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Term (2025 plus addition of the project) and at Specific Plan Build Out (2045 including addition of the project). The study further includes the considerations of the City’s recent adoption of a round-about first policy.
The conclusions and results of the 2025 Kimley-Horn Traffic, Access, and Circulation Study can be found within the 209-page report that has been submitted in conjunction with the project application.
Subsequent to traffic study submittal, the City additionally required Toll Brothers to pay for a “peer review” conducted by Fehr & Peers of the Kimley-Horn Traffic, Access, and Circulation Study. The conclusions of the peer review agreed with the findings in the Kimley-Horn study.
Oak Tree Preservation and Removal
The Toll Brothers at Alder Creek project contains both oak woodland areas and individual free-standing oak trees. An Arborist Report has been prepared by ECORP Consulting who has vast experience with the FPASP, and was submitted with the application materials. The purpose of the Arborist Report is to quantify the amount of oak woodland area within the project area and provide an assessment of the size and health condition of the individual trees.
There are 73 isolated oak trees on the project site, and oak woodland areas up to an estimated maximum of 107 acres which includes the property boundaries, all grading slopes, plus a 20-buffer around and within the entire development area. Additional individual tree survey data will be collected as needed to support evaluation of individual tree impacts, and applications for tree work permits or tree removal permits.
The FPASP does acknowledge that development will result in “unavoidable impacts” to isolated oak trees and oak woodlands. The policies in the Specific Plan state that oak trees included in residential and non-residential development parcels are encouraged to be preserved wherever practical, provided preservation does not:
• Cause a reduction in the number of lots or a significant reduction in the size of residential lots. • Require mass grading that eliminates level pads or requires specialized foundations. • Require the use of retaining walls or extended earthen slopes greater than 4-feet in height, as measured from the bottom of the footing to the top of the retaining wall. • Require the preservation of any trees certified by an arborist to be dead or in poor or hazardous or non-correctable condition or trees that pose a safety risk to the public. • Cost more to preserve the tree than to mitigate for its loss, based on the isolated oak tree mitigation requirements of the plan.
The Toll Brothers at Alder Creek project has been, and will continue to be designed to meet all FPASP applicable objectives and every practical effort will be made to preserve oak woodlands and isolated oak trees within the development parcels.
Minor Administrative Modification and Land Use Exhibit
The Toll Brothers at Alder Creek project is proposing certain minor boundary modifications to the approved boundaries shown in the FPASP. While the FPASP presents a good model or starting point, the next level of detail has been undertaken to analyze and determine how the roadways need to function, how boundaries should be amended to meet certain objectives of the Plan, and what infrastructure is necessary to serve the development area. Accordingly, these minor adjustments have resulted in our request for a Minor Administrative Modification request.
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Toll Brothers has submitted two separate documents to illustrate and detail these minor amendments.
The Land Use Exhibit identifies each minor amendment by zoning designation, by acreage and pictorially. The MAM Exhibit identifies each minor amendment by FPASP Parcel ID, by acreage and pictorially. As depicted in the table below, the most significant acreage modifications (although minor in scope) are increases in Open Space by nearly 6 acres, increases in Landscape corridors, increases in Parklands and reduction in roadways. We believe these minor modifications comply with the intent of the Specific Plan, and in fact enhance the overall project site.
Land Use FPASP Approved VTM Proposed Variance
SF 171.5 171.1 -0.4
SFHD 56.2 54.6 -1.6
MLD 53.9 52.2 -1.7
Park 10.3 13.6 +3.3
PQP 10.0 10.0 0.0
OS 131.2 137.1 + 5.9
OS-LC 9.8 10.4 + 0.6
ROW 21.3 18.8 -3.0
Walls and Fencing
The City of Folsom has an exterior noise level standard of (60 dB Ldn). The FPASP EIR/EIS addresses noise standards and in development areas where the noise levels of adjacent roadways may exceed the City’s standard, mitigation measures are required. The required mitigation measures are widely known throughout the development community, and the Toll Brothers at Alder Creek project proposes to voluntarily implement those measures without having to prove the mitigation measures are necessary.
Therefore, the Toll Brothers at Alder Creek project proposes the following noise mitigation measures be implemented through a specific condition of approval.
1) Solid noise barriers or similar natural features (earthen berms, etc.) shall be constructed adjacent to Oak Avenue Parkway, Mangini Parkway, Street D, and Prairie City Road to reduce future traffic noise levels to below the City of Folsom exterior criteria of 60 dB Ldn at the proposed residential backyards.
Barrier heights are specified relative to backyard elevations, and may vary from 6 feet to 8 feet in height depending on the backyard elevation relative to the adjacent roadway. 2) Mechanical ventilation (air conditioning) shall be provided for allresidences within the Toll Brothers project to allow the occupants to close doors and windows as desired to achieve compliance with the applicable interior noise level criteria.
3) Second-floor windows of residences located adjacent to Prairie City Road shall have second-floor windows with a minimum STC (Sound Transmission Class) rating of 34.2.
A split-face block wall is proposed around the perimeter of the project except at locations adjacent to open space. Generally, these walls will be 6 feet in height but increasing up to 8 feet in height to implement recommended noise reductions measures.
Private yard areas for the individual residential lots are proposed to be screened by a combination of wood fencing, open-view tubular steel fencing, and masonry walls. The wood fencing will be utilized for the interior side yards, street side yards, and rear yards of the residential lots. The open-view tubular steel fencing will be utilized for the rear yards on residential lots located adjacent to open space areas
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(where noise mitigation is not required). Masonry walls will be installed at various locations throughout the project site to minimize potential noise and privacy concerns.
Homeowners Associations
The Toll Brothers at Alder Creek community will be divided into two distinct Homeowners’ Associations (HOAs). One located in the north-west portion of the project site, south of Alder Creek Parkway, west of Oak Avenue, and north of Street D (Specific Plan Parcel ID #58), will be a gated neighborhood, temporarily named the Gated HOA. A second HOA located in the east and west portion of Oak Avenue extending up to east and west of Oak Avenue and north of Mangini Parkway extending up to east of the Powerline contains Specific Plan Parcel numbers 19A, 19B, 20A, 23-27, 173 and 254-256, which will not be gated, will fall under its own HOA, temporarily named the Non-Gated HOA. These two HOAs will be established in accordance with the California Davis-Stirling Common Interest Development Act and will operate as California nonprofit mutual benefit corporations.
List of Improvements HOA will cover
The Gated HOA will be responsible for maintaining the entry gates, parks, and internal landscape corridors. The community will feature two gated entries into this portion of the community, one located south of Alder Creek Parkway on the north side of the property, and the other located north of Haven Parkway at the south end of the property. Each of these gates will include two interior landscaped corridors, bringing the total to four landscaped buffer areas within the community. These corridors will enhance the aesthetic appeal and provide a green buffer between the gate system and residential areas.
The HOA will maintain the gates, sidewalks, and roadways, while the City will own and maintain the underground utilities.
A 51.4-acre open space Oak Woodland preserve area (Specific Plan Parcel ID #103) spans the heart of the community, which will provide a natural setting for residents, and ultimately contain a Class 1 Pedestrian Trail that will be constructed and maintained by the City through the collection of Specific Plan Impact Fees. The 51-acre Oak Woodland preserve area will endure in its natural state, and not be maintained by the Gated HOA.
Within the Gated HOA, there will be three designated private mini parks of approximately one-half acre each, along with two paseos connecting to the future Class 1 pedestrian trails that will serve as recreational spaces for residents. The HOA will be responsible for maintaining the mini parks and paseos to ensure their long-term upkeep and accessibility for residents. The Gated HOA will also oversee the surface improvements of private streets, ensuring their maintenance and upkeep while coordinating with the City on any necessary underground maintenance. Access will be granted to the City and other governmental agencies, utility companies, etc. through a series of easements, ROW’s, etc., dedicated at the time of Small Lot Final Map(s). Residents outside of the Gated HOA will be able to access the public trail system that passes through the area via the paseos, which will remain ungated.
The Non-Gated HOA will serve as a vibrant and well-maintained community, offering a variety of amenities and services exclusively for its residents. The residential component of the community will consist of a thoughtfully designed mix of housing types, catering to a variety of homebuyers. The plan includes 6-pack homes, 4-pack homes, duet homes and single-family homes of varying lot sizes. This diverse range of home designs will provide options for different household sizes and preferences while maintaining a cohesive architectural style. The community amenity labeled as “Private Park” will be developed as a central gathering space for homeowners in this community. The “Private Park” will feature amenities such as a swimming pool, restrooms, spa, and showers, and will be owned and maintained by the Non-Gated HOA. Access to this facility will be restricted to residents of the Non-Gated HOA, ensuring it remains exclusive to its members. In addition to the “Private Park,” the maintenance of
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the interior landscaped corridors near the 4- and 6-pack homes will also fall under the responsibility of the Non-Gated HOA. The 4-pack homes will include planter strips and sidewalks, which the Non-Gated HOA will maintain.
The Non-Gated community will also include multiple mini parks maintained by the HOA, and a private park maintained by the HOA offering ample open space for recreation, relaxation, and social interaction.
The mini parks have been incorporated to promote community interaction and socialization. The HOA will support homeowner connections by organizing community events like Easter egg hunts, ice cream socials, outdoor movie nights (strictly complying with noise ordinances of course), holiday light contests, etc. The FPASP public neighborhood park adjacent to the elementary school, will also offer all residents access to additional recreational opportunities. The proximity of the school to the residential areas will provide convenience for families with children and foster a strong connection between the neighborhood and educational institutions. The school district will be responsible for owning and maintaining the school, while the City will own and maintain the neighborhood public park.
Inclusionary Housing Agreement
On January 13, 2026, the City amended the Folsom Municipal Code relating to Inclusionary Housing. As described in Section 17.104 of the Code, there are several methods to meet the inclusionary housing requirement, including payment of in-lieu fee. Accordingly, Toll Brothers elects to rely on this section of the Code utilizing the payment of in-lieu fees to satisfy its inclusionary housing requirement.
Home Architecture
Toll Brothers and the City have discussed the standard tentative map submittal requirement of full building elevation plans, color and material boards, colored renderings, monumentation signage renderings, etc., as described in Section 13.4 of the FPASP. Both parties have agreed to forgo these required submittals with the Toll Brothers at Alder Creek Vesting Small Lot Tentative Map for the following reasons.
The standard architectural submittals make sense for a standard tentative map application with a substantially smaller dwelling unit count. However, the duration of time between tentative map submittal, preparation and approval of improvement plans, physical development of the property, etc., is vast. Developing architecture for 1,424 units containing twelve (12) different lot sizes, with each of the twelve lot sizes containing multiple home plans prior to the submittal of the vesting tentative map is simply premature. Toll Brothers takes great care, and performs extensive due diligence in developing our home architecture, and to artificially force the completion of architecture years before the first building permit is even applied for simply to check a box on an application form isn’t rational. Toll Brothers extends its appreciation to the City for recognizing these facts, and allowing us to forgo this standard requirement at the time of tentative map submittal.
Given this mutual understanding with the City, Toll Brothers will fully comply with all City design review requirements and commits to securing Design Review Committee approval prior to submitting masterplan home construction drawings to the City’s Building Department for review. We anticipate this requirement will be made one of the conditions to the vesting tentative map approval.
As a further gesture of Toll Brothers appreciation of the City’s reasonableness, we have developed preliminary architecture themes, design objectives, architectural styles, homesite examples, and a set of development standards for the City’s review. These items are contained within the document titled Toll Brothers at Alder Creek Design Guidelines submitted with the Small Lot Vesting Tentative Map application. One area of the project site that has garnered particular interest from Staff are the 4-Pack and 6-Pack areas of the land plan.
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Included within the Toll Brothers at Alder Creek Design Guidelines document are specific setback standards for the 4-Pack and 6-Pack homesites that are expressly part of the Planned Development Permit portion of the overall application. Toll Brothers is seeking approval of these setbacks as part of the PD and VTM application.
4-Pack and 6-Pack Land Use Pattern Description
The southeast portion of the Vesting Tentative Map has a Specific Plan zoning designation of MultiFamily Low Density (MLD) with a required density of 7-12 DU/Ac. Toll Brothers has carefully designed this area of the project (Specific Plan Parcel ID’s of 24 and 173) to comply with the zoning designations.
The lotting patterns in this area are commonly referred to a 4-Pack and 6-Pack designs. The 4-Pack and 6-Pack lotting patterns are identified on the Vesting Tentative Map as Villages 1B and 1C respectively.
Although these lotting patterns may not be common or familiar to the City of Folsom, they are employed widely throughout the country, and Toll Brothers has built a multitude of desirable and successful communities utilizing this pattern, and we have included photographs of actual Toll Brothers homes for reference in this application. It is also worth noting that the use of these lot types not only allows for the higher density required by the zoning designation, but also allows us to introduce a more affordable product in an area that is highly desired by first-time or entry-level homebuyers.
Because these design patterns may not be common or familiar to the City of Folsom, we have prepared not only a design guideline table, but also made the effort to prepare a colored graphic to further assist the City with understanding how these lotting patterns work. Both the guidelines table and color graphic can be found on the following pages.
The 4-Pack pattern is designed to have the two (2) homes closest to the primary neighborhood roadway facing the primary neighborhood roadway, providing a traditional look and feel. Employing these extra design elements will make the homesites comparable to a more traditional residential design. The two (2) remaining homes in the 4-Pack pattern will face the motor-court as is standard with this type of land use. The 6-Pack pattern has been designed with a standard configuration with all homes facing the motor-court. This configuration presents its own unique needs for relief and space planning, and we will incorporate the use of street trees, thoughtful planting, and attractive masonry wall (as opposed to traditional wood fencing) to elevate the aesthetic of the homesites with street frontage.
As is the norm with any “X-Pack” land plan design, there will be zero (0) lot line homesites with a use easement on the adjacent property, and Toll Brothers has also carefully prepared the design guidelines to ensure there remains a minimum separation between structures. Please refer to the design guideline tables and color graphics on the following pages to gain a better understanding of how the zero-lot line and building separation minimums function.
The motor-courts contained within both the 4-Pack and 6-Pack neighborhoods will be privately owned and maintained, enforced through a series of recorded Homeowners Association Use, and Maintenance Declarations, while the primary neighborhood roadways will remain public.
Landscape Design
Toll Brothers understands the importance of landscaping to any new community. A well designed and thoughtfully implemented landscape is central to achieving the visual and design aesthetic envisioned for Toll Brothers at Alder Creek. Accordingly, and in compliance with the FPASP, we have prepared a set of Landscape Design Guidelines that include the following primary representations. Location & Setting, Project Vision, Streetscape, Master Plant List, Gated Entry Monumentation, and Site Amenities. The
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Landscape Design Guidelines are included as a separate document within the overall application. Please refer to these guidelines for detail and approval.
Summary
Toll Brothers is requesting approval of a Small Lot Vesting Tentative Map, Planned Development Permit, Design Guidelines, and Minor Administrative Modification containing 1,424 single family dwelling units with varying densities covering 464.2 acres. A variety of other parcels are also included for land uses such as private recreation, parks, landscaping, open space, roadways, a fire station, and an elementary school. In total, 1,488 total lots will be created.
Should anyone reading this Project Narrative not already be familiar with Toll Brothers and the highquality developments we create, we encourage you to visit our Regency at Folsom Ranch project within the FPASP. For even more information on Toll Brothers commitment to quality and to see real life examples of the type of communities and homes we build here in Folsom and nationwide, please visit our website at www.tollbrothers.com
Finally, while we recognize municipalities typically do not consider financial investment or time investment into a community, Toll Brothers investment into the City of Folsom for this proposed project is very substantial from both perspectives. Irrespective of the property tax revenue this project will generate, the employment it will generate, the local business revenue it will generate (all of which are substantial in their own right), the impact fees and building permit fees alone that will be paid to the City of Folsom are estimated to be over $130,000,000. This project will also extend our already strong relationship with the City by 10 (+/-) years. These financial and relationship realities demonstrate Toll Bothers commitment to this project and investment within the City of Folsom.
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Attachment 20
Alder Creek Conformity Analysis with Appendices,
date November 19, 2025
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Section 15182 and 15162 Conformity Analysis for the
Toll Brothers Property, Alder Creek Subdivision
Tentative Map, City of Folsom, California
Lead Agency:
City of Folsom
50 Natoma Street
Folsom, CA 95630
Prepared by:
2525 Warren Drive
Rocklin, CA 95677
August 2025
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TABLE OF CONTENTS
1.0 BACKGROUND................................................................................................................................................................. 1-1
1.1 Summary............................................................................................................................................................ 1-1
1.2 Introduction...................................................................................................................................................... 1-1
2.0 PROJECT DESCRIPTION................................................................................................................................................ 2-3
2.1 Project Description ........................................................................................................................................ 2-3
2.1.1 Residential Land Plan Overview............................................................................................... 2-3
2.1.2 General Plan, Specific Plan, and Zoning Consistency ..................................................... 2-7
2.1.3 Prairie City Road Improvements.............................................................................................. 2-8
2.2 California Environmental Quality Act Compliance............................................................................ 2-8
2.2.1 Overview of CEQA Guidelines Section 15182 .................................................................... 2-9
3.0 CONFORMITY ANALYSIS ...........................................................................................................................................3-12
3.1 Aesthetics ........................................................................................................................................................3-12
3.1.1 Environmental Setting...............................................................................................................3-12
3.1.2 FPASP EIR/EIS Summary ...........................................................................................................3-13
3.1.3 Aesthetics Conformity Analysis..............................................................................................3-13
3.1.4 Conclusion......................................................................................................................................3-14
3.2 Agriculture and Forestry Resources......................................................................................................3-15
3.2.1 Environmental Setting...............................................................................................................3-15
3.2.2 FPASP EIR/EIS Summary ...........................................................................................................3-15
3.2.3 Agriculture and Forestry Resources Conformity Analysis ...........................................3-15
3.2.4 Conclusion......................................................................................................................................3-15
3.3 Air Quality .......................................................................................................................................................3-16
3.3.1 Environmental Setting...............................................................................................................3-16
3.3.2 FPASP EIR/EIS Summary ...........................................................................................................3-18
3.3.3 Air Quality Conformity Analysis.............................................................................................3-18
3.3.4 Conclusion......................................................................................................................................3-30
3.4 Biological Resources ...................................................................................................................................3-30
3.4.1 Environmental Setting...............................................................................................................3-30
3.4.2 FPASP EIR/EIS Summary ...........................................................................................................3-31
3.4.3 Biological Resources Conformity Analysis.........................................................................3-32
3.4.4 Conclusion......................................................................................................................................3-33
3.5 Cultural Resources .......................................................................................................................................3-35
3.5.1 Environmental Setting...............................................................................................................3-35
3.5.2 Summary of Cultural Resources ............................................................................................3-37
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3.5.3 FPASP EIR/EIS Summary ...........................................................................................................3-39
3.5.4 Cultural Resources Conformity Analysis.............................................................................3-39
3.5.5 Conclusion......................................................................................................................................3-40
3.6 Energy...............................................................................................................................................................3-40
3.7 Geology and Soils ........................................................................................................................................3-40
3.7.1 Environmental Setting...............................................................................................................3-40
3.7.2 FPASP EIR/EIS Summary ...........................................................................................................3-41
3.7.3 Geology and Soils Conformity Analysis..............................................................................3-41
3.7.4 Conclusion......................................................................................................................................3-43
3.8 Greenhouse Gas Emissions ......................................................................................................................3-43
3.8.1 Environmental Setting...............................................................................................................3-43
3.8.2 Regulatory Setting ......................................................................................................................3-44
3.8.3 FPASP EIR/EIS Summary ...........................................................................................................3-45
3.8.4 Greenhouse Gas Emissions Conformity Analysis............................................................3-45
3.8.5 Conclusion......................................................................................................................................3-48
3.9 Hazards and Hazardous Materials.........................................................................................................3-49
3.9.1 Environmental Setting...............................................................................................................3-49
3.9.2 FPASP EIR/EIS Summary ...........................................................................................................3-50
3.9.3 Hazards and Hazardous Materials Summary ...................................................................3-50
3.9.4 Conclusion......................................................................................................................................3-51
3.10 Hydrology and Water Quality .................................................................................................................3-52
3.10.1 Environmental Setting...............................................................................................................3-52
3.10.2 FPASP EIR/EIS Summary ...........................................................................................................3-53
3.10.3 Hydrology and Water Quality Conformity Analysis.......................................................3-53
3.10.4 Conclusion......................................................................................................................................3-54
3.11 Land Use and Planning ..............................................................................................................................3-55
3.11.1 Environmental Setting...............................................................................................................3-55
3.11.2 FPASP EIR/EIS Summary ...........................................................................................................3-55
3.11.3 Land Use and Planning Conformity Analysis....................................................................3-55
3.11.4 Conclusion......................................................................................................................................3-55
3.12 Mineral Resources........................................................................................................................................3-56
3.12.1 Environmental Setting...............................................................................................................3-56
3.12.2 FPASP EIR/EIS Summary ...........................................................................................................3-57
3.12.3 Mineral Resources Conformity Analysis .............................................................................3-57
3.12.4 Conclusion......................................................................................................................................3-57
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3.13 Noise .................................................................................................................................................................3-58
3.13.1 Environmental Setting...............................................................................................................3-58
3.13.2 FPASP EIR/EIS Summary ...........................................................................................................3-62
3.13.3 Noise Conformity Analysis.......................................................................................................3-62
3.13.4 Conclusion......................................................................................................................................3-71
3.14 Population and Housing ...........................................................................................................................3-71
3.14.1 Environmental Setting...............................................................................................................3-71
3.14.2 FPASP EIR/EIS Summary ...........................................................................................................3-72
3.14.3 Population and Housing Conformity Analysis.................................................................3-72
3.14.4 Conclusion......................................................................................................................................3-72
3.15 Public Services...............................................................................................................................................3-73
3.15.1 Environmental Setting...............................................................................................................3-73
3.15.2 FPASP EIR/EIS Summary ...........................................................................................................3-73
3.15.3 Public Services Conformity Analysis ....................................................................................3-73
3.15.4 Conclusion......................................................................................................................................3-74
3.16 Recreation .......................................................................................................................................................3-74
3.16.1 Environmental Setting...............................................................................................................3-74
3.16.2 FPASP EIR/EIS Summary ...........................................................................................................3-74
3.16.3 Recreation Conformity Analysis.............................................................................................3-75
3.16.4 Conclusion......................................................................................................................................3-75
3.17 Transportation...............................................................................................................................................3-76
3.17.1 Environmental Setting...............................................................................................................3-76
3.17.2 FPASP EIR/EIS Traffic Summary .............................................................................................3-76
3.17.3 Transportation Conformity Analysis ....................................................................................3-77
3.17.4 Conclusion......................................................................................................................................3-78
3.18 Tribal Cultural Resources ..........................................................................................................................3-79
3.19 Utilities and Service Systems ...................................................................................................................3-79
3.19.1 Environmental Setting...............................................................................................................3-79
3.19.2 Utilities and Service Systems Conformity Analysis.........................................................3-81
3.19.3 Conclusion......................................................................................................................................3-81
3.20 Wildfire.............................................................................................................................................................3-82
3.20.1 Environmental Setting...............................................................................................................3-82
3.20.2 Wildfire Conformity Analysis...................................................................................................3-82
3.20.3 Conclusion......................................................................................................................................3-82
4.0 LIST OF PREPARERS ....................................................................................................................................................... 4-1
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4.1 ECORP Consulting, Inc. ................................................................................................................................ 4-1
5.0 REFERENCES...................................................................................................................................................................... 5-1
LIST OF TABLES
Table 2.1-1. Vesting Small Lot Tentative Map Land Use Summary............................................................................. 2-3 Table 2.1-2. Residential Land Plan Overview........................................................................................................................ 2-7 Table 2.1-3. Project Changes in Acreages ............................................................................................................................. 2-8 Table 3.3-1. Construction-Related Emissions.....................................................................................................................3-21 Table 3.3-2. Operational-Related Emissions.......................................................................................................................3-24 Table 3.5-1. Cultural Resources within the Subject Property.......................................................................................3-37 Table 3.8-1. Construction-Related Greenhouse Gas Emissions ..................................................................................3-46 Table 3.8-2. Operational-Related Greenhouse Gas Emissions ....................................................................................3-47 Table 3.13-1. Existing (Baseline) Noise Measurements ..................................................................................................3-61 Table 3.13-2. Construction Average (dBA) Noise Levels at Nearest Receptors....................................................3-64 Table 3.13-3. Representative Vibration Source Levels for Construction Equipment..........................................3-69 Table 4.13-4. Groundborne Vibration Impact Criteria for General Assessment...................................................3-70
LIST OF FIGURES
Figure 2-1. Alder Creek Aerial .................................................................................................................................................... 2-0
LIST OF APPENDICES
Appendix A – Folsom Plan Area Specific Plan EIR/EIS Mitigation Monitoring and Reporting Program City of Folsom, 2011.
Appendix B – Alder Creek Property Project Emissions Report ECORP Consulting, Inc. July 2025.
Appendix C – Alder Creek Property Project Roadway Construction ECORP Consulting, Inc. July 2025.
Appendix D – Alder Creek Property Project Traffic Noise Levels.
ECORP Consulting, Inc. July 2025.
Appendix E – Prairie City Road Phase 1 Improvements and Interim Connections.
MacKay & Somps. August 2025.
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LIST OF ACRONYMS AND ABBREVIATIONS
Term Definition
AB 52 Assembly Bill 52
AQMP Air Quality Management Plan
BACT Best Available Control Technology
BB IS/MND Backbone Initial Study/Mitigated Negative Declaration BMPs Best Management Practices
BP Before Present
CAAQS California Ambient Air Quality Standards
CAL FIRE California Department of Forestry and Fire Protection CalEEMod California Emissions Estimator Model
Caltrans California Department of Transportation
CARB California Air Resources Board
CBC California Building Standards Code
CCR California Code of Regulations
CDFW California Department of Fish and Wildlife
CEC California Energy Commission
CEQA California Environmental Quality Act
CFR Code of Federal Regulations
CH4 Methane
CHP California Highway Patrol
City City of Folsom
CIWM California Integrated Waste Management
CNEL Community Noise Equivalence Levels
CO Carbon Monoxide
CO2 Carbon Dioxide
CO2e Carbon Dioxide Equivalent
COC Chemical Of Concern
CRHR California Register of Historic Resources
CUPA Certified Unified Program Agency
CWA Clean Water Act
dB decibels
dBA A-weighted decibels
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DHS California Department of Health Services
DOC California Department of Conservation
DPM Diesel Particulate Matter
DTSC Department of Toxic Substances Control
ECORP ECORP Consulting, Inc.
EID El Dorado Irrigation District
EIR Environmental Impact Report
EIS Environmental Impact Statement
ESA Endangered Species Act
FEIR Final EIR
FHSZ Fire Hazard Severity Zone
FHWA Federal Highway Administration
FPASP Folsom Plan Area Specific Plan
FTA Federal Transit Administration
GHG Greenhouse Gas
HCP Habitat Conservation Plan
hp Horse Power
HPMP Historic Property Management Plan
HVAC Heating, ventilation, and air conditioning
IS Initial Study
ITE Institute of Traffic Engineers
J&Z Javanifard and Zarghami
mg/L milligrams per liter
MLD Most Likely Descendent
MMRP Mitigation Monitoring and Reporting Plan
MND Mitigated Negative Declaration
MRZ Mineral Resource Zone
N2O Nitrous Oxide
NAAQS National Ambient Air Quality Standards
NAHC Native American Heritage Commission
NEPA National Environmental Policy Act
NIOSH National Institute for Occupational Safety and Health
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NOA Naturally Occurring Asbestos
NOD Notice of Determination
NOx Nitrogen Oxides
NPDES National Pollutant Discharge Elimination System
NRCS Natural Resources Conservation Service
NRHP National Register of Historic Places
O3 Ozone
OPR California Office of Planning and Research
OS Open Space
PA Programmatic Agreement
PEA Preliminary Environmental Assessment
PM Post Mile
PM10 Particulate matter with a diameter of 10 microns or less PM2.5 Particulate matter with a diameter of 2.5 microns or less ppm parts per million
PQP Public Quasi-Public
PRC Public Resources Code
Proposed Project Alder Creek Elementary School Project
RDMD Rhoades’ Diggings Mining District
ROG Reactive Organic Gases
RPA Registered Professional Archaeologist
RWQCB Regional Water Quality Control Board
SB Senate Bill
SCAQMD South Coast Air Quality Management District
SCH State Clearinghouse
SFHD Single Family High Density
SHPO State Historic Preservation Officer
SIP State Implementation Plan
SMAQMD Sacramento Metropolitan Air Quality Management District SMARA Surface Mining and Reclamation Act of 1975
SO2 Sulfur Dioxide
SPA Specific Plan Area
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Alder Creek Subdivision Conformity Analysis 2024-012.01 Term Definition
SRCSD Sacramento Regional County Sanitation District
SRWTP Sacramento Regional Wastewater Treatment Plant
STC sound transmission class
SVAB Sacramento Valley Air Basin
SWPPP Stormwater Pollution Prevention Plan
SWRCB State Water Resources Control Board
TDS Total Dissolved Solids
USACE United States Army Corps of Engineers
USEPA U.S. Environmental Protection Agency
VdB vibration decibels
VTM Vesting Tentative Map
WTP Water Treatment Plant
WTP Wastewater Treatment Plant
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1.0 BACKGROUND
1.1 Summary
Project Title: Toll Brothers Property – Alder Creek Subdivision Tentative Map Conformity Analysis
Lead Agency Name and Address: City of Folsom
50 Natoma Street
Folsom, CA 95630
Contact Person and Phone Number: Jessica Brandt, Principal Planner (916) 461-6207
[email protected]
Project Description Summary: The Project proposed by Toll Brothers (applicant) is requesting approval of a Small Lot Vesting Tentative
Map, Planned Development Permit, Design
Guidelines, Landscape Guidelines, and Minor
Administrative Modification containing 1,424 single
family dwelling units with varying densities covering
464.2 acres. A variety of other parcels are also
included for land uses such as private recreation,
parks, landscaping, open space, roadways, a fire
station, and an elementary school. In total, 1,488
total lots will be created.
1.2 Introduction
The City of Folsom is the Lead Agency for this California Environmental Quality Act (CEQA) Conformity Analysis. This Conformity Analysis has been prepared to identify and assess compliance of the Alder Creek Subdivision Tentative Map Project (Proposed Project) with the program-level Folsom Plan Area Specific Plan (FPASP) Environmental Impact Report/Environmental Impact Statement (EIR/EIS, State Clearinghouse [SCH]# 2008092051). This Conformity Analysis also satisfies CEQA (Public Resources Code [PRC], Section 21000 et seq.) and state CEQA Guidelines (Title 14, California Code of Regulations [CCR] 15000 et seq.).
CEQA requires that all state and local government agencies consider the environmental consequences before approving projects.
Pursuant to CEQA Guidelines Section 15182(c), where a public agency has prepared an EIR on a specific plan after January 1, 1980, a residential project undertaken pursuant to and in conformity to that specific plan is exempt from CEQA if the project meets the requirements of this section. Residential projects covered by this section include but are not limited to land subdivisions, zoning changes, and residential planned unit developments.
If after the adoption of the specific plan, an event described in Section 15162 occurs, the exemption in this subdivision shall not apply until the city or county which adopted the specific plan completes a
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Alder Creek Subdivision Conformity Analysis 2024-012.01 subsequent EIR or a supplement to an EIR on the specific plan. The exemption provided by this section shall again be available to residential projects after the Lead Agency has filed a Notice of Determination on the specific plan as reconsidered by the subsequent EIR or supplement to the EIR.
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2.0 PROJECT DESCRIPTION
2.1 Project Description
The Project proposed by Toll Brothers (applicant) is requesting approval of a Small Lot Vesting Tentative Map, Planned Development Permit, Design Guidelines, Landscape Guidelines, and Minor Administrative Modification containing 1,424 single family dwelling units with varying densities covering 464.2 acres. A variety of other parcels are also included for land uses such as private recreation, parks, landscaping, open space, roadways, a fire station, and an elementary school. In total, 1,488 total lots will be created. The Project is part of the FPASP, which is covered by several federal and state permits and includes backbone infrastructure serving the entire Folsom Plan Area. Within the FPASP, the Toll Brothers at Alder Creek project spans five permit areas: Mangini Ranch, Alder Ranch (also known as Folsom 560 and Hillsborough), Carpenter Ranch, Javanifard and Zarghami Property (J&Z Property), and the Backbone Infrastructure. Table 2.1-1 below shows the Vesting Small Lot Tentative Map Land Use Summary. A figure of the Project Location is found on Figure 2-1.
Table 2.1-1. Vesting Small Lot Tentative Map Land Use Summary Total Acreage 464.2
Dwelling Units 1,424
Number of Parks 10.0
Park Acreage 13.8
Number of Open Space Lots 16.0
Open Space Acreage 137.1
Major Roadway Acreage 19.7
Number of Roadway Landscape Lots 21.0
Roadway Landscape Acreage 10.7
Number of Village Landscape Lots 23.0
Fire Station Acreage 1.9
Elementary School Acreage 10.0
2.1.1 Residential Land Plan Overview
The Vesting Small Lot Tentative Map contains 1,424 residential lots with varying zoning densities. Toll Brothers have designed the Map in a concerted effort to accommodate a wide variety of housing types and price points. In total, there are thirteen (13) different lot sizes, each of which comply with the zoning designations and densities identified in the General Plan and the Specific Plan. The summary of each lot size, type, zoning designation and density can be found in Table 2.1-2 below. Net density is calculated using gross acreage, as required by the Specific Plan.
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Map Date: 7/8/2025
Figure 2-1.
Alder Creek Aerial
I
0 700
Sca le i n F ee t 2024-012 Alder Creek Photo Source: NAIP, 2022 1 ECORP, MSCE and Foothill Associates (MAG)-trotellini 7/8/2025 Location: J:\GIS_Maps\2005-429_Folsom_Area_South_Group\Draft_Maps_Data\2024-01-11 Alder Creek Due Dilligence\AlderCreek_Aerial_20250708.mxd Map Features
Service Layer Credits: Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Specific Plan Boundary
Alder Creek Project Area - 517.37 acres
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Alder Creek Subdivision Conformity Analysis 2024-012.01 Table 2.1-2. Residential Land Plan Overview
Tentative
Map
Village
Number
Zoning
Designation Lot Size Gross Acres
Dwelling
Units
Net
Density
1A MLD 42' x 65' Duets 12.8 106 8.3
1B MLD 4-Pack 12.8 101 7.9
1C MLD 6-Pack 11.6 124 10.7
2A SFHD 47' x 85' 13.2 93 7.0
2B SFHD 47' x 75' 10.2 71 7.0
3A MLD 45' x 65' 14.2 132 9.2
3B MLD 70' x 110' 6.5 25 3.8
4A SF 65' x 105' 8.5 31 3.6
4B SF 70' x 110' 19.2 63 3.3
5 SF 65' x 105' 11.9 47 4.0
6 SFHD 50' x 100' 16.5 99 6.0
7A SF 75' x 110' 17.4 58 3.3
7B SFHD/SF 60' x 110' and 75' x 100' 18.6 81 4.4
8A SF 60' x 105' and 65' x 105' 24.9 105 4.2
8B SF 70' x 100' 9.8 27 2.8
8C SF 75' x 100' 29.3 96 3.3
9A SF 70' x 110' 17.7 62 3.5
9B SF 60' x 105' 21.5 103 4.8
Note: MLD = Multi-Family Low-Density; SF = Single-Family; SFHD = Single-Family High Density;
2.1.2 General Plan, Specific Plan, and Zoning Consistency The 464.2‐acre project site has General Plan land use designations of: SF, SFHD, MLD, OS (Open Space), PQP (Public Quasi-Public), P (Parks), and F (Fire Station). The Specific Plan adds the prefix of “SP” in front of the General Plan land use designations. Table 2.1-3 below demonstrates the Toll Brothers at Alder Creek project’s consistency with currently approved designations.
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Alder Creek Subdivision Conformity Analysis 2024-012.01 Table 2.1-3. Project Changes in Acreages
Land Use FPASP Approved VTM Proposed Variance
SF 171.5 171.1 -0.4
SFHD 56.2 54.6 -1.6
MLD 53.9 52.2 -1.7
P 10.3 10.0 -0.3
PQP 10.0 10.0 0.0
OS 131.2 137.1 5.9
OS-LC 9.8 10.4 0.6
ROW 21.3 18.8 -3.0
Note: FPASP = Folsom Plan Area Specific Plan; MLD = Multi-Family Low Density; P = Parks; PQP = Public/Quasi-Public; OS = Open Space; OS-LC = ; ROW = Right-of-Way; SF = Single Family; SFHD = Single Family High Density; VTM = Vesting Tentative Map
2.1.3 Prairie City Road Improvements
The FPASP identifies the southern section of Prairie City Road (from Alder Creek Parkway south to White Rock Road) as a required four lane minor arterial, two lanes in each direction (north-south) with a planted median and landscape corridor. Part of the proposed Project includes construction of Phase 1 of Prairie City Road improvements, consisting of the easterly travel lanes in the ultimate and final alignment, sidewalk and landscape corridor. This work would include rough grading, rail corridor crossings and installation of pavement, curbs, gutters, street lighting, sidewalks, landscaping and striping. These construction specifications shall be consistent with Figure 7.9 of the FSPASP. The design drawings have been included in Appendix E. The Prairie City Road improvements that are part of the proposed Project are within the existing CWA Section 404 permit boundaries.
As part of the improvements to Prairie City Road, the proposed 69-kilovolt (kV) transmission lines will be realigned to the western side of Prairie City Road. The line relocation work would occur in the area along Prairie City Road already included in the project permitting.
2.2 California Environmental Quality Act Compliance
CEQA applies to proposed projects initiated by, funded by, or requiring discretionary approvals from state or local government agencies. As such, the proposed project constitutes a project as defined by CEQA (California Public Resources Code, Section 21000 et seq.). CEQA Guidelines Section 15367 states that a “Lead Agency” is “the public agency which has the principal responsibility for carrying out or approving a project.” Therefore, the City of Folsom (City) is the lead agency responsible for compliance with CEQA for the proposed project.
An Environmental Impact Report/Environmental Impact Statement (EIR/EIS) for the Folsom South of U.S.
Highway 50 Specific Plan Project was prepared jointly by the City of Folsom and U.S. Army Corps of Engineers (USACE) to fulfill requirements of the California Environmental Quality Act (CEQA) and National
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Alder Creek Subdivision Conformity Analysis 2024-012.01 Environmental Policy Act, respectively. A Notice of Determination (NOD) for the EIR was filed by the City of Folsom on June 15, 2011 (State Clearinghouse [SCH] #2008092051), and a Record of Decision for the EIR/EIS was filed by the USACE on August 12, 2011, (SPK-2007-02159). A Mitigation Monitoring and Reporting Program (MMRP) was prepared and adopted with the FPASP and is a binding document applicable to the Alder Creek Property development (Appendix A, Mitigation Monitoring and Reporting Program). The approved MMRP outlines mitigation measures required for all projects located within the FPASP.
An Initial Study (IS) and Mitigated Negative Declaration (MND) was prepared for the FPASP Backbone Infrastructure (BB IS/MND), and an NOD was filed by the City of Folsom on February 25, 2015 (SCH# 2114122018). The BB IS/MND outlines mitigation measures specifically for the Backbone Infrastructure development. The mitigation measures in the BB IS/MND mirror the original EIR/EIS with some modifications.
This Conformity Analysis has been prepared to examine the project in light of the FPASP EIR/EIS (City of Folsom 2011), pursuant to CEQA Guidelines Section 15182, to determine if any of the events described in CEQA Guidelines Section 15162 have occurred, and were not considered in the FPASP. The background information referenced in this document is from information contained in that document.
2.2.1 Overview of CEQA Guidelines Section 15182
The CEQA Guidelines section 15182(c) states that "Where a public agency has prepared an EIR on a specific plan after January 1, 1980, a residential project undertaken pursuant to and in conformity to that specific plan is exempt from CEQA if the project meets the requirements of this section. Residential projects covered by this section include but are not limited to land subdivisions, zoning changes, and residential planned unit developments." The 15182 exemption shall not apply if an event described in Section 15162 occurs, which includes the following circumstances:
“(1) substantial changes are proposed in the project which will require major revisions of the previous EIR or negative declaration due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified significant effects; (2) substantial changes occur with respect to the circumstances under which the project is undertaken which will require major revisions of the previous EIR or Negative Declaration due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified significant effects; or
(3) New information of substantial importance, which was not known and could not have been known with the exercise of reasonable diligence at the time the previous EIR was certified as complete or the Negative Declaration was adopted, shows any of the following:
A. The project will have one or more significant effects not discussed in the previous EIR or negative declaration;
B. Significant effects previously examined will be substantially more severe than shown in the previous EIR;
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Alder Creek Subdivision Conformity Analysis 2024-012.01 C. Mitigation measures or alternatives previously found not to be feasible would in fact be feasible, and would substantially reduce one or more significant effects of the project, but the project proponents decline to adopt the mitigation measure or alternative; or D. Mitigation measures or alternatives which are considerably different from those analyzed in the previous EIR would substantially reduce one or more significant effects on the environment, but the project proponents decline to adopt the mitigation measure or alternative.” For purposes of this analysis, however, because the proposed project implements and is consistent with the FPASP, and none of the factors set forth in CEQA Guidelines Section 15162 are present or have been identified, pursuant to CEQA Guidelines Section 15182, the City finds that the project is exempt from further CEQA compliance. The City further finds that the project is also exempt pursuant to Government Code Section 65457.
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3.0 CONFORMITY ANALYSIS
3.1 Aesthetics
3.1.1 Environmental Setting
The Project is located within the City of Folsom Plan Area in eastern Sacramento County. The Plan Area is generally bounded by U.S. Highway 50 to the north, White Rock Road to the south, Prairie City Road to the west, and the Sacramento/El Dorado County line to the east. It is located partially within the Sierra Nevada foothills and partially within the eastern edge of the Sacramento Valley. The Sierra Nevada foothills consist of gently rolling terrain that grades upward to the east into the higher mountain elevations. The Sacramento Valley is a nearly flat alluvial plain that extends almost 180 miles from the Sacramento-San Joaquin Delta on the south to the city of Redding on the north, and approximately 50 miles from the Sierra Nevada mountains on the east to the Coast Range on the west.
Urbanized development within the City of Folsom exists north of U.S. 50. The urban areas consist of large residential and commercial developments. Neighborhoods and shopping centers are generally concentrated along major roadways and are separated by areas of open space. Land south of U.S. 50 was historically characterized by seasonal grazing land. Since implementation of the FPASP EIR/EIS, the area has been developed to include a mix of residential units and graded sites proposed for future residential and commercial uses. The El Dorado County line forms the eastern boundary of the City of Folsom. The Stonebriar subdivision is located east of the County boundary in the community of El Dorado Hills.
Industrial land owned by GenCorp and associated buffer lands are located to the west of Prairie City Road.
3.1.1.1 Regional Setting
State Scenic Highways
The California Scenic Highway Program protects and enhances the scenic beauty of California’s highways and adjacent corridors. The California Department of Transportation (Caltrans) can designate a highway as scenic based on how much natural beauty can be seen by users of the highway, the quality of the scenic landscape, and if development impacts the enjoyment of the view. There are no officially designated scenic highways within or near the Project Site.
Scenic Resource Designations
Scott Road, from White Rock Road south to Latrobe Road, is a designated scenic corridor in the Sacramento County General Plan. While this portion of Scott Road is not located within the Folsom Plan Area, the Plan Area is visible from the scenic corridor. According to the Scenic Highways Element of the Sacramento County General Plan, the visual character of the roadway was considered to be particularly scenic and thus warranted scenic corridor protection.
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3.1.1.2 Visual Character of the Project Site
The Project site is located within the central lowlands of the Folsom Plan Area. Historically, the landscape of this portion of the Plan Area was characterized by gently rolling hills covered with annual grasses and scattered trees, water features, and rock outcroppings. Since the implementation of the FPASP EIR/EIS, foreground views consist of graded plots and construction activities for residential communities. Middle ground views consist of farmland to the south, oak woodlands to the west, the City of Folsom and U.S. 50 to the north, and the rolling hills within the Plan Area to the east. In the background, the Sierra Nevada mountains are visible to the east, and Mount Diablo is within view to the southwest.
3.1.2 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, implementation of mitigation measures would reduce impacts associated with new light and glare to a less than significant level. Impacts related to substantial alteration of a scenic vista, damage to designated scenic corridor, and substantial degradation of visual character due to development would be significant and unavoidable because no feasible mitigation measures are available to reduce these impacts to a less than significant level.
3.1.3 Aesthetics Conformity Analysis
3.1.3.1 Scenic Vistas
Project implementation would have no substantial change to aesthetic environmental checklist items described in the FPASP EIR/EIS. Planned development has been approved and built adjacent to the Project site. Impacts to scenic vistas were identified as a significant and unavoidable impact in the FPASP EIR/EIS and the Project does not introduce any new or unique visual features that were not analyzed in the FPASP EIR/EIS. No new circumstances or Project changes have occurred nor has any new information been found requiring new analysis or verification on scenic vistas. Therefore, the Proposed Project would have no new impact on scenic vistas.
3.1.3.2 Scenic Resources
At the time of the certification of FPASP EIR/EIS, there were no officially designated State Scenic Highways with views of the site. However, Scott Road south of White Rock Road was identified as a designated scenic corridor in Sacramento County because it is considered to be located within an especially scenic rural portion of Sacramento County. It continues to remain a designated scenic corridor; therefore, the same visual impacts to this corridor would occur with implementation of the Project as described in the FPASP EIR/EIS. Because the Project would develop the site with a similar development pattern and land uses as described in the FPASP EIR/EIS, no new impacts would occur. The findings of the certified EIR/EIS remain valid, and no further analysis is required. Therefore, the Proposed Project would have no new impact on state scenic highways or corridors.
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3.1.3.3 Visual Character
The Project is part of the greater implementation of the FPASP, resulting in the conversion of grassy hillsides to urban areas generally consisting of housing units and commercial developments. The Project would affect the same area analyzed for development in the FPASP EIR/EIS and would not alter the development type or density at the Project site. Development surrounding the Project site is ongoing, so the visual character of the site and surrounding area will not be significantly impacted by Project implementation. Therefore, the visual character of the site and surroundings will not change, and the findings of the certified EIR/EIS remain valid and no further analysis is required. No new impact would occur.
3.1.3.4 Light and Glare
To minimize potential light and glare impacts, the Proposed Project would be consistent with FPASP development standards that address street and outdoor lighting. Therefore, the proposed Project would increase severity of impacts related to light and glare beyond those previously identified and analyzed in the FPASP EIR and the Backbone Infrastructure Initial Study. No new impact would occur.
3.1.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan Final EIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan Final EIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included seven mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to aesthetic resources that the proposed Project would have to adhere to.
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3.2 Agriculture and Forestry Resources
3.2.1 Environmental Setting
The California Department of Conservation manages the Farmland Mapping and Monitoring Program, which identifies and maps significant farmland. Farmland is classified using a system of five categories including Prime Farmland, Farmland of Statewide Importance, Unique Farmland, Farmland of Local Importance, and Grazing Land. The classification of farmland as Prime Farmland, Unique Farmland, and Farmland of Statewide Importance is based on the suitability of soils for agricultural production, as determined by a soil survey conducted by the Natural Resources Conservation Service. The California Department of Conservation manages an interactive website, the California Important Farmland Finder.
This website identifies the Project site as being outside of the survey area and therefore not considered to be agriculturally important land.
The California Department of Conservation (DOC) identifies the Project site as Grazing Land (DOC 2022).
After adoption of the FPASP, the Project site is not intended for agricultural uses and contains no forest or timber resources, is not zoned for forestland protection or timber production. The Project site is not located adjacent to or within the vicinity of any farmland.
3.2.2 FPASP EIR/EIS Summary
Impacts to Agriculture resources was combined with impacts to Land Use in the FPASP EIR/EIS. According to the FPASP EIR/EIS, impacts related to the cancellation of existing on-site Williamson Act contracts to accommodate the FPASP development would be significant and unavoidable and no feasible mitigation measures are available to reduce impacts to a less than significant level. In addition, FPASP implementation could conflict with previously existing off-site Williamson Act contracts or result in the cancellation of such contracts on lands south of the Specific Plan Area (SPA) and no feasible mitigation measures are available to reduce this impact to a less than significant level.
3.2.3 Agriculture and Forestry Resources Conformity Analysis The proposed Project site is located within the FPASP and is not used for agriculture. Thus, the proposed Project would have no impacts on agriculture or forestry resources. The proposed Project would neither result in new significant impacts nor substantially increase the severity of impacts related to agriculture and forestry resources beyond those previously identified and analyzed in the FPASP EIR/EIS. No new impacts would occur.
3.2.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
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2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included two mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to land use and agriculture resources that the proposed Project would have to adhere to.
3.3 Air Quality
3.3.1 Environmental Setting
The City of Folsom is located in Sacramento County. The California Air Resources Board (CARB) divides the State into air basins that share similar meteorological and topographical features. The City of Folsom portion of Sacramento County is located in a region identified as the Sacramento Valley Air Basin (SVAB).
The SVAB is comprised all of Butte, Colusa, Sacramento, Shasta, Sutter, Tehama, Yolo, and Yuba counties and parts of Solano and Placer County. The air basin is relatively flat, bordered by mountains to the east, west, and north and by the San Joaquin Valley to the south. Air flows into the SVAB through the Carquinez Strait, moving across the Sacramento Delta, and bringing pollutants from the heavily populated San Francisco Bay Area. The climate is characterized by hot, dry summers and cool, rainy winters.
Characteristic of SVAB winter weather are periods of dense and persistent low-level fog, which are most prevalent between storm systems. From May to October, the region’s intense heat and sunlight lead to high ozone pollutant concentrations. Summer inversions are strong and frequent but are less troublesome than those that occur in the fall. Autumn inversions, formed by warm air subsiding in a region of high pressure, have accompanying light winds that do not provide adequate dispersion of air pollutants.
Both the U.S. Environmental Protection Agency (USEPA) and CARB have established ambient air quality standards for common pollutants. These ambient air quality standards are levels of contaminants representing safe levels that avoid specific adverse health effects associated with each pollutant. The ambient air quality standards cover what are called “criteria” pollutants because the health and other effects of each pollutant are described in criteria documents. The six criteria pollutants are ozone (O3), carbon monoxide (CO), particulate matter (PM), nitrogen oxides (NOx), sulfur dioxide (SO2), and lead.
Areas that meet ambient air quality standards are classified as attainment areas, while areas that do not meet these standards are classified as nonattainment areas. The portion of Sacramento County encompassing the City of Folsom and the development site is designated as a nonattainment area for the
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Alder Creek Subdivision Conformity Analysis 2024-012.01 federal O3 and fine particulate matter (PM2.5) standards and is also a nonattainment area for the state standards for O3 and coarse particulate matter (PM10) (CARB 2023).
The Sacramento Metropolitan Air Quality Management District (SMAQMD) is the air pollution control agency for Sacramento County, including the development site. The agency’s primary responsibility is ensuring that the National Ambient Air Quality Standards (NAAQS) and California Ambient Air Quality Standards (CAAQS) are attained and maintained in the Sacramento County portion of the SVAB. The SMAQMD coordinates the work of government agencies, businesses, and private citizens to achieve and maintain healthy air quality for the Sacramento area. The SMAQMD develops market-based programs to reduce emissions associated with mobile sources, processes permits, ensures compliance with permit conditions and with SMAQMD rules and regulations, and conducts long-term planning related to air quality. The SMAQMD is also responsible for adopting and enforcing rules and regulations concerning air pollutant sources, issuing permits for stationary sources of air pollutants, inspecting stationary sources of air pollutants, responding to citizen complaints, monitoring ambient air quality and meteorological conditions, awarding grants to reduce motor vehicle emissions, and conducting public education campaigns, as well as many other activities.
The following is a list of noteworthy SMAQMD rules that are required of construction activities associated with the Alder Creek Property development:
Rule 201: General Permit Requirements. Any project that includes the use of equipment capable of releasing emissions to the atmosphere may require permit(s) from SMAQMD prior to equipment operation. The applicant, developer, or operator of a project that includes an emergency generator, boiler, or heater should contact the SMAQMD early to determine if a permit is required, and to begin the permit application process. Other general types of uses that require a permit include, but are not limited to, dry cleaners, gasoline stations, spray booths, and operations that generate airborne particulate emissions. Portable construction equipment (e.g., generators, compressors, pile drivers, lighting equipment, etc.) with an internal combustion engine over 50 horsepower is required to have a SMAQMD permit or a CARB portable equipment registration.
Rule 402: Nuisance. The purpose of this rule is to limit emissions which cause injury, detriment, nuisance, or annoyance to any considerable number of persons or the public, or which endanger the comfort, repose, health, or safety of any such persons or the public, or which cause or have natural tendency to cause injury or damage to business or property. Rule 403: Fugitive Dust. The purpose of this rule is to require that reasonable precautions be taken so as not to cause or allow the emissions of fugitive dust from non-combustion sources from being airborne beyond the property line from which the emission originates. Rule 442: Architectural Coatings. The purpose of this rule is to limit the emissions of volatile organic compounds from the use of architectural coatings supplied, sold, offered for sale, applied, solicited for application, or manufactured for use within the SMAQMD.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-18 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
3.3.2 FPASP EIR/EIS Summary
According to the EIR/EIS, with implementation of mitigation measures, impacts would be reduced that are associated with temporary, short-term construction-related emissions of criteria air pollutants and precursors; long-term operation-related (regional) emissions of criteria air pollutants and precursors; exposure to TACs; and exposure to odorous emissions from construction activity; and exposure to odorous emissions from operation of the proposed corporation yard, but not to a less than significant level, because emissions and exposure levels would (or could potentially) still exceed applicable thresholds and, therefore, residual significant impacts would occur. All other air quality impacts were found to be less than significant
3.3.3 Air Quality Conformity Analysis
3.3.3.1 Air Quality Emissions Assessment
This information was obtained from Appendix B, the Alder Creek Property Emissions Report (ECORP Consulting, Inc. [ECORP] 2025a). The FPASP EIR/EIS addressed air quality issues related to the development of the entire FPASP, of which the Alder Creek Subdivision development is a part. The Alder Creek Subdivision development will be subject to the Mitigation Monitoring and Reporting Plan (MMRP) adopted for the Specific Plan, including implementation of mitigation measures required to reduce air quality impacts. The impact evaluation below utilizes the analyses completed in the EIR/EIS to determine the means of compliance with the EIR/EIS by the Alder Creek Subdivision development, or whether implementation of the Alder Creek Subdivision development would result in a new impact on air quality not previously addressed in the EIR/EIS or increase the severity of previously identified EIR/EIS impacts.
3.3.3.2 Methodology
Air pollutant emission impacts were assessed in accordance with methodologies recommended by the SMAQMD and the requirements of the FPASP EIR/EIS. Where criteria air pollutant quantification was required, emissions were modeled using the California Emissions Estimator Model (CalEEMod), version 2022.1. CalEEMod is a statewide land use emissions computer model designed to quantify potential criteria pollutant emissions associated with both construction and operations from a variety of land use projects. Construction-generated air pollutant emissions were calculated using CalEEMod model defaults for Sacramento County and information provided in the Project Description, such as the site acreage, lot acreages for each land use, and total amount of building square footage for the single-family homes. The fire station’s building square footage was derived from the lot acreage provided and the building coverage provided in the City’s Municipal Code Section 17.11.060, which allows for the development of 30 percent of the lot acreage. Operational air pollutant emissions were also calculated using CalEEMod model defaults and the information provided in the Project Description.
3.3.3.3 Conflict with Any Applicable Air Quality Management Plan As part of its enforcement responsibilities, the USEPA requires each state with nonattainment areas to prepare and submit a State Implementation Plan (SIP) that demonstrates the means to attain the federal
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-19 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 standards. The SIP must integrate federal, state, and local plan components and regulations to identify specific measures to reduce pollution in nonattainment areas, using a combination of performance standards and market-based programs. Similarly, under state law, the California Clean Air Act requires an air quality attainment plan to be prepared for areas designated as nonattainment with regard to the NAAQS and CAAQS. Air quality attainment plans outline emissions limits and control measures to achieve and maintain these standards by the earliest practical date .
As previously described, the development site is located in the SVAB, which is under the jurisdiction of the SMAQMD. The SMAQMD is required, pursuant to the federal Clean Air Act, to reduce emissions of criteria pollutants for which the SVAB is in nonattainment. The SMAQMD is required to submit air quality plans and rate-of-progress milestone evaluations in accordance with the federal Clean Air Act. The SMAQMD air quality attainment plans and reports, which include the 2017 Sacramento Regional 8-Hour Ozone Attainment and Reasonable Further Progress Plan (2018), the 2021 Sacramento County Second 10-Year PM10 Maintenance Plan (2024), the PM10 Implementation/Maintenance Plan and Re-Designation Request (2010), and PM2.5 Implementation/Maintenance Plan and Re-designation Request for Sacramento PM2.5 Nonattainment Area (2013), present comprehensive strategies to reduce the O3 precursor pollutants (ROG and NOx) as well as PM emissions from stationary, area, mobile, and indirect sources. A project is consistent with regional air quality planning efforts in part if it is consistent with the population and housing assumptions that were used in the development of the SMAQMD air quality plans and does nothing to inhibit the region’s achievement of air quality standards.
The FPASP EIR/EIS was certified by the City Council on June 14, 2011. The Specific Plan EIR/EIS evaluates air quality impacts, including compliance with federal, state, and regional air quality standards, associated with the development of a range of different land uses at various densities on more than 3,500 acres. The EIR/EIS identifies significance thresholds for all project impacts and includes specific mitigation measures to address both site-specific and cumulative air quality–related effects of development. The development site is located within the FPASP and is thus subject to the air pollutant–reducing mitigation measures contained in the Specific Plan EIR/EIS (see Appendix 4.3-1).
The FPASP has multiple land use designations, specifically: Single Family, Single Family High Density, Multi-Family Low Density, Parks, Open Space, and Right of Way. The FPASP includes the Alder Creek Property development site to serve the future residents within the specific plan area. The Alder Creek Property development would construct the Alder Creek Property Subdivision, which is consistent with the FPASP land use designations for the development site.
The Alder Creek Property development is consistent with the types, intensity, and patterns of land use evaluated by the FPASP EIR/EIS. The Alder Creek Property development is not proposing to amend the City General Plan, FPASP, or Zoning Code, and is consistent with all land use designations applied to the site. Therefore, the Alder Creek Property development would not increase the number of people residing in the area beyond that anticipated. Thus, it would not be contributing to an increase in population or housing growth beyond that currently anticipated and planned for in the FPASP. As such, the Alder Creek Property development would not conflict with the growth projections used by SMAQMD to develop its air quality attainment plans. The Alder Creek Property development would adhere to all applicable planning efforts and documents.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-20 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
3.3.3.4 Construction and Operations Generated Criteria Air Quality Emissions Air pollution is largely a cumulative impact. No single project is sufficient in size, by itself, to result in nonattainment of ambient air quality standards. Instead, a project’s individual emissions contribute to existing cumulatively significant adverse air quality impacts. If a project’s individual emissions exceed its identified significance thresholds, the project would be cumulatively considerable. Projects that do not exceed significance thresholds would not be considered cumulative considerable.
Construction-Generated Emission Analysis
Construction-generated emissions are temporary and short-term but have the potential to represent a significant air quality impact. Three basic sources of short-term emissions will be generated through construction of the Alder Creek Property development: operation of the construction vehicles (i.e., excavators, trenchers, dump trucks), the creation of fugitive dust during clearing and grading, and the use of asphalt or other oil-based substances during paving activities. Construction activities such as excavation and grading operations, construction vehicle traffic, and wind blowing over exposed soils would generate exhaust emissions and fugitive PM emissions that affect local air quality at various times during construction. Effects would be variable depending on the weather, soil conditions, the amount of activity taking place, and the nature of dust control efforts. The dry climate of the area during the summer months creates a high potential for dust generation.
The analysis prepared in the FPASP EIR/EIS found that construction activities associated with the development of the FPASP would contribute to air pollutants to a level that is significant and unavoidable despite the imposition of several mitigation measures that reduce the Specific Plan’s construction impact.
These measures (listed in Appendix 4.3-1) include:
Specific Plan EIR Mitigation Measure 3A.2-1a: Implement Measures to Control Air Pollutant Emissions Generated by Construction of On-Site Elements. • To reduce short-term construction emissions, the project applicant(s) for any particular discretionary development application shall require their contractors to implement SMAQMD’s list of Basic Construction Emission Control Practices, Enhanced Fugitive PM Dust Control Practices, and Enhanced Exhaust Control Practices (list below) in effect at the time individual portions of the site undergo construction. In addition to SMAQMD-recommended measures, construction operations shall comply with all applicable SMAQMD rules and regulations.
Specific Plan EIR Mitigation Measure 3A.2-1b: Pay Off-site Mitigation Fee to SMAQMD to Off-Set NOx Emissions Generated by Construction of On-Site Elements. • Implementation of the Proposed Project or the other four other action alternatives would result in construction-generated NOX emissions that exceed the SMAQMD threshold of significance, even after implementation of the SMAQMD Enhanced Exhaust Control Practices (listed in Mitigation Measure 3A.2-1a). Additionally, Mitigation Measure 3A.4-1 has the potential to both reduce and increase NOX emissions, depending on the types of alternative
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-21 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 fuels and engine types employed. Therefore, the project applicant(s) shall pay SMAQMD an off-site mitigation fee for implementation of any of the five action alternatives for the purpose of reducing NOX emissions to a less-than-significant level (i.e., less than 85 lb/day).
All NOX emission reductions and increases associated with greenhouse GHG mitigation shall be added to or subtracted from the amount above the construction threshold to determine off-site mitigation fees, when possible.
Specific Plan EIR Mitigation Measure 3A.2-1c: Analyze and Disclose Projected PM10 Emission Concentrations at Nearby Sensitive Receptors Resulting from Construction of On-Site Elements. • Prior to construction of each discretionary development entitlement of on-site land uses, the project applicant shall perform a project-level CEQA analysis (e.g., supporting documentation for an exemption, negative declaration, or project-specific EIR) that includes detailed dispersion modeling of construction-generated PM10 to disclose what PM10 concentrations would be at nearby sensitive receptors. The dispersion modeling shall be performed in accordance with applicable SMAQMD guidance that is in place at the time the analysis is performed.
Specific Plan EIR Mitigation Measure 3A.2-1f: Implement SMAQMD's Enhanced Exhaust Control Practices during Construction of all Off-site Elements. Implement SMAQMD's Enhanced Exhaust Control Practices in order to control NOx emissions generated by construction of all off-site elements (in Sacramento and El Dorado Counties, or Caltrans right-of-way).
An MMRP was prepared and adopted with the Specific Plan and is a binding document applicable to the Alder Creek Property development. The specific mitigations in the MMRP applicable to the Alder Creek Property development’s construction includes EIR/EIS measures 3A.2-1a, 3A.2-1b, 3A.2-1c, and 3A.2-1f.
For instance, mitigation measures 3A.2-1a and 3A.2-1f require the implementation of appropriate dust control measures and that SMAQMD emissions standards be met for all heavy-duty construction equipment. Therefore, construction activities would be required to implement the applicable MMRP mitigation measures and the SMAQMD’s Basic Construction Emission Control Practices, known as Best Management Practices (BMPs) during construction.
Predicted maximum daily construction-generated emissions for the Alder Creek Property development are summarized in Table 3.3-1.
Table 3.3-1. Construction-Related Emissions
Construction Year
Pollutant
ROG NOX CO SO2 PM10 PM2.5
Daily (pounds per day)
Construction Calendar Year One 32.10 29.20 63.00 0.07 21.10 11.30 Construction Calendar Year Two 31.90 27.00 60.80 0.07 8.37 2.50
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-22 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 Table 3.3-1. Construction-Related Emissions
Construction Year
Pollutant
ROG NOX CO SO2 PM10 PM2.5
Construction Calendar Year Three 31.50 25.40 58.50 0.07 8.28 2.42 Construction Calendar Year Four 31.30 24.20 56.60 0.07 8.24 2.38 Construction Calendar Year Five 31.20 23.40 54.80 0.07 8.20 2.32 MMRP Mitigation Measure 3A.2-1b
Significance Threshold – 85
pounds/day – – – –
Exceed MMRP Threshold? – No – – – –
Annual (tons per year)
Construction Calendar Year One 2.02 2.99 4.59 0.01 1.03 0.40 Construction Calendar Year Two 4.09 3.46 6.82 0.01 1.08 0.32 Construction Calendar Year Three 4.09 3.28 6.62 0.01 1.08 0.31 Construction Calendar Year Four 4.05 3.11 6.41 0.01 1.07 0.31 Construction Calendar Year Five 1.08 0.81 1.67 0.00 0.29 0.08 Notes: Emission reduction/credits for construction emissions are applied based on the required implementation of SMAQMD Rule 403. The specific Rule 403 measures applied in CalEEMod include sweeping/cleaning adjacent roadway access areas daily, water exposed surfaces twice daily, and limit speeds on unpaved roads to 15 miles per hour. Emissions taken of the season, summer or winter, with the highest outputs.
Building construction, paving and painting assumed to occur simultaneously.
CO = Carbon Monoxide; NOx = Nitrogen Oxide; PM2.5 = Fine Particulate Matter; PM10 = Coarse Particulate Matter; ROG = Reactive Organic Gas; SMAQMD = Sacramento Metropolitan Air Quality Management District; SO2 = Sulfur dioxide.
Source: California Energy Emissions Module (CalEEMod) version 2022.1. Refer to Appendix 4.3-2 for Model Data Outputs.
As shown in Table 3.3-1, emissions generated during construction would not exceed the daily threshold for NOx provided in Mitigation Measure 3.A.2-1b. As the Alder Creek Property development does not surpass the daily NOx thresholds, Mitigation Measure 3.A.2-1b is not required to be implemented.
However, it is acknowledged that the Alder Creek Property development must adhere to all SMAQMD’s Best Available Control Technology (BACT)/BMPs in order to be considered less than significant. As previously described, the Alder Creek Property development would be required to adhere to FPASP mitigation measures 3A.2-1a and 3A.2-1f, which require the implementation of appropriate SMAQMD construction emission-reducing control measures. Therefore, construction activities would be required to implement the BMPs during construction. Criteria pollutant emissions generated during construction
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-23 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 would not result in a cumulatively considerable net increase of any criteria pollutant for which the region is nonattainment under an applicable federal or state ambient air quality standard, and no health effects from criteria pollutants would occur.
As demonstrated, the Alder Creek Property development complies with the requirements of the FPASP EIR/EIS. The Alder Creek Property development is consistent with the types, intensity, and patterns of land use evaluated by the FPASP EIR/EIS. Since the Alder Creek Property development is consistent with the land uses analyzed under the FPASP EIR/EIS, construction-related air quality impacts would be the same as analyzed in the EIR/EIS and there would not be an increase in the severity of impacts as a result of the Alder Creek Property development. There would not be a new or substantially more severe significant impact compared with the significance determination contained in the EIR/EIS.
Long-Term Operational Impacts
Implementation of the Alder Creek Property development would result in long-term operational emissions of criteria air pollutants such as PM10, PM2.5, CO, and SO2 as well as O3 precursors such as ROGs and NOX. Increases in emissions would be predominantly associated with motor vehicle use. Long-term operational emissions attributable to the Alder Creek Property development are identified in Table 3.3-2.
As mentioned previously, implementation of the BMPs provided in the MMRP is necessary in the operations of the Alder Creek Property development. These BMPs include controls for PM and NOx emissions, compliance with mandatory measures in the California Building Energy Efficiency Standards (Title 24, Part 6) that pertain to efficient use of energy, and compliance with mandatory measures in the California Green Building Code (Title 24, Part 11).
The analysis under the FPASP EIR/EIS found that the long-term increase of criteria air pollutants resulting from implementation of the Folsom Plan Area would be significant and unavoidable. This conclusion was reached despite required adherence to the FPASP MMRP (see Appendix 4.3-1). The MMRP includes measures that reflect SMAQMD guidelines and require the compliance of the SMAQMD-approved FPASP Air Quality Mitigation Plan (AQMP). The AQMP includes measure designed to provide bicycle parking at commercial land uses, an integrated pedestrian/bicycle path network, transit stops with shelters, a prohibition against the use the wood-burning fireplaces, Energy Star roofing materials, electric lawn mowers provided to homeowners at no charge, and on-site transportation alternatives to passenger vehicles (including light rail) that provide connectivity with other local and regional alternative transportation networks. The Alder Creek Property development would be subject to the SMAQMD BACT/BMPs and the applicable mitigation measures under the MMRP, including Mitigation Measure 3A.2-2, which requires project applicants for any particular discretionary development application in the Folsom Plan Area to implement all measures prescribed in the AQMP, including those just described.
Projected daily emissions from operations of the Alder Creek Property development are summarized in Table 3.3-2 accounting for the quantifiable components of the AQMP required by EIR/EIS mitigation measure 3A.2-2. Because many required air pollutant–reducing components of the AQMP cannot be quantified due to limitations in the modeling software, projected daily emissions would most likely be less than identified in Table 3.3-2.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-24 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 Table 3.3-2. Operational-Related Emissions
Emission Source Pollutant (pounds per day)
ROG NOX CO SO2 PM10 PM2.5
Summer Emissions
Mobile 59.40 54.50 579.00 1.35 120.00 13.00
Area 12.50 0.15 17.50 0.00 0.03 0.02
Energy 0.13 2.43 2.04 0.01 0.18 0.18
Total: 39.63 27.48 274.54 0.59 50.41 13.20
Winter Emissions
Mobile 24.30 29.20 213.00 0.53 50.20 13.00
Area 9.63 0.00 0.00 0.00 0.00 0.00
Energy 0.13 2.43 2.04 0.01 0.18 0.18
Total: 34.06 31.63 215.04 0.54 50.38 13.18
Notes: Emission projections predominately based on CalEEMod model defaults for Sacramento County.
CalEEMod = California Emissions Estimator Model; CO = Carbon Monoxide; NOx = Nitrogen Oxide; PM2.5 = Fine Particulate Matter; PM10 = Coarse Particulate Matter; ROG = Reactive Organic Gas; SO2 = Sulfur dioxide
Source: CalEEMod version 2022.1. Refer to Appendix 4.3-2 for Model Data Outputs.
As previously described, the analysis under the FPASP EIR/EIS found that the long-term increase of criteria air pollutants resulting from implementation of the Folsom Plan Area would be a significant and unavoidable impact. The applicable air quality mitigations in the MMRP are intended to reduce the impacts of the Alder Creek Property development’s emissions. The Alder Creek Property development complies with the requirements of the EIR/EIS, including adherence to the MMRP that contains mitigation measure 3A.2-2, which requires the Alder Creek Property development to implement all measures prescribed in the AQMP. The Alder Creek Property development is consistent with the types, intensity, and patterns of land use evaluated by the FPASP EIR/EIS. Since the Alder Creek Property development is consistent with the land uses analyzed under the FPASP EIR/EIS, operational-related air quality impacts would be the same as analyzed in the EIR/EIS and there would not be an increase in the severity of impacts as a result of the Alder Creek Property development. There would not be a new or substantially more severe significant impact compared with the significance determination contained in the EIR/EIS.
Exposure of Sensitive Receptors to Substantial Pollution Concentrations Sensitive receptors are defined as facilities or land uses that include members of the population that are particularly sensitive to the effects of air pollutants, such as children, the elderly, and people with illnesses.
Examples of these sensitive receptors are residences, schools, hospitals, and daycare centers. CARB has identified the following groups of individuals as the most likely to be affected by air pollution: the elderly over age 65, children under age 14, athletes, and persons with cardiovascular and chronic respiratory diseases such as asthma, emphysema, and bronchitis. The nearest sensitive receptors are several singlefamily homes across Mangini Parkway from the southern boundary of the development site.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-25 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 Construction-Generated Air Contaminants
Construction-related activities would result in temporary, short-term development-generated emissions of diesel particulate matter (DPM), ROG, NOx, CO, and PM10 from the exhaust of off-road, heavy-duty diesel equipment for site preparation (e.g., clearing, grading); soil hauling truck traffic; paving; and other miscellaneous activities. The portion of the SVAB which encompasses the development area is designated as a nonattainment area for federal O3 and PM2.5 standards and is also a nonattainment area for the state standards for O3 and PM10 standards (CARB 2023). Thus, existing O3, PM10, and PM2.5 levels in the SVAB are at unhealthy levels during certain periods. However, as shown in Table 3.3-1, the Alder Creek Property development would not exceed the SMAQMD significance thresholds for emissions during construction.
The health effects associated with O3 are generally associated with reduced lung function. O3 is not emitted directly into the air but is formed through complex chemical reactions between precursor emissions of ROG and NOx in the presence of sunlight. The reactivity of O3 causes health problems because it damages lung tissue, reduces lung function and sensitizes the lungs to other irritants. Scientific evidence indicates that ambient levels of O3 not only affect people with impaired respiratory systems, such as asthmatics, but healthy adults and children as well. Exposure to O3 for several hours at relatively low concentrations has been found to significantly reduce lung function and induce respiratory inflammation in normal, healthy people during exercise. This decrease in lung function generally is accompanied by symptoms including chest pain, coughing, sneezing and pulmonary congestion.
Studies show associations between short-term O3 exposure and non-accidental mortality, including deaths from respiratory issues. Studies also suggest long-term exposure to O3 may increase the risk of respiratory-related deaths. The concentration of O3 at which health effects are observed depends on an individual’s sensitivity, level of exertion (i.e., breathing rate), and duration of exposure. Studies show large individual differences in the intensity of symptomatic responses, with one study finding no symptoms to the least responsive individual after a 2-hour exposure to 400 parts per billion of O3 and a 50 percent decrement in forced airway volume in the most responsive individual. Although the results vary, evidence suggests that sensitive populations (e.g., asthmatics) may be affected on days when the 8-hour maximum O3 concentration reaches 80 parts per billion. Because the development would not involve construction activities that would result in O3 precursor emissions (ROG or NOx) in excess of the SMAQMD thresholds, which are set to be protective of human health and account for cumulative emissions in the SVAB, the Alder Creek Property development is not anticipated to substantially contribute to regional O3 concentrations and the associated health impacts.
CO tends to be a localized impact associated with congested intersections. In terms of adverse health effects, CO competes with oxygen, often replacing it in the blood, reducing the blood’s ability to transport oxygen to vital organs. The results of excess CO exposure can include dizziness, fatigue, and impairment of central nervous system functions. The development would not involve construction activities that would result in CO emissions more than any common significance thresholds. Thus, the Alder Creek Property development’s CO emissions would not contribute to the health effects associated with this pollutant.
Particulate matter (PM10 and PM2.5) contains microscopic solids or liquid droplets that are so small that they can get deep into the lungs and cause serious health problems. Particulate matter exposure has been
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-26 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 linked to a variety of problems, including premature death in people with heart or lung disease, nonfatal heart attacks, irregular heartbeat, aggravated asthma, decreased lung function, and increased respiratory symptoms such as irritation of the airways, coughing, or difficulty breathing. For construction activity, DPM is the primary toxic air contaminant of concern. PM10 exhaust is considered a surrogate for DPM as all diesel exhaust is considered to be DPM and it contains PM2.5 exhaust as a subset. As with O3 and NOx, the development would not generate emissions of PM10 that would exceed the SMAQMD’s thresholds.
The increases of these pollutants generated by the Alder Creek Property development would not on their own generate an increase in the number of days exceeding the NAAQS or CAAQS standards. Therefore, PM10 and PM2.5 emissions, when combined with the existing PM emitted regionally, would have minimal health effect on people located in the immediate vicinity of the development site. Additionally, the Alder Creek Property development’s PM10 and PM2.5 emissions are not expected to cause any increase in related regional health effects from these pollutants.
In summary, construction would not result in a potentially significant contribution to regional concentrations of nonattainment pollutants and would not result in a significant contribution to the adverse health impacts associated with those pollutants.
Consistent with FPASP EIR/EIS requirements, particulate matter concentration and dispersion was modeled for the construction of the development using the EPA’s AERMOD air toxic dispersion model (see Appendix 4.3-3). AERMOD is a steady-state plume model that incorporates air dispersion based on planetary boundary layer turbulence structure and scaling concepts, including treatment of both surface and elevated sources, and both simple and complex terrain.
As stated in the FPASP EIR/EIS, particulate matter is a pollutant of greatest concern with respect to construction activities. The Alder Creek Property development is surrounded by a developing community of planned and existing single-family residential homes. The nearest sensitive receptors would be several approved and planned single-family homes across Mangini Parkway on the southern boundary of the development site. These parcels are currently undeveloped, however the FPASP EIR/EIS identifies that these parcels will be developed into single family homes. As such, FPASP EIR/EIS mitigation measure 3A.2- 1c requires that Specific Plan project applicants prepare detailed dispersion modeling of constructiongenerated PM10 to disclose the PM10 concentrations at nearby sensitive receptors. In order to fulfill the requirements of this measure, PM10 concentrations associated with the construction of the Alder Creek Property development were modeled in accordance with applicable SMAQMD guidance (see Appendix
4.3-3). Appendix 4.3-3 presents the calculated PM10 concentrations in the vicinity of the development site.
The AERMOD program generated an estimate of 24-hour average concentrations using a 1-year data file of hourly weather observations recorded at Sacramento International Airport. The SMAQMD does not currently promulgate a particulate matter concentration threshold. The maximum 24-hour concentration would reach 422.96 μg/m3.
Construction of the Alder Creek Property development complies with the requirements of the FPASP EIR/EIS and would not result in an increase in the severity of air toxic–related air quality impacts compared with the FPASP EIR/EIS.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-27 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 Consistent with FPASP EIR/EIS Cumulative Mitigation Measure AIR-1, a project-level screening analysis was conducted to evaluate whether proposed residential uses on the Project Site would be exposed to substantial health risks from TACs, including DPM, emitted by vehicles traveling on Prairie City Road. Prairie City Road traverses adjacent to the Proposed Project Site and is expected to accommodate future FPASPrelated traffic as well as haul truck traffic associated with regional quarry operations.
Consistent with FPASP EIR/EIS Cumulative Mitigation Measure AIR-1, this screening analysis applies the SMAQMD Recommended Protocol for Evaluating the Location of Sensitive Land Uses Adjacent to Major Roadways (2011). Under this protocol, a project warrants a full health risk assessment (HRA) only if it is located (1) within 500 feet of a high-traffic roadway, defined as a freeway, an urban roadway carrying more than 100,000 vehicles per day, or a rural roadway carrying more than 50,000 vehicles per day. Existing traffic volumes on Prairie City Road are approximately 3,309 average daily trips (City of Folsom 2017 Traffic Count Map). To account for future cumulative conditions, buildout traffic volumes from the FPASP EIR/EIS and related quarry EIRs were reviewed. The FPASP EIR/EIS identifies approximately 40,600 average daily trips (ADT), while the Teichert Quarry EIR (2010) and Stoneridge Quarry EIR (2011) estimate 47,198 ADT and 37,000 ADT, respectively, for this same segment under cumulative conditions.
Even under the most conservative estimate, future cumulative volumes would remain well below 50,000 ADT, meaning Prairie City Road does not meet SMAQMD’s definition of a high-traffic roadway. Because the Project is not located adjacent to a roadway that exceeds SMAQMD’s high-traffic volume thresholds, the Project does not trigger the need for a detailed HRA under the SMAQMD protocol. Accordingly, development of the Alder Creek Property would not expose future sensitive receptors to substantial TAC emissions from quarry truck traffic or other vehicles traveling on Prairie City Road, and the Project is consistent with FPASP EIR/EIS Cumulative Mitigation Measure AIR-1.
Operational Air Contaminants
The health risk public-notification thresholds adopted by the SMAQMD is 10 excess cancer cases in a million for cancer risk and a hazard index of more than one (1.0) for non-cancer risk. Examples of projects that emit toxic pollutants over long-term operations include oil and gas processing, gasoline dispensing, dry cleaning, electronic and parts manufacturing, medical equipment sterilization, freeways, and rail yards.
Implementation of the Alder Creek Property development would not result in the development of any substantial sources of air toxics. There are no stationary sources associated with the operations of the development; nor would the development attract additional heavy-duty vehicles that spend long periods queuing and idling at the site. Onsite emissions would not result in significant concentrations of pollutants at nearby sensitive receptors. The Alder Creek Property development would not have a high carcinogenic or non-carcinogenic risk during operation.
Carbon Monoxide Hot Spots
It has long been recognized that CO exceedances are caused by vehicular emissions, primarily when idling at intersections. Concentrations of CO are a direct function of the number of vehicles, length of delay, and traffic flow conditions. Under certain meteorological conditions, CO concentrations close to congested intersections that experience high levels of traffic and elevated background concentrations may reach
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-28 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 unhealthy levels, affecting nearby sensitive receptors. Given the high traffic volume potential, areas of high CO concentrations, or “hot spots,” are typically associated with intersections that are projected to operate at unacceptable levels of service during the peak commute hours. It has long been recognized that CO hotspots are caused by vehicular emissions, primarily when idling at congested intersections.
However, transport of this criteria pollutant is extremely limited, and CO disperses rapidly with distance from the source under normal meteorological conditions. Furthermore, vehicle emissions standards have become increasingly more stringent in the last 20 years. Currently, the allowable CO emissions standard in California is a maximum of 3.4 grams/mile for passenger cars (there are requirements for certain vehicles that are more stringent). With the turnover of older vehicles, introduction of cleaner fuels, and implementation of increasingly sophisticated and efficient emissions control technologies, CO concentration in the SVAB is designated as in attainment. Detailed modeling of development-specific CO “hot spots” is not necessary and thus this potential impact is addressed qualitatively.
A CO “hot spot” would occur if an exceedance of the state one-hour standard of 20 parts per million (ppm) or the eight-hour standard of 9 ppm were to occur. The analysis prepared for CO attainment in the South Coast Air Quality Management District’s (SCAQMD’s) 1992 Federal Attainment Plan for Carbon Monoxide in Los Angeles County and a Modeling and Attainment Demonstration prepared by the SCAQMD as part of the 2003 AQMP can be used to demonstrate the potential for CO exceedances of these standards. The SCAQMD is the air pollution control officer for much of southern California. The SCAQMD conducted a CO hot spot analysis as part of the 1992 CO Federal Attainment Plan at four busy intersections in Los Angeles County during the peak morning and afternoon time periods. The intersections evaluated included Long Beach Boulevard and Imperial Highway (Lynwood), Wilshire Boulevard and Veteran Avenue (Westwood), Sunset Boulevard and Highland Avenue (Hollywood), and La Cienega Boulevard and Century Boulevard (Inglewood). The busiest intersection evaluated was at Wilshire Boulevard and Veteran Avenue, which has a traffic volume of approximately 100,000 vehicles per day.
Despite this level of traffic, the CO analysis concluded that there was no violation of CO standards (SCAQMD 2024). In order to establish a more accurate record of baseline CO concentrations affecting the Los Angeles, a CO “hot spot” analysis was conducted in 2003 at the same four busy intersections in Los Angeles at the peak morning and afternoon time periods. This “hot spot” analysis did not predict any violation of CO standards. The highest one-hour concentration was measured at 4.6 ppm at Wilshire Boulevard and Veteran Avenue and the highest eight-hour concentration was measured at 8.4 ppm at Long Beach Boulevard and Imperial Highway. Thus, there was no violation of CO standards.
Similar considerations are also employed by other Air Districts when evaluating potential CO concentration impacts. More specifically, the Bay Area Air Quality Management District, the air pollution control officer for the San Francisco Bay Area, concludes that under existing and future vehicle emission rates, a given project would have to increase traffic volumes at a single intersection by more than 44,000 vehicles per hour or 24,000 vehicles per hour where vertical and/or horizontal air does not mix—in order to generate a significant CO impact.
According to CalEEMod default inputs, which are based on the Institute of Traffic Engineers (ITE) Trip Generation Manual, the single-family homes would generate an average of 13,068 trips per weekday, and the fire station would generate 561 trips per day. Combining the two of these, the average daily trips for
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-29 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 the Alder Creek Property development would be 13,628 daily trips. Thus, the Alder Creek Property development would not generate traffic volumes at any intersection of more than 100,000 vehicles per day (or 44,000 vehicles per hour) and there is no likelihood of it traffic exceeding CO values.
Odors that Could Potentially Affect Sensitive Receptors Typically, odors are regarded as an annoyance rather than a health hazard. However, manifestations of a person’s reaction to foul odors can range from psychological (e.g., irritation, anger, or anxiety) to physiological (e.g., circulatory and respiratory effects, nausea, vomiting, and headache).
With respect to odors, the human nose is the sole sensing device. The ability to detect odors varies considerably among the population and overall is quite subjective. Some individuals have the ability to smell minute quantities of specific substances; others may not have the same sensitivity but may have sensitivities to odors of other substances. In addition, people may have different reactions to the same odor; in fact, an odor that is offensive to one person (e.g., from a fast-food restaurant) may be perfectly acceptable to another. It is also important to note that an unfamiliar odor is more easily detected and is more likely to cause complaints than a familiar one. This is because of the phenomenon known as odor fatigue, in which a person can become desensitized to almost any odor and recognition only occurs with an alteration in the intensity.
Quality and intensity are two properties present in any odor. The quality of an odor indicates the nature of the smell experience. For instance, if a person describes an odor as flowery or sweet, then the person is describing the quality of the odor. Intensity refers to the strength of the odor. For example, a person may use the word “strong” to describe the intensity of an odor. Odor intensity depends on the odorant concentration in the air. When an odorous sample is progressively diluted, the odorant concentration decreases. As this occurs, the odor intensity weakens and eventually becomes so low that the detection or recognition of the odor is quite difficult. At some point during dilution, the concentration of the odorant reaches a detection threshold. An odorant concentration below the detection threshold means that the concentration in the air is not detectable by the average human.
During construction, the Alder Creek Property development presents the potential for generation of objectionable odors in the form of diesel exhaust in the immediate vicinity of the site. However, these emissions are short-term in nature and will rapidly dissipate and be diluted by the atmosphere downwind of the emission sources. Additionally, odors would be localized and generally confined to the construction area. Therefore, construction odors would not adversely expose a substantial number of people to odor emissions.
According to the SMAQMD, land uses commonly considered to be potential sources of obnoxious odorous emissions include wastewater treatment plants, sanitary landfills, composting/green waste facilities, recycling facilities, petroleum refineries, chemical manufacturing plants, painting/coating operations, rendering plants, and food packaging plants. The Alder Creek Property development does not include any uses identified by the SMAQMD as being associated with odors.
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Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-30 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
3.3.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included 20 mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to air quality/greenhouse gas emissions that the proposed Project would have to adhere to.
3.4 Biological Resources
3.4.1 Environmental Setting
ECORP Consulting, Inc. is preparing the Biological Resources Assessment for the Proposed Toll Brothers Alder Creek Project Within the FPASP (ECORP 2025e) and is summarized hereto.
The Project Area is located within relatively flat to gently rolling terrain. The Project Area is situated at an elevational range of approximately 260 to 400 feet above mean sea level in the Sacramento Valley Subregion of the Great Central Valley floristic region of California. The average winter low temperature in the vicinity of the BSA is 39.8 degrees Fahrenheit (˚F) and the average summer high temperature is 92.7˚F.
Average annual precipitation is approximately 24.48 inches, which falls as rain.
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Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-31 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 The following vegetation communities and land cover types within the Project Area as observed during the field surveys:
• Annual Grassland
• Blue Oak Woodland
• Valley Needlegrass Grassland
• Fremont Cottonwood Woodland
• Arroyo Willow Thicket
• Goodding’s Willow Woodland
• Disturbed/Developed
A total of 8.944-acres of aquatic resources were mapped within the Project Area. The aquatic features identified onsite include vernal pool, seasonal wetland, seasonal wetland swale, creek, intermittent drainage, seep, pond and ditch.
Seasonal wetland swales and ephemeral and intermittent drainages connect vernal pools and seasonal wetlands throughout the site. The majority of these features drain to Alder Creek to the north and east of the site. Predominant vegetation within the aquatic features include toad rush (Juncus bufonius), Mediterranean barley (Hordeum marinum ssp. gussoneanum), annual rabbit-foot grass (Polypogon monspeliensis), hyssop loosestrife (Lythrum hyssopifolia), and pennyroyal (Mentha pulegium)., annual hairgrass (Deschampsia danthonioides), and Carter’s buttercup (Ranunculus bonariensis)Two farm ponds are located along the eastern portion of the BSA with emergent vegetation along the margins and Fremont’s cottonwood (Populus fremontii) and willow (Salix sp.) in the overstory.
3.4.2 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, although impacts on some biological resources were reduced to less than significant levels through implementation of mitigation measures, impacts on jurisdictional waters of the United States, including wetlands, and blue oak woodlands would remain significant and unavoidable even with implementation of the mitigation measures because the project would contribute substantially to the regional loss of these habitats and temporal losses of aquatic resources and blue oak woodland would occur during implementation of mitigation. Until performance standards and success criteria are met and the FPASP EIR/EIS found it was unknown whether the acreage and functions of these habitats can be replaced through preservation and creation since a mitigation plan had not been developed. The FPASP EIR/EIS found that even after a mitigation plan would be developed and implemented, there would be a substantial regional loss of this resource for many decades and the full range of habitat functions may never be successfully replaced. Impacts on trees protected under Folsom Municipal Code and County Tree Preservation Ordinance were found to be significant and unavoidable because temporal losses of oak tree resources would persist until replacement trees reached comparable sizes to the trees to be removed; a process that would take many decades, and it was unknown if suitable mitigation sites would be available in the region to establish replacement trees at appropriate ratios to compensate for the loss of
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-32 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 oak tree resources in the SPA. Cumulative impacts on aquatic resources, oak woodlands, nesting and foraging habitat for raptors, including Swainson’s hawk, and potential habitat for special-status plant species remained significant and unavoidable even with implementation of mitigation measures because the project would contribute substantially to the regional loss and degradation of these habitats.
3.4.3 Biological Resources Conformity Analysis
3.4.3.1 Special Status Species
Impacts to biological resources were identified as a significant and unavoidable impact in the FPASP EIR/EIS. Mitigation Measures within FPASP EIR/EIS require protocol-level pre-construction special-status plant surveys and special-status wildlife species be conducted prior to breaking ground for new Projects within the FPASP. If special-status species are found during the focused surveys, consultation will occur with CDFW and/or USFWS, as appropriate depending upon species status, to determine the appropriate mitigation measures for direct and indirect impacts on any special-status species population that could occur as a result of Project implementation. Therefore, the analysis under the FPASP EIR/EIS remains accurate with respect to the proposed Project. Additionally, the Project would be required to adhere to all mitigation measures listed in the FPASP EIR/EIS.
Subsequent to the issuance of the FPASP EIR/EIS, Crotch bumble bee was added as a candidate for listing as endangered under the California Endangered Species Act. The Project has potential foraging, nesting, and overwintering habitat for Crotch bumble bee. A habitat assessment and focused survey for Crotch’s bumble bee may be required by CDFW prior to the commencement of construction activities. If Crotch’s bumble bee nests are found within the Proposed Project impacts, additional mitigation and avoidance measures shall be developed in consultation with CDFW. This potential impact would be less than significant with the requirement of preconstruction surveys.
3.4.3.2 Aquatic Resources
A total of 8.944-acres of aquatic resources were mapped within the Project Area. The FPASP EIR/EIS required mitigation that all Project would be required to secure CWA Section 404, Section 401, and/or Porter-Cologne Water Quality Control Act permits and implement corresponding mitigation measures prior to Project implementation.
A CWA 404 permit (SPK-2007-02159) and CWA 401 certification (Waste Discharge Identification #5A34CR00519) was previously issued for the aquatic resources within the Backbone Infrastructure Project Area. The majority of the Project Area falls under the CWA 404 permit (SPK-2006-00561) and CWA 401 Certification (Waste Discharge Identification #5A34CR00681) for the Alder Ranch Project. Prior to Project implementation, the Project shall acquire permit authorizations for the remainder of the BSA located in the Javanifard and Zarghami property.
A Master Streambed Alteration Agreement (MSAA) for the FPASP was issued by CDFW on February 11, 2014 (1600-2012-0198-R2). The MSAA outlines several required conditions for all projects located within the FPASP. Per Section 6 of the MSAA, the Project shall meet the requirements of and submit a SubNotification Form prior to CDFW prior to Project implementation.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-33 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 Therefore, the analysis under the FPASP EIR/EIS remains accurate with respect to the proposed Project.
3.4.3.3 Movement Corridors
There are no designated or potential wildlife movement corridors, California Essential Habitat Connectivity areas, or potential nursery sites are known to occur in the Project Area or would be adversely affected by Project activities. Therefore, the analysis under the FPASP EIR/EIS remains accurate with respect to the proposed Project.
3.4.3.4 Local Plans and Ordinances
The proposed Project may impact individual oak trees and oak woodlands within the Project Area. The FPASP EIR/EIS requires mitigation for impacts to oak trees and oak woodland prior to tree removal. An Oak Woodland Impact and Mitigation Plan shall be developed and approved by the City of Folsom prior to Project implementation, and appliable tree removal and tree work permits will be obtained from the City of Folsom and Sacramento County. Oak trees outside of the development footprint will be protected during construction in accordance with the applicable requirements and permits. Therefore, the analysis under the FPASP EIR/EIS remains accurate with respect to the proposed Project.
The Project has been designed to be consistent with the Folsom Plan Area Open Space Plan. Prior to initiation of construction, Conservation Areas will be protected by a declaration of covenants and restrictions or conservation easement. Conservation Areas and Passive Recreation Open Space Areas will be protected and managed in accordance with the Open Space Plan during construction and then transferred by deed to the City of Folsom for permanent protection.
3.4.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
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Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-34 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
7. The FPASP EIR/EIS included 18 mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to biological resources that the proposed Project would have to adhere to.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-35 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
3.5 Cultural Resources
3.5.1 Environmental Setting
The following summary is extracted from the Historic Property Management Plan for the Folsom Plan Area (City of Folsom 2011), within which primary sources are cited. It is intended to provide context that is scaled to the Project but is not a comprehensive historical overview.
It is generally believed that human occupation of California began at least 10,000 years Before Present (BP). The archaeological record indicates that between approximately 10,000 and 8,000 BP, a predominantly hunting economy existed, characterized by archaeological sites containing numerous projectile points and butchered large animal bones. Around 8,000 BP, there was a shift in focus from hunting toward a greater reliance on plant resources. Archaeological evidence of this trend consists of a much greater number of milling tools (e.g., metates and manos) for processing seeds and other vegetable matter. This period, which extended until around 5,000 BP, is sometimes referred to as the Millingstone Horizon. Projectile points are found in archaeological sites from this period, but they are far fewer in number than from sites dating to 8,000 BP. An increase in the size of groups and the stability of settlements is indicated by deep, extensive middens at some sites from this period.
Archaeological evidence indicates that reliance on both plant gathering and hunting continued as in the previous period, with more specialized adaptation to particular environments in sites dating to after about 5,000 BP. Mortars and pestles were added to metates and manos for grinding seeds and other vegetable material. Flaked-stone tools became more refined and specialized, and bone tools were more common.
New peoples from the Great Basin began entering Southern California during this period. These immigrants, who spoke a language of the Uto-Aztecan linguistic stock, seem to have displaced or absorbed the earlier population of Hokan-speaking peoples. Regional subcultures also started to develop, each with its own geographical territory and language or dialect. The presence of small projectile points indicates the introduction of the bow and arrow into the region sometime around 2,000 BP.
Archaeological work during the 1920s and 1930s led to the cultural chronology for Central California that was based on the results of excavations conducted in the lower Sacramento River Valley. The Paleoindian Period began when the first people began to inhabit what is now known as the California culture area. It was commonly believed these first people (i.e., hunters and gatherers) subsisted on big game and minimally processed foods, presumably with no trade networks. Populations likely consisted of small groups traveling frequently to exploit plant and animal resources. The Archaic period was characterized by an increase in plant exploitation for subsistence, more elaborate burial accoutrements, and increase in trade network complexity.
Prior to the arrival of European-Americans in the region, Indigenous groups speaking more than 100 different languages and occupying a variety of ecological settings inhabited California. Ethnographically, the Project Area is in the southwestern portion of the territory occupied by the Penutian-speaking Nisenan. Nisenan inhabited the drainages of the Yuba, Bear, and American rivers. As a language group, Nisenan (meaning from among us or of our side) are members of the Maiduan Family of the Penutian stock and are generally divided into three groups based on dialect differences: the Northern Hill
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-36 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 (mountain) Nisenan in the Yuba River drainage; the Valley Nisenan along the Sacramento River; and the Southern Hill (foothills) Nisenan along the American River.
Nisenan practiced seasonal migration, a subsistence strategy involving moving from one area or elevation to another to harvest plants, fish, and hunt game across contrasting ecosystems that were in relatively close proximity. Valley Nisenan generally did not range beyond the valley and lower foothills, while foothill and mountain groups ranged across a more extensive area that included jointly shared territory whose entry was subject to traditional understandings of priority of ownership and current relations between the groups. Communally organized Nisenan task groups exploited a wide variety of resources.
Communal hunting drives were undertaken to obtain deer, quail, rabbits, and grasshoppers. Acorns were gathered in the fall and stored in granaries for use during the rest of the year.
The Spanish arrived on the Central California coast in 1769. Early contact with the first Spanish explorers to enter California was limited to the peripheries of Nisenan territory; they occurred mainly to the south on lands of the Miwok which had been explored by José Canizares in 1776, with only ephemeral explorations into Nisenan lands. There are no records of Nisenan groups being removed to the missions.
However, they received escapees from the missions, as well as pressure of displaced Miwok populations on their southern borders. A deadly epidemic (probably malaria) swept through the Sacramento Valley in 1833 and it had a devastating effect on Nisenan populations. Entire villages were lost and surviving Nisenan retreated into the hills. An estimated 75 percent of their population was wiped out, and only a handful were left to face the gold miners and settlers who were soon to follow.
After Mexico became independent from Spain in 1821, what is now California became the Mexican province of Alta California with its capital at Monterey. In 1827, American trapper Jedediah Smith traveled along the Sacramento River and into the San Joaquin Valley. The Mexican government closed the missions in the 1830s and former mission lands, as well as previously unoccupied areas, were granted to retired soldiers and other Mexican citizens for use as cattle ranches. Much of the land along the coast and in the interior valleys became part of Mexican land grants or ranchos.
John Sutter, a European immigrant, built a fort at the confluence of the Sacramento and American rivers in 1839 and petitioned the Mexican governor of Alta California for a land grant, which he received in 1841.
Gold was discovered in the flume of Sutter’s lumber mill at Coloma on the South Fork of the American River in January 1848. The discovery of gold initiated the 1849 California Gold Rush, which brought thousands of miners and settlers to the Sierra foothills east and southeast of Sacramento.
Mining is the dominant historical theme in the Project Area and in the surrounding lands. The region later known as the Folsom Mining District was extensively placer mined during the Gold Rush. The Folsom area was originally settled in 1849 by African-American miners, and from that circumstance the area became known as Negro Bar. By 1855, Chinese miners were reworking abandoned diggings and a large number of them were employed at various regional mines through the 1880s.
Initially, during the early 1850s, surface deposits (usually less than 3 feet deep) were placer mined through a series of small hand-dug excavations. The surface gravel was washed by pan or by higher-volume methods that employed rockers, long toms, and/or sluice boxes. These activities were often initially concentrated along drainages and swales such as Morrison Creek, which drains the Project Area. Ground
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-37 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 sluicing, a technique that uses water (not under pressure) to break down gold-bearing gravels, could have occurred any time from the 1850s up until the turn of the century. Low-pressure hydraulic mining took place at Rebel Hill sometime between the mid-1850s and 1884.
From the early 1850s until the late 1890s and again in 1925, drift mining was employed at Alder Creek. As cemented gravels cap some of the area, shafts were sunk through this hard surface layer into the "softer" gravels. Gold-bearing leads were followed out with drift-mining techniques in these softer gravels. A more detailed historic context statement is provided in the Historic Property Management Plan .
3.5.2 Summary of Cultural Resources
ECORP Consulting, Inc. prepared the Cultural Resources Due Diligence for the Proposed Toll Brothers Alder Creek Project Within the FPASP (ECORP 2024) and is summarized hereto. Through various studies and consultations, the entire Carpenter Ranch, Hillsborough (Alder Ranch), Mangini Ranch, and J&Z, and Backbone Infrastructure permit areas (including the proposed Alder Creek Project) have been fully inventoried for Historical Resources and Historic Properties. In some cases, pre-construction compliance verifications have been received.
ECORP documented 55 sites as a result of these efforts that are located within the Property (Table 3.5-1).
Many of these resources are elements of the historic Rhoades’ Diggings Mining District (RDMD) (P-34- 4667).
Table 3.5-1. Cultural Resources within the Subject Property Site # Description Significance
P-34-1067 Ditch Not eligible for the NRHP or CRHR
P-34-1694 Dam Not eligible for the NRHP or CRHR
P-34-1696 Windmill and Well Site Not eligible for the NRHP or CRHR P-34-1742 Rhoades' Branch Ditch Individually eligible NRHP/CRHR A/1 and D/4 / Contributing Element to RDMD
P-34-1743 Shallow Quartz Prospecting Site Contributing Element to RDMD P-34-1752 Prospect Pits (Filled with Modern Refuse) and Wooden Post Not eligible for the NRHP or CRHR
P-34-1753 Ditch Contributing Element to RDMD
P-34-1754 Prospect Pit Not eligible for the NRHP or CRHR P-34-1756 Ditch Contributing Element to RDMD
P-34-1757 Prospect Pit Not eligible for the NRHP or CRHR P-34-1791 Ravine Diggings, Ground Sluicing, Mine Adit,
Hydraulic Mining Contributing Element to RDMD
P-34-1793 Ravine Diggings, Placer Mining Landscape Contributing Element to RDMD P-34-1794 Ditch Contributing Element to RDMD
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Alder Creek Subdivision Conformity Analysis
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Alder Creek Subdivision Conformity Analysis 2024-012.01 Table 3.5-1. Cultural Resources within the Subject Property Site # Description Significance
P-34-1821 Cabin or Campsite Individually Eligible NRHP/CRHR D/4 / Contributing Element to RDMD
P-34-1907 Ravine Diggings Contributing Element to RDMD
P-34-1918 Ditch Contributing Element to RDMD
P-34-1919 Ravine Diggings, Rock Dams, Ditch Segments,
Filled-In Mine Shaft, Pits Contributing Element to RDMD P-34-1922 Ditch Contributing Element to RDMD
P-34-2084 Placer Mining Landscape Contributing Element to RDMD P-34-2085 Residential Site Individually Eligible NRHP/CRHR D/4 / Contributing Element to RDMD
P-34-2195 Transmission Line Not eligible for the NRHP or CRHR P-34-2227 Stone Foundation Contributing Element to RDMD - Pending P-34-2228 Modern Debris Not a resource
P-34-2229 Stone Foundation Contributing Element to RDMD - Pending P-34-2230 Dam and Reservoir Not eligible for the NRHP or CRHR - Pending P-34-2231 Prospect Pit Contributing Element to RDMD - Pending P-34-4676 Ravine Diggings Contributing Element to RDMD
P-34-4677 Placer Mining Landscape (Shallow Diggings) Contributing Element to RDMD P-34-4704 Prospect Pits (Quartz) Contributing Element to RDMD P-34-4705 Pocket Mining Landscape Contributing Element to RDMD P-34-4707 Ravine Diggings Contributing Element to RDMD
P-34-4709 Shallow Quartz Prospecting Site Contributing Element to RDMD P-34-4711 Isolate Not eligible for the NRHP or CRHR
P-34-4712 Rock Fence Not eligible for the NRHP or CRHR
P-34-4713 Prospect Pit Not eligible for the NRHP or CRHR P-34-4714 Residential Site Individually Eligible NRHP/CRHR D/4 / Contributing Element to RDMD
P-34-4715 Prospect Pits Not eligible for the NRHP or CRHR P-34-4718 Prospect Pit (Hilltop) Not eligible for the NRHP or CRHR P-34-4719 Prospect Pits/Trenches Contributing Element to RDMD P-34-4720 Prospect Pit (Hilltop) Not eligible for the NRHP or CRHR P-34-4721 Prospect Pit (Hilltop) Not eligible for the NRHP or CRHR P-34-4751 Placer Mining Landscape, Ravine Diggings Contributing Element to RDMD P-34-4760 Ditch Contributing Element to RDMD
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-39 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 Table 3.5-1. Cultural Resources within the Subject Property Site # Description Significance
P-34-4761 Berm Not eligible for the NRHP or CRHR
P-34-4762 Trench and Prospecting Pits Not eligible for the NRHP or CRHR P-34-4763 Berm Not eligible for the NRHP or CRHR
P-34-4764 Ditch Not eligible for the NRHP or CRHR
P-34-4768 Prospect Pits and Berm Contributing Element to RDMD P-34-4977 Ravine Diggings Contributing Element to RDMD - Pending P-34-4978 Ditch Contributing Element to RDMD - Pending
P-34-4979 Ravine Diggings Contributing Element to RDMD - Pending P-34-4980 Isolated Arrastra Fragment Not eligible for the NRHP or CRHR - Pending P-34-4981 Isolated Bottle-Glass Not eligible for the NRHP or CRHR - Pending P-34-4982 Ravine Diggings Contributing Element to RDMD - Pending P-34-4983 Prospect Pit Contributing Element to RDMD - Pending Note: CRHR = California Register of Historic Resources; NRHP = National Register of Historic Places; RDMD = Rhoades’ Diggings Mining District
3.5.3 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, with implementation of required mitigation measures, potential impacts to previously unknown human remains would be less than significant. Additionally, with mitigation incorporated, impacts to historical resources would be less than significant. It was detailed that when resources cannot be avoided, appropriate documentation or data recovery excavation must be performed and locations of known cultural resources must be monitored for the potential discovery of cultural resources. However, it was found that beyond the inventory, evaluation, treatment, and monitoring required as stated in the required mitigation measures, there was no other feasible mitigations measures that may be performed to minimize potentially significant impacts on cultural resources. Therefore, impacts on identified and previously undiscovered cultural resources were found to be potentially significant and unavoidable.
3.5.4 Cultural Resources Conformity Analysis
Project implementation would have no substantial change to cultural environmental checklist items described in the FPASP EIR/EIS. Impacts to identified and previously undiscovered cultural resources were identified as a significant and unavoidable impact in the FPASP EIR/EIS and the Project does not introduce any new or unique features that were not analyzed in the FPASP EIR/EIS or 2016 Addendum. No new circumstances or Project changes have occurred. Therefore, the Proposed Project would have no new impact on cultural resources, historic resources, or human remains.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-40 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
3.5.5 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included four mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to cultural resources that the proposed Project would have to adhere to.
3.6 Energy
Energy was formally added as a distinct topic in the CEQA Environmental Checklist (Appendix G) in 2019.
The EIR/EIS for the FPASP was certified prior to July 1, 2019. As such, the analysis of Energy impacts does not retroactively apply to the certified EIR.
3.7 Geology and Soils
3.7.1 Environmental Setting
3.7.1.1 Geomorphic Setting
The site is located in the westernmost extent of the Sierra Nevada Foothills, between the Central Sierra Nevada and the Central Valley Geomorphic Provinces. The Sierra Nevada is dominated by younger plutonic rocks within older metamorphic wall rock that was emplaced during active plate subduction along the paleo-continental margin. The Central Valley Geomorphic Province is an alluvial plain with sediment derived from the eastern and western flanking mountain ranges. The valley drains via the Sacramento and San Joaquin Rivers into the San Francisco Bay area. The site is underlain by Jurassic-age Gopher Ridge Volcanics and Salt Springs Slate. The Gopher Ridge Volcanics consist primarily of mafic pyroclastic rock and Salt Springs Slate consisting of dark grey slate with some mica schist. The geologic
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Alder Creek Subdivision Conformity Analysis 2024-012.01 units found at the Project site are striking approximately northwest-southeast, similar to most metamorphic rock of the Sierra Nevada Foothills.
3.7.1.2 Regional Seismicity and Fault Zones
The California Department of Conservation, Division of Mines and Geology, defines an active fault as one that has been subjected to surface displacement within the last 11,000 years. A fault is considered inactive if it has not shown geologic evidence of surface displacement in the last 11,000 years.
According to the Fault Activity Map of California and Adjacent Areas, no active faults or Earthquake Fault Zones are located on the Project site. The nearest active fault is the Dunnigan Hills Fault Zone, approximately 46 miles northwest of the Project site (DOC 2015).
3.7.1.3 Paleontological Resources
The following information was obtained by the Paleontological Assessment Memorandum for the Alder Creek Property Project, Sacramento County, California (ECORP 2025d). ECORP conducted a paleontological record search through the Sierra College Museum of Natural History, Rocklin, California.
There were no records of previous finds within the 1-mile buffer zone of the Project site. Outside a 1-mile radius, there is the possibility of fossil findings in the Cretaceous Chico Formation to the north and Pleistocene vertebrate locations to the north and south.
In addition to the record search results, ECORP conducted reviews of published and unpublished literature. One of the closest known fossil finds was the discovery of a late Pleistocene biota during the construction of the Arco Arena site in Sacramento, California. The fossils were recovered from overbank deposits of the Riverbank Formation and include Harlan’s ground sloth (Paramylodon harlani), bison (Bison antiquus), coyote (Canis cf. latrans), horse (Equus sp.), camel (Camelops hesternus), a squirrel (cf.
Sciurus sp.), an antelope (Antilocapridae) or deer (Cervidae); and mammoth (Mammuthus sp.). Plant fossils include unidentified leaf and a holly leaf cherry seed, Prunus cf. ilicifolia.
3.7.2 FPASP EIR/EIS Summary
With implementation of mitigation measures, impacts related to strong seismic ground shaking, construction-related erosion, construction in bedrock/rock outcroppings and landslides, subsurface water flows, and unsuitability for septic systems were found to be reduced to less than significant levels.
3.7.3 Geology and Soils Conformity Analysis
3.7.3.1 Alquist-Priolo Earthquake Fault Impacts
As described in Section 3.7.1, no active or inactive faults of Earthquake Fault Zones are located on the Project site. The analysis under the FPASP EIR/EIS remains accurate with respect to the proposed project.
The mitigation measures included in the FPASP EIR/EIS would reduce potential impacts to less than significant. As such, impacts associated with the development of the proposed project would be
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Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-42 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 consistent with the analysis in the FPASP EIR/EIS and the proposed Project would not result in any significant impacts.
3.7.3.2 Topsoil and Erosion
As described in the FPASP EIR/EIS, the project would be required to comply with existing regulations and implement all identified mitigation measures, which would reduce potential impacts regarding soil erosion or the loss of topsoil to less than significant. The proposed Project would include the same development and uses as described in the FPASP EIR/EIS and is within the same boundaries as described in the FPASP EIR/EIS. The Project would not have impacts to soil erosion or the loss of topsoil beyond what was identified in the FPASP EIR/EIS. Therefore, the project would have a less than significant impact.
3.7.3.3 Landslide, Lateral Spreading, Liquefaction Impacts The analysis under the Specific Plan FEIR remains accurate with respect to the proposed project.
Implementation of all required mitigation measures would reduce project impacts associated with a geologic unit that or soil that is unstable, or that would become unstable to less than significant. The proposed Project would not have impacts to unstable geologic units or soil beyond what was identified in the FPASP EIR/EIS. Therefore, the project would have a less than significant impact.
3.7.3.4 Expansive Soil
As noted in the FPASP EIR/EIS, the project site is underlain by soils with low expansion potential.
Compliance with required mitigation would reduce impacts associated with expansive soils. The proposed Project is in the same location as the project described in the FPASP EIR/EIS and would not be located on expansive soil beyond what was addressed in the FPASP EIR/EIS. As such, impacts associated with the project would be consistent with the analysis in the FPASP EIR/EIS and the proposed Project would not result in any significant impacts related to expansive soil.
3.7.3.5 Septic Tanks
As discussed in the FPASP EIR/EIS, the project would not include septic tanks or other alternative wastewater treatment methods. Therefore, the project would have no impact.
3.7.3.6 Paleontological Resources
Within California valley areas, late Pleistocene fossils typically appear anywhere from 8 to 10 feet in depth.
The sensitivity for producing fossils may range from low (Holocene alluvium) to high (Pleistocene alluvium) with depth. Excavations should proceed with caution upon reaching depths near 8 feet and beyond. Due to the low sensitivity of the Project area to produce fossils, full paleontological monitoring is not recommended unless a find is made with depth. By following all required mitigation measures within the FSASP EIR/EIS, all impacts would be considered less than significant.
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3.7.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included 11 mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to geology and minerals that the proposed Project would have to adhere to.
3.8 Greenhouse Gas Emissions
3.8.1 Environmental Setting
Greenhouse Gas (GHG) emissions are released as byproducts of fossil fuel combustion, waste disposal, energy use, land use changes, and other human activities. This release of gases, such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and chlorofluorocarbons, creates a blanket around the earth that allows light to pass through but traps heat at the surface, preventing its escape into space. While this is a naturally occurring process known as the greenhouse effect, human activities have accelerated the generation of GHGs beyond natural levels. The overabundance of GHGs in the atmosphere has led to an unexpected warming of the earth and has the potential to severely impact the earth’s climate system.
Each GHG differs in its ability to absorb heat in the atmosphere based on the lifetime, or persistence, of the gas molecule in the atmosphere. CH4 traps more than 25 times more heat per molecule than CO2, and N2O absorbs 298 times more heat per molecule than CO2. Often, estimates of GHG emissions are presented in carbon dioxide equivalents (CO2e). Expressing GHG emissions in carbon dioxide equivalents takes the contribution of all GHG emissions to the greenhouse effect and converts them to a single unit equivalent to the effect that would occur if only CO2 were being emitted.
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3.8.2 Regulatory Setting
To provide guidance to local lead agencies on determining significance for GHG emissions in CEQA documents, SMAQMD has established operation GHG reduction thresholds. The GHG targets and reduction recommendations made by the SMAQMD have taken into consideration reports and guidelines from various state agencies and organizations, such as the California Air Pollution Control Officers Association CEQA & Climate Change guidelines, the CARB Scoping Plan, the California Natural Resource Agency’s CEQA Guidelines, and other reputable sources. In February 2021, the SMAQMD revised the Greenhouse Gas Emissions Chapter within their CEQA Guide.
The SMAQMD has adopted both construction and operational thresholds for GHG emissions. Their construction thresholds establish a bright line threshold of 1,100 metric tons/year. For projects with operations, the SMAQMD has created an Operational Screening Level Table, which specifies land uses that are not expected to go over 1,100 metric tons/year and thus are sufficiently addressed in a CEQA analysis by qualitative measures. The Proposed Project falls outside of the Screening Table range, and thus is subject to a quantitative measure of analysis, including the implementation of SMAQMD Tier 1 Best Management Practices (BMPs). The Tier 1 BMPs are as follows:
BMP 1 - projects shall be designed and constructed without natural gas infrastructure; and BMP 2 - projects shall meet the current CalGreen Tier 2 standards, except all electric vehicle capable spaces shall instead be electric vehicle ready.
Land use projects that are over the 1,100 metric tons of CO2e per year level are subject to implementing Tier 2 BMPs (BMP 3):
BMP 3 - Residential projects shall achieve a 15% reduction in vehicle miles traveled per resident, office projects shall achieve a 15% reduction in vehicle miles traveled per worker compared to existing average vehicle miles traveled for the county, or retail projects shall achieve a no net increase in total vehicle miles traveled.
These Tier 1 and Tier 2 BMPs would show consistency with the State’s 2045 Carbon Neutrality Goal. If the Project achieves BMP 3, then the operational impact is considered less than significant, and no further analysis is needed. If a project cannot incorporate the required BMPs, other reductions or purchasing and retiring GHG/carbon offsets from a registry approved by the SMAQMD may be required. Carbon offsets are instruments that can be bought, sold, and traded. Like a stock or equity that represents a unit of ownership in a company, a carbon offset represents a unit of GHG emissions reductions. Each offset is essentially a certification that a certain quantity of GHG emissions has been avoided, prevented, or sequestered. Offset registries that the SMAQMD may approve have developed a broad consensus around the standards that are necessary to ensure that offsets are environmentally sound, namely, that offsets be real, permanent, quantifiable, verifiable, enforceable, and additional. Approved registries may include but are not limited to any of the following: (i) the Climate Action Reserve, the American Carbon Registry and Verra, which are all approved by CARB; (ii) any entity approved at any time by CARB to act as an “offset project registry” under the state’s cap-and-trade program; (iii) other regulatory or voluntary credits that
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Alder Creek Subdivision Conformity Analysis 2024-012.01 demonstrate, based on substantial evidence, that the offsets are real, permanent, quantifiable, verifiable, enforceable, and additional.
The FPASP EIR/EIS addresses GHG-related issues related to the development of the entire FPASP, which includes the Project area. The Proposed Project will be subject to the MMRP adopted for the FPASP, including implementation of mitigation measures required to reduce GHG-related impacts. More specifically, mitigation measure 3A.4-2a states that each increment of new development within the FPASP must be compared to any SMAQMD-adopted thresholds established at the time of development.
The significance of the Project’s GHG emissions is evaluated consistent with CEQA Guidelines Section 15064.4(b)(2) by considering whether the Project complies with applicable plans, policies, regulations, and requirements adopted to implement a statewide, regional, or local plan for the reduction or mitigation of GHG emissions. The City of Folsom may set a project-specific threshold based on the context of each particular project, including using the SMAQMD expert recommendation. For the Proposed Project, the SMAQMD’s 1,100 metric tons of CO2e per year threshold is used as the significance threshold. If the Proposed Project exceeds the bright line threshold of 1,100 metric tons/year with the implementation of Tier 1 BMPs, the Project will be required to implement Tier 2 BMPs.
Therefore, in order to be less than significant, the Proposed Project would need to adhere to all SMAQMD guidelines, policies, and thresholds.
3.8.3 FPASP EIR/EIS Summary
According to the EIR/EIS, with implementation of mitigation measures impacts would be reduced that are associated with temporary, short-term construction-related emissions of criteria air pollutants and precursors; long-term operation-related (regional) emissions of criteria air pollutants and precursors; exposure to TACs; and exposure to odorous emissions from construction activity; and exposure to odorous emissions from operation of the proposed corporation yard, but not to a less than significant level, because emissions and exposure levels would (or could potentially) still exceed applicable thresholds and, therefore, residual significant impacts would occur.
3.8.4 Greenhouse Gas Emissions Conformity Analysis
3.8.4.1 Methodology
This information was obtained from Appendix B, the Alder Creek Property Emissions Report (ECORP 2025a). GHG emission-related impacts were assessed in accordance with methodologies recommended by the SMAQMD and required by the FPASP EIR/EIS. Where GHG emissions quantification was required, emissions were modeled using the California Emissions Estimator Model version 2022.1. CalEEMod is a statewide land use emissions computer model designed to quantify potential GHG emissions associated with both construction and operations from a variety of land use projects. Construction-generated GHG emissions were calculated using CalEEMod model defaults for Sacramento County and information provided in the Project Description, such as the site acreage, lot acreages for each land use, and total amount of building square footage for the single-family homes. The fire station’s building square footage was derived from the lot acreage provided and the building coverage provided in the City’s Municipal
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Alder Creek Subdivision Conformity Analysis 2024-012.01 Code Section 17.11.060, which allows for 30 percent of the lot acreage. Operational GHG emissions were also calculated using CalEEMod model defaults and the information provided in the Project Description.
3.8.4.2 Construction and Operations Generated GHG Emissions Construction-Generated Emission Analysis
Construction-related activities that would generate GHG emissions include worker commute trips, haul trucks carrying supplies and materials to and from the Project Site, and off-road construction equipment (e.g., dozers, loaders, excavators). Table 3.8-1 illustrates the specific construction generated GHG emissions that would result from construction of the Project. Once construction is complete, the generation of these GHG emissions would cease.
Table 3.8-1. Construction-Related Greenhouse Gas Emissions Emissions Source CO2e (Metric Tons/Year)
Construction Calendar Year One 964
Construction Calendar Year Two 1,779
Construction Calendar Year Three 1,754
Construction Calendar Year Four 1,720
Construction Calendar Year Five 665
Maximum Annual Construction Emissions 1,779
SMAQMD Significance Threshold 1,100
Exceed SMAQMD Threshold? Yes
Note: CO2e = carbon dioxide equivalent; SMAQMD = Sacramento Metropolitan Air Quality Management District
Source: California Energy Emissions Module (CalEEMod) version 2022.1. Refer to Appendix 3.3-2 for Model Data Outputs.
As shown in Table 3.8-1, construction would result in the generation of a maximum of 1,779 metric tons of CO2e during a single year of construction, which is above the SMAQMD significant threshold. However, all land uses designated in the Alder Creek Property development are aligned with the FPASP EIR/EIS designations and have therefore been accounted for in the EIR/EIS. The applicable GHG mitigations in the MMRP are intended to reduce the impacts of the Alder Creek Property development’s emissions. The MMRP includes measures that reflect SMAQMD guidelines, specifically Specific Plan Mitigation Measure
3.A.4-1. Specific Plan Mitigation Measure 3.A.4-1 requires the Alder Creek Property development to implement additional measures to control construction-generated GHG emissions as recommended by the SMAQMD. Such reduction measures may reduce GHG exhaust emissions from the use of on-site equipment, worker commute trips, and truck trips carrying materials and equipment to and from the
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Alder Creek Subdivision Conformity Analysis 2024-012.01 development site, as well as GHG emissions embodied in the materials selected for construction. Further reduction measures are mentioned in the MMRP (Appendix 3.3-1). Adhering to this mitigation measure would mean that the Alder Creek Property development is compliant with the MMRP and would not result in GHG emissions greater than what was detailed in the EIR/EIS. Once construction is complete, the generation of these GHG emissions would cease. The Alder Creek Property development is consistent with the types, intensity, and patterns of land use evaluated by the FPASP EIR/EIS. Since the Alder Creek Property development is consistent with the land uses analyzed under the FPASP EIR/EIS, constructionrelated GHG impacts would be the same as analyzed in the EIR/EIS and there would not be an increase in the severity of impacts as a result of the Alder Creek Property development. There would not be a new or substantially more severe significant impact compared with the significance determination contained in the EIR/EIS.
Operations-Generated Emission Analysis
Operation of the Project would result in an increase in GHG emissions primarily associated with motor vehicle trips. Long-term operational GHG emissions attributed to the Project are identified in Table 3.8-2.
Table 3.8-2. Operational-Related Greenhouse Gas Emissions Emission Source CO2e (Metric Tons/Year)
Mobile 21,126
Area Source 25
Energy 5,283
Waste 139
Water 300
Refrigeration 3
Total: 26,876
SMAQMD Significance Threshold 1,100
Exceed SMAQMD Threshold? Yes
Notes: Emission projections predominately based on CalEEMod model defaults for Sacramento County. Average daily vehicle trips provided by ITE Trip Generation Manual. The Project will have no natural gas infrastructure to comply with Sacramento Metropolitan Air Quality Management District’s (SMAQMD’s) Tier 1 Best Management Practices, which prohibit natural gas infrastructure in all new operational Projects (see Mitigation Measure GHG-1). The emission projections take into account no natural gas infrastructure.
CO2e = Carbon Dioxide equivalent
Source: California Energy Emissions Module (CalEEMod) version 2022.1. Refer to Appendix B for Model Data Outputs.
As shown in Table 3.8-2, operations would result in 26,876 metric tons/year of CO2e. The SMAQMD CEQA Guidance on GHG Emissions states that “Projects that exceed 1,100 metric tons/year after implementation of Tier 1 BMPs must implement Tier 2 BMPs (BMP 3)”. As shown in Table 3.8-2, the GHG emissions produced by Project operations would exceed the 1,100 metric tons per year threshold with the implementation of Tier 1 BMPs. In order to ensure compliance with the SMAQMD guidelines, this development is subject to Tier 1 and Tier 2 BMPs.
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Alder Creek Subdivision Conformity Analysis 2024-012.01 In the case of the Tier 2 BMPs (BMP 3), the Alder Creek Property development is classified as a residential project, due to the majority of the land uses within the Alder Creek Property development being designated for single-family residences. Residential Tier 2 BMPs require the Alder Creek Property development to achieve a 15 percent reduction in vehicle miles traveled per resident. If the project achieves BMP 3, then the operational impact is considered less than significant, and no further analysis is needed. As previously mentioned, if a project cannot incorporate the required BMPs, other reductions or purchasing and retiring GHG/carbon offsets from a registry approved by the SMAQMD may be required.
Approved registries may include but are not limited to any of the following: (i) the Climate Action Reserve, the American Carbon Registry and Verra, which are all approved by CARB; (ii) any entity approved at any time by CARB to act as an “offset project registry” under the state’s cap-and-trade program; (iii) other regulatory or voluntary credits that demonstrate, based on substantial evidence, that the offsets are real, permanent, quantifiable, verifiable, enforceable, and additional.
Implementation of required SMAQMD Tier 1 and Tier 2 BMPs will ensure that the impacts associated with the Alder Creek Property development will be less than significant.
3.8.4.3 Conflict with the Applicable Plan for Reduction of Greenhouse Gas Emissions The significance of the Project’s GHG emissions is evaluated consistent with CEQA Guidelines Section 15064.4(b)(2) by considering whether the Project complies with applicable plans, policies, regulations and requirements adopted to implement a statewide, regional, or local plan for the reduction or mitigation of GHG emissions. The previous analysis prepared in the FPASP EIR/EIS found that the development of the FPASP would contribute to GHG emissions to a level that is significant and unavoidable despite the imposition of mitigation measures designed to reduce the Specific Plan’s related GHG emissions impact.
The Alder Creek Property development is subject to adherence to the MMRP, which directs all Projects that are developed as a part of the FPASP adhere to SMAQMD GHG thresholds and measures. As previously described, the Alder Creek Property development will be required to implement all possible SMAQMD BMP measures to reduce GHG emissions in order to comply with all regulations.
California promulgates several mandates and goals to reduce statewide GHG emissions, including the goal to reduce statewide GHG emissions to 40 percent below 1990 levels by the year 2030 (California Senate Bill [SB] 32). The Alder Creek Property development is subject to compliance with SB 32. As discussed previously, implementation of Tier 1 and Tier 2 BMPs ensure compliance with the SMAQMD’s GHG planning and policies, which were prepared with the purpose of complying with statewide GHGreduction efforts. Mitigation measure GHG-1 ensures that the development would not conflict with an applicable plan, policy, or regulation adopted for the purpose of reducing GHG emissions. Thus, there is not a new or substantially more severe significant impact compared with the significance determination contained in the FPASP EIR/EIS.
3.8.5 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to
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Alder Creek Subdivision Conformity Analysis 2024-012.01 what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included 20 mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to air quality/greenhouse gas emissions that the proposed Project would have to adhere to.
3.9 Hazards and Hazardous Materials
3.9.1 Environmental Setting
A material is considered hazardous if it appears on a list of hazardous materials prepared by a federal, state, or local agency, or if it has characteristics defined as hazardous by such an agency. A hazardous material is defined by the California Health and Safety Code, Section 25501 as follows:
“Hazardous material” means any material that, because of its quantity, concentration, or physical or chemical characteristics, poses a significant present or potential hazard to human health and safety or to the environment if released into the workplace or the environment. "Hazardous materials" include, but are not limited to, hazardous substances, hazardous waste, and any material that a handler or the administering agency has a reasonable basis for believing that it would be injurious to the health and safety of persons or harmful to the environment if released into the workplace or the environment.
A hazardous material is defined in 22 CCR Section 662601.10 as follows:
A substance or combination of substances which, because of its quantity, concentration, or physical, chemical or infectious characteristics, may either (1) cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or (2) pose a substantial present or potential hazard to human health or environment when improperly treated, stored, transported or disposed of or otherwise managed.
Transporters of hazardous waste in California are subject to several federal and state regulations. They must register with the California Department of Health Services (DHS) and ensure that vehicle and waste
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Alder Creek Subdivision Conformity Analysis 2024-012.01 container operators have been trained in the proper handling of hazardous waste. Vehicles used for the transportation of hazardous waste must pass an annual inspection by the California Highway Patrol (CHP).
Transporters must allow the CHP or DHS to inspect its vehicles and must make certain required inspection records available to both agencies. The transport of hazardous materials that are not wastes is regulated by the U.S. Department of Transportation through national safety standards.
Other risks resulting from hazardous materials include the use of these materials in local industry, businesses, and agricultural production. The owner or operator of any business or entity that handles a hazardous material above threshold quantities is required by state and federal laws to submit a business plan to the local Certified Unified Program Agency (CUPA). The Sacramento County Environmental Management Department is designated by the State Secretary for Environmental Protection as the CUPA for Sacramento County in order to focus the management of specific environmental programs at the local government level. The CUPA program is designed to consolidate, coordinate, and uniformly and consistently administer permits and conduct inspection and enforcement activities throughout Sacramento County. This approach strives to reduce overlapping and sometimes conflicting requirements of different governmental agencies independently managing these programs. The County will refer large cases of hazardous materials contamination or violations to the Central Valley Regional Water Quality Control Board (RWQCB) (Region 5) and the Department of Toxic Substances Control (DTSC). It is not uncommon for other agencies, such as federal and state Occupational Safety and Health Administrations, to become involved when issues of hazardous materials arise.
3.9.1.1 Cortese Lists
Under Government Code Section 65962.5, both the DTSC and State Water Resources Control Board (SWRCB) are required to maintain lists of sites known to have hazardous substances present in the environment (Cortese List). Both agencies maintain up-to-date lists on their websites. The Project site is not listed on the DTSC (DTSC 2025). According to the SWRCB GeoTracker website, there are 67 remediated Aerojet cleanup sites within the Project Site (SWRCB 2025).
3.9.2 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, with implementation of mitigation measures, all potential impacts relating to hazards and hazardous material would be reduced to a less than significant level.
3.9.3 Hazards and Hazardous Materials Summary
3.9.3.1 Hazardous Materials Transportation
As noted in the FPASP EIR/EIS, all hazardous materials would be transported and handled in accordance with all federal, state, and local laws regulating the management and use of hazardous materials. The proposed Project would include the same development and uses as described in the FPASP EIR/EIS. As such, the project would be required to comply with all federal, state, and local laws regulating the management, use, storage, and transportation of hazardous materials.
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Alder Creek Subdivision Conformity Analysis 2024-012.01 For these reasons, the project would have a less than significant impact related to the routine transport, use, disposal, or release of hazardous materials.
3.9.3.2 Significant Hazard to the Public
As described in the FPASP EIR/EIS, the Specific Plan would result in less than significant impacts with mitigation incorporated associated with the reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment. The proposed Project would not result in hazardous materials beyond what was previously analyzed in the FPASP EIR/EIS. Therefore, the project would have a less than significant impact.
3.9.3.3 Cortese List
As mentioned above, review of Cortese List sites indicate that the project site is not listed as a hazardous waste site according to the EnviroStor but does have 67 sites according to the GeoTracker database.
However, all sites have been identified as remediated and were all noted within the FPASP EIR/EIS. The proposed Project would not result in any impacts beyond what was previously analyzed in the FPASP EIR/EIS. Therefore, the project would have a less than significant impact.
3.9.3.4 Emergency Evacuation
The proposed Project would result in the same access and uses as analyzed in the FPASP EIR/EIS. As described in the FPASP EIR/EIS, the project’s evacuation approach would be consistent with the City’s and County’s evacuation approach. The proposed Project would be consistent with the Specific Plan’s guidelines and provide adequate emergency access throughout the project site. The Project is consistent with the roadway analysis included in the FPASP EIR/EIS and would provide adequate emergency access to the project site. The project site access, including road widths and connectivity, would be consistent with the City’s roadway standards and all applicable requirements. Therefore, impacts would be less than significant
3.9.3.5 Wildfire
According to the FPASP EIR/EIS, the FPASP is located within a state responsibility area designated as a moderate fire hazard severity zone. It was determined to not be near an area of high or extremely high fire hazard severity. Therefore, the FPASP EIR/EIS found that implementation would not expose people or structures to a significant risk of loss, injury, or death involving wildland fires, including where wildlands are adjacent to urbanized areas and it was not discussed further within the EIR/EIS.
3.9.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
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1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included 14 mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to hazards that the proposed Project would have to adhere to.
3.10 Hydrology and Water Quality
3.10.1 Environmental Setting
3.10.1.1 Regional Hydrology
Surface Water
The main surface waters in Sacramento County are related to the American and Sacramento River systems. The American River watershed covers approximately 2,100 square miles northeast of Sacramento.
The watershed spans portions of three different counties: Sacramento, El Dorado, and Placer. The average annual runoff is approximately 2.7 million acre-feet. In the past, annual runoff has varied from 900,000 acre-feet to 5,000,000 acre-feet. The American River watershed, including all its tributaries, is divided into three major sub-basins, the North Fork American River, the South Fork American River and the Lower Fork American River. The Lower Fork American River sub- basin begins at Folsom Dam and extends 30 miles downstream to the mouth of the American River at the confluence of the Sacramento River. The Lower American Basin contains eight dams and has 380 miles of naturally occurring waterways. The precipitation in the Lower American River basin averages 20.83 inches per year. North of Highway 50, storm drains collect and convey urbanized runoff into Willow Creek, Humbug Creek, Hinkle Creek, Gold Creek, and Alder Creek; all of which drain into the Lower American River. Hinkle Creek and Gold Creek drain the northwestern portion of Folsom north of the American River, while Willow Creek and Humbug Creek drain the southeastern portion of the City. Although Alder Creek only drains a small portion north of Highway 50, it drains most of Folsom south of U.S. 50 (City of Folsom 2011).
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Alder Creek Subdivision Conformity Analysis
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Alder Creek Subdivision Conformity Analysis 2024-012.01 Water Quality
The City of Folsom obtains all of its potable water supply from Folsom Lake. The City’s current water rights amount to 34,000 acre-feet of raw water per year. Raw water from Folsom Lake is treated at the City Water Treatment Plant (WTP). The treatment plant has a nominal capacity of 50 million gallons per day (mgd). Recent annual deliveries from the WTP have been less than half of its annual capacity of approximately 50,000 acre-feet (City of Folsom 2014).
Groundwater
The portions of Folsom south of the American River are located in the South American sub-basin. The South American Sub-basin has inflows including natural and applied water recharge of 257,168 acre-feet and a net subsurface outflow of 29,676 acre-feet annually. The South American Sub-basin is approximately 248,000 acres, or 388 square miles. Groundwater is typically of calcium magnesium bicarbonate or magnesium calcium bicarbonate. Other minor groundwater types include a sodium calcium bicarbonate or calcium bicarbonate or sodium magnesium bicarbonate near the confluence of the Sacramento and American Rivers. Total Dissolved Solids (TDS) ranges from 24 to 581 milligrams per liter (mg/L) and averages 221 mg/L based on 462 records (California Department of Water Resources 2020). A range of 500 TDS is desired for agricultural uses, any range above that requires slight restrictions on water use (City of Folsom 2014).
3.10.2 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, with implementation of required mitigation, the Project would not result in any residual significant impacts related to short-term alteration of drainages and associated surface water quality and sedimentation, increased risk of flooding or hydromodification from stormwater runoff, water quality and hydrology effects from long-term urban runoff, or groundwater recharge.
3.10.3 Hydrology and Water Quality Conformity Analysis
3.10.3.1 Water Quality
As discussed in the FPASP EIR/EIS, onsite drainage improvement as well as compliance with all existing water quality regulations and implementation of Stormwater Pollution Prevention Plan requirements would ensure impacts to water quality standards or waste discharge requirements would be less than significant. The Project includes the same drainage improvements as described in the FPASP EIR/EIS and would not result in impacts to water quality standards or waste discharge requirements beyond what was identified in the FPASP EIR/EIS.
3.10.3.2 Groundwater Supplies
The FPASP EIR/EIS concluded that there was sufficient water supplies available to serve the project and reasonably foreseeable future development during normal, dry, and multiple dry years. The Project would include the same development and uses as described in the FPASP EIR/EIS and would not impact
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Alder Creek Subdivision Conformity Analysis 2024-012.01 groundwater beyond what was identified in the FPASP EIR/EIS. The Project would be required to follow all required mitigation measures outlined in the FPASP EIR/EIS.
3.10.3.3 Drainage Pattern
The FPASP EIR/EIS concluded that impacts regarding altering the existing drainage pattern of the site would be less than significant. With the inclusion required mitigation measures, impacts to erosion would be less than significant. The Project would include the same development and uses as described in the FPASP EIR/EIS and is in the same location as described in the FPASP EIR/EIS. The analysis under the FPASP EIR/EIS remains accurate with respect to the proposed project. The Project would not substantially alter the existing drainage pattern of the site beyond what was identified in the FPASP EIR/EIS.
3.10.3.4 Flood Impacts
As stated in the FPASP EIR/EIS, impacts associated with flood hazard, tsunami, or seiche zones, and risk release of pollutants due to project inundation would be less than significant. FPASP EIR/EIS states that the site is not in an area protected by levees; however, Folsom Dam is located approximately 4.5 miles north of the Specific Plan Area. However, according to the FPASP EIR/EIS, the Specific Plan Area is outside of the mapped inundation area. The Project would include the same development and uses as described in the FPASP EIR/EIS and is in the same location as described in the FPASP EIR/EIS. The analysis under the FPASP EIR/EIS remains accurate with respect to the proposed project.
3.10.3.5 Conflict with Any Approved Water Quality or Groundwater Plans The FPASP EIR/EIS states that the project would be consistent with objectives and policies identified in the Basin Plan and therefore would not obstruct implementation of a water quality plan or sustainable groundwater management plan. The Project includes features consistent with the Specific Plan FEIR, therefore, the analysis under the Specific Plan FEIR remains accurate with respect to the proposed project.
Therefore, the project would not obstruct implementation of a water quality plan or sustainable groundwater management plan; thus, impacts would be less than significant.
3.10.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
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Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-55 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included eight mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to hydrology that the proposed Project would have to adhere to.
3.11 Land Use and Planning
3.11.1 Environmental Setting
The FPASP consists of over 3,510 acres that is generally located in eastern Sacramento County, within the City of Folsom (City of Folsom 2011). The Specific Plan area has already started to be built out.
3.11.2 FPASP EIR/EIS Summary
Agriculture resources and land use impacts were combined into one section the FPASP EIR/EIS. The EIR/EIS determined that there was no feasible mitigation available to reduce the impacts to Sacramento Area Council of Governments (SACOG) Preferred Blueprint Scenario with implementation of the FPASP to a less than significant level. Additionally, with the General Plan Amendment that was required for the FSPASP, impacts were considered significant and unavoidable.
3.11.3 Land Use and Planning Conformity Analysis
3.11.3.1 Land Use Changes
As mentioned above in the Project Description, the Project is proposing a slight variation to the land use designations that were originally approved in the original FPASP EIR/EIS. However, this change is minimal and would result in no impacts to the land use designations. Therefore, the analysis under the FPASP EIR/EIS remains accurate with respect to the proposed project. Additionally, the Project would be required to adhere to all mitigation measures listed in the FPASP EIR/EIS.
3.11.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
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Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-56 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included two mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to land use and agriculture resources that the proposed Project would have to adhere to.
3.12 Mineral Resources
3.12.1 Environmental Setting
Minerals are defined as any naturally occurring chemical elements or compounds formed by inorganic processes and organic substances. Minable minerals are defined as a deposit of ore or minerals having a value materially in excess of the cost of developing, mining, and processing the mineral and reclaiming the project area. The conservation, extraction, and processing of mineral resources is essential to meeting the needs of society.
The Surface Mining and Reclamation Act of 1975 (SMARA) states that cities and counties shall adopt ordinances “...that establish procedures for the review and approval of reclamation plans and financial assurances and the issuance of a permit to conduct surface mining operations...” (PRC Section 2774). The intent of this legislation is to ensure the prevention or mitigation of the adverse environmental impacts of mining, the reclamation of mined lands, and the production and conservation of mineral resources are consistent with recreation, watershed, wildlife, and public safety objectives (PRC Section 2712).
SMARA requires the State Geologist to classify land into Mineral Resource Zones (MRZs) according to the known or inferred mineral potential of that land. The process is based solely on geology, without regard to existing land use or land ownership. The primary goal of mineral land classification is to ensure that the mineral potential of land is recognized by local government decision makers and considered before land use decisions, which could preclude mining, are made. Areas subject to California mineral land classification studies are divided into the following MRZ categories that reflect varying degrees of mineral potential:
MRZ-1: Areas of no mineral resource significance
MRZ-2: Areas of identified mineral resource significance MRZ-3: Areas of undetermined mineral resource significance
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Alder Creek Subdivision Conformity Analysis 2024-012.01 MRZ-4: Areas of unknown mineral resource significance According to the FPASP EIR/EIS, the Specific Plan Area is in areas that are either zoned MRZ-1 for construction aggregate (where no mineral resources are present) or are located in MRZ-3 construction aggregate areas that have already been developed with urban uses (where any resources that may have been present have been covered over by development and are no longer available for extraction). In 2003, the City of Folsom determined that because it did not have any active mining operations, and because none were expected in the future, that it would not update its SMARA ordinance. The Specific Plan Area is not delineated as an area of known mineral resources in either the City of Folsom or Sacramento County General Plans.
3.12.2 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, if economically valuable kaolin clay deposits were found to be present in the Project Area, they would be covered over as a result of SPA development with urban land uses and would no longer be available for mining. Therefore, this impact is considered potentially significant and unavoidable.
3.12.3 Mineral Resources Conformity Analysis
3.12.3.1 Mineral Resources
The project site is located within an area mapped as MRZ-3 which indicates areas of undetermined mineral resource significance (DOC 2018). Because the project site does not contain known mineral resources of value, impacts would remain as identified in the Specific Plan FEIR. The project would have no impact on mineral resources.
3.12.4 Conclusion
The proposed project is consistent with the development evaluated in the Specific Plan FEIR and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
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Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-58 August 2025
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6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included 11 mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to geology and minerals that the proposed Project would have to adhere to.
3.13 Noise
3.13.1 Environmental Setting
3.13.1.1 Noise Fundamentals
Noise is generally defined as sound that is loud, disagreeable, or unexpected. The selection of a proper noise descriptor for a specific source is dependent on the spatial and temporal distribution, duration, and fluctuation of the noise. The noise descriptors most often encountered when dealing with traffic, community, and environmental noise include the average hourly noise level (in Leq) and the Average Daily Noise Levels/Community Noise Equivalent Level (in Ldn/CNEL). The Leq is a measure of ambient noise, while the Ldn and CNEL are measures of community noise. Each is applicable to this analysis and defined as follows:
Equivalent Noise Level (Leq ) is the average acoustic energy content of noise for a stated period of time. Thus, the Leq of a time-varying noise and that of a steady noise are the same if they deliver the same acoustic energy to the ear during exposure. For evaluating community impacts, this rating scale does not vary, regardless of whether the noise occurs during the day or the night. Day-Night Average (Ldn) is a 24-hour average Leq with a 10-A-weighted decibel (dBA) weighting added to noise during the hours of 10:00 pm to 7:00 am to account for noise sensitivity in the nighttime. The logarithmic effect of these additions is that a 60 dBA 24-hour Leq would result in a measurement of 66.4 dBA Ldn.
Community Noise Equivalent Level (CNEL) is a 24-hour average Leq with a 5-dBA weighting during the hours of 7:00 pm to 10:00 pm and a 10-dBA weighting added to noise during the hours of 10:00 pm to 7:00 am to account for noise sensitivity in the evening and nighttime, respectively.
Noise can be generated by a number of sources, including mobile sources, such as automobiles, trucks and airplanes, and stationary sources, such as construction sites, machinery, and industrial operations.
Sound spreads (propagates) uniformly outward in a spherical pattern, and the sound level decreases (attenuates) at a rate of approximately 6 decibels (dB) for each doubling of distance from a stationary or point source. Sound from a line source, such as a highway, propagates outward in a cylindrical pattern, often referred to as cylindrical spreading. Sound levels attenuate at a rate of approximately 3 dB for each doubling of distance from a line source, such as a roadway, depending on ground surface characteristics (Federal Highway Administration [FHWA] 2017a). Soft surfaces, such as soft dirt or grass, can absorb sound, so an excess ground-attenuation value of 1.5 dB per doubling of distance is normally assumed (FHWA 2017a).
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ECORP Consulting, Inc. 3-59 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 Noise levels may also be reduced by intervening structures; generally, a single row of detached buildings between the receptor and the noise source reduces the noise level by about 5 dBA (FHWA 2006), while a solid wall or berm generally reduces noise levels by 5 to 10 dBA (FHWA 2017b). According to the FHWA (2017b), noise barriers can reduce noise levels by 15 dBA in certain instances, yet this level of noise reduction is very difficult to achieve. To achieve the most potent noise-reducing effect, a noise enclosure/barrier must physically fit in the available space, must completely break the “line of sight” between the noise source and the receptors, must be free of degrading holes or gaps, and must not be flanked by nearby reflective surfaces. Noise barriers must be sizable enough to cover the entire noise source and extend lengthwise and vertically as far as feasibly possible to be most effective. The limiting factor for a noise barrier is not the component of noise transmitted through the material, but rather the amount of noise flanking around and over the barrier. In general, barriers contribute to decreasing noise levels only when the structure breaks the "line of sight" between the source and the receiver.
The manner in which older homes in California were constructed generally provides a reduction of exterior-to-interior noise levels of about 20 to 25 dBA with closed windows (Caltrans 2002). The exteriorto-interior reduction of newer residential units is generally 30 dBA or more (Harris Miller, Miller & Hanson Inc. 2006). Generally, in exterior noise environments ranging from 60 dBA CNEL to 65 dBA CNEL, interior noise levels can typically be maintained below 45 dBA, a typical residential interior noise standard, with the incorporation of an adequate forced air mechanical ventilation system in each residential building, and standard thermal-pane residential windows/doors with a minimum rating of Sound Transmission Class (STC) 28. (STC is an integer rating of how well a building partition attenuates airborne sound. In the U.S., it is widely used to rate interior partitions, ceilings, floors, doors, windows, and exterior wall configurations). In exterior noise environments of 65 dBA CNEL or greater, a combination of forced-air mechanical ventilation and sound-rated construction methods is often required to meet the interior noise level limit. Attaining the necessary noise reduction from exterior to interior spaces is readily achievable in noise environments experiencing less than 75 dBA CNEL with proper wall construction techniques following California Building Code methods, the selections of proper windows and doors, and the incorporation of forced-air mechanical ventilation systems.
3.13.1.2 Human Response to Noise
The human response to environmental noise is subjective and varies considerably from individual to individual. Noise in the community has often been cited as a health problem, not in terms of actual physiological damage, such as hearing impairment, but in terms of inhibiting general well-being and contributing to undue stress and annoyance. The health effects of noise in the community arise from interference with human activities, including sleep, speech, recreation, and tasks that demand concentration or coordination. Hearing loss can occur at the highest noise intensity levels.
Noise environments and consequences of human activities are usually well represented by median noise levels during the day or night or over a 24-hour period. Environmental noise levels are generally considered low when the CNEL is below 60 dBA, moderate in the 60- to 70-dBA range, and high, above 70 dBA. Examples of low daytime levels are isolated, natural settings with noise levels as low as 20 dBA and quiet, suburban, residential streets with noise levels around 40 dBA. Noise levels above 45 dBA at night
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Alder Creek Subdivision Conformity Analysis 2024-012.01 can disrupt sleep. Examples of moderate-level noise environments are urban residential or semicommercial areas (typically 55 to 60 dBA) and commercial locations (typically 60 dBA). People may consider louder environments adverse, but most will accept the higher levels associated with noisier urban residential or residential-commercial areas (60 to 75 dBA) or dense urban or industrial areas (65 to 80 dBA). Regarding increases in dBA, the following relationships should be noted in understanding this analysis:
Except in carefully controlled laboratory experiments, a change of 1.0 dBA cannot be perceived by humans.
Outside of the laboratory, a 3.0-dBA change is considered a just-perceivable difference. A change in level of at least 5.0 dBA is required before any noticeable change in community response would be expected. An increase of 5.0 dBA is typically considered substantial. A 10.0-dBA change is subjectively heard as an approximate doubling in loudness and would almost certainly cause an adverse change in community response.
3.13.1.3 Noise Sensitive Land Uses
Noise-sensitive land uses are generally considered to include those uses where noise exposure could result in health-related risks to individuals, as well as places where quiet is an essential element of their intended purpose. Residential dwellings are of primary concern because of the potential for increased and prolonged exposure of individuals to both interior and exterior noise levels. Additional land uses such as hospitals, historic sites, cemeteries, and certain recreation areas are considered sensitive to increases in exterior noise levels. Schools, churches, hotels, libraries, and other places where low interior noise levels are essential are also considered noise-sensitive land uses.
As noted in the Environmental Impact Report/Environmental Impact Statement (EIR/EIS) for the FPASP, the nearest existing sensitive receptors include Folsom High School and single-family homes accessible via Iron Point Road approximately 2,000 feet north of the Alder Creek Property development’s northern boundary. The nearest future noise-sensitive land receptors are single-family homes (both low and high density units) directly adjacent to the southern boundary of the Alder Creek Property development site, fronting Mangini Parkway and a currently unmarked roadway that bisects Prairie City Road, multi-family high density units directly adjacent to the northwestern boundary of the Project Site, fronting Prairie City Road, and elementary, middle, and high schools directly adjacent to the Proposed Project’s southern and southwestern boundaries.
Additionally, the Alder Creek Property development would lead to the development of new receptors sensitive to noise and vibration impacts. While specific future site plans under the Alder Creek Property development are currently unknown, the development is consistent with the types, intensity, and patterns of land use evaluated by the FPASP EIR/EIS.
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Alder Creek Subdivision Conformity Analysis
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Alder Creek Subdivision Conformity Analysis 2024-012.01
3.13.1.4 Vibration Fundamentals
Ground vibration can be measured several ways to quantify the amplitude of vibration produced, including through peak particle velocity or root mean square velocity. These velocity measurements measure maximum particle at one point or the average of the squared amplitude of the signal, respectively.
Vibration impacts on people can be described as the level of annoyance and can vary depending on an individual’s sensitivity. Generally, low-level vibrations may cause window rattling but do not pose any threats to the integrity of buildings or structures.
3.13.1.5 Existing Ambient Noise Environment
The most common and significant sources of noise in the Project Area will be traffic and common activity typical of residential neighborhoods, as the area surrounding the Project Site is currently a developing residential community. As shown in Table 3.13-1 below, the ambient recorded noise levels range from
56.5 to 76.7 dBA Leq near the Project Site.
3.13.1.6 Existing Ambient Noise Measurements
The development site is located in the western portion of the FPASP. The development site is currently vacant and surrounded by a developing residential community as a part of the FPASP. To quantify existing ambient noise levels in the Project Area, ECORP Consulting, Inc. conducted four short-term (15-minute) noise measurements in areas around the Project Site on the afternoon of February 25, 2025. These shortterm noise measurements are representative of typical daytime noise exposure adjacent to the development site’s southern boundary (see Appendix C, Noise ). The measurements were taken between 1:02 p.m. and 2:13 p.m. Average noise levels at each location are listed in Table 4.13-1.
Table 3.13-1. Existing (Baseline) Noise Measurements
Location
Number Location dBA Time Leq Lmin Lmax
ST 1* Adjacent to corner of Oak Avenue
and Mangini Parkway 56.5 37.0 73.1 1:02 p.m. – 1:17 p.m.
ST 2 Adjacent to corner of Oak Avenue
Parkway and Gateway Drive 59.2 40.5 77.5 1:20 p.m. – 1:35 p.m.
ST 3 Adjacent to corner of Oak Avenue
Parkway and White Rock Road 64.3 41.3 76.8 1:38 p.m. – 1:53 p.m.
ST 4 Adjacent to corner of White Rock
Road and Scott Road 76.7 41.9 87.9 1:58 p.m. – 2:13 p.m.
Notes: Leq is the average acoustic energy content of noise for a stated period of time. Thus, the Leq of a timevarying noise and that of a steady noise are the same if they deliver the same acoustic energy to the ear during exposure. Lmin is the minimum noise level during the measurement period and Lmax is the maximum noise level during the measurement period.
*ST 1 was taken nearest the development site’s southern boundary.
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Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-62 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 Table 3.13-1. Existing (Baseline) Noise Measurements
Location
Number Location dBA Time Leq Lmin Lmax
Source: Measurements were taken by ECORP with a Larson Davis SoundExpert 821 precision sound level meter, which satisfies the American National Standards Institute for general environmental noise measurement instrumentation. Prior to the measurements, the SoundExpert 821 sound level meter was calibrated according to manufacturer specifications with a Larson Davis CAL200 Class I Calibrator.
As shown in Table 3.13-1, ambient recorded noise levels range from 56.5 to 76.7 dBA Leq across the four short-term noise measurements taken in the Project vicinity. The predominant sources of noise in the area include fast-moving vehicular traffic on White Rock Road, pedestrians walking by, and nearby construction activity. Measurement Site 4 recorded the highest noise levels. This measurement was not only influenced by the fast-moving vehicular traffic on White Rock Road, but also the rapid braking of vehicular traffic on Scott Road as it approached the stop sign at the White Rock Road/Scott Road intersection, and rapid acceleration of this same traffic onto White Rock Road.
Noise measurements were also collected in 2009 for the FPASP EIR/EIS analysis. Since then, no new development has occurred in the immediate vicinity of the Proposed Project. The nearest 2009 measurement site, Site C, was located on Prairie City Road, approximately 1,400 feet from the development boundary. Noise levels at that location were 58.1 dBA Leq during the daytime hours (7:00 a.m. to 10:00 p.m.) and 51.9 dBA Leq during the nighttime hours (10:00 p.m. to 7:00 a.m.), with an Ldn/CNEL of 60.0 dBA. The FPASP EIR/EIS found that vehicular traffic on U.S. 50 and White Rock Road was the primary source of noise at most measurement locations.
3.13.2 FPASP EIR/EIS Summary
According to the EIR/EIS, with implementation of mitigation measures, impacts associated with temporary, short-term exposure of sensitive receptors, ground borne noise, and vibration from project construction and the long-term exposure of sensitive receptors to increased operational traffic noise levels from project operation, would be reduced but not to a less than significant level. This is because noise levels would (or could potentially) still exceed applicable thresholds and, therefore, residual significant impacts would occur. All other noise impacts were found to be reduced to a less than significant level following implementation of mitigation measures.
3.13.3 Noise Conformity Analysis
3.13.3.1 Construction Noise Analysis - Onsite Construction Noise This information was obtained from Appendix C, Roadway Construction Noise, and D, the Alder Creek Property Emissions Report (ECORP 2025b and 2025c). The Alder Creek Property development is proposing the construction and operation of a fire station and 1,424 residential lots with varying zoning densities. All thirteen proposed lot sizes comply with the zoning designations and density requirements in the City of Folsom’s General Plan and the FPASP. The Alder Creek Property development also proposes land uses
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Alder Creek Subdivision Conformity Analysis 2024-012.01 such as private recreation, parks, landscaping, open space, and roadways as a part of the developing FPASP.
Construction noise would be temporary and vary depending on the nature of specific activities. Noise generated would primarily be associated with the operation of off-road equipment for onsite construction activities as well as construction vehicle traffic on area roadways. Construction noise typically occurs intermittently and varies depending on the nature or phase of construction (e.g., site preparation, excavation, paving). Noise generated by construction equipment, including earth movers, pile drivers, and portable generators, can reach high levels. Typical operating cycles for these types of construction equipment may involve one or two minutes of full power operation followed by three to four minutes at lower power settings. Other primary sources of acoustical disturbance would be random incidents, which would last less than one minute (such as dropping large pieces of equipment or the hydraulic movement of machinery lifts). During construction, exterior noise levels could negatively affect sensitive land uses in the vicinity of the construction site.
The FPASP EIR/EIS was certified by the City Council on June 14, 2011. The FPASP EIR/EIS evaluates noise impacts, including noise and vibrational impacts associated with construction and operation of development projects within the Folsom Plan Area. The previous analysis prepared in the FPASP EIR/EIS found that construction activities associated with the development of the FPASP would result in a direct, significant impact despite the imposition of several mitigation measures that reduce the FPASP construction impact. These measures (listed as Mitigation Measure 3A.11-1 in Appendix A) include the requirement that all construction contractors building in the FPASP implement a noise control plan and monitor and record construction noise near sensitive receptors. A Mitigation Monitoring and Reporting Program (MMRP) was prepared and adopted with the FPASP and is a binding document applicable to the Alder Creek Property development. The Alder Creek Subdivision Site is subject to the noise–reducing mitigation measures contained in the Specific Plan EIR/EIS.
The FPASP EIR/EIS projected that the existing noise sensitive receptors located in the City of Folsom would not be affected by construction noise during the daytime hours due to the intervening location of U.S. 50 that serves as a major dominating noise source. However, as the FPASP buildout occurs, sensitive residential receptors would be added to the area and may become operational while construction of other residential developments proposed by the FPASP is in progress. Since specific future site plans under the Alder Creek Property development are unknown at this time, it is conservatively assumed that the construction areas associated with this development could be located within 50 feet of sensitive receptors.
According to the California Emissions Estimator Model (CalEEMod), which is designed to model emissions for land use development projects based on typical construction requirements, the phase with the highest quantity of construction equipment for the buildout of the Alder Creek Property development is the building construction phase. It is acknowledged that construction equipment would generally be distributed across the site rather than concentrated in one area, resulting in varying distances between equipment and nearby sensitive receptors. The anticipated short-term construction noise levels generated for the necessary equipment at a distance of 50 feet are presented in Table 3.13-2.
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Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-64 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 Table 3.13-2. Construction Average (dBA) Noise Levels at Nearest Receptors Construction Phase Ambient Noise Levels*
(Leq)
Existing Ambient Noise + Exterior
Construction Noise Levels (Leq)
Building Construction 56.5 88.1
Notes: *Ambient noise level is the nearest short-term noise measurement to the Alder Creek Property development area taken on February 25, 2025, and identified in Table 4.13-1.
Construction equipment used during construction was identified using the California Emissions Estimator Model (CalEEMod), version 2022.1. CalEEMod is a statewide land use emissions computer model designed to quantify potential criteria pollutant emissions for land use development projects, based on typical construction requirements. CalEEMod creates the construction assumptions, including construction equipment and duration, used in this analysis. Since specific future site plans under the Alder Creek Property development are unknown at this time, it is assumed that the construction areas associated with the future development could be located within 50 feet of sensitive structures.
Leq = The equivalent energy noise level, is the average acoustic energy content of noise for a stated period of time. Thus, the Leq of a time-varying noise and that of a steady noise are the same if they deliver the same acoustic energy to the ear during exposure. For evaluating community impacts, this rating scale does not vary, regardless of whether the noise occurs during the day or the night.
Source: Construction noise levels were calculated by ECORP Consulting using the FHWA Roadway Noise Construction Model (FHWA 2006). Refer to Appendix C for Model Data Outputs.
As shown in Table 3.13-2, construction activities could reach up to 88.1 dBA Leq. It is noted that construction noise was modeled on a worst-case basis. It is very unlikely that all pieces of construction equipment would be operating at the same time.
The City of Folsom does not promulgate a numeric threshold pertaining to the noise associated with construction (City of Folsom 2024a). This is because construction noise is temporary, short term, intermittent in nature, and would cease on completion of construction. Instead, the City regulates construction noise by limiting it to the daytime hours, the portion of the day when such noise is generally accepted. Specifically, the City’s Municipal Code Chapter 8.42.060 prohibits construction taking place before 7:00 a.m. or after 6:00 p.m. on any day except Saturday or Sunday, or before 8:00 a.m. or after 5:00 p.m. on Saturday or Sunday. Adherence with this regulation would ensure compliance with the City’s construction noise standard. Although the City of Folsom exempts daytime construction noise from the applicable standards, the FPASP EIR/EIS considered construction noise for projects under the FPASP as a direct, significant impact. The Alder Creek Property development is consistent with the types, intensity, and patterns of land use evaluated by the FPASP EIR/EIS. Therefore, since the Alder Creek Property development is consistent with the land uses analyzed under the FPASP EIR/EIS, construction noise impacts would be the same as analyzed in the EIR/EIS and there would not be an increase in the severity of construction noise impacts as a result of the Alder Creek Property development. There would not be a new or substantially more severe significant impact compared with the significance determination contained in the EIR/EIS.
3.13.3.2 Construction Noise Analysis – Offsite Construction Worker Trips Construction of the Alder Creek Property development would result in additional traffic on adjacent roadways over the period that construction occurs. According to the CalEEMod, which is designed to model emissions for land use development projects based on typical construction requirements, including construction equipment duration and the number of construction-related automotive trips, the maximum
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-65 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 number of construction trips traveling to and from the Alder Creek Property development site during a single construction phase is expected to be 969 daily trips in total. According to Caltrans Technical Noise Supplement to the Traffic Noise Analysis Protocol (2013), a doubling of traffic on a roadway is required to result in an increase of 3 dB (outside of the laboratory, a 3-dBA change is considered a just-perceivable difference). The development site is currently accessible from Prairie City Road and is proposed within the FPASP, which is planned to accommodate 10,210 residential units at various densities, as well as 362.8 acres of commercial, industrial, and public uses, including a fire station.
Baseline average daily traffic volumes for several roadway segments throughout the City of Folsom were included in the 2035 General Plan Amendment (City of Folsom 2024b). The roadway segment bordering the eastern boundary of the Alder Creek Property development site (Prairie City Road from U.S. 50 to White Rock Road) was included in the General Plan Amendment analysis, which identified a baseline average daily traffic volume of 11,008 vehicles (City of Folsom 2024b). Thus, the maximum of 969 daily trips generated during construction would not result in a doubling of traffic, and therefore its contribution to existing traffic noise would not be perceptible. Additionally, it is noted that construction is temporary, and these trips would cease upon completion of construction. The FPASP EIR/EIS deemed that construction traffic noise would not result in a substantial temporary or periodic increase in ambient noise levels in the FPASP vicinity above levels existing without the FPASP. As a result, the FPASP EIR/EIS deemed construction traffic noise would be a less than significant impact. The Alder Creek Property development is consistent with the types, intensity, and patterns of land use evaluated by the FPASP EIR/EIS. Therefore, since the Alder Creek Property development is consistent with the land uses analyzed under the FPASP EIR/EIS, construction traffic noise impacts would be the same as analyzed in the EIR/EIS and there would not be an increase in the severity of construction traffic noise impacts as a result of the Alder Creek Property development. There would not be a new or substantially more severe significant impact compared with the significance determination contained in the EIR/EIS.
3.13.3.3 Operational Noise Analysis
Noise-sensitive land uses are locations where people reside or where the presence of unwanted sound could adversely affect the use of the land. Residences, schools, hospitals, guest lodging, libraries, and some passive recreation areas would each be considered noise-sensitive and may warrant unique measures for protection from intruding noise. The nearest existing sensitive receptors to the Alder Creek Property site include Folsom High School and single-family homes located approximately 2,000 feet north of the Project’s northern boundary. The nearest future sensitive receptors are residential units and schools directly adjacent to the Project Site, including single- and multi-family homes along Prairie City Road, Mangini Parkway, and surrounding areas. The Proposed Project would also introduce new noise-sensitive uses consistent with those anticipated in the FPASP EIR/EIS.
The FPASP EIR/EIS, certified by the City Council on June 14, 2011, includes an MMRP to address noise and vibration impacts on nearby sensitive receptors. The Alder Creek Subdivision Site is located within the FPASP and is thus subject to the noise–reducing mitigation measures contained in the Specific Plan EIR/EIS. The previous analysis prepared in the FPASP EIR/EIS found that Project implementation would result in long-term increases in daily traffic volumes on roadway segments in the area. Increased traffic
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-66 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 volumes would result in a substantial increase in ambient noise levels on- and off-site at nearby noisesensitive receptors (City of Folsom 2011). The FPASP EIR/EIS requires all project applicants of all project phases to implement noise reduction standards for buildings and conduct site-specific acoustical analyses for roadway noise impacts. Specifically, construction of noise-sensitive land uses (i.e., residential dwellings and school classrooms) must produce a minimum composite STC rating for buildings of 30 or greater. The MMRP was prepared and adopted with the FPASP and is a binding document applicable to the Alder Creek Property development. The specific mitigations in the MMRP applicable to Proposed Project’s operations are FPASP EIR/EIS measures 3A.11-4 and 3A.11-5 (see Appendix A).
3.13.3.4 Operational Traffic Noise
The FHWA roadway noise prediction model is used to calculate the noise levels from the existing average daily traffic volumes currently accommodated by Prairie City Road, as reported in the City of Folsom’s 2035 General Plan Amendment. Existing traffic noise is then compared to the predicted noise levels resulting from the Alder Creek Property development’s traffic contributions. The segment of Prairie City Road from U.S. 50 to White Rock Road, which borders the eastern boundary of the Alder Creek Property development, accommodates a baseline average daily traffic volume of 11,008 vehicles (City of Folsom 2024b). Based on this volume, existing traffic noise on this segment is estimated as 71.5 dBA CNEL (see Appendix D).
The Alder Creek Property development includes a fire station and 1,424 residential lots with varying densities. According to CalEEMod, which applies information from the Institute of Transportation Engineers’ Trip Generation Manual, residential uses of this scale are expected to generate up to 13,585 trips per day. Because CalEEMod does not include a category for fire stations, a comparable “government office building” land use was used to estimate operational trips from the fire station and projected 561 trips per day. In total, the Alder Creek Property development could generate approximately 14,146 daily vehicle trips. These additional trips would contribute to increased traffic noise levels.
Using the FHWA model and applicable trip generation rates, the combined traffic from the Alder Creek Property development and existing baseline volumes is projected to result in a noise level of 75.1 dBA CNEL, which is an increase of 3.6 dBA over existing conditions (75.1 dBA – 71.5 dBA = 3.6 dBA (see Appendix C). Outside of the laboratory, a 3-dBA change is considered a just-perceivable difference. Thus, the Alder Creek Property development’s contribution of traffic noise would result in a perceivable increase in traffic noise levels.
The FPASP EIR/EIS previously evaluated operational traffic noise to determine whether cumulative projects allowed under the FPASP would result in substantial noise increases. The FPASP EIR/EIS found that FPASP implementation would result in significant impacts on numerous roadway segments due to permanent increases in ambient noise levels at on- and off-site sensitive receptors. The Alder Creek Property development is consistent with the types, intensity, and patterns of land use evaluated by the FPASP EIR/EIS. Therefore, since the Alder Creek Property development is consistent with the land uses analyzed under the FPASP EIR/EIS, traffic noise impacts would be the same as analyzed in the EIR/EIS and there would not be an increase in the severity of traffic noise impacts as a result of the Alder Creek Property
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-67 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 development. There would not be a new or substantially more severe significant impact compared with the significance determination contained in the EIR/EIS.
3.13.3.5 On-Site Operational Noise
Operational noise generated by the proposed residential units and fire station is anticipated to be consistent with the type and intensity of noise levels previously evaluated in the FPASP EIR/EIS. Primary residential noise sources would include mechanical equipment and typical neighborhood sounds such as barking dogs, internal traffic circulation, power tools and landscaping equipment, radios, and people talking. The proposed fire station would produce intermittent high noise levels from sirens and emergency vehicle movement; however, the City exempts any equipment or mechanical noise associated with emergency services in Section 8.42.060(B) of the Municipal Code. Potential stationary noise sources associated with both residential and fire station uses, such as heating, ventilation, and air conditioning (HVAC) systems and emergency generators, were previously assessed in the FPASP EIR/EIS and determined to be direct, potentially significant impacts under applicable City standards.
The City of Folsom’s Municipal Code contains interior and exterior noise standards that may not be exceeded when measured at any affected single- or multi-family residence, school, church, hospital or public library. Exterior noise is limited to 50 dBA during the day (between the hours of 7:00 a.m. and 10:00 p.m.) and 45 dBA during the night (between the hours of 10:00 p.m. to 7:00 a.m.) for more than 30 minutes in any one-hour period, with absolute maximum thresholds of 70 dBA (daytime) and 65 dBA (nighttime).
According to the FPASP EIR/EIS analysis, HVAC equipment noise can vary from 45 to 70 Leq at 50 feet, potentially exceeding City thresholds. Although noise from emergency equipment is exempt, the FPASP EIR/EIS still assessed routine generator maintenance. Reference data indicate noise levels from generators (50–125 kilowatts) can range from 61 to 73 dB Leq and 63 to 84 dB Lmax at 45 feet. Generators within 700 feet of sensitive receptors may exceed daytime standards, while those within 1,200 feet may exceed nighttime standards, resulting in a potentially significant impact.
According to previous field noise measurements conducted by ECORP, residential HVAC equipment generates noise levels less than 45 dBA at 20 feet, which is within City noise limits. Additionally, previous field measurements within six different residential neighborhoods, including two multi-family neighborhoods, two single-family neighborhoods, and two mixed density neighborhoods identify an average daytime noise environment of 51.9 dBA, which is under the City’s daytime standard for 15-minute increments but exceeds the City’s daytime standard of no more than 50 dBA during a 30-minute period.
The Alder Creek Property development proposes residential uses adjacent to other residential areas, which is a fundamental planning strategy to minimize noise conflicts. As the Alder Creek Property development’s proposed land uses are consistent with those evaluated in the FPASP EIR/EIS, no new or substantially different significance determination is anticipated. The Alder Creek Property development must implement Mitigation Measure 3A.11-5 of the EIR/EIS (see Appendix A), which implements measures to reduce noise from Project-generated stationary sources.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-68 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
3.13.3.6 Noise/Land Use Compatibility
Consistent with FPASP EIR/EIS Cumulative Mitigation Measure NOISE-1, this analysis evaluates whether proposed residential uses on the Project Site would be exposed to interior noise levels of 45 dBA CNEL due to roadway traffic, including quarry truck traffic, on Prairie City Road. As previously described, Prairie City Road can be expected to generate noise levels of 75.1 dBA CNEL at 50 feet from centerline after the Alder Creek Property development is operational. This is comparable to the FPASP EIR/EIS projection of
74.1 dBA CNEL, confirming the reasonableness of the model inputs. New residential construction in California typically achieves 30 dBA of exterior-to-interior attenuation with windows closed (Harris Miller Miller & Hanson 2006), which would reduce exterior levels of 74–75 dBA CNEL to approximately 45 dBA CNEL within interior spaces. In addition, the Project includes a decorative soundwall between Prairie City Road and the nearest proposed residential units. Based on FHWA (2006) guidance, this wall is expected to provide an additional 8 dBA reduction in exterior levels. When this Project design feature is considered, interior noise levels would be reduced to approximately 37 dBA CNEL, which is well below the 45 dBA CNEL significance criterion.
However, these predicted traffic noise levels do not account for quarry truck traffic. According to the FPASP EIR/EIS, the three quarries generating truck traffic traversing the FPASP contribute 12,662 daily truck trips under cumulative conditions. Because the primary uncertainty in the cumulative noise environment is the contribution from quarry truck traffic, a conservative calculation was conducted assuming the entire volume of quarry truck trips reported in the FPASP EIR/EIS, 12,662 daily trucks, would travel on Prairie City Road. Under this extremely conservative assumption, trucks would represent roughly half of all cumulative traffic and would generate an exterior level of 82.5 dBA CNEL at 50 feet (FHWA roadway noise prediction model). Applying the 8 dBA reduction from the soundwall and the 30 dBA exterior-to-interior attenuation for new residential construction results in predicted interior noise levels of approximately 44.5 dBA CNEL (82.5 dBA – 8 dBA – 30 dBA = 44.5).
Even under this highly conservative scenario, one that overstates truck traffic on Prairie City Road, interior noise levels would remain below the FPASP threshold of 45 dBA CNEL. Accordingly, proposed residential uses on the Project Site would not be exposed to interior noise levels exceeding 45 dBA CNEL from roadway or quarry truck traffic, and the Project is consistent with FPASP EIR/EIS Cumulative Mitigation Measure NOISE-1.
3.13.3.7 Groundborne Vibration Analysis
The Alder Creek Property development consists of the construction of 1,424 single family dwelling units with varying density as well as land uses such as private recreation, parks, landscaping, open space, roadways, and a fire station as a part of the developing FPASP. Operations at proposed residential units and the fire station would not include the use of any large-scale stationary equipment that would result in excessive vibration levels. Therefore, the Alder Creek Property development would not result in groundborne vibration impacts during operations.
Excessive groundborne vibration impacts result from continuously occurring vibration levels. Increases in groundborne vibration levels attributable to the Alder Creek Property development would be primarily
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-69 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 associated with short-term construction-related activities. Construction would have the potential to result in varying degrees of temporary groundborne vibration, depending on the specific construction equipment used and the operations involved. Ground vibration generated by construction equipment spreads through the ground and diminishes in magnitude with increases in distance.
Construction activities that generate excessive vibration, such as blasting, would not be expected to occur from future development due to the topography of the area, which is relatively flat and devoid of rock outcroppings. The FPASP EIR/EIS addressed the use of blasting but predicted it would only occur on the eastern portion of the Specific Plan Area, in El Dorado Hills, which is outside the boundary of the Alder Creek Property development. Most construction equipment would be mobile and dispersed across the site, rather than concentrated in a single area. Since detailed site plans are not yet finalized, it is assumed that construction activities could occur within 50 feet of sensitive structures.
The primary vibration-generating activities would occur during grading, placement of underground utilities, and construction of foundations. Table 3.13-3 shows the typical vibration levels produced by construction equipment at 50 feet.
Table 3.13-3. Representative Vibration Source Levels for Construction Equipment Equipment Peak Particle Velocity at 50
Feet (inches per second)
Vibration Level Vibration
Velocity at 50 Feet (VdB)
Pile Driver (Impact) 0.225 95
Pile Driver (Sonic) 0.059 84
Vibratory Roller 0.073 85
Hoe Ram 0.031 78
Large Bulldozer 0.031 78
Caisson Drilling 0.031 78
Loaded Trucks 0.026 77
Jackhammer 0.012 70
Small Bulldozer 0.001 49
Note: VdB = vibration decibels
Source: California Department of Transportation (Caltrans) 2020 The City’s vibration threshold requires construction projects and new developments anticipated to generate a significant amount of vibration to ensure acceptable interior vibration levels at nearby noisesensitive uses using the following standards presented below in Table 3.13-4. The City’s standards are based on criteria from the Federal Transit Administration’s recommendations.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-70 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01 Table 4.13-4. Groundborne Vibration Impact Criteria for General Assessment Land use Category
Impact Levels (VdB)
Frequent
Events1
Occasional
Events2
Infrequent
Events3
Category 1: Buildings where vibration would interfere
with interior operations 654 654 654
Category 2: Residences and buildings where people
normally sleep 72 75 80
Category 3: Institutional land uses with primarily
daytime uses 75 78 83
Notes: Vibration levels are measured in or near the vibration-sensitive use. 1 “Frequent Events” is defined as more than 70 vibration events of the same source per day 2 “Occasional Events” is defined as between 30 and 70 vibration events of the same source per day 3 “Infrequent Events” is defined as fewer than 30 vibration events of the same source per day 4 This criterion limit is based on levels that are acceptable for most moderately-sensitive equipment such as optical microscopes. Vibration-sensitive manufacturing or research will require detailed evaluation to define the acceptable vibration levels.
Source: City of Folsom General Plan Chapter 9 Safety and Noise (2021).
Due to the nature of the Alder Creek Property development, the impact levels for frequent events will be used to evaluate its construction. It is noted that this can be classified as frequent because although the construction is temporary, the construction’s vibrational impacts would be consistent and frequent throughout the construction period. With a Category 2 and frequent events classification, the impact events cannot exceed 72 VdB without exceeding the significance threshold. As indicated in Table 4.13-4, several types of equipment, including pile drives and vibratory rollers, can exceed the 72 VdB threshold at 50 feet. While actual distances may vary depending on future site design, the potential exists for construction activities to expose nearby receptors to vibration levels above the City’s threshold. The FPASP EIR/EIS, certified by the City Council on June 14, 2011, includes an MMRP to address vibration impacts on nearby sensitive receptors. The Alder Creek Subdivision Site is located within the FPASP and is thus subject to the vibration–reducing mitigation measures contained in the Specific Plan EIR/EIS, specifically Mitigation Measure 3A.11-3 (see Appendix A).
The FPASP EIR/EIS explained that the nearest sensitive receptors (e.g., existing off-site El Dorado residences to the east of the steep hillside area where blasting could occur and planned on-site receptors) could be located within the distances modeled above that correspond to the exceedance levels recommended by Caltrans and the Federal Transit Administration (FTA). The Alder Creek Property development is consistent with the types, intensity, and patterns of land use evaluated by the FPASP EIR/EIS. Therefore, since the Alder Creek Property development is consistent with the land uses analyzed under the FPASP EIR/EIS, construction vibration impacts would be the same as analyzed in the EIR/EIS and there would not be an increase in the severity of impacts as a result of the Alder Creek Property development. There would not be a new or substantially more severe significant impact compared with the significance determination contained in the EIR/EIS.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-71 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
3.13.3.8 Airport Noise Analysis
The development site is located approximately 8.94 miles northeast of the Sacramento Mather Airport.
The site is located within the review area identified in the Mather Airport Land Use Compatibility Plan; however, it is not within the 60 dBA noise contour for the airport (Environmental Science Associates 2022).
Implementation of the Alder Creek Property development would not affect airport operations, nor result in increased exposure of those on the development site to aircraft noise. There is not a new or substantially more severe significant impact compared with the significance determination contained in the FPASP EIR/EIS for airport noise impacts associated with the Alder Creek Property development.
3.13.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included 10 mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to noise that the proposed Project would have to adhere to.
3.14 Population and Housing
3.14.1 Environmental Setting
The Project site is located in the Folsom Plan Area within the City of Folsom. As such, land use in the area is governed by the City of Folsom General Plan 2035, FPASP, Zoning Ordinance, and related adopted plans. The FPASP EIR/EIS assessed population and housing impacts. The FPASP EIR/EIS concluded that the growth would not exceed anticipated forecast and impacts to housing, population, and employment would be less than significant.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
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Alder Creek Subdivision Conformity Analysis 2024-012.01
3.14.2 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, impacts associated with population growth and housing demand are considered less than significant.
3.14.3 Population and Housing Conformity Analysis
3.14.3.1 Population and Housing Impacts
The Proposed Project is consistent with the General Plan and FPASP and would not induce unplanned growth. Implementation of the proposed Project would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively.
3.14.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The conclusion of the FPASP EIR/EIS relating to population and housing found all impacts to be less than significant. There are no mitigation measures contained in the FPASP EIR/EIS that apply to impacts to population and housing.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-73 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
3.15 Public Services
3.15.1 Environmental Setting
3.15.1.1 Police Services
The City of Folsom Police Department is headquartered 46 Natoma Street. A substation is proposed to serve the Folsom Plan Area in the FPASP, tentatively planned to be located on the corner of East Bidwell Street and Old Ranch Way. The City monitors service ratios per the requirements of the General Plan and will add the substation as necessitated by Folsom Plan Area buildout.
3.15.1.2 Fire Services
The City of Folsom Fire Department operates five stations and serves the City of Folsom. Station 37, located at 70 Clarksville Road, is nearest the Project site. Future Station 34 is proposed to serve the Folsom Plan Area and is tentatively planned to be located on the corner of East Bidwell Street and Old Ranch Way. The City monitors service ratios per the requirements of the General Plan and will add Station 34 as necessitated by Folsom Plan Area buildout.
3.15.1.3 Schools
Folsom Cordova Unified School District currently manages 34 schools ranging from transitional kindergarten through adult education and has jurisdiction over the Proposed Project.
3.15.2 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, with implementation of all listed mitigation measures, all impacts related to public services would be reduced to a less than significant level.
3.15.3 Public Services Conformity Analysis
3.15.3.1 Impacts to Public Services
As described in the FPASP EIR/EIS, with implementation of mitigation measures, the project would not result in substantial on-site adverse physical impacts associated with the provision of new or physically altered governmental facilities, need for new or physically altered governmental facilities, the construction of which could cause significant environmental impacts. The proposed Project would include the same development and uses as described in the FPASP EIR/EIS and therefore would not impact public facilities beyond what was identified in the Specific Plan FEIR. The Project includes 10 acres for a neighborhood public park, whereas the FPASP states that there would be 10.03 acres for a neighborhood public park.
However, this change is minimal and would not result in impacts to parks. Therefore, the analysis under the FPASP EIR/EIS remains accurate with respect to the proposed project and impacts would be less than significant.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-74 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
3.15.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included four mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to public services that the proposed Project would have to adhere to.
3.16 Recreation
3.16.1 Environmental Setting
Over 1,000 acres of the total Folsom Plan Area is being maintained as permanently protected open space to preserve sensitive habitat areas. This protected area includes thick stands of oak woodlands, Alder Creek and streams that flow into it, wetlands, ponds, and hillsides. A network of more than 30 miles of bike paths, trails and picnic areas are planned to wind through the Plan Area for residents to enjoy the area's natural setting, as well as to connect residents to shopping, transit, schools, parks, woodlands, the American River Parkway and beyond.
In addition to preserved open space, the Folsom Plan Area will have more than 130 acres of public parks, including two large community parks and smaller parks accessible to every neighborhood. Parks are important to defining a community's character by providing places for children to play and for friends and families to gather and socialize. Parks within the Plan Area are planned to be close to schools, within a half-mile from homes and connected by walking and bicycle paths.
3.16.2 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, with implementation of all listed mitigation measures, all impacts related to recreation and parks would be reduced to a less than significant level.
06/23/2026 Item No.18.
Alder Creek Subdivision Conformity Analysis
ECORP Consulting, Inc. 3-75 August 2025
Alder Creek Subdivision Conformity Analysis 2024-012.01
3.16.3 Recreation Conformity Analysis
3.16.3.1 Parkland Impacts
As mentioned above, the Project includes 10 acres for a neighborhood public park, whereas the FPASP states that there would be 10.03 acres for a neighborhood public park. According to the FPASP, Section 9.3 Park Land Dedication, General Plan Policy 35.12 and Municipal Code Section 16.32.040 sets the minimum standard for parks, open space and recreation facilities in the City of Folsom at five acres per thousand population (5-acres per 1,000 persons). The formula shown herein provides the basis for determining the required park acreage per dwelling type.
Government Code Section 66477 provided the City of Folsom the ability to create Municipal Code Section
16.32.040 that allows the city to require the dedication of land or impose a requirement for the payment of fees in lieu thereof, or a combination of both, for park or recreation purposes as a condition to the approval of a tentative map or parcel map. The FPASP proposes to satisfy the park land dedication requirement by dedication of land and the payment of in lieu fees. Therefore, impacts associated with park and recreation facilities with implementation of the proposed Project would be less than significant with the slight decrease of parkland proposed and incorporation of in lieu fees. The Project would be required to adhere to all mitigation and avoidance measures listed within the FPASP EIR/EIS.
3.16.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included one mitigation measure (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to recreation and parks that the proposed Project would have to adhere to.
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3.17 Transportation
3.17.1 Environmental Setting
3.17.1.1 Public Transit Service
The City of Folsom provides local bus transit within the City. The Sacramento Regional Transit District (SacRT) operates bus and light-rail transit service in Sacramento County. SacRT service is provided from downtown Sacramento along the Folsom Blvd/U.S. 50 corridor to the Historic Folsom light-rail station.
3.17.1.2 Bicycle Facilities
The General Plan includes Class I bicycle paths, and Class II bicycle lanes for the Folsom Plan Area.
Development of Project area bicycle and pedestrian facilities is ongoing, and bicycle lanes have been installed on portions of East Bidwell Street and Savannah Parkway. Curbs, gutters, and sidewalks that meet City standards will be provided on all roadways in the area.
3.17.1.3 Pedestrian Facilities
Sidewalks have been constructed along public streets in the developed portions of the Folsom Plan Area, including along Old Ranch Way, Alder Creek Parkway, Savannah Parkway, and East Bidwell Street within the Project area. Major intersections on East Bidwell Street have or will have crosswalks, and other nearby signalized intersections have pedestrian crossing hardware and signal phases.
3.17.1.4 Planned Improvements
The U.S. 50/Empire Ranch Road Interchange Project will create new freeway access at a location north of the Project site. This improvement is projected to be complete in 2030-2035.
3.17.2 FPASP EIR/EIS Traffic Summary
According to the FPASP EIR/EIS, implementation of the FPASP would result in significant impacts to numerous intersections and roadways. However, mitigation measures, including construction of roadway and intersection improvements, reduced all but five of these impacts to a less-than-significant level. Five impacts remained significant and unavoidable under the project plus cumulative scenario. Two intersection impacts, at Oak Avenue Parkway/East Bidwell Street and East Bidwell Street/Iron Point Road remained significant and unavoidable because it is contrary to City policy to construct 8-lane roadways, as would be required to fully mitigate the impact. Impacts to three roadway segments on eastbound U.S. 50, including the Zinfandel Drive to Sunrise Boulevard segment, the Rancho Cordova Parkway to Hazel Avenue segment, and the Folsom Boulevard to Prairie City Road segment, remained potentially significant and unavoidable. The mitigation measures included for these segments call for fair-share payments to support the construction of the Southeast Capitol Connector. However, based on available information, it could not be determined that the proposed Southeast Capitol Connector would reduce traffic volumes on U.S. 50 to an acceptable level of service, and therefore these impacts were considered significant and unavoidable in the EIR/EIS.
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3.17.3 Transportation Conformity Analysis
3.17.3.1 Conflict with Plan or Ordinance
The Project roadways would be consistent with the analysis and proposed roadways included in the FPASP EIR/EIS. Therefore, the analysis under the FPASP EIR/EIS remains accurate with respect to the proposed project. The proposed Project includes construction of roads that would create an efficient and safe transportation system through the project site consistent with the City’s General Plan goals and policies addressing the circulation system. Therefore, impacts would be less than significant.
3.17.3.2 Consistency with CEQA Guidelines 15064.3, subdivision (b).
CEQA Guidelines Section 15064.3 subdivision (b) addresses the criteria for analyzing transportation impacts and establishes Vehicle Miles Traveled as the metric most appropriate to measure transportation impacts in a CEQA document. The Office of Planning and Research (OPR) Technical Advisory on Evaluating Transportation Impacts in CEQA cites increased access to common goods and services, such as schools, as a potential way to reduce vehicle miles travelled (OPR 2018). The Proposed Project is consistent with the FPASP and supporting Final EIR/EIS, the General Plan, and is consistent with all land use designations applied to the site. Additionally, the Proposed Project would not increase the number of people residing in the area beyond anticipated in previous analysis. Thus, the Project would not contribute to an increase in population or housing growth beyond that currently anticipated and planned for in the FPASP.
3.17.3.3 Traffic Hazards
The proposed Project is consistent with the roadway analysis included in the FPASP EIR/EIS. The Project does not include any project elements that could potentially create a traffic hazard for motor vehicles, bicycles, or pedestrians due to a proposed, non-standard design feature. Therefore, impacts would be less than significant.
3.17.3.4 Emergency Access
The proposed Project would result in the same access and uses as analyzed in the FPASP EIR/EIS. As described in the FPASP EIR/EIS, the project’s evacuation approach would be consistent with the City’s and County’s evacuation approach. The proposed Project would be consistent with the Specific Plan’s guidelines and provide adequate emergency access throughout the project site. The Project is consistent with the roadway analysis included in the FPASP EIR/EIS and would provide adequate emergency access to the project site. The project site access, including road widths and connectivity, would be consistent with the City’s roadway standards and all applicable requirements. Therefore, impacts would be less than significant.
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3.17.3.5 Prairie City Road Improvements
The proposed road improvements to Prairie City Road were previously analyzed in the following planning documents: FPASP EIR/EIS, the South of Highway 50 Backbone Infrastructure IS/MND, and the Easton Project: Glenborough at Easton and Easton Place, and.
The South of Highway 50 Backbone Infrastructure Initial Study and Mitigated Negative Declaration (prepared and adopted by the City in 2014), tiered from the FPASP EIR/EIS in accordance with CEQA Guidelines section 15152. The project description for the IS/MND included a section on “Roadway Construction” explaining that the street system outlined in the FPASP would be constructed, including the regional connectors, major arterials, and some of the minor arterials. This work included rough grading, rail corridor crossings and installation of pavement, curbs, gutters, street lighting, sidewalks, landscaping and striping. Because the widening of Prairie City Road was expressly contemplated in the FPASP EIR, and then the Backbone Infrastructure IS/MND purported to provide project level impact analysis of all the planned roads in the FPASP area, the IS/MND provides the required lower-tier CEQA analysis of the required improvements to Prairie City Road adjacent to the Toll Brothers development. The Backbone Infrastructure IS/MND supported the subsequent environmental permits covering the FPASP infrastructure footprints
Additionally, the Easton Project: Glenborough at Easton and Easton Place, which is located within Sacramento County and borders the proposed Project, analyzed the impacts of expanding Prairie City Road and included mitigation measure TC-6a, which was to construct improvements to widen Prairie City Road to six lanes between U.S. 50 and White Rock Road (Sacramento County 2008).
As mentioned in Section 2.1.3 above, the Project would only be constructed within the confines of the existing CWA Section 404 permit boundaries. The findings of the certified EIR/EIS remain valid, and no new significant or more severe impacts were identified.
3.17.4 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
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6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
7. The FPASP EIR/EIS included 59 mitigation measure (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to traffic that the proposed Project would have to adhere to.
3.18 Tribal Cultural Resources
Assembly Bill 52 (AB 52), codified in Public Resources Code Sections 21073, 21074, 21080.3.1, and 21080.3.2, requires lead agencies to consult with California Native American tribes that are traditionally and culturally affiliated with the project area if those tribes have requested notification of projects under CEQA).
The EIR/EIS for the FPASP was certified prior to July 1, 2015, the effective date of AB 52. As such, AB 52 does not retroactively apply to the certified EIR. The proposed Project analyzed in this conformity analysis does not introduce new significant impacts or substantially increase the severity of previously identified impacts related to tribal cultural resources. No new information of substantial importance has been identified regarding tribal cultural resources that would require revisions to the EIR/EIS.
3.19 Utilities and Service Systems
3.19.1 Environmental Setting
The Project site is currently graded and undeveloped. As such, the Project would require the installation of utilities and stormwater collection infrastructure. These facilities would be coordinated with the installation of backbone infrastructure being developed in support of the Folsom Ranch development and the proposed utilities would connect to the appropriate service providers. The Project would include the installation of sanitary sewer lines, domestic water lines, fire lines, and storm drain utilities. All utility installation would be below ground in utility trenches. Water and sewer services will be provided by the City of Folsom.
3.19.1.1 Water
Water service to the site is provided by the City of Folsom, which obtains all of its potable water supply from Folsom Lake. The City's current water rights amount to 34,000 acre-feet of raw water per year. Water is treated at the City treatment plant, which has a capacity of 50 million gallons per day (mgd).
3.19.1.2 Wastewater
The City of Folsom will provide wastewater/sewage collection services to the site. All wastewater in the City of Folsom is treated by the Sacramento County Regional Sanitation District at the regional treatment facility located in Elk Grove, the Sacramento Regional Wastewater Treatment Plant (SRWTP). The current capacity of the treatment system is not expected to be reached until after 2030 with regional growth in the area. The SRWTP serves approximately 1.61 million people (Central Valley RWQCB 2021).
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Alder Creek Subdivision Conformity Analysis 2024-012.01 In May 2021, the Central Valley RWQCB issued a new discharge permit for Sacramento Regional County Sanitation District (SRCSD). The 2016 National Pollutant Discharge Elimination System (NPDES) discharge permit largely continued the requirements from the prior 2010 NPDES discharge permit (Permit No.
CA0077682). The 2010 discharge permit required the Sacramento region to move to an advanced, or tertiary, treatment process (known as the EchoWater Project). SRCSD is now in the process of constructing significant new treatment processes to at the SRWTP to (1) remove ammonia and nitrates and (2) add filtration and enhanced disinfection to inactivate pathogens. This new system produces cleaner water for discharge into the Sacramento River, as well as for potential reuse as recycled water (e.g., for landscape and agricultural irrigation). Under the 2021 NPDES discharge permit, the average dry weather flows cannot exceed 181 mgd (Central Valley RWQCB 2021).
3.19.1.3 Stormwater
The City of Folsom Department of Public Works is responsible for stormwater management in the City.
The City operates and maintains an extensive storm drainage system, including about 200 miles of pipe, 23 miles of natural drainage channels/creeks, 60 flood control and/or water quality detention basins, and over 200 outfalls to creeks/rivers. The City is active in the Sacramento Stormwater Quality Partnership designed to reduce and manage run-off throughout the area. The City also holds and complies with a National Pollutant Discharge Elimination System (NPDES) permit for commercial projects (including schools) that create one acre or more of impervious surface and residential projects 20 acres and larger.
The Project site will be served by a stormwater collection system, utilizing storm drains and central retention basins for the surrounding community. All stormwater collected from the Project site will run to these retention basins, with the most likely recipient being a basin located on the southern end of Timberline Meadow Way, approximately 650 feet south of the southeastern corner of the Project site. The Project site’s new storm drain system would connect to the existing stormwater collection infrastructure through an easement directly south of the Project site.
3.19.1.4 Solid Waste
Solid waste and recycling materials are collected by the City of Folsom Solid Waste Division. Most refuse from Folsom is sent to Keifer Landfill, a Class III landfill located at 12701 Kiefer Boulevard in Sloughhouse, about 11 miles south of Highway 50. The landfill is permitted to receive a maximum of 10,815 tons per day and as of 2005 it had remaining capacity of 112,900,000 cubic yards, with an estimated closure in the year 2064. However, solid waste at school sites are handled under contract by Allied Waste, a private hauler, for the Folsom Cordova Unified School District and the Folsom Prison; Allied takes materials to the Forward Landfill in Stockton.
3.19.1.5 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, impacts associated with increased demand for SRCSD off-site wastewater collection and conveyance facilities; increased temporary and short-term and long-term generation of solid waste; and increased demands for electrical, natural gas, and communications service and infrastructure were considered less than significant. Implementation of mitigation measures contained in
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Alder Creek Subdivision Conformity Analysis 2024-012.01 the FPASP EIR/EIS were found to reduce impacts associated with increased demand for on-site wastewater collection and conveyance facilities and the off-site force main to a less than significant level.
In addition, FPASP implementation would increase demand for SRWTP facilities and would contribute to the need to expand the SRWTP; therefore, the FPASP would contribute indirectly to one significant and unavoidable impact (related to air quality) identified in the 2020 Master Plan EIR. Therefore, a residual significant and unavoidable impact would occur.
3.19.2 Utilities and Service Systems Conformity Analysis The Project is part of the greater implementation of the FPASP. The Project would affect the same area analyzed for development in the FPASP EIR/EIS and would not alter the development type or density at the Project site.
As mentioned above, the proposed 69-kilovolt (kV) transmission lines will be realigned to the western side of Prairie City Road adjacent to the proposed improvements, to allow for the expanding of Prairie City Road. This change was not explicitly stated within the FPASP EIR/EIS; however, the line relocation work would occur in the area along Prairie City Road already cleared for permitting in the Backbone Infrastructure IS/MND, and the type and extent of grading, construction, and operation would be consistent with the activities already studied and approved for that area. This modification would not result in new or worse impacts that were not previously discussed in the FPASP EIR/EIS. Therefore, the impacts to public utilities would not change, and the findings of the certified EIR/EIS remain valid and no further analysis is required. No new impact would occur.
3.19.3 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
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7. The FPASP EIR/EIS included 12 mitigation measures (as seen in Appendix A, FPASP EIR/EIS Mitigation Monitoring and Reporting Program) to address impacts to utilities that the proposed Project would have to adhere to.
3.20 Wildfire
3.20.1 Environmental Setting
Generally, California fire season extends from spring to late fall. Fire conditions arise from a combination of hot weather, an accumulation of vegetation, and low moisture content in the air. These conditions, when combined with high winds and years of drought, increase the potential for wildfire to occur.
California Department of Forestry and Fire Protection (CAL FIRE) provides wildland fire protection services on private, non-federal lands for the purpose of life, property, and resource protection. U.S. Forest Service and Bureau of Land Management provide wildland fire protection services on federal lands in Federal Responsibility Areas for watershed and resource protection. Some areas are also identified as Local Responsibility Areas.
The Project site is within a Local Responsibility Area and is served by the Folsom Fire Department. CAL FIRE classifies the Folsom Plan Area as a moderate Fire Hazard Severity Zone.
3.20.1.1 FPASP EIR/EIS Summary
According to the FPASP EIR/EIS, the FPASP is located within a state responsibility area designated as a moderate fire hazard severity zone. It was determined to not be near an area of high or extremely high fire hazard severity. Therefore, the FPASP EIR/EIS found that implementation would not expose people or structures to a significant risk of loss, injury, or death involving wildland fires, including where wildlands are adjacent to urbanized areas and it was not discussed further within the EIR/EIS.
3.20.2 Wildfire Conformity Analysis
As mentioned above, the FPASP EIR/EIS dismissed any impacts regarding wildfires as less than significant.
The Project is part of the greater implementation of the FPASP. The Project would affect the same area analyzed for development in the FPASP EIR/EIS and would not alter the development type or density at the Project site. Therefore, the impacts to wildfires would not change, and the findings of the certified EIR/EIS remain valid and no further analysis is required. No new impact would occur.
3.20.3 Conclusion
The proposed project is consistent with the development evaluated in the FPASP EIR/EIS and would not result in any new impacts or increase the severity of any previously identified impacts as compared to what was already identified and disclosed, either individually or cumulatively. Further environmental analysis is not required because:
1. No substantial changes are proposed which result in new or worse effects.
2. There are no changes in circumstances surrounding the project that create new or worse effects.
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3. There is no new information that results in significant effects that are not discussed in the Specific Plan FEIR.
4. There is no new information that results in new or worse effects than discussed in the Specific Plan FEIR.
5. There is no new information that results in mitigation measures that were previously found not to be feasible in the Specific Plan FEIR, to now be feasible.
6. There is no new information that results in mitigation measures that are considerably different than in the Specific Plan FEIR.
The conclusion of the FPASP EIR/EIS relating to wildfire found all impacts to be less than significant. There are no mitigation measures contained in the FPASP EIR/EIS that apply to impacts to wildfire.
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4.0 LIST OF PREPARERS
4.1 ECORP Consulting, Inc.
Amberly Morgan, Senior Environmental Planner/Project Manager Brianna Gustafson, Environmental Planner
Seth Myers, Air Quality/Noise Task Manager
Marco Caipo, Air Quality/Noise Analyst
Sophia Winter, Air Quality/Noise Analyst
Niranjala Kottachchi, Principal Paleontologist
Laura Hesse, Technical Editor
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5.0 REFERENCES
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CARB (California Air Resources Board). 2023. State Area Designation Maps. http://www.arb.ca.gov/desig/adm/adm.htm.
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_____. 2010. 2010 Sacramento County PM10 Implementation/Maintenance Plan and Re-Designation Request.
California Department of Conservation. 2022. California Important Farmland Finder. https://maps.conservation.ca.gov/DLRP/CIFF/. Accessed July 3, 2025. _____. 2018. Special Report 245 – Mineral Land Classification: Concrete Aggregate in the Greater Sacramento Area Production-Consumption Region.
_____. 2015. Fault Activity Map of California. https://maps.conservation.ca.gov/cgs/fam/. Accessed July 3, 2025.
_____. 2014. City of Folsom General Plan Update Existing Conditions Report. https://www.folsom.ca.us/home/showdocument?id=228. Accessed January 2023.
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California Department of Transportation (Caltrans). 2020. Transportation and Construction Vibration Guidance Manual.
_____. 2013. Technical Noise Supplement to the Traffic Noise Analysis Protocol. _____. 2002. California Airport Land Use Planning Handbook California Department of Water Resources. 2020. California’s Groundwater (Bulletin 118).
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Alder Creek Subdivision Conformity Analysis 2024-012.01 Central Valley Regional Water Quality Control Board (RWQCB). 2021. Waste Discharge Requirements for the Sacramento Regional County Sanitation District Sacramento Regional Wastewater Treatment Plant. NPDES CA0077682 ORDER R5-2021-0019.
City of Folsom. 2024a. General Plan Amendment EIR. August _____. 2024b. 2035 General Plan Amendment. August
_____. 2021. City of Folsom General Plan – Chapter 9 Safety and Noise. _____. 2011. Folsom Plan Area Specific Plan Environmental Impact Report/Environmental Impact Statement.
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ECORP Consulting, Inc. (ECORP) 2025a. Alder Creek Property Project Emissions Report. _____. 2025b. Alder Creek Property Roadway Construction Noise Model. July. _____. 2025c. Alder Creek Property Project Traffic Noise Levels. July. _____. 2025d. Paleontological Assessment Memorandum for the Alder Creek Property Project, Sacramento County, California. July.
_____. 2025e. Biological Resources Assessment for the Alder Creek Project. July. Draft _____. 2024. Cultural Resources Due Diligence for the Proposed Toll Brothers Alder Creek Project Within the Folsom Plan Area Specific Plan.
Environmental Science Associates. 2022. Mather Airport Land Use Compatibility Plan. https://www.sacog.org/home/showpublisheddocument/2728/638715078803870000 Federal Highway Administration. 2017a. Construction Noise Handbook. https://www.fhwa.dot.gov/Environment/noise/construction_noise/handbook/handbook02.cfm.
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https://www.codepublishing.com/CA/Folsom/#!/html/Folsom08/Folsom0842.html024b. _____. 2024b. 2035 General Plan Amendment Environmental Impact Report Appendix C: Noise. https://www.folsom.ca.us/home/showpublisheddocument/17104/638491219530530000
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https://www.folsom.ca.us/home/showdocument?id=18784&t=638630306939444676 2017. 2017 Traffic County Map. https://www.folsom.ca.us/government/public-works/traffic _____. 2011. Folsom Plan Area Specific Plan Public Draft EIR/EIS. https://www.folsom.ca.us/home/showpublisheddocument/1694/637477103202830000.
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Raney 2014. 2014. Folsom Plan Area Specific Plan Backbone Infrastructure Initial Study/Mitigated Negative Declaration. MONTH.
Sacramento, County of. 2011. Stoneridge Quarry General Plan Amendment, Rezone, Use Permit, Reclamation Plan and Development Agreement Final Environmental Impact Report.
Sacramento County. 2008. Easton Project: Easton Place and Glenborough at Easton Mitigation Monitoring and Reporting Program. November 2008.
_____. 2010. Teichert Quarry General Plan Amendment, Rezone, Use Permit, Reclamation Plan, Grading Permit, Encroachment Permit, and Development Agreement Final Environmental Impact Report.
Sacramento Metropolitan Air Quality Management District. (SMAQMD). 2024. 2021 Sacramento County Second 10-Year PM10 Maintenance Plan.
_____. 2018. 2017 Sacramento Regional 8-Hour Ozone Attainment and Reasonable Further Progress Plan. _____. 2013. PM2.5 Implementation/Maintenance Plan and Re-designation Request for Sacramento PM2.5 Nonattainment Area.
_____. 2011. Recommended Protocol for Evaluating the Location of Sensitive Land Uses Adjacent to Major Roadways.
_____. 2010. PM10 Implementation/Maintenance Plan and Re-Designation Request.
State Water Resources Control Board (SWRCB). 2025. GeoTracker. https://geotracker.waterboards.ca.gov/map/?global_id=T0600700017. Accessed July 8, 2025.