Pleasanton City Council
July 21, 2026

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
FCS 23
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx The project applicant proposes three single-family lot design standards, as outlined in Table 1 below and shown in Exhibit 4.

Table 1: Proposed 50x70 Lot, 50x80 Lot, and 59.5x97 Design Standards Development Standard
Lots 1–102 50x70
Lot Standard
(approx.)
Lots 103–130
Lots 162–178 50x80
Lot Standard
(approx.)
Lots 131–161

59.5x97
Lot Standard
(approx.)
Minimum Lot Size (square feet) 3,500 4,000 5,652.5
Minimum Front Setback to Structure (feet) 10 10 10
Minimum Front Setback to Garage (feet) 18 18 18
Minimum Rear Setback to Living (feet) 10 8 15
Minimum Rear Setback to Covered
Outdoor Patio (feet)
5 5 15
Minimum Side Setback to Structure (feet) 5 5 5
Maximum Lot Coverage (percent) 60 60 60
Maximum Coverage (square feet) 2,100 2,400 3,391.5
Source: KTGY. 2026. Schematic Design. February 6.

2.3.2 - Comparison of Proposed Project to Approved County Project
Differences between the County Project, Alternative 2 evaluated in the Prior FEIR, and the proposed project are outlined in Table 2 below.

Table 2: Comparison of County Project, Alternative 2, and Proposed Project Development Detail
County Project as
Evaluated in
Prior FEIR
Alternative 2:

Annexation into
Pleasanton Proposed Project
Number of Units 194 single-family
49 junior ADUs
(243 total units)
Same as County Project 189 single-family
48 junior ADUs
(237 total units)
Project Acres 26.6 26.6 30.0
(includes approx. 3.4
acres for Street A)
Percentage of Homes with
Deed-restricted Junior ADUs
~25%
(49 out of 194 homes)
Same as County Project ~25%
(48 out of 189 homes)

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
24 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Development Detail
County Project as
Evaluated in
Prior FEIR
Alternative 2:

Annexation into
Pleasanton Proposed Project
Height of Units 26–30 feet Same as County Project 19.5-30 feet Density (du/ac) ~7.3 units per acre Same as County Project ~6.3 units per gross acre Total Number of Residents ~691 residents (based on
County’s average
household size of 2.84
persons per unit)
Same as County Project ~588 residents (based on
City’s average household
size of 2.48 persons per
unit)
Off-site Improvements Includes water storage
and booster pump facility,
WWTP, recycled water
storage, agricultural
irrigation fields,
bioretention areas,
stormwater conveyance
to Cope Lake; Street A;
Busch Road
improvements
Eliminates water storage
and booster pump facility,
WWTP, recycled water
storage, agricultural
irrigation fields,
bioretention areas; would
include Busch Road
improvements and Street
A, and a new trail
connection
Eliminates water storage
and booster pump facility,
WWTP, recycled water
storage, agricultural
irrigation fields; Citymanaged infrastructure
and services (subject to
stormwater conveyance
option to Cope Lake if
approved by Zone 7);
would include
bioretention area and
detention basin; would
include potential Busch
Road improvements.

Notes:

WWTP = Wastewater Treatment Plant
Source: KTGY. 2026. Schematic Design. February 6, 2026.

2.3.3 - Proposed Land Use Designations and Zoning
The proposed project includes annexation of the approximately 30-acre project site into the City. The proposed project would include a General Plan Amendment to redesignate the project site from the County MDR land use to the City’s MDR land use (Exhibit 5). According to the City’s General Plan, MDR allows for 2 to 8 du/acre. Annexation would involve City approval of a resolution to initiate annexation proceedings, as well as Alameda County Local Agency Formation Commission (LAFCo) approval of the boundary change.

The proposed project would also include pre-zoning of the project site to Planned Unit Development (PUD)–MDR to be consistent with the proposed project density and General Plan land use designation (Exhibit 5). The purpose of the PUD district, as stated in the City’s Municipal Code, is to allow for tailored development standards, which ensure that the goals and objectives of the City's General Plan are promoted without the discouragement of innovation by application of restrictive development standards.

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
FCS 25
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx

2.3.4 - Proposed Off-site Improvements
The proposed project would also include off-site improvements, as described below. Additional off-site improvements are discussed in Section 2.3.7, Proposed Utilities.

Roadway, Bicycle, and Pedestrian Improvements
A separate approved and entitled project, known as the Villages at the Quarry Project, located south of Busch Road, was approved by the City of Pleasanton on April 23, 2025. The Villages at the Quarry Project is required to make various roadway, bicycle, and pedestrian improvements to Busch Road, including bike lanes, sidewalks, a Class IV multiuse path, roundabouts into both the Villages at the Quarry Project and the proposed project’s entrances, and a dedicated queueing lane for the PGS facility.

If the proposed project is approved, the approval documents would include a binding provision in the Pre-Annexation Development Agreement (PADA) obligating the Arroyo Lago project applicant to implement the Busch Road improvements identified above and codified in Condition 14516 of the Villages at the Quarry approval, in the event that the Villages at the Quarry Project does not move forward or if the proposed project develops first. In addition to project-specific on-site and off-site improvements, the project applicant would financially contribute to future planned improvements along El Charro Road.
16 Condition 145 from the Villages at the Quarry Project reads as follows: The Project shall construct Busch Road along the entirety of the Project frontage, as a two-lane roadway, in accordance with Section 19.36.050 of the Pleasanton Municipal Code, inclusive of a single-lane roundabout which is the appropriate means of traffic control for safe and efficient operation of the intersection of Busch Road and Street D (“Busch Road Improvements”). The roundabout shall be designed to fit entirely within the existing right-of-way without requiring any dedication of additional right(s)-of-way by developer or third parties. As a condition precedent to approval of the final map, the City and the applicant shall enter into a subdivision improvement agreement, subject to the City’s bonding requirements, for the completion of the Busch Road Improvements. The Busch Road Improvements shall be eligible for a fee credit in accordance with Pleasanton Municipal Code Section 3.26.070. Should the applicable fee credits exceed the required transportation development fee, the applicant shall be entitled to reimbursement pursuant to a reimbursement agreement in accordance with Pleasanton Municipal Code Section 3.26.080.

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A R R O Y O L A G O R E S I D E N T I A L P R O J E C T

ADDENDUM
21480036 • 03/2026 | 5_proposed_land_use_zoning.m xd
Exhibit 5
Source: ESRI Aerial Im agery . City of Pleasanton. County of Alam eda.

F C S
Proposed Land Use and Zoning
Busch Rd
Stanley Blvd
El Charro Rd
Mohr Ave
Chatham Pl
Bradford Way
Martin Ave
Nichole Ave
Cameron Ave
Ironwood Dr
Baur Ct
Donahue Ct
Wenig Ct
Nolan Ct
Mils Ct
Madsen Ct
Kamp Dr
Valley Ave
Union Pacific Rail Line
Boulder St
Serpentine Ln
Quarry Ln
California
Ave
Lake I
Lake
H
Cope Lake
County of Alameda
City of Pleasanton

ECAP-WM

ECAP-LPA
ECAP-P
LD
MD
MD
LD
HD
PI
LI
LI
LI
MD
PHS
C
C
C
MD
PI
HD
HD
PR
MD
HD
PHS
MD
HD

ECAP-LPA
WO
MD

ECAP-MDR
Busch Rd
Stanley Blvd
El Charro Rd
Mohr Ave
Chatham Pl
Bradford Way
Martin Ave
Nichole Ave
Cameron Ave
Ironwood Dr
Baur Ct
Donahue Ct
Wenig Ct
Nolan Ct
Mils Ct
Madsen Ct
Kamp Dr
Valley Ave
Union Pacific Rail Line
Boulder St
Serpentine Ln
Quarry Ln
California Ave
Lake I
Lake
H
Cope Lake
County of Alameda
City of Pleasanton
A

PUD-LDR

PUD-MDR

PUD-LDR/HDR/P&I
& Mixed P&I/MDR
S
P
I-G-40
PUD-R-1-65

C-S PUD-C
PUD-C
MD
A

PUD-HDR

PUD-HDR
P
MD C-F RM-4

PUD-MDR

PUD-MDR

PUD-LDR

PUD-LDR
PUD-I
PUD-C
I-G-40
PUD-I

PUD-MDR-HDR/HOZ
A
C1
U

PUD-MDR
Legend
Project Site
Lim its of Disturbance
County Land Use Designations
ECAP-LPA: Large Parcel Agriculture
ECAP-MDR: Medium Density Residential
ECAP-P: Park lands
ECAP-W M: W ater Managem ent
City Land Use Designations
C - Com m ercial
LI - Lim ited Industrial
HD - High Density
LD - Low Density
MD - Medium Density
PR - Park s and Recreation
PHS - Public Health and Safety
PI - Public and Institutional
W O - W ildland Overlay
Legend
Project Site
Lim its of Disturbance
County Land Use Designations
A - Agriculture
U - Unspecified
City Zoning Designations
A - Agriculture
C-F - Com m ercial Freew ay
C-S - Com m ercial Service
I-G-40 - General Industrial
P - Public & Institutional
PUD-C - Com m ercial-PUD
PUD-HDR - PUD - High Density Residential
PUD-I - Industrial-PUD
PUD-LDR - Low Density Residential
PUD-LDR/HDR/P&I & Mix P&I/MDR - Low Den Res/Hi Den Res/Pub & Inst-Mix Pub & Inst/Med Den Res-PUD PUD-MDR - PUD - Medium Density Residential
PUD-MDR-HDR/HOZ - Med Den Res & Hi Den Res/Historic Overlay Zone PUD-R-1-65 - Single Fam ily Residential-PUD
RM-4 - Multiple-Fam ily Residential
S - Study District
¥ 1,000 500 0 1,000
Feet

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ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
FCS 29
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx A new trail connection is proposed along the northern project site boundary and the western side of the proposed Street A, as shown in Exhibit 4, within which project infrastructure would be installed for storm drain, sanitary sewer, and water; in addition, the trail connection would be available for restricted public access (limited to bikes, pedestrians, and authorized City maintenance equipment).

The proposed trail connection would require an access easement from Zone 7 Water Agency, the property owner, to the City. These upgrades are designed to enhance flood protection and utility reliability for the proposed project, as well as provide pedestrian/bicycle connectivity for the benefit of the project residents, guests, and members of the public.

The proposed project would include the addition of a landscaped multiuse trail north of the project site, as shown in Exhibit 9c. Development of the trail would require removal or realignment of an existing chain-link fence and would provide an improved pedestrian and bicycle connection between the project site, Mohr Elementary School, and surrounding neighborhoods, thereby enhancing local circulation and neighborhood connectivity.

2.3.5 - Circulation and Access
Vehicle
The proposed project would include a 2-car garage attached to each proposed single-family home . .

All applicable City off-street parking standards would be satisfied. Additional parking would be provided along the proposed project’s internal streets. Primary vehicular access to the project site would be via Busch Road, as shown on Exhibit 4. Additionally, speed bumps are proposed on Streets A and B as a traffic calming measure.

During project operation, emergency access would be provided via Busch Road from Valley Avenue.

Bicycle
Currently, there are no bicycle lanes on Busch Road adjacent to the project site. The nearest existing bicycle route is a Class II bicycle path, which starts at the Ironwood Drive and Bradford Way/Cornerstone Court traffic circle and connects to the Iron Horse Trail, approximately 1,000 feet west of the project site (Exhibit 6).
17 West and north of this intersection, bicycle lanes are provided on both sides of Ironwood Drive and Busch Road. In addition, the Iron Horse Regional Trail, a paved multiuse path that stretches over 30 miles from Concord to Pleasanton, is located approximately 1,500 feet west of the project site, providing access to the Dublin/Pleasanton BART Station.

As discussed above, the Villages at the Quarry Project, or the proposed project, if necessary,18 would be required to construct off-site bicycle lane improvements to Busch Road that would connect to the existing bicycle lanes on Busch Road and Ironwood Drive. 17 City of Pleasanton. 2019. Trails Master Plan. Website: https://www.cityofpleasantonca.gov/assets/our-government/publicworks/engineering/landscape-ordinance/trails/trails-master-plan.pdf. Accessed March 10, 2026. 18 As previously described, the approved and entitled Villages at the Quarry Project is responsible for the implementation of this improvement. If that project does not move forward, or does not proceed in a timely manner, the Arroyo Lago project developer would be responsible for implementation.

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F C S 21480036 • 11/2025 | 6_existing_planned_pleasonton_bicycle_facilities.cdr Existing and Planned City of Pleasanton Bicycle Facilities Exhibit 6
Source: Fehr & Peers, 2018.

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ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
FCS 33
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Pedestrian
The proposed project would include construction of approximately 0.5 mile of multiuse trails on the northern boundary of the project site and western side of Street A. In addition, all proposed roads on the project site would contain 5-foot sidewalks on both sides (except for the eastern side of Street A) and would also provide crosswalks at all internal intersections (except for adjacent to Street A’s roundabout), in accordance with the City’s applicable Standard Specifications and Details.

There are no sidewalks currently in the vicinity of the project site, including on Busch Road. The traffic signal at the Busch Road and Ironwood Drive intersection includes crosswalks with pedestrian signal heads to facilitate pedestrian crossings, and sidewalks extend on Busch Road west of the intersection and on Ironwood Drive.

As discussed above, the Villages at the Quarry Project, or the proposed project if the Villages at the Quarry Project does not proceed to implement these improvements, would be required to construct off-site sidewalk improvements to Busch Road that would connect to existing sidewalks on Busch Road and Ironwood Drive.

2.3.6 - Design and Landscaping
Building Design and Height
Building heights would range from approximately 19.5 (single-story homes) to a maximum of 30 feet (2-story homes). Buildings would be set back from the proposed streets in accordance with the development standards set forth in Table 1.

In conformance with the proposed development standards, the project applicant proposes three housing unit types for the 50x70 Lot Development Standards, three housing unit types for the 50x80 Lot Development Standards, and two housing unit types for the 59.5x97 Lot Development Standards.

Details about the proposed housing are provided in Table 3.

Table 3: Housing Details
Housing Unit Type
Lots 1–102
50x70 Lot Standard
(approximate)
Lots 103–130 Lots
162–178
50x80 Lot Standard
(approximate)
Lots 131–161

59.5x97 Lot
Standard
(approximate)
Home Size (square feet) 2,541 to 2,648 2,991 to 3,398 2,642 to 2,660 Height 2 story 2 story 1 story
Attached Garage 2 car 2 car 2 car
Bedrooms 4 to 5 4 to 5 3 to 4
Bathrooms 3 to 3.5 3 to 4.5 2.5 to 3.5

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
34 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Housing Unit Type
Lots 1–102
50x70 Lot Standard
(approximate)
Lots 103–130 Lots
162–178
50x80 Lot Standard
(approximate)
Lots 131–161

59.5x97 Lot
Standard
(approximate)
Floor Area Ratio (FAR) 0.73 to 0.76 0.75 to 0.85 0.46
Source: KTGY. 2026. Schematic Design. February 6.

The exterior of the homes would be constructed with Farmhouse, Craftsman, and Modern Ranch and Prairie designs. To achieve architectural variety throughout the project site, duplicate styles would not be adjacent to each other. Design features would include slate and metal roofing, lap siding with adjacent trim boards, gable siding with horizontal trim, batten board sidings with adjacent trim boards, fascia, eaves, knee braces, corbels, shutters, and painted garage and entry doors. The exterior color palette depends upon the architectural design type, with palettes ranging between whites, grays and browns, blues, grays, yellows, stone and terracotta, and brighter greens, blues, and reds.

Landscaping
The project applicant proposes to construct a private, approximately 0.7-acre park that would be owned and maintained by the Homeowner’s Association (HOA) and approximately 0.5 mile of multiuse trails, as shown on Exhibit 7a and Exhibit 7b. A Public Access Easement would be provided to allow the public to use the park amenities.

The park on the project site would be landscaped with various drought-resistant grasses and shrubs of non-native and native origin, which are consistent with the Model Water Efficient Landscape Ordinance (MWELO). Paving across the park, streets, and other open space landscaped areas would consist of concrete and decomposed granite, with accent paving being used to demarcate crossings.

Ornamental fencing would be used to separate residences and public spaces. Other amenities, such as benches, tables, and chairs, would be installed in the park. All project landscaping would meet applicable standards and other requirements, including the City’s Standard Specifications and Details.

Internal streets on the project site would be lined with street trees, with the exception of the eastern side of Street C which would have a monolithic sidewalk, and the park would contain trees as well.

Trees would also be installed along the north side of the project site boundary along Lake I, along the front yards of the proposed homes, along the Busch Road frontage, and within the Busch Road median. Proposed project trees would include the crape myrtle, Chinese pistache, native oak, Indian hawthorn, little leaf linden, and Chinese elm species.

2.3.7 - Proposed Utilities
Exhibit 8a and 8b show the proposed on-site utilities for the proposed project, and Exhibit 9a, 9b, 9c, and 9d show the proposed on- and off-site utility improvements for the proposed project.

F C S 21480036 • 03/2026 | 7a_landscape_plan.cdr
Landscape Plan
Exhibit 7a
Source: Gates & Associates, Inc., February, 2026.

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F C S 21480036 • 03/2026 | 7b_park_plan.cdr
Park Plan
Exhibit 7b
Source: Gates & Associates, Inc., February, 2026.

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F C S 21480036 • 03/2026 | 8a_utility_plan_nportion.cdr Utility Plan (Northern Portion)
Exhibit 8a
Source: CBG Civil Engineers, January, 2026.

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F C S 21480036 • 03/2026 | 8b_utility_plan_nsportion.cdr Utility Plan (Southern Portion)
Exhibit 8b
Source: CBG Civil Engineers, January, 2026.

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F C S 21480036 • 03/2026 | 9a_overall_off-site_utility_plan.cdr Overall Off-site Utility Plan
Exhibit 9a
Source: CBG Civil Engineers, January, 2026.

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F C S 21480036 • 03/2026 | 9b_off-site_utility_plan_el_charro.cdr Off-site Utility Plan - East Toward El Charro
Exhibit 9b
Source: CBG Civil Engineers, January, 2026.

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F C S 21480036 • 03/2026 | 9c_off-site_utility_plan_mohr_ave.cdr Off-site Utility Plan - Mohr Avenue Connection
Exhibit 9c
Source: CBG Civil Engineers, January, 2026.

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F C S 21480036 • 05/2026 | 9d_potential_bio_loc.cdr
Potential Bioretention Locations
Exhibit 9d
Source: CBG Civil Engineers, May, 2026.

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ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
FCS 51
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Domestic Water
Water service for the proposed project would be provided by the City via connection to an existing 12- inch diameter water line along Busch Road and an off-site existing 16-inch diameter water line on Mohr Avenue. To access the existing water line in Mohr Avenue, as shown in Exhibit 9c, the proposed project would construct a new 12-inch diameter water line extending from the northwest corner of the project site, following the existing utility road, to Mohr Avenue.

Stormwater Drainage
Two options are being studied for handling the proposed project’s stormwater drainage: one involving conveyance to the City’s existing storm drain system (City Stormwater Option) and the second option involving the stormwater discharging into Zone 7’s facilities (Zone 7 Stormwater Option). The Zone 7 Stormwater Option would be subject to Zone 7 approval. Both options are described further below.19 City Stormwater Option
Stormwater generated by the proposed project would be collected via 6-inch storm gutters along the proposed internal streets and conveyed through an on-site network of 18-inch underground storm drain pipes to the City’s existing storm drain system. Under normal operating conditions, stormwater would be conveyed via an approximately 45-inch diameter pipe to a proposed primary bioretention area located approximately 0.45 mile east of the project site, adjacent to El Charro Road (Exhibits 9b and 9d). The applicant would be responsible for the maintenance and ongoing operations of this facility in compliance with City standards as conditioned through the Conditions of Approval or the PADA.

The primary bioretention area would include a treatment area of approximately 40,000 square feet.

The bioretention area would contain two layers: an approximately 18-inch layer of bioretention soil mix and an approximately 12-inch layer of Class II permeable rock. After being treated, the stormwater would be pumped out of the bioretention basin into a storm drain force main that would be located in El Charro Road and would flow south to Busch Road where it would flow west and connect to an existing City storm drainpipe in Busch Road (Exhibit 9a).

In larger storm events, stormwater would be temporarily stored in a detention basin just northeast of the bioretention area. The detention basin has been sized to accommodate back-to-back 100-year storm events in accordance with all applicable standards and requirements, allowing stormwater discharge to be metered to ensure that the capacity of the City’s storm drain system is not exceeded.

In addition to the normal stormwater system, the proposed project is also designed with overland release, which includes a path for surface floodwater to flow through the development in a manner that protects structures should the underground storm drain system be blocked or overwhelmed. 19 The proposed project would implement one of the two stormwater options, and thus, both stormwater options are being considered in this Addendum for purposes of a conservative analysis.

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
52 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx In order to protect structures from flooding at the project site, the overland release would direct most of the surface flow south to Busch Road, but a portion of the project site starting from approximately Lot 118 and proceeding north has been designed to be captured in a secondary overland release inlet which would convey the stormwater into an approximately 24-inch diameter pipe that would connect with an existing storm drain line in Mohr Avenue.

All stormwater infrastructure improvements would be designed and constructed in accordance with all applicable requirements set forth in the City of Pleasanton’s Standard Specifications and Details and implemented through the City’s COAs for the proposed project.

Zone 7 Stormwater Option
The proposed project includes another stormwater management configuration that would be implemented only if approved by the Board of Directors of Zone 7. This option would allow treated stormwater from the proposed bioretention areas to discharge to lands located east of El Charro Road, from which flows would ultimately drain toward Cope Lake.

Under this configuration, the proposed project would continue to treat stormwater through the proposed bioretention facilities (as described above) in compliance with applicable water quality standards. However, rather than conveying treated stormwater via a detention basin, pumps, and a storm drain force main, the treated flows would be discharged from the bioretention areas and allowed to drain naturally toward Cope Lake, consistent with the historic drainage pattern that has conveyed runoff from these parcels toward Cope Lake. As a result, the detention basin, pump facilities, and storm drain force main described above would not be constructed.

While the proposed project has been designed to avoid direct stormwater discharge to Cope Lake via the City Stormwater Option, the project entitlements would also incorporate the ability of the applicant to pursue the Zone 7 Stormwater Option instead, subject to Zone 7 approval. This option is included to provide flexibility should Zone 7 determine that discharge of treated stormwater to the land east of El Charro Road is acceptable. The Zone 7 Stormwater Option is consistent with the stormwater design evaluated under the County-approved Tentative Map and considered in the Prior FEIR and, thus, would not introduce new or substantially more severe environmental impacts compared to those analyzed in the Prior FEIR, as detailed more fully in this Addendum.

Implementation of this option would remain subject to all applicable regulatory approvals and would be required to comply with City and Zone 7 stormwater requirements, including water quality treatment, erosion control, and post-construction stormwater management standards.

Sanitary Sewer
Sanitary sewer services for the proposed project would be provided by the City, via a connection to an existing off-site 8-inch diameter sewer line in Mohr Avenue, northwest of the project site. The proposed sewer connection would require that an access easement from Zone 7 Water Agency, the property owner, be granted to the City. Similar to the proposed water and stormwater lines, the proposed project would construct a new 8-inch diameter sewer line extending from the northwest

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
FCS 53
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx corner of the project site, following the existing utility road, to Mohr Avenue to access the existing sewer line. Sanitary sewer service throughout the project site would be provided in 8-inch diameter sanitary sewer lines under the proposed internal streets.

Solid Waste, Organics, and Recycling Collection
The proposed project would be served by the PGS, which would provide weekly solid waste, organics, and recycling services.

Power and Telecommunications
Electric and gas services for the proposed project would be provided by Pacific Gas and Electric Company (PG&E). Ava Community Energy (Ava) would provide electricity generation services, while PG&E would provide transmission and delivery services for electricity to the project site. The proposed project would be served by existing utility lines on the north side of the project site and along Busch Road. Both power lines are currently located above ground but would be moved underground as part of the proposed project. AT&T would provide phone services, and Comcast would provide phone and high-speed internet services.

2.3.8 - Phasing and Construction
For the purposes of this analysis, construction of the proposed project components and off-site improvements is anticipated to occur over a period of approximately 4 years, starting in June 2026 and ending in September 2030.
20 All site preparation and grading for the entire project site could also be completed at this time. Grading and site preparation would include the import of approximately 150,000 cubic yards fill; in connection therewith, as previously described and considered in the Prior FEIR, the project applicant intends to commence with surcharging of the project site under an approved County permit as soon as June 2026, via the shifting of dirt from an on-site borrow pit to another on-site location where it would be loaded upon the imported fill to accelerate soil consolidation and improve the soil’s bearing capacity. The amount of import would be slightly less than contemplated in the Prior FEIR because the proposed project would not raise the elevation of the building pads adjacent to the existing Villages at Ironwood residential community to the same extent as the County Project, thereby reducing the need for imported fill relative to what was previously assumed. The preliminary construction schedule is provided in Table 4. 20 If construction begins at a date later than the timeframe assumed for this analysis, the conclusions herein would continue to be conservative. This is because regulatory requirements applicable to construction equipment—such as off-road diesel engine standards, on-road vehicle emission standards, and other California Air Resources Board (ARB) or local air district rules—become more stringent over time. As a result, future construction equipment fleets generally emit fewer criteria air pollutants and greenhouse gases than those assumed in this evaluation. Therefore, delaying construction would not increase environmental impacts and would, in most cases, reduce them relative to the assumptions used in this analysis.

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Horizontal Construction (In Tract and Off-site)
Surcharge June 2026-April 2027
Mass Grading May 2027-July 2027
Underground Utilities August–December 2027
Topside Improvements January–April 2028
Off-site Street Improvements (Busch Road etc.) August–December 2027 Horizontal Construction Complete May–June 2028
Vertical Construction
Model Home Starts February 2028
First Production Phase Start March 2028
Second Production Phase Start June 2028
Third Production Phase Start September 2028
Fourth Production Phase Start January 2029
Fifth Production Phase Start May 2029
Sixth Production Phase Start September 2029
Vertical Construction Complete September 2030
Source: 330 Land Company. 2026.

2.4 - Required Actions and Approvals
The proposed project would require the following discretionary and ministerial permits and approvals.

2.4.1 - Discretionary Actions
Discretionary approvals and permits are required by the City for implementation of the proposed project. The proposed project would require the following discretionary approvals and actions, including:
• General Plan Amendment
• Pre-zoning and PUD Development Plan
• Approval of a PADA
• Approval of Vesting Tentative Subdivision Map

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• Approval of Affordable Housing Agreement
• Approval of Resolution to Initiate Annexation Proceedings • Approval of easements for storm drain, sanitary sewer, water, utilities, and restricted public access
• Approval to form project CFD(s)

2.4.2 - Ministerial Actions
Subsequent ministerial actions would be required for the implementation of the proposed project. including, but not limited to, issuance of grading and building permits and certificates of occupancy.

2.5 - Responsible and Trustee Agencies
A number of other agencies, in addition to the City, will serve as Responsible and/or Trustee Agencies, pursuant to CEQA Guidelines Section 15381 and Section 15386, respectively. This Addendum will provide environmental information to these agencies and other public agencies, which may be required to grant approvals for aspects of the proposed project that fall within the agencies' respective jurisdictional authority, as part of project implementation. These agencies may include, but are not limited to, the following:
• California Department of Fish and Wildlife (CDFW)
• California State Water Resources Control Board (State Water Board) • Alameda County Local Agency Formation Commission (LAFCo) • Alameda County Environmental Health Department
• Alameda County Public Works Agency
• Zone 7 Water Agency (Zone 7)
• Dublin San Ramon Services District (DSRSD)

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The purpose of the checklist is to evaluate the categories in terms of any changed condition (e.g., changed circumstances, project changes, or new information of substantial importance) that may result in a changed environmental result (e.g., a new significant impact or substantial increase in the severity of a previously identified significant effect) such that the prior certified environmental document would require major revisions to ensure it is adequate for purposes of the modified project (CEQA Guidelines § 15162).

The questions posed in the checklist come from Appendix G of the CEQA Guidelines. A “no” answer does not necessarily mean that there are no potential impacts relative to the environmental category, but rather that there is no change in the impact conclusion since it was analyzed and addressed in the Prior FEIR. In other words, these environmental categories might be answered with a “no” in the checklist because it has been determined that the proposed project does not introduce changes that would result in a modification to the impact conclusion of the previously approved CEQA document.

This Addendum addresses the conclusions of the Prior FEIR to confirm whether additional environmental review would be triggered for the proposed project pursuant to CEQA Guidelines Sections 15162 and 15164.

3.1 - Explanation of Checklist Evaluation Categories
(1) Conclusion in Prior FEIR
This column summarizes the conclusion of the Prior FEIR relative to the environmental issue listed under each topic. Because the County Project and Alternative 2 are substantially similar in design, scope, and environmental considerations, the summary of the Prior FEIR addresses them together for purposes of analysis in this document. Unless specifically noted, descriptions of the Prior FEIR conclusions made with respect to the County Project are also generally applicable to Alternative 2. Where the Prior FEIR reached different conclusions regarding specific environmental topics or impact levels between the County Project and Alternative 2, those distinctions are identified and discussed to ensure clarity and accuracy. (2) Do the Proposed Changes Involve New or More Severe
Impacts?
The second column asks whether the proposed project, as compared to the County Project, would involve significant new impacts or a substantial increase in severity of previously identified impacts in the Prior FEIR. Pursuant to CEQA Guidelines Section 15162 (a)(1), this column indicates whether the changes represented by the proposed project would result in new significant environmental impacts not previously identified or mitigated by the Prior FEIR

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(4) New Information Requiring New Analysis or Verification? Pursuant to CEQA Guidelines Section 15162 (a)(3)(A-D), the fourth column indicates whether there is 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 Prior FEIR was certified, such that any of the following would occur:
(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;
(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.

If the additional analysis completed as part of this Addendum were to find that the impact conclusions of the Prior FEIR remain the same such that (1) no new significant impacts are identified, (2) identified impacts are not found to be substantially more severe than previously evaluated, and (3) additional mitigation is not necessary, then the question would be answered “no” and no additional supplemental or subsequent EIR would be required. (5) Mitigation Measures
Pursuant to CEQA Guidelines Section 15162 (a)(3), the final column indicates whether the Prior FEIR provides mitigation measures to address effects in the related impact category.

Any previously adopted mitigation measures will be identified. The response will also address proposed revisions to previously adopted mitigation measures (if any). These mitigation

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3.2 - Discussion and Mitigation Sections
The following sections include three components for each environmental checklist question:
discussion of each checklist question and any potential impacts to the environment, any mitigation measures required, and a conclusion of the analysis. Each component is further described below:
(1) Discussion
A discussion of the elements of the checklist is provided under each environmental category in order to clarify the answers. The discussion provides information about the particular environmental issue, how the proposed project relates to the issue, and the status of any mitigation that may be required.
(2) Mitigation Measures
Applicable mitigation measures from the Prior FEIR that apply to the proposed project are listed under each environmental category.
(3) Conclusions
A discussion of the conclusion relating to the analysis is contained in each section.

3.3 - Environmental Topics
The following topics are evaluated in accordance with CEQA requirements:
• Aesthetics, Light, and Glare
• Agriculture and Forestry Resources
• Air Quality
• Biological Resources
• Cultural Resources and Tribal Cultural
Resources
• Energy
• Geology and Soils
• Greenhouse Gas Emissions
• Hazards and Hazardous Materials
• Hydrology and Water Quality
• Land Use and Planning
• Mineral Resources
• Noise
• Population and Housing
• Public Services
• Recreation
• Transportation
• Utilities and Service Systems
• Wildfire

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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
I. Aesthetics, Light, and Glare
Except as provided in Public Resources Code Section 21099, would the project:
a) Have a substantial
adverse effect on a
scenic vista?
Less than
significant
impact
No No No NA
b) Substantially
damage scenic
resources,
including, but not
limited to, trees,
rock outcroppings,
and historic
buildings within a
State Scenic
Highway?
No impact No No No NA
c) In non-urbanized
areas, substantially
degrade the
existing visual
character or quality
of public views of
the site and its
surroundings?
(Public views are
those that are
experienced from
publicly accessible
vantage point). If
the project is in an
urbanized area,
would the project
conflict with
applicable zoning
and other
regulations
Less than
significant
impact
No No No NA

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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
governing scenic
quality?
d) Create a new
source of
substantial light or
glare which would
adversely affect day
or nighttime views
in the area?
Less than
significant
impact
No No No NA
Discussion
a) Scenic Vista
Would the project: Have a substantial adverse effect on a scenic vista? Prior FEIR Conclusions
The Prior FEIR concluded that the project site does not contain any designated scenic vistas as defined by the Alameda County General Plan or the ECAP. The nearest scenic resource, Lake I of the Zone 7 Chain of Lakes, is adjacent to the northern boundary of the project site; however, public access is restricted, and views are limited except from neighboring properties. Given the County Project’s maximum height of approximately 30 feet and its setback of roughly 295 feet from Lake I, the Prior FEIR found that it would not obstruct views of the lake from adjacent development.

Additionally, the nearest ridgelines (Happy Valley ridgelines) lie approximately 2.44 miles south of the project site, while designated scenic roadways such as I-680 and SR-84 are over a mile away and visually disconnected due to intervening development. Temporary visibility of construction equipment was also determined to have no substantial impact on scenic views.

The project site itself lacks prominent visual features such as scenic ridges, hillsides, or rock outcroppings. Planned grading and landscaping, including a retaining wall, would maintain the area’s visual character. Based on these findings, the Prior FEIR concluded that neither the County Project nor Alternative 2, Annexation into the City of Pleasanton, would result in a substantial adverse effect on scenic vistas, and therefore, impacts would be less than significant. (Draft EIR, pp. 3.1-14, 6-11).

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The proposed project would occur in the same location as the County Project. There are no scenic resources, as defined by the City’s General Plan, located on the project site. Scenic resources identified by the City’s General Plan include the hillsides, wildlands, and open space areas adjacent to the City’s western, southern, and eastern borders, which are located between 2 and 4 miles from the project site. Views of these areas are visible from the project site intermittently and are partially obstructed by existing development and vegetation. The project site is bounded to the north by Lake I of the Zone 7 Chain of Lakes and to the east by vacant land. As such, there are no sensitive viewpoints located adjacent to the project site from which views of the scenic hillsides, wildlands, and open space areas adjacent to the City’s western, southern, and eastern borders would be obstructed.

Additionally, the maximum height of the proposed project would be 30 feet, and the proposed project would comply with the setback requirements of the PUD-MDR zone. As such, views of these areas from neighboring properties would not be obstructed.

Construction equipment would be present on the project site intermittently throughout the construction period and could be visible from public viewpoints located within nearby scenic resources, such as the hillsides, wildlands, and open space areas adjacent to the City’s western, southern, and eastern borders, although since its presence would be temporary, it would not result in a substantial impact on public views from any scenic resources. The project site, which is relatively flat in elevation, vacant, and graded, does not contain any scenic ridges, hillsides, rock outcroppings, or other designated scenic resources, which would be damaged or affected by the proposed development. As such, consistent with the conclusions in the Prior FEIR, implementation of the proposed project would not result in a substantial adverse effect on a scenic vista. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required. b) State Scenic Highways
Would the project: Substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a State Scenic Highway?
Prior FEIR Conclusions
As stated above, the Prior FEIR found that the project site does not contain any officially designated scenic resources as defined by the Alameda County General Plan and ECAP, including significant trees, rock outcroppings, or historic buildings within or adjacent to a State Scenic Highway. The project site is relatively flat in elevation and is vacant and graded. The nearest designated State Scenic Highway is I-680, approximately 3 miles away, while the nearest highway eligible for State Scenic Highway designation is I-580, approximately 1.4 miles away; neither of which are visible from the project site due to distance and intervening development. The Prior FEIR determined that the County Project would not result in substantial damage to scenic resources in a State Scenic Highway.

Therefore, the Prior FEIR concluded that impacts would be less than significant for the County Project and under Alternative 2, Annexation to City of Pleasanton. (Draft EIR, pp. 3.1-15, 6-11).

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There are no officially designated State Scenic Highways or City scenic roadways in or adjacent to the project site. As discussed in the Prior FEIR, the nearest officially designated State Scenic Highway is I-680, located approximately 3 miles west of the project site. The nearest highway eligible for State Scenic Highway designation is I-580, located approximately 1.4 miles north of the project site. Given the distance of the project site to these resources and the intervening development, the proposed project would not be visible from either highway. Given the absence of scenic highways proximate to the project site, the lack of designated scenic resources (i.e., ridgelines, hillsides, rock outcroppings) on the project site, and the presence of intervening development between the project site and the nearest scenic highways, the proposed project would not substantially damage scenic resources in a State Scenic Highway. Thus, consistent with the Prior FEIR’s conclusions, there would be less than significant impacts in this regard. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required. c) Visual Character
Would the project: In non-urbanized areas, substantially degrade the existing visual character or quality of public views of the site and its surroundings? (Public views are those that are experienced from publicly accessible vantage point). If the project is in an urbanized area, would the project conflict with applicable zoning and other regulations governing scenic quality?
Prior FEIR Conclusions
The Prior FEIR determined that the project site is currently vacant and surrounded by residential, industrial, and public facility uses. Because the County does not have quantitative thresholds for the evaluation of aesthetics, the Prior FEIR addressed both consistency with zoning and other regulations governing scenic quality, as well as changes to the existing visual character and quality. The County Project would introduce new residential development consistent with the ECAP’s MDR designation.

The County Project would include single-family homes, junior ADUs, internal streets, and landscaped open space. The Prior FEIR found that the design, materials, and color palette of the homes would be compatible with surrounding development. The County Project would also include a retaining wall and an approximately 8-foot “good neighbor” fence along the western boundary to address grade differences and provide privacy. While the County Project would alter the visual character of the project site, these changes would be consistent with the planned land use and would not degrade the visual quality of the area. Therefore, the Prior FEIR concluded that impacts would be less than significant with respect to the County Project and Alternative 2. (Draft EIR, pp. 3.1-17, 6-11).

Proposed Project Analysis and Conclusion
Although the project site is located in an urbanized area, for which this checklist question limits the analysis to conflict with applicable zoning and other regulations governing scenic quality, this analysis of operational impacts addresses both consistency with zoning and other regulations governing

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Construction-related impacts related to degradation of existing visual character, quality, or natural topography of the project site and area would be temporary and less than significant. The proposed project includes annexation of the approximately 30-acre project site into the City. The proposed project would include a General Plan Amendment to redesignate the project site from the County MDR land use to the City’s MDR land use. According to the City’s General Plan, MDR allows for 2 to 8 du/acre. The proposed project would have a density of 6.3 du/acre, consistent with the MDR designation.

The proposed project would also include pre-zoning of the project site to PUD-MDR to be consistent with the proposed project density and General Plan land use designation. The purpose of the PUD district, as stated in the Municipal Code, is to allow for tailored zoning, which helps to ensure that the goals and objectives of the City's General Plan are promoted without discouraging innovation by application of restrictive developmental standards. As the proposed project would be subject to the design/development standards of the MDR designation and the related PUD development plan, the proposed project would be consistent (and would not conflict with) applicable zoning and regulations governing scenic quality.

Additionally, the City’s General Plan Community Character Element establishes a comprehensive framework to preserve and enhance the City’s visual identity and sense of place. Goal 1 (Preserve and enhance Pleasanton’s community character) provides overarching direction to maintain visual harmony through high-quality design, while Policy 17 (Maintain, enhance, and protect the quality, character, and distinctiveness of residential neighborhoods) requires new development to respect established patterns of scale, massing, orientation, setbacks, and landscaping. The proposed project would adhere to these goals and policies through residential building forms, site layout, and streetscape design that reflect surrounding neighborhood patterns and maintain compatible visual transitions. Consistent with Policy 15, which encourages attractive architectural and site-design features, the proposed project would incorporate articulated pedestrian-oriented frontage, and coordinated landscaping. Streetscape improvements and on-site frontage design would further support Goal 5 and Policy 9 by incorporating street trees, landscaped setbacks, and screening elements that soften the visual presence of development and enhance the public realm. In addition, the proposed project’s design would be consistent with Goal 4 and Policy 7, which emphasize high-quality design near City entryways, by providing a cohesive architectural vocabulary and landscaped edges that reinforce the City’s visual identity, while maintaining appropriate visual separation in accordance with Policy 8 where applicable. Adherence to these General Plan goals and policies support the proposed project’s integration with the existing visual character of the area and would not result in a substantial adverse change to the City’s visual quality or community character.

For informational purposes, it is also noted that the proposed project has been designed such that it would have visual characteristics compatible with adjoining residential development. In addition, the design of the proposed residences provides for a harmonious composition of mass, scale, color, and

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The proposed project also includes implementation of a landscaping plan that would adhere to all applicable requirements, including the planting of trees, shrubs, vines, and groundcover to replace trees proposed for removal, in accordance with Chapter 17.16, Tree Preservation, of the Municipal Code and Policy 2 of the General Plan’s Open Space and Conservation Element. 21 Furthermore, the
proposed project would include construction of an approximately 0.7-acre central park to provide visual character, recreational uses, and park space for both residents of the proposed project and the wider local community. Therefore, consistent with the conclusions in the Prior FEIR, impacts related to consistency with applicable scenic quality regulations and visual quality and character would be less than significant.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
d) Light or Glare
Would the project: Create a new source of substantial light or glare which would adversely affect day or nighttime views in the area?
Prior FEIR Conclusions
The Prior FEIR found that the County Project would introduce new sources of light and glare typical of residential development, including street lighting, exterior home lighting, and vehicle headlights. All exterior lighting would be designed, located, and shielded to confine direct rays of light to the project site, consistent with ECAP Policy 115 and the California Building Standards Code (CBC). Building materials would be similar to those used in surrounding residential areas and would not create substantial daytime glare, and windows would not produce excessive glare as residential glass typically has a low reflectivity rate. Based on the foregoing, the County Project would not introduce excessive nighttime lighting or glare that would adversely affect day or nighttime views in the area, including adjacent properties or public views. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.1-20, 6-11).

Proposed Project Analysis and Conclusion
The project site is currently undeveloped and does not contain existing sources of light and glare. The proposed project would result in slightly fewer overall residential units as compared to the County Project evaluated in the Prior FEIR (189 single-family homes and 48 junior ADUs with associated windows), as well as exterior lighting similar to, albeit slightly less than, the County Project. In addition, the proposed project incorporates refined grading plans that would reduce grade differences 21 City of Pleasanton. 2009. Pleasanton General Plan 2005–2025, Open Space and Conservation Element. July 21.

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The project site is surrounded by residential uses, industrial uses, public services and utilities facilities, and open space. The existing residential and industrial uses contribute to the existing daytime glare and nighttime lighting of the area. Exterior lighting would be located around and within the project site. Consistent with the Prior FEIR’s assessment, potential sources of light associated with the proposed project would consist of typical sources of lighting associated with residential development and from vehicles traveling to and from the project site. Lampposts would be evenly dispersed within the project site, with safety lighting as needed throughout the project site. All exterior lighting would be designed, located, and shielded to confine direct rays of light to the project site and would adhere to all applicable standards and requirements.

Furthermore, in accordance with Section 20.36.160 of the City Municipal Code, the proposed project would also comply with all applicable State regulations relating light and glare, including regulations in Title 24 of the California Code of Regulations Building Energy Efficiency Standards California Building Code (CCR Title 24), including Title 24, Part 6, and Section 132 of the Building Energy Efficiency Standards, which regulates lighting characteristics, such as maximum power and brightness, shielding, and sensor controls to turn lighting on and off. The proposed project would also include single-story homes along the western property line, compared to the 2-story homes evaluated in the Prior FEIR for the County Project, which would reduce impacts related to the proposed project’s effects on light availability in the backyards of adjacent homes. In addition, the proposed project’s grading would reduce relative elevation differences between the proposed project and adjacent homes, further reducing the potential for shadowing, light spill, and glare intrusion onto nearby residential properties. Glare resulting from the proposed residences’ windows would be minimal and would be partially obscured by landscaping, depending on the time of day and the location of the reflecting light source. Furthermore, residential glass typically has a low reflectivity rate. Glare may also occur from on-site vehicles; however, such glare would be transient, depending upon the time of day and location of the vehicle. Therefore, consistent with the conclusions in the Prior FEIR, lighting and glare impacts from the proposed project would be less than significant.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe impacts than those previously identified in the Prior FEIR. No additional analysis is required.

Zone 7 Stormwater Option
The Zone 7 Stormwater Option would not result in any new or more severe aesthetic impacts compared to those previously analyzed. Under this option, which was considered in the Prior FEIR, treated stormwater would be discharged from the proposed bioretention facilities and allowed to drain naturally toward Cope Lake, eliminating the need for the detention basin, pump facilities, and storm drain force main. Consistent with the analysis in the Prior FEIR, this option would not introduce new visible structures or substantially alter the visual character of the project site or the surrounding area, and it would reduce the amount of above-grade infrastructure. Accordingly, the Zone 7 Stormwater

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Mitigation Measures
None.

Conclusion
There is no new information of substantial importance, changes in the project, or changes in circumstances under which it will be undertaken, identifying new significant effects, nor is there a substantial increase in the severity of previously identified significant impacts related to aesthetics, light, and glare. The conclusions from the Prior FEIR remain unchanged when considering the implementation of the proposed project. No further environmental review is required.

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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
II. Agriculture and Forestry Resources
In determining whether impacts to agricultural resources are significant environmental effects, lead agencies may refer to the California Agricultural Land Evaluation and Site Assessment Model (1997) prepared by the California Dept. of Conservation as an optional model to use in assessing impacts on agriculture and farmland. In determining whether impacts to forest resources, including timberland, are significant environmental effects, lead agencies may refer to information compiled by the California Department of Forestry and Fire Protection regarding the State’s inventory of forest land, including the Forest and Range Assessment Project and the Forest Legacy Assessment project; and forest carbon measurement methodology provided in Forest Protocols adopted by the California Air Resources Board. Would the project:
a) Convert Prime
Farmland, Unique
Farmland, or
Farmland of
Statewide
Importance
(Farmland), as
shown on the maps
prepared pursuant
to the Farmland
Mapping and
Monitoring Program
of the California
Resources Agency,
to nonagricultural
use?
No impact No No No NA
b) Conflict with
existing zoning for
agricultural use, or
a Williamson Act
Contract?
No impact No No No NA
c) Conflict with
existing zoning for,
or cause rezoning
of, forest land (as
No impact No No No NA

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ADDENDUM
FCS 69
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
defined in Public
Resources Code
Section 12220(g)),
timberland (as
defined by Public
Resources Code
Section 4526), or
timberland zoned
Timberland
Production (as
defined by
Government Code
Section 51104(g))?
d) Result in the loss of
forest land or
conversion of forest
land to non-forest
use?
No impact No No No NA
e) Involve other
changes in the
existing
environment which,
due to their location
or nature, could
result in conversion
of Farmland, to
nonagricultural use
or conversion of
forest land to nonforest use?
No impact No No No NA

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ADDENDUM
70 FCS
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a-e) Conversion of Important Farmland; Agricultural Zoning and Williamson Act Contracts; Forest Zoning; Conversion of Forest Land; and Pressures to Convert Farmland or Forest Land
Would the project: a) Convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps
prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to nonagricultural use?
b) Conflict with existing zoning for agricultural use, or a Williamson Act Contract?
c) Conflict with existing zoning for forest land (as defined in Public Resources Code Section 12220(g)), timberland (as defined by Public Resources Code Section 4526), or timberland zoned Timberland Production (as defined by Government Code Section 51104(g))?
d) Result in the loss of forest land or conversion of forest land to non-forest use?
e) Involve other changes in the existing environment which, due to their location or nature, could result in conversion of Farmland, to nonagricultural use or conversion of forest land to non-forest use?
Prior FEIR Conclusions
The Prior FEIR determined that the project site is mapped as “Other Land” by the California Department of Conservation Farmland Mapping and Monitoring Program (FMMP), which is considered a nonagricultural soil classification. The Prior FEIR determined that the soil on the proposed project site is Class IIIs5, which is not suitable for a Prime or Unique Farmland designation.

Additionally, the project site is not under a Williamson Act Contract.

While the project site is zoned for Agriculture (A) under the County’s zoning ordinance, the County’s MDR General Plan land use designation supersedes the primary uses allowed by the zoning.

Therefore, the Prior FEIR determined that the County Project would be consistent with the applicable Alameda County General Plan regulations and would not conflict with the project site’s zoning. As such, construction and operation of the County Project would not result in the conversion of Prime Farmland, Unique Farmland, or Farmland of Statewide Importance to nonagricultural uses, or result in the loss or conversion of forestland to non-forest uses.

Neither the County Project nor Alternative 2 would conflict with any zoning for agricultural use or a Williamson Act Contract, or any zoning for forestland, timberland, or timberland zoned for Timberland Production. Finally, the Prior FEIR determined that the County Project would not involve other changes that could result in the conversion of Important Farmland to nonagricultural uses or convert

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ADDENDUM
FCS 71
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Proposed Project Analysis and Conclusion
The project site involves the same land evaluated in the Prior FEIR and, therefore, consistent with the determinations made in the Prior FEIR, the proposed project would have no impacts related to agriculture and forestry resources. The project site is not designated as Prime Farmland, Unique Farmland, or Farmland of Statewide Importance, and is not encumbered by a Williamson Act Contract or zoned for Timberland Production.

While the project site is currently zoned A by the County’s zoning ordinance, the project site would be rezoned to PUD-MDR as part of the proposed project. Therefore, the proposed project would not conflict with the project site’s agricultural zoning. Further, the proposed project site is mapped as “Other Land,” confirming that there would be no impact to land classified as Farmland or Forestland.

The project site has a nonagricultural soil classification and is not under a Williamson Act Contract.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

Zone 7 Stormwater Option
Consistent with the analysis in the Prior FEIR, the Zone 7 Stormwater Option would not result in any new or more severe agricultural impacts. It would not convert FMMP-designated farmland, conflict with agricultural zoning, or result in the loss or indirect conversion of agricultural land; therefore, impacts would remain less than significant and consistent with the Prior FEIR.

Mitigation Measures
None.

Conclusion
There is no new information of substantial importance, changes in the project, or changes in circumstances under which it will be undertaken, identifying new significant effects, nor is there a substantial increase in the severity of previously identified significant impacts related to agriculture and forestry resources. The conclusions from the Prior FEIR remain unchanged when considering the implementation of the proposed project. No further environmental review is required.

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ADDENDUM
72 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Environmental Issue
Area
Conclusion
in Prior
FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
III. Air Quality
Where available, the significance criteria established by the applicable air quality management district or air pollution control district may be relied upon to make the following determinations.

Would the project:
a) Conflict with or
obstruct
implementation of
the applicable air
quality plan?
Less than
significant
impact with
mitigation
incorporated
No No No MM AIR-1
b) Result in a
cumulatively
considerable net
increase of any
criteria pollutant for
which the project
region is
nonattainment
under an applicable
federal or State
ambient air quality
standard?
Less than
significant
impact with
mitigation
incorporated
No No No MM AIR-1
c) Expose sensitive
receptors to
substantial pollutant
concentrations?
Less than
significant
impact with
mitigation
incorporated
No No No MM AIR-3
d) Result in other
emissions (such as
those leading to
odors) adversely
affecting a
substantial number
of people?
Less than
significant
impact
No No No NA

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ADDENDUM
FCS 73
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a) Air Quality Plan Conflict
Would the project: Conflict with or obstruct implementation of the applicable air quality plan?
Prior FEIR Conclusions
The Prior FEIR determined that the project site is located within the San Francisco Bay Area Air Basin (SFBAAB), which is regulated by the Bay Area Air Quality Management District (Bay Area Air District).

The 2017 Clean Air Plan includes control measures aimed at reducing regional air pollutants and GHGs. Under the Bay Area Air District’s CEQA Air Quality Guidelines, a project’s consistency with the Clean Air Plan is evaluated in part by determining its consistency with the regional significance thresholds. Although the County Project’s construction emissions would be below these thresholds and therefore would not result in substantial new regional emissions not already accounted for in regional air quality planning, the Bay Area Air District also requires implementation of its recommended Best Management Practices (BMPs) for construction dust as a qualitative criterion for determining CEQA significance.

Importantly, the Bay Area Air District’s construction dust guidance is based not on the level of modeled emissions, but on whether the project incorporates the recommended BMPs. Because projects that do not implement dust-control BMPs are considered potentially significant regardless of calculated reductions, the Prior FEIR required implementation of Mitigation Measure (MM) AIR-122 to ensure consistency with Bay Area Air District guidance.

With MM AIR-1 incorporated, the County Project would implement the Bay Area Air District’s recommended BMPs and therefore would not conflict with the control measures in the 2017 Clean Air Plan. Alternative 2 would result in similar construction activities, and MM AIR-1 would also be required to ensure consistency with the guidance. Therefore, the Prior FEIR concluded that neither the County Project’s nor Alternative 2’s impacts would conflict with the applicable air quality plan, and impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.2-44, 6-11, 6-12).

Proposed Project Analysis and Conclusion
The Bay Area Air District is responsible for reducing emissions from area, stationary, and mobile sources in the SFBAAB to achieve National and California Ambient Air Quality Standards (AAQS).

The Bay Area Air District 2017 Clean Air Plan is a regional and multiagency effort to reduce air pollution in the Air Basin. A consistency determination with the 2017 Clean Air Plan plays an important role in local agency project review by linking local planning and individual projects to the 2017 Clean Air Plan. It fulfills the CEQA goal of informing decision-makers of the proposed project's environmental effects under consideration early enough to ensure that air quality concerns are fully 22 Note: MM AIR-1 includes minor modifications to update the abbreviation for the Bay Area Air Quality Management District, which has changed since the publication of the Prior FEIR. These edits reflect minor typographical corrections.

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ADDENDUM
74 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx addressed. It also provides the local agency with ongoing information as to whether they are contributing to the clean air goals in the 2017 Clean Air Plan.

The proposed project would result in the construction of 189 single-family houses, 48 junior ADU’s, and related improvements on approximately 30 acres. Demographics trends such as employment and population growth were estimated in the Association of Bay Area Government (ABAG) Plan Bay Area 2040 based on local general plan land use patterns, which the Bay Area Air District utilized in part to inform the emissions inventory and projections contained in the 2017 Clean Air Plan. Currently, the project site has a County land use designation of MDR, which serves as the land use basis for the Bay Area Air District’s emissions inventory and projections in the 2017 Clean Air Plan. The proposed project would be consistent with the Bay Area Air District’s projections. The 2017 Clean Air Plan also contains control measures required by the Bay Area Air District to reduce emissions for a wide range of stationary and mobile sources. As described above, the Prior FEIR determined that the County Project would be consistent with the applicable control measures in the 2017 Clean Air Plan, including those related to stationary source emissions, transportation, energy and climate, buildings, natural working lands, waste management, water, and GHG emissions after incorporation of MM AIR-1. The proposed project would be largely the same as the County Project, only with fewer proposed dwelling units and the elimination of a substantial amount of off-site utility improvements. As such, the proposed project would also be consistent with the applicable control measures with implementation of MM AIR-1, including those related to waste management, water control, and energy, if not to a greater extent.

Given the slightly reduced unit count and the elimination of substantial off-site utility improvements, the proposed project emissions would result in similar or fewer emissions than what were analyzed in the Prior FEIR, which were already below the Bay Area Air District’s significance thresholds.

Therefore, potential impacts would be considered less than significant, consistent with the analysis in the Prior FEIR. Regarding impacts related to construction fugitive dust, the Bay Area Air District requires that a project implement construction BMPs, which would ensure that impacts would be less than significant. Therefore, similar to the County Project and Alternative 2, MM AIR-1 would still be required to ensure implementation of construction BMPs recommended by the Bay Area Air District.

Because of reduced unit count and elimination of substantial off-site utility infrastructure, combined with adherence to applicable control measures in the 2017 Clean Air Plan and the implementation of MM AIR-1, the proposed project would not result in any new or more severe significant impacts related to conflicts with implementation of the 2017 Clean Air Plan beyond what was analyzed in the Previous FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

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ADDENDUM
FCS 75
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx b) Cumulative Criteria Pollutant Emissions Impacts
Would the project: Result in a cumulatively considerable net increase of any criteria pollutant for which the project region is nonattainment under an applicable federal or State ambient air quality standard? Prior FEIR Conclusions
The Prior FEIR found that the SFBAAB is in nonattainment for ozone (O3), particulate matter less than 2.5 microns in diameter (PM2.5), and particulate matter less than 10 microns in diameter (PM10).

The County Project would generate emissions during construction and operation, including criteria pollutants such as nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), and particulate matter. Emissions modeling was conducted using the California Emissions Estimator Model (CalEEMod) and assumed implementation of MM AIR-1, which includes dust control, equipment maintenance, and idling restrictions. With respect to construction-related impacts, the Prior FEIR determined that MM AIR-1 would be required to reduce construction-related criteria pollutant impacts to less than significant levels because the Bay Area Air District requires implementation of its BMPs for construction dust as a qualitative criterion for determining CEQA significance. Operational emissions were also evaluated and found to be below the Bay Area Air District thresholds, and therefore, mitigation was not triggered. Therefore, the Prior FEIR concluded, with respect to criteria air pollutants, that construction-related impacts would be less than significant with mitigation incorporated, and operational-related impacts would be less than significant. (Draft EIR, pp. 3.2-50, 6- 12, 6-13).

Proposed Project Analysis and Conclusion
This impact is related to the cumulative effect of a project’s regional criteria pollutant emissions. By its nature, air pollution is largely a cumulative impact resulting from emissions generated over a large geographic region. The nonattainment status of regional pollutants results from past and present development within the Air Basin, and this regional impact is a cumulative impact. Therefore, new development projects (such as the proposed project) within the Air Basin would contribute to this impact only on a cumulative basis. No single project would be sufficient in size, by itself, to result in nonattainment of regional air quality standards. Instead, a project’s emissions may be individually limited, but cumulatively considerable when evaluated in combination with past, present, and future development projects.

The HRA conducted in the Prior FEIR conservatively assumed that construction would occur seven days per week. A more realistic scenario involves a 5-day workweek while maintaining the same total number of construction days, thereby extending the overall schedule in calendar time.

Under Office of Environmental Health Hazard Assessment (OEHHA) guidance, chronic risk estimates (cancer risk and hazard quotients) are based on total cumulative exposure over time. Because the total number of construction days—and thus total emissions—would remain unchanged, chronic risk results are not expected to differ materially.

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ADDENDUM
76 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx However, limiting construction to five days per week introduces non-operational periods, reducing the frequency of short-term exposures. As such, the original 7-day assumption is conservative, and refining it improves realism without increasing long-term risk estimates.

With respect to significance thresholds established by the Bay Area Air District, construction-related emissions are typically evaluated on a daily basis (e.g., pounds per day). Under a 5-day schedule, daily emission rates during active construction would remain unchanged, and therefore maximum daily emissions—and associated threshold comparisons—would not be affected.

The proposed project would be substantially similar to the County Project, though with fewer proposed dwelling units. The proposed project would also reflect an elimination of a substantial amount of off-site utility improvements from the County Project, including the removal of the proposed water storage and booster pump facility, WWTP, recycled water storage, and agricultural irrigation fields. The County Project was found to result in operational and construction-related criteria air pollutants or ozone precursors below the Bay Area Air District’s thresholds of significance for all criteria pollutants. The proposed project is also substantially similar to Alternative 2, which, because it anticipated annexation to the City, did not consider a water storage and booster pump facility, WWTP, recycled water storage facility, and agricultural irrigation fields. Alternative 2 was also determined to result in a less than significant impact in this regard for both construction and operation. Therefore, given the reduced scope of the proposed project, it would result in fewer total emissions and would also result in operational and construction-related criteria air pollutants or ozone precursors below the Bay Area Air District’s thresholds of significance for all criteria pollutants.

The Bay Area Air District does not have a quantitative emissions threshold for determining potentially significant impacts related to construction fugitive dust. Instead, consistent with the approach taken in the Prior FEIR, this analysis identified a potentially significant impact related to construction fugitive dust given that the Bay Area Air District considers a project to result in a potentially significant impact if that project were not to implement construction BMPs to minimize the extent of fugitive dust emissions, such as soil erosion, sediment migration, roadway dust re-entrainment, and soil trackout, during project construction. For purposes of a conservative analysis, this assessment (consistent with the approach taken in the Prior FEIR) incorporated the implementation of construction BMPs into mitigation to minimize fugitive dust emissions. Therefore, MM AIR-1, discussed above, would still be required to ensure implementation of construction BMPs recommended by the Bay Area Air District, irrespective of the emissions reductions achieved by those BMPs. Consequently, consistent with the analysis in the Prior FEIR, given the reduced nature and scope of the proposed project, combined with the adherence to applicable control measures, other applicable laws and regulations, and the implementation of MM AIR-1, project construction emissions would be less than significant.

The proposed project would not result in any new or more severe significant impacts related to cumulative criteria pollutant emissions beyond what was analyzed in the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
FCS 77
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx c) Sensitive Receptors
Would the project: Expose sensitive receptors to substantial pollutant concentrations? Prior FEIR Conclusions
Sensitive receptors near the project site include residential neighborhoods directly adjacent to the west, less than 50 feet from the project site. The Prior FEIR evaluated potential exposure to toxic air contaminants (TACs), particularly diesel particulate matter (DPM) during construction. A constructionrelated Health Risk Assessment (HRA) was conducted, which determined that impacts could be potentially significant because cancer risk resulting from the construction of the County Project would exceed the Bay Area Air District’s project-level significance thresholds. As such, the County Project would be required to implement MM AIR-3, which includes the use of Tier 4 interim engines and preparation of a construction operations plan. These measures would reduce construction-related exposure to TACs for nearby sensitive receptors to a less than significant level. Construction and operational air emissions would be reduced under Alternative 2 because off-site utility improvements would not be built, resulting in a smaller total impact area and less disturbance. However, the same identified mitigation would still be required.

In terms of operational impacts, the Prior FEIR determined that the County Project would not be a significant source of TAC, DPM, or carbon monoxide (CO). Additionally, the First Production Phase (in the northwest part of the project site) was assumed to start in October 2025 and be completed in late May 2026, when the first group of occupants would be expected to move into the completed houses; the surrounding vertical construction would continue until late August 2027.

The Prior FEIR determined that the first group of occupants’ exposure to criteria pollutants would not exceed the Bay Area Air District health risk threshold from DPM generated during the subsequent 15 months of vertical construction; therefore, the DPM health risk impact for the first group of occupants would be less than significant, and operational impacts were also found to be less than significant.

Criteria pollutant emissions would remain below significance thresholds, and required mitigation for fugitive dust and construction health risks would still apply. (Draft EIR, pp. 6-12–6-13). Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.2-25, 6-12).

Proposed Project Analysis and Conclusion
The closest sensitive receptors to the project site include single-family residences located immediately to the west, less than 50 feet from the project site.

Unlike regional emissions, localized emissions are typically evaluated in terms of air concentration rather than mass, so they can be more readily correlated to potential health effects. As described in the Prior FEIR, the cancer risk resulting from the construction of the County Project would exceed the Bay Area Air District’s project-level significance thresholds. The proposed project would be substantially similar to the County Project, though with fewer proposed dwelling units, in addition to a substantial reduction in off-site improvements, including the removal of the proposed water storage and booster pump facility, WWTP, recycled water storage, and agricultural irrigation fields from the

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
78 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx County Project. As such, the proposed project would result in similar impacts to construction-related cancer risk, albeit slightly less given its reduced scope. Therefore, the proposed project would still be required to implement MM AIR-3 to reduce this impact to less than significant levels. MM AIR-3 requires all applicable construction equipment utilized in mass grading, paving, and building construction phases to be Tier 4 or Tier 4 Equivalent.

The Prior FEIR determined that construction of the County Project would not exceed the Bay Area Air District’s community health risk, DPM, or TAC emissions significance thresholds with implementation of MM AIR-3. This includes thresholds for the first group of residents, who would be present during a portion of the construction phase.23 In addition, the Prior FEIR determined that the operation of the County Project would not generate sufficient vehicle traffic during project operation to substantiate creating a CO hotspot, and thus, no significant operational impacts would occur. Because of the fact that the proposed project would be substantially similar to the County Project, only with less development, the proposed project’s operations would also not exceed the Bay Area Air District’s significance thresholds for community health risk, DPM, or TAC, or generate sufficient vehicle traffic during project operation to substantiate creating a CO hotspot.

With implementation of MM AIR-3 for construction-related impacts, the proposed project would not result in any new or more severe significant impacts related to exposure of sensitive receptors to substantial pollutant concentrations beyond what was analyzed in the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
e) Odors
Would the project: Result in other emissions (such as those leading to odors) adversely affecting a substantial number of people?
Prior FEIR Conclusions
Residential projects are not typically considered an operational source of odor; therefore, the Prior FEIR focused its analysis of potential odor impacts on the County Project’s construction activities and the proposed WWTP.

In terms of construction-related impacts, the Prior FEIR found that any construction-related odor emissions would be temporary and intermittent. Additionally, noxious odors would be confined to the immediate vicinity of the construction equipment. It was anticipated that by the time such emissions reach any sensitive receptor sites, they would be diluted to well below any air quality or odor concern level. Therefore, construction odor impacts would be less than significant. 23 The first production phase is expected to start in March 2028, with some residents moving into homes after the first homes are constructed (June 2028). Construction is expected to continue until September 2030.

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ADDENDUM
FCS 79
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Bay Area Air District Regulation 1, Rule 301 and Regulation 7 govern odorous emissions and public nuisance thresholds. Although the County Project’s WWTP could be a potential source of odors, the Prior FEIR determined that it would include odor control systems. The Bay Area Air District’s odor screening thresholds were applied, and the County Project was found to be outside the screeninglevel distances for odor-generating facilities. The Prior FEIR determined that the County Project was not expected to generate odors that would affect a substantial number of people, and no mitigation was deemed necessary. Any potential odor impacts would be further reduced under Alternative 2 because the WWTP and related facilities would not be built. (Draft EIR, pp. 6-12–6-13). Therefore, the Prior FEIR concluded that construction- and operation-related impacts would be less than significant. (Draft EIR, pp. 3.2-56, 6-12, 6-13).

Proposed Project Analysis and Conclusion
Consistent with the analysis in the Prior FEIR, during construction activities, construction equipment exhaust and application of asphalt and architectural coatings would temporarily generate odors. Any construction-related odor emissions would be temporary and intermittent. Additionally, any such noxious odors would be confined to the immediate vicinity of the construction equipment. It is anticipated that by the time such emissions reach any sensitive receptor sites, they would be diluted to well below any air quality or odor concern level. Therefore, consistent with the Prior FEIR’s impact conclusions, construction odor impacts would be less than significant.

Land uses typically associated with objectionable odors include WWTPs, compost facilities, landfills, solid waste transfer stations, fiberglass manufacturing facilities, paint/coating operations (e.g., auto body shops), dairy farms, petroleum refineries, asphalt batch plants, chemical manufacturing, and food manufacturing facilities, as shown in the 2022 Bay Area Air District CEQA Guidelines. The proposed project would involve the development of residences whose operations could lead to typical odors from associated laundry cleaning, vehicle exhaust, outdoor cooking, and waste disposal.

However, such odors generated by project operation would be small in quantity and duration and would not pose an objectionable odor impact to future and existing receptors. The Prior FEIR identified the WWTP included under the County Project as an additional potential odor source, although it confirmed that this would not result in a significant impact. The Prior FEIR also evaluated Alternative 2, which would not include the off-site utility improvements. Similar to Alternative 2, the proposed project would not include the WWTP, removing it as a potential odor source.

The proposed project is located approximately 160 feet northwest of Pleasanton Garbage Services Inc., which is a transfer station. CEQA does not require analysis of the environment’s impact on a proposed project (i.e., whether the existing transfer station would subject the new residents to odor or other effects). However, public records from the Bay Area Air District indicate that no confirmed odor complaints have been filed against the facility in the past five years, suggesting a low likelihood of nuisance-level emissions. Additionally, meteorological data from the nearest Bay Area Air District monitoring station in Livermore shows that prevailing winds in the area typically blow from west to east. Given that the project site is located northwest of the transfer station, prevailing wind patterns would generally carry odors away from the proposed development.

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ADDENDUM
80 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Additionally, the Prior FEIR identified Vulcan Materials Company (501 El Charro Road, Pleasanton, 94588), located approximately 1.5 miles east of the project site, as a potential odor producer. Public records retrieved from the Bay Area Air District show that one odor complaint was made in August 2025, and the Bay Area Air District reporting inspector subsequently informed Vulcan Materials Company of this complaint. However, an updated public records request conducted in April 2026 (the latest available at the time of writing) indicates that no additional odor complaints had been filed for Vulcan Materials Company since then. Based on the odor guidelines by the Bay Area Air District, odor impacts would be significant if more than five confirmed odor complaints are received for a facility or location per year, averaged over the past three years. Therefore, Vulcan Materials Company currently does not present a significant odor impact to nearby sensitive receptors. Should Vulcan Materials Company cause any nuisance for future residents, Vulcan Materials Company would be required to comply with the Bay Area Air District Regulation 1 Rule 301 (odorous emissions) and implement applicable control measures to reduce the odor impacts. Based on the absence of documented complaints and the regional wind conditions, substantial odor impacts on future residents are not anticipated, and impacts would be less than significant.

In summary, consistent with the Prior FEIR’s conclusions, construction and operation of the proposed project would not result in emissions adversely affecting a substantial number of people; impacts would be less than significant.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

Zone 7 Stormwater Option
The Zone 7 Stormwater Option would not result in any new or more severe air quality impacts since it was previously considered in the Prior FEIR. The configuration would eliminate the need for construction and operation of the detention basin, pump facilities, and storm drain force main, thereby incrementally reducing construction-related equipment use and associated emissions; however, all mitigation measures would remain applicable to the proposed project. Consistent with the evaluation in the Prior FEIR, operation of the Zone 7 Stormwater Option would not generate new stationary or mobile sources of air emissions. Accordingly, air quality impacts would remain less than significant and consistent with the conclusions of the Prior FEIR.

Mitigation Measures
MM AIR-1 Implement Bay Area Air District Best Management Practices to Control Dust During Construction
The following dust control measures, as recommended by the Bay Area Air Quality Management District (Bay Area Air District), shall be included in the design of the proposed project and implemented during construction:

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ADDENDUM
FCS 81
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx • All exposed nonpaved surfaces (e.g., parking areas, staging areas, soil piles, graded areas, and access roads) shall be watered at least two times per day and/or non-toxic soil stabilizers shall be applied to exposed nonpaved surfaces. • All haul trucks transporting soil, sand, or other loose material off-site shall be covered and/or shall maintain at least 2 feet of freeboard. • All visible mud or dirt tracked out onto adjacent public roads shall be removed using wet power vacuum street sweepers at least once per day. The use of dry power sweeping is prohibited.
• All vehicle speeds on unpaved roads shall be limited to 15 miles per hour. • All roadways, driveways, and sidewalks to be paved shall be completed as soon as possible. Building pads shall be laid as soon as possible after grading unless seeding or soil binders are used.
• Idling times shall be minimized either by shutting equipment off when not in use or reducing the maximum idling time to 5 minutes, as required by the California Airborne Toxics Control Measure (ATCM) Title 13, Section 2485 of California Code of Regulations. Clear signage regarding idling restrictions shall be provided for construction workers at all access points.
• All construction equipment shall be maintained and properly tuned in accordance with the manufacturer’s specifications. All equipment shall be checked by a certified mechanic and determined to be running in proper condition prior to operation.
• The prime construction contractor shall post a publicly visible sign with the telephone number and person to contact regarding dust complaints. The construction contractor shall take corrective action within 48 hours. The Bay Area Air District’s and the County’s phone numbers shall also be visible to ensure compliance with applicable regulations.

Implementing Measure for MM AIR-1
Upon annexation of the proposed project into the City of Pleasanton (City), the applicant shall update the publicly visible sign required by MM AIR-1 to display the City’s phone number in place of the County’s phone number. The sign shall include the contact person for dust complaints and the Bay Area Air District’s phone number, as required. The applicant shall ensure that all Bay Area Air District Best Management Practices (BMPs) for dust control listed in MM AIR-1 are incorporated into the construction plans and implemented during construction and shall submit these plans to the City for approval prior to construction.

MM AIR-3 The following measure shall be implemented during mass grading, paving, and building construction phases of construction to reduce potential exposure of diesel particulate matter (DPM) and particulate matter less than 2.5 micrometers in diameter (PM2.5) emissions to nearby sensitive receptors:

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ADDENDUM
82 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx • Prior to the issuance of any demolition, grading, or building permits (whichever occurs earliest), the project applicant and/or construction contractor shall prepare a construction operations plan that, during construction activities, requires all offroad equipment with engines greater than 50 horsepower to meet particulate matter emissions standards for Tier 4 interim engines. The construction contractor shall maintain records documenting its efforts to comply with this requirement, including equipment lists. Off-road equipment descriptions and information shall include, but are not limited to, equipment type, equipment manufacturer, equipment identification number, engine model year, engine certification (Tier rating), horsepower, and engine serial number. The project applicant and/or construction contractor shall submit the construction operations plan and records of compliance to the County.

Implementing Measure for MM AIR-3
Upon annexation of the proposed project into the City of Pleasanton (City), the applicant shall submit the construction operations plan required by MM AIR-3 to the City for review and approval prior to issuance of any demolition, grading, or building permits (whichever occurs earliest). The plan shall include documentation demonstrating that all off-road equipment with engines greater than 50 horsepower meets the particulate matter emissions standards for Tier 4 interim engines (or equivalent), consistent with MM AIR-3, and shall include the equipment lists and records described in MM AIR-3. All submittals, notifications, and approvals previously directed to the County shall instead be directed to the City.

Conclusion
There is no new information of substantial importance, changes in the project, or changes in circumstances under which it will be undertaken, identifying new significant effects, nor is there a substantial increase in the severity of previously identified significant impacts related to air quality.

The conclusions from the Prior FEIR remain unchanged when considering the implementation of the proposed project. No further environmental review is required.

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ADDENDUM
FCS 83
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
IV. Biological Resources
Would the project:
a) Have a substantial
adverse effect,
either directly or
through habitat
modifications, on
any species
identified as a
candidate,
sensitive, or
special-status
species in local or
regional plans,
policies, or
regulations, or by
the California
Department of Fish
and Wildlife or
United States Fish
and Wildlife
Service?
Less than
significant
impact with
mitigation
incorporated
No No No MM BIO-1a
and
MM BIO-1b
b) Have a substantial
adverse effect on
any riparian habitat
or other sensitive
natural community
identified in local or
regional plans,
policies, and
regulations or by
the California
Department of Fish
and Wildlife or
United States Fish
Less than
significant
impact with
mitigation
incorporated
No No No MM BIO-2a
and
MM BIO-2b

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ADDENDUM
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
and Wildlife
Service?
c) Have a substantial
adverse effect on
State or federally
protected wetlands
(including, but not
limited to, marsh,
vernal pool, coastal,
etc.) through direct
removal, filling,
hydrological
interruption, or
other means?
Less than
significant
impact
No No No NA
d) Interfere
substantially with
the movement of
any native resident
or migratory fish or
wildlife species or
with established
native resident or
migratory wildlife
corridors, or impede
the use of wildlife
nursery sites?
Less than
significant
impact with
mitigation
incorporated
No No No MM BIO-1a
and
MM BIO-1b
e) Conflict with any
local policies or
ordinances
protecting biological
resources, such as
a tree preservation
policy or
ordinance?
Less than
significant
impact with
mitigation
incorporated
No No No MM BIO-1a,
MM BIO-1b,
MM BIO-2a,
and
MM BIO-2b

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ADDENDUM
FCS 85
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
f) Conflict with the
provisions of an
adopted Habitat
Conservation Plan,
Natural Community
Conservation Plan,
or other approved
local, regional, or
State Habitat
Conservation Plan?
Less than
significant
impact with
mitigation
incorporated
No No No MM BIO-1a,
MM BIO-1b,
MM BIO-2a,
and
MM BIO-2b
Discussion
a) Special-status Species
Would the project: Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special-status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Wildlife or United States Fish and Wildlife Service?
Prior FEIR Conclusions
The Prior FEIR found that the project site supports habitat for special-status species, including burrowing owls and nesting birds, but does not support special-status plant species. To avoid potential impacts, MM BIO-1a and MM BIO-1b require protocol-level surveys for burrowing owls per CDFW guidelines and establishment of no-activity zones during nesting seasons. For nesting birds, pre-construction surveys are required if vegetation removal occurs between February 1 and August

31. If active nests are found, appropriate buffers must be established and monitored. These measures are designed to prevent nest abandonment and help to ensure reproductive success.

With no off-site utility improvements, Alternative 2 would avoid development in areas east of El Charro Road where sensitive biological resources are present, reducing the potential for impacts on wildlife and habitats. For this reason, biological impacts for Alternative 2 would be slightly lower than the County Project, though mitigation for the residential component would still be required. (Draft EIR, p. 6-13). Therefore, with respect to both the County Project and Alternative 2, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.3- 26, 6-13).

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ADDENDUM
86 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Proposed Project Analysis and Conclusion
The proposed project would be constructed in the same location as the land studied in the Prior FEIR, which determined that special-status plant species were absent from the project site and, accordingly, found there were no impacts on special-status or rare plant species. The proposed project would have slightly fewer units than the County Project and would not involve the construction and operation of the substantial off-site utility infrastructure contemplated by the County Project, other than the bioretention area and detention basin. Therefore, the proposed project would result in less overall soil disturbance due to the updated project design. As such, impacts related to habitats of special-status plant and animal species would be slightly less than those of the County Project.

With respect to special-status wildlife, even though the proposed project would result in a reduced amount of ground disturbance due to the reduction of proposed dwelling units and off-site infrastructure, the proposed project would still be located in an area that supports habitat for specialstatus nesting birds and burrowing owls. As such, the proposed project would be required to implement MM BIO-1a and MM BIO-1b, which require protocol-level burrowing owl surveys, preconstruction nesting bird surveys, and avoidance of direct and indirect impacts on nests. With the implementation of these mitigation measures, impacts on special-status species would be less than significant. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
b) Riparian Habitat and Sensitive Natural Communities
Would the project: Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, and regulations or by the California Department of Fish and Wildlife or United States Fish and Wildlife Service?
Prior FEIR Conclusions
The Prior FEIR found that the eastern portion of the Study Area, east of El Charro Road, contains approximately 5.87 acres of Fremont poplar and mixed willow stands, as well as a drainage swale, which contains riparian habitat.24 The Prior FEIR considered the location of an approximately 0.9-acre bioretention area under two design options. Design Option A would cluster the bioretention area directly east of the WWTP and south of the recycled water storage facility. Design Option B would locate the bioretention area southwest of the agricultural irrigation fields, adjacent to the east side of El Charro Road. The Prior FEIR determined that neither Design Option A nor Design Option B is expected to have direct or indirect impacts on the potential depressional wetland feature. However, under Design Option B, the proposed project may result in indirect impacts to the adjacent drainage swale and associated riparian vegetation due to the location of the proposed bioretention area. 24 The Study Area is generally located south of Lakes I and H, and west of Cope Lake (part of the Zone 7 Water Agency Chain of Lakes), although there is a portion of the Study Area that bisects Lake I and Cope Lake. The Study Area consists of three Assessor’s Parcel Numbers (APNs)—APN 946-4634-1, 946-4634-2, and 946-1350-3-10.

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ADDENDUM
FCS 87
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Therefore, under Design Option B, the County Project would be required to implement MM BIO-2a25 and MM BIO-2b, which include obtaining a Construction General Permit from the RWQCB, preparing a Storm Water Pollution Prevention Plan (SWPPP), and implementing BMPs. Additional measures require installation of silt fencing and straw wattles, monitored by a qualified Biologist, and postconstruction stormwater management to prevent pollution and hydromodification. Therefore, the Prior FEIR concluded that impacts with respect to any riparian habitat or other sensitive natural community would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.3-28, 6-13).

Proposed Project Analysis and Conclusion
Similar to the County Project, 5.87 acres of Fremont poplar and mixed willow stands, as well as a drainage swale, which contains riparian habitat, are located east of the project site. The proposed bioretention area and detention basin, to be located off-site east of the proposed residential development portion of the project site, would be in close proximity to the existing drainage swale and associated riparian vegetation. As such, the proposed project could result in pollutant loading, increased erosion and sedimentation, and trash or debris dispersal in the adjacent drainage swale. As such, MM BIO-2a and MM BIO-2b would still be required to reduce potentially significant impacts to sensitive riparian areas and water quality in the drainage swale. With the implementation of these mitigation measures, impacts on riparian habitats or other sensitive natural communities would be reduced to a less than significant level. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required. c) Federally Protected Wetlands
Would the project: Have a substantial adverse effect on State or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means?
Prior FEIR Conclusions
The Prior FEIR found that the County Project would avoid any direct or indirect impacts to State or federally protected waters and/or wetlands because the County Project would not impact the water quality of the potential depressional wetland within the eastern portion of the Study Area, which is the only potential jurisdictional feature within the project site. The closest proposed project component, a storm drain outfall, would be located more than 120 feet from the potential depressional wetland feature and would not result in direct or indirect impacts. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.3-35, 6-13). 25 Note: The National Pollutant Discharge Elimination System (NPDES) was inadvertently misidentified as the “National Pollutant Discharge Effluent Standards” in MM BIO-2a of the Prior FEIR. MM BIO-2a, as detailed below, has been revised to correct this minor typographical error.

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ADDENDUM
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Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Proposed Project Analysis and Conclusion
Similar to the County Project, the proposed project is designed to avoid any direct and indirect impacts to State or federally protected waters and/or wetlands and would not significantly impact the water quality of the potential depressional wetland east of the project site. The proposed bioretention area and detention basin would be constructed at an adequate distance from the potential depressional wetland to avoid any significant adverse impacts. As such, impacts to State or federally protected wetlands would be less than significant, consistent with the impact conclusions set forth in the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
d) Fish or Wildlife Movement
Would the project: Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of wildlife nursery sites?
Prior FEIR Conclusions
The Prior FEIR found that the project site does not function as a critical wildlife movement corridor because the Study Area is surrounded by urban and industrial developments, man-made lakes with limited habitat value, and active roadways, which limit the potential for wildlife movement through the site, and no substantial wildlife nursery sites are present on-site.

Individual nesting birds have the potential to be present within disturbance distances seasonally, and construction activities, vegetation removal, and site disturbance could disrupt wildlife movement and nesting behavior. To address these concerns, MM BIO-1a and MM BIO-1b require pre-construction surveys for burrowing owls and nesting birds, establishment of appropriate buffer zones, and biological monitoring during construction. These measures are designed to prevent nest abandonment and ensure that wildlife movement and nursery functions are not impeded. Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.3-35, 6-13).

Proposed Project Analysis and Conclusion
Similar to the analysis in the Prior FEIR, individual nesting birds have the potential of being present within disturbance distances seasonally. As such, implementation of MM BIO-1a and MM BIO-1b would be required to reduce impacts on nesting birds to less than significant levels. As such, the proposed project’s impacts on wildlife movement and nursery sites would be less than significant with mitigation incorporated, consistent with the impact conclusions set forth in the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
FCS 89
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx e) Conflict with Local Policies or Ordinances
Would the project: Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? Prior FEIR Conclusions
Local policies or ordinances protecting biological resources applicable to the County Project include the ECAP and the Alameda County Ordinance Code Chapter 12.11. The Prior FEIR determined that the County Project would be consistent with the ECAP through the implementation of MM BIO-1a and MM BIO-1b, as well as MM BIO-2a and MM BIO-2b, if Design Option B is selected, which would protect and preserve sensitive habitat and special-status species with the potential to occur within the Study Area. Additionally, the requirements set forth in Alameda County Ordinance Code Chapter

12.11, which details the County’s Tree Preservation Guidelines, would be met as no trees stipulated as protected under the Chapter would be affected by the County Project. Therefore, with adherence to the Alameda County Ordinance Code, the ECAP, and implementation of MM BIO-1a and MM BIO1b, as well as MM BIO-2a and MM BIO-2b, if Design Option B is selected, the County Project would not conflict with the County’s local policies or ordinances. Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, p. 3.3-36, 6-13).

Proposed Project Analysis and Conclusion
Given the proposed annexation, this Addendum considered local City policies or ordinances applicable to the proposed project, which include Goal 2, Policy 1 of the Conservation and Open Space Element of the City’s General Plan, which serves to “preserve and enhance natural wildlife habitats and wildlife corridors”; the City’s Urban Forest Master Plan; and Chapter 17.16 of the Municipal Code, which intends to preserve as many trees as possible throughout the City through staff review and the development review process.

The proposed project would meet the requirements of the General Plan through the implementation of MM BIO-1a and MM BIO-1b, as well as MM BIO-2a and MM BIO-2b, which would protect and preserve sensitive habitat and special-status species with the potential to occur within the Study Area.

Additionally, Chapter 17.16 of the Municipal Code and the City’s Urban Forest Master Plan, which set forth the City’s Tree Preservation Guidelines, would be met as no trees stipulated as protected under the Chapter would be affected by the proposed project. By following the City's Tree Preservation Guidelines; complying with Goal 2, Policy 1 of the City’s General Plan Conservation and Open Space Element; and the Urban Forest Master Plan; and implementing MM BIO-1a, MM BIO-1b, MM BIO-2a, and MM BIO-2b, the proposed project would not conflict with local policies or ordinances. Thus, impacts would be less than significant with mitigation, consistent with conclusions from the Prior FEIR.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
90 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx f) Habitat Conservation Plan/Natural Community Conservation Plan Would the project: Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or State Habitat Conservation Plan?
Prior FEIR Conclusions
The Prior FEIR determined that the project site is located within the boundaries of the East Alameda County Conservation Strategy (EACCS).
26 The EACCS is a framework for guidance by regulatory
agencies and does not include incidental take permits for threatened or endangered species, similar to those provided by a Habitat Conservation Plan. In addition to the mitigation measures outlined above, the Prior FEIR recommended that the County Project adhere to general avoidance and minimization measures identified in the EACCS with some modifications to reflect project-specific circumstances. Implementation of the avoidance measures and MM BIO-1a and MM BIO-1b, as well as MM BIO-2a and MM BIO-2b if Design Option B is selected, would mitigate all potentially significant biological impacts to a less than significant level and ensure that the County Project would ensure there is no conflict with the EACCS. Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.3-37, 6-13).

Proposed Project Analysis and Conclusion
Similar to the County Project, the proposed project would be required to implement MM BIO-1a and MM BIO-1b, as well as MM BIO-2a and MM BIO-2b. The proposed project would also be required to adhere to the general avoidance and minimization measures identified in the EACCS, such as EACCS Measure GEN-05, which requires that vehicles and equipment be parked on pavement, existing roads, and previously disturbed areas to the extent practicable. Implementation of applicable avoidance and minimization measures, and MM BIO-1a, MM BIO-1b, MM BIO-2a, and MM BIO-2b, would mitigate all potentially significant biological impacts to a less than significant level and ensure that the proposed project would not be in conflict with the EACCS, consistent with the impact conclusions set forth in the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

Zone 7 Stormwater Option
The Zone 7 Stormwater Option would not result in any new or more severe impacts to biological resources compared to those previously analyzed since it was considered in the Prior FEIR. Under this option, ground disturbance would be reduced as compared to the City Stormwater Option because the detention basin, pump facilities, and storm drain force main would not be constructed.

Accordingly, potential impacts associated with ground disturbance would be incrementally reduced.

Treated stormwater would continue to be managed through the proposed bioretention facilities and would be discharged to naturally drain toward Cope Lake, subject to Zone 7’s approval. This option 26 Although the project site is not within the boundaries of a Habitat Conservation Plan, the EACCS was treated as one for the purposes of this analysis.

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ADDENDUM
FCS 91
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx would not introduce a new mechanism for direct disturbance to aquatic habitat, shoreline vegetation, or aquatic species. Therefore, consistent with the impact conclusions in the Prior FEIR, this option would not increase the potential for impacts to sensitive habitats or special-status species and would remain subject to all applicable water quality treatment and regulatory requirements as well as all mitigation identified in the Prior FEIR. Accordingly, biological resource impacts would remain less than significant and consistent with the conclusions of the Prior FEIR.

Mitigation Measures
MM BIO-1a Burrowing Owl
• To avoid potential impacts to active burrowing owl nests and adult owls, a qualified Biologist shall conduct protocol-level burrowing owl surveys in accordance with the California Department of Fish and Wildlife (CDFW) 2012 Staff Report. • If an active nest is identified near a proposed work area and work cannot be conducted outside of the nesting season (March 15 to September 1), a no-activity zone will be established by a qualified Biologist. The no-activity zone shall be large enough to avoid nest abandonment and shall, at a minimum, be a 250-feet radius from the nest.
• If the burrowing owls are present at the site during the nonbreeding period, a qualified Biologist shall establish a no-activity zone of at least 150 feet. • If an effective no-activity zone cannot be established in either case, an experienced burrowing owl Biologist shall develop a site-specific plan (i.e., a plan that considers the type and extent of the proposed activity, the duration and timing of the activity, the sensitive and habituation of the owls, and the dissimilarity of the proposed activity with background activities) to minimize the potential to affect the reproductive success of the owls.

MM BIO-1b Protection of Active Bird Nests (includes pre-construction survey and implementation of avoidance buffer, if found).

1. Removal of trees shall be limited to only those necessary to construct the proposed project as reflected in the relevant project approval documents.

2. If the proposed project requires vegetation to be removed during the nesting season (February 1 to August 31), pre-construction surveys shall be conducted no more than 7 days prior to the start of ground or vegetation disturbance (including tree removal) to determine whether or not active nests are present.

3. If an active nest is located during pre-construction surveys, a qualified Biologist shall determine an appropriately sized avoidance buffer based on the species and anticipated disturbance level. (The California Department of Fish and Wildlife [CDFW] recommends a minimum no-disturbance buffer of 250 feet around active nests of non-listed bird species and a 500-foot no-disturbance buffer around active nests of non-listed raptors.) A qualified Biologist shall delineate the avoidance buffer using Environmentally Sensitive Area fencing, pin flags, and/or

ARROYO LAGO RESIDENTIAL PROJECT

ADDENDUM
92 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx yellow caution tape. The buffer zone shall be maintained around the active nest site(s) until the young have fledged and are foraging independently. No construction activities or construction foot traffic is allowed to occur within the avoidance buffer(s).

4. The qualified Biologist shall monitor the active nest during construction activities and modify the protection zone accordingly to prevent project-related nest disturbance, until the young have fledged.

MM BIO-2a Avoidance and Minimization of Indirect Temporary Impacts to Water Quality and Riparian Vegetation (Design Option B)
The project applicant shall obtain a Construction General Permit from the Regional Water Quality Control Board (RWQCB) if Design Option B is selected. The applicant shall ensure that the project Civil Engineer prepares all required stormwater planning documents consistent with the requirements of the RWQCB (e.g., a Storm Water Pollution Prevention Plan [SWPPP] that complies with current National Pollutant Discharge Elimination System [NPDES]; Best Management Practices [BMPs] to control the pollutants in stormwater runoff; and/or a Storm Water Management Plan [SWMP]) shall be developed and integrated into the project plan.

MM BIO-2b Avoidance and Minimization of Indirect Permanent Impacts to Water Quality and Riparian Vegetation (Design Option B)
Prior to construction the applicant shall install silt fencing including the placement of straw wattles between all construction areas and the adjacent drainage swales to avoid impacts to water quality by grading and construction if Design Option B is selected. A qualified Biologist shall be on-site to monitor the installation of fencing.

Fencing shall be in place and regularly maintained during project implementation.

The project applicant shall install post-construction stormwater management measures and establish a long-term maintenance plan. This requirement is intended to ensure that the post-construction conditions at the Study Area do not cause or contribute to direct or indirect water quality impacts (i.e., pollution and/or hydromodification) upstream and downstream. Specifically, the discharger shall demonstrate compliance with the post-construction standards set forth in the General Permit.

Conclusion
There is no new information of substantial importance, changes in the project, or changes in circumstances under which it will be undertaken, identifying new significant effects, nor is there a substantial increase in the severity of previously identified significant impacts related to biological resources. The conclusions from the Prior FEIR remain unchanged when considering the implementation of the proposed project. No further environmental review is required.

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ADDENDUM
FCS 93
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
V. Cultural and Tribal Cultural Resources
Would the project:
a) Cause a substantial
adverse change in
the significance of a
historical resource
as pursuant to
Section 15064.5?
No impact No No No NA
b) Cause a substantial
adverse change in
the significance of
an archaeological
resource pursuant
to Section 15064.5?
Less than
significant
impact with
mitigation
incorporated
No No No MM CUL-2a,
MM CUL-2b
c) Disturb any human
remains, including
those interred
outside of formal
cemeteries?
Less than
significant
impact with
mitigation
incorporated
No No No MM CUL-3
Would the project cause a substantial adverse change in the significance of a Tribal Cultural Resource, defined in Public Resources Code Section 21074 as either a site, feature, place, cultural landscape that is geographically defined in terms of the size and scope of the landscape, sacred place, or object with cultural value to a California Native American Tribe, and that is:
d) Listed or eligible for
listing in the
California Register
of Historical
Resources, or in a
local register of
historical resources
as defined in Public
Resources Code
Section 5020.1(k),
or
Less than
significant
impact with
mitigation
incorporated
No No No MM CUL-2a,
MM CUL-2b,
MM CUL-3

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ADDENDUM
94 FCS
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
e) A resource
determined by the
lead agency, in its
discretion and
supported by
substantial
evidence, to be
significant pursuant
to criteria set forth
in subdivision (c) of
Public Resources
Code Section
5024.1. In applying
the criteria set forth
in subdivision (c) of
Public Resource
Code Section
5024.1, the lead
agency shall
consider the
significance of the
resource to a
California Native
American Tribe.

Less than
significant
impact with
mitigation
incorporated
No No No MM CUL-2a,
MM CUL-2b,
MM CUL-3
Discussion
a) Historical Resources
Would the project: Cause a substantial adverse change in the significance of a historical resource as pursuant to Section 15064.5?
Prior FEIR Conclusions
The Prior FEIR determined that no historical resources listed or eligible for listing in the California Register of Historical Resources (CRHR) or local registers were present within the project site. A records search and field survey did not identify any built environment features or structures of

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ADDENDUM
FCS 95
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Proposed Project Analysis and Conclusion
As described in the Prior FEIR, records search results conducted at the Northwest Information Center (NWIC) identified three historic resources (P-01-000193, P-01-001783, and P 01-002190) located within the 0.5-mile records search radius around the project site. However, similar to the County Project, these resources are not located within the project site or the limit of disturbance areas, nor would they be adversely impacted by the proposed project. Additionally, no historic resources were encountered during the pedestrian field survey conducted as part of the Prior FEIR. As such, because the proposed project would be constructed in the same location as the County Project albeit with less overall ground disturbance, the results of the record searches and community survey conducted under the Prior FEIR would still apply to the proposed project. Therefore, the proposed project would not have a significant adverse impact on historic era built environment resources. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
b) Archaeological Resources
Would the project: Cause a substantial adverse change in the significance of an archaeological resource pursuant to Section 15064.5?
Prior FEIR Conclusions
As described in the Prior FEIR, record search results from the NWIC did not identify any prehistoric archaeological resources located within the project site or within the 0.5-mile search radius around the project site. Additionally, the Sacred Lands File search conducted by the Native American Heritage Commission (NAHC) was negative for Tribal Cultural Resources (TCRs) within the project site. However, the Prior FEIR found that the project site has the potential to contain buried archaeological resources because the project site and limit of disturbance areas are situated on undivided Holocene and/or earlier Pleistocene deposits that have the potential to contain archaeological resources.

Although no archaeological resources were encountered during the field survey, MM CUL-2a and MM CUL-2b require a Worker Environmental Awareness Program (WEAP) training for construction personnel and outline procedures for halting work near the find and consulting a qualified Archaeologist if resources are discovered during ground disturbance. These measures would ensure that any inadvertently encountered significant archaeological resources are properly identified and treated. Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.4-24, 6-14).

Proposed Project Analysis and Conclusion
The proposed project would be constructed in the same location as the County Project; therefore, the results of the record searches and the pedestrian field survey conducted under the Prior FEIR would

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ADDENDUM
96 FCS
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Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
c) Human Remains
Would the project: Disturb any human remains, including those interred outside of formal cemeteries?
Prior FEIR Conclusions
The Prior FEIR acknowledged that, while no formal cemeteries or areas containing human remains are known to be in the project vicinity, the possibility always exists that construction-related ground disturbance may uncover previously undiscovered human remains. In the unlikely event such a discovery is made, CEQA Guidelines Section 15064.5, Health and Safety Code Section 7050.5, and Public Resources Code Sections 5097.94 and Section 5097.98 must be followed. MM CUL-3 outlines procedures in accordance with Public Resources Code Section 5097.98, including contacting the County Coroner and, if remains are determined to be Native American, notifying the NAHC. The Most Likely Descendant (MLD) would be consulted regarding appropriate treatment pursuant to the identified mitigation and applicable State law. Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.4-26, 6-14).

Proposed Project Analysis and Conclusion
Similar to the analysis of the County Project, no formal cemeteries or areas containing human remains are known to be in the project vicinity. However, CEQA Guidelines Section 15064.5, Health and Safety Code Section 7050.5, and Public Resources Code Sections 5097.94 and 5097.98 would still be followed under the proposed project. In addition to compliance with applicable laws and regulations, implementation of MM CUL-3 would still be required and would reduce potential impacts to previously undiscovered human remains to a less than significant level, consistent with the impact conclusion in the Prior FEIR. Therefore, the proposed project would not introduce new significant

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ADDENDUM
FCS 97
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d) Listed or Eligible Tribal Cultural Resources
Would the project: Cause a substantial adverse change in the significance of a Tribal Cultural Resource, defined in Public Resources Code Section 21074 as either a site, feature, place, cultural landscape that is geographically defined in terms of the size and scope of the landscape, sacred place, or object with cultural value to a California Native American Tribe, and that is listed or eligible for listing in the California Register of Historical Resources, or in a local register of historical resources as defined in Public Resources Code Section 5020.1(k)?
Prior FEIR Conclusions
The Prior FEIR detailed that records search results from the NWIC indicate that three historic resources are located within 0.5 mile of the project site and the limit of disturbance areas, and a review of the NAHC Sacred Lands File search was negative for recorded TCRs within the project site.

Consistent with requirements under CEQA, a letter containing project information requesting any additional information and consultation regarding TCRs was sent to each Tribal representative on February 27, 2023. No responses were received. As of the writing of the Prior FEIR, no TCRs listed or eligible for listing were identified within the project site. Nevertheless, inadvertent discovery of TCRs is always possible. Should TCRs be discovered during ground disturbance activities, implementation of MM CUL-2a, MM CUL-2b, and MM CUL-3 would reduce potential impacts on TCRs to a less than significant level. Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.4-28, 6-14).

Proposed Project Analysis and Conclusion
Because the proposed project would be constructed in the same location as the County Project, the results of the record searches and the pedestrian field survey conducted under the Prior FEIR would still apply. However, the proposed project would reduce the overall scope and nature of off-site improvements compared to the County Project, reducing the area where TCRs could be affected.

On February 18, 2026, the City sent out Tribal consultation letters pursuant to Senate Bill (SB) 18, which requires Tribal consultation for projects proposing a General Plan Amendment, to identify additional significant TCRs meeting the criteria set forth in subdivision (c) of the Public Resources Code Section 5024.1.27 Tribes have 90 days to respond and request consultation, (i.e., until May 18, 27 Assembly Bill (AB) 52 consultation requirements under Public Resources Code §21080.3.1 apply to projects subject to CEQA that may affect Tribal Cultural Resources (TCRs); however, Section 21080.3.1(a) applies only to negative declarations, mitigated negative declarations and environmental impact reports and is not applicable to this addendum.

Therefore, AB 52 consultation is not required for this addendum. In contrast, SB 18 consultation requirements under Government Code Section 65352.3 apply to adoption or amendment of a general plan. Because the proposed General

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ADDENDUM
98 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx 2026). A response was received from Wilton Rancheria on March 17, 2026, stating that the Tribe did not have any comments and did not wish to open consultation at this time. The Lisjan Nation responded on March 17, 2026, requesting additional information related to the proposed project. The City provided additional information in response to their request, and the Tribe did not request any further consultation. No other responses were received pursuant to SB 18 consultation requirements.

The proposed project would still require the implementation of MM CUL-2a, MM CUL-2b, and MM CUL-3 to reduce potential impacts on TCRs to a less than significant level. As such, the proposed project’s impacts related to TCRs would be less than significant with mitigation, consistent with the impact conclusions of the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required. e) Lead Agency Determined Tribal Cultural Resources
Would the project: Cause a substantial adverse change in the significance of a Tribal Cultural Resource, defined in Public Resources Code Section 21074 as either a site, feature, place, cultural landscape that is geographically defined in terms of the size and scope of the landscape, sacred place, or object with cultural value to a California Native American Tribe, and that is a resource determined by the lead agency, in its discretion and supported by substantial evidence, to be significant pursuant to criteria set forth in subdivision (c) of Public Resources Code Section 5024.1?
Prior FEIR Conclusions
The Prior FEIR found that no TCRs were identified during Tribal consultation or field investigations.

Nonetheless, given that inadvertent discovery of TCRs during construction activities is always possible, the Prior FEIR identified MM CUL-2a, MM CUL-2b, and MM CUL-3, which would apply to ensure appropriate evaluation and treatment if such resources are discovered during construction.

With respect to Alternative 2, ground disturbance would be less than that of the County Project, reducing the area where archaeological or TCRs could be affected. While mitigation for inadvertent discovery would still be required, the overall potential for impact would be lower than the County Project. (Draft EIR, p. 6-14). Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.4-28, 6-14).

Proposed Project Analysis and Conclusion
Because the proposed project would be constructed in the same location as the County Project, the findings of the Tribal consultation and field investigations conducted under the Prior FEIR would still apply. Additionally, as described above, the City completed Tribal consultation pursuant to SB 18. A response was received from Wilton Rancheria on March 17, 2026, stating that the Tribe did not have any comments and did not wish to open consultation at this time. The Lisjan Nation responded on Plan Amendment was not previously triggered by the County Project, SB 18 consultation with California Native American Tribes is required prior to its adoption by the City.

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ADDENDUM
FCS 99
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The proposed project would still require the implementation of MM CUL-2a, MM CUL-2b, and MM CUL-3 to reduce potential impacts on any previously undiscovered TCRs to a less than significant level. As such, the proposed project’s potential to cause a substantial adverse change in the significance of a Lead Agency-determined TCR would be less than significant with mitigation, consistent with the impact conclusions of the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

Zone 7 Stormwater Option
The Zone 7 Stormwater Option would not result in any new or more severe impacts to cultural resources compared to those previously analyzed since it was considered in the Prior FEIR. Under this option, ground disturbance, and related potential impacts, would be incrementally reduced as compared to the City Stormwater Option because the detention basin, pump facilities, and storm drain force main would not be constructed. This option would not involve new areas of grading or excavation beyond the approved project footprint and would not affect known or unknown archaeological resources, historic resources, or TCRs. All previously adopted cultural resource avoidance and inadvertent discovery measures would continue to apply. Accordingly, impacts to cultural resources would remain less than significant and consistent with the conclusions of the Prior FEIR.

Mitigation Measures
MM CUL-2a Prior to the initiation of construction activities, all construction personnel directly involved with project-related ground disturbance within the residential project site and off-site improvement areas, both west and east of El Charro Road, attend a “tailgate” Worker Environmental Awareness Program (WEAP) training for archaeological resources. The training should include visual aids, a discussion of applicable laws and statutes relating to archaeological resources, types of resources that may be found within the limit of disturbance areas, and procedures to be followed in the event such resources are encountered. The training should be conducted by an Archaeologist who meets the Secretary of the Interior’s Professional Qualification Standards for archaeology. FirstCarbon Solutions (FCS) recommