volumes are provided in Appendix B.
4-15
Table 4-6 (Continued)
Project -Related Increase
in Year 2010 Motor Vehicle Noise
Roadway Link
2010 Ambientb
CNEL at 50 Feeta
2010+Project
CNEL at 50 Feeta
Increase
(dBA)
Airport Boulevard
- E/O Madison Street
69.1
70.5
1.4
- E/O Monroe Street
69.6
71.7
2.1
Avenue 58
- W/O Madison Street
70.3
70.3
0.0
- E/O Madison Street
71.2
72.9
1.7
- E/O Monroe Street
67.8
69.4
1.6
Avenue 60
- E/O Madison Street
66.6
74.3
7.7
- W/O Monroe Street
66.6
72.3
5.7
- E/O Monroe Street
64.6
66.6
2.0
Avenue 62
- W/O Monroe Street
69.5
69.5
0.0
- E/O Monroe Street
67.6
67.6
0.0
a. CNEL values are given at 50 feet from all roadway centerlines (see Appendix B for assumptions).
b. Year 2010 ambient roadway noise levels and traffic volumes are provided in Appendix B.
Although the Riverside County Circulation Element shows Madison Street as an urban
arterial highway, Madison Street (north of the project site) is located within the City of La
Quinta and is designated as an arterial highway. The Coral Mountain Specific Plan
proposes Madison Street as turning 90 degrees to connect to Avenue 60. Although Avenue
60 is shown on the Riverside County Circulation Element as a secondary highway between
Madison Street and Monroe Street, the Coral Mountain Specific Plan proposes Avenue 60
as an arterial highway. Although Avenue 62 (west of Monroe Street) is not shown on the
Riverside County Circulation Element, the proposed classification south of the project site
is a secondary highway.
Although Riverside County typically specifies that the traffic volume at the design
capacities of the roadways be utilized as a "worst case" assumption, the potential ultimate
traffic volumes along the streets within the project site appear to be well below their design
capacities. Furthermore, the Riverside County Department of Health has specified an 8%
truck mix for all roadways equal to or larger than secondary highways. Although classified
as secondary or larger highways, the residential character of the area would indicate that the
vehicular mix utilized for collector streets (2.58% trucks) may be appropriate for roadways
on-site.
Residential uses proposed on-site adjacent to the master planned roadways have the
potential to be impacted by noise from future traffic. Noise levels greater than 65 CNEL
are considered normally unacceptable and would require mitigation. Prior to the issuance
of building permits, the applicant should be required to submit an acoustical analysis of the
residential lots adjacent to the master planned roadways that details the specific mitigation
proposed to achieve the Riverside County exterior noise standards.
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4.3 NOISE MITIGATION MEASURES
Noise standards are implemented at various points in the planning and design of a devel-
opment. At the preliminary planning levels, the land use type and density near noisy
transportation facilities can be controlled. Later, at more detailed planning levels, proper
structure arrangement and orientation can be evaluated, with approval conditioned upon
setbacks, landscaped buffers, etc., that can resolve noise difficulties. Detailed noise
abatement requirements such as architectural design, acoustic construction techniques and
the erection of noise barriers are established at the final stages of the planning process,
when deemed necessary.
Long-term acoustic impacts can be mitigated more effectively through proper site design
than through the use of noise reducing construction techniques. Consequently, the mitiga-
tion strategies identified in the pages which follow take the form of suggested design
guidelines for use in detailed planning efforts.
4.3.1 GENERAL METHODS TO REDUCE NOISE IMPACTS
There are several basic techniques available to minimize the adverse effects of noise on
sensitive noise receivers. Classical engineering principles suggest controlling the noise
source when ever feasible and protecting the noise receptors when noise source control
measures are inadequate. Many of the noise source control mechanisms are being applied
by state and Federal governments. Acoustic site planning, architectural design, acoustic
construction techniques and the erection of noise barriers are all effective methods for
reducing noise impacts when source control mechanisms are insufficient to achieve desired
results.
Acoustic site planning involves the careful arrangement of land uses, lots and buildings to
minimize intrusive noise levels. The placement of noise compatible land uses between the
roadway and more sensitive uses is an effective planning technique. The use of buildings
as noise barriers and their orientation away from the source of noise, can shield sensitive
activities, entrances and common open space areas. Clustered and planned unit develop-
ments can maximize the amount of open space available for landscaped buffers in place of
continuous noise barriers next to heavily traveled roadways.
Acoustic architectural design involves the incorporation of noise reducing strategies in the
design and lay -out of individual structures. Building heights, room arrangements, window
size and placement, balcony and courtyard design, and the provision of air conditioning all
play an important role in shielding noise sensitive activities from intrusive noise levels.
Roof designs which reflect the noise back towards the roadway also reduce noise intrusion
into adjacent tracts.
Acoustic construction is the treatment of various parts of a building to reduce interior noise
levels. Acoustic wall design, doors, ceilings and floors, as well as dense building
materials, the use of acoustic windows (double glazed, double paned, thick, non-openable,
or small with air -tight seals) and the inclusion of maximum air spaces in attics and walls are
all available options.
Normal construction techniques generally provide a 20 dBA reduction from outside to
inside noise levels with windows closed. New energy insulation requirements for
buildings can produce up to 25 dBA exterior to interior noise reductions with windows
closed and 10 dBA reductions with open windows. Consequently, buildings with exterior
noise exposures up to 70 dBA can achieve 45 dBA interior noise levels with standard
construction techniques.
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Any solid barrier that hides the passing vehicles from view on abutting properties will
reduce traffic noise. To be an adequate noise shield, the mass and stiffness of the barrier
must be sufficient to prevent bending or buckling and it must not vibrate easily or leak air.
Up to 15 dBA reductions can be achieved using noise barriers such as berms and walls
made of stucco, reinforced concrete, concrete blocks, or precast concrete panels. Various
roadway designs are also effective in reducing traffic noise. Both depressed and elevated
roadway designs can by themselves, or in combination with noise barriers, prevent
adjacent areas from being exposed to excessive noise levels.
4.3.2 SPECIFIC RECOMMENDATIONS
The following specific mitigation measures are recommended for incorporation in the
Mitigation Monitoring Program associated with the project to minimize noise impacts and
insure compliance with applicable noise standards.
1. Construction activities on-site should take place only during the days and hours
specified by the Riverside County Noise Ordinance to reduce noise impacts during
more sensitive time periods.
2. All construction equipment, fixed or mobile, should be equipped with properly
operating and maintained mufflers.
3. Stationary equipment should be placed such that emitted noise is directed away from
noise sensitive receivers.
4. Stockpiling and vehicle staging areas should be located as far as practical from noise
sensitive receptors.
5. Every effort should be made to create the greatest distance between noise sources and
sensitive receptors during construction activities.
6. Residential development located adjacent to master planned streets on-site (Madison
Street, Monroe Street, Avenue 58, Avenue 60, and Avenue 62) shall be carefully
designed and evaluated at more detailed levels of planning to ensure that adequate
noise mitigation is incorporated to meet the Riverside County noise standard of 65
CNEL in outside living areas. Buildings with exterior noise exposures up to 70 dBA
can achieve 45 dBA interior noise levels with standard construction techniques.
7. Building setbacks and pad elevations shall be used in conjunction with acoustic berm
or berm and barrier combinations to reduce intrusive noise to acceptable levels (65
CNEL or less) in outdoor living areas of all residential units located within the
ultimate 65 CNEL contours adjacent to Madison Street, Monroe Street, Avenue 58,
Avenue 60, and Avenue 62. With exterior noise levels of 65 dBA, standard
construction practices will be adequate to ensure that interior noise levels for
residential units shall not exceed 45 dBA.
8. The architectural details of the commercial/retail buildings and their location and
orientation shall be reviewed prior to submittal of the building permit application to
ensure that interior noise levels will not exceed 50 CNEL.
9. Prior to the issuance of building permits, the final lot layout, pad elevations, building
design, and acoustic berm or berm and barrier combinations shall be evaluated by a
qualified acoustical consultant to verify that proper noise mitigation has been provided
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to ensure consistency with the standards and policies in the Noise Element of the
Riverside County General Plan. The resulting acoustical study shall be submitted for
approval to Riverside County.
10. If a perimeter wall is to be constructed between the commercial development on-site
and adjacent noise sensitive areas, it should be a solid barrier constructed as early in
the construction process as feasible so that it will shield sensitive areas from intrusive
construction -related noise.
11. Truck access, parking area design and air conditioning refrigeration units proposed in
the commercial area on-site shall be carefully designed and evaluated at more detailed
levels of planning to minimize the potential for acoustic impacts to adjacent noise
sensitive development.
MUG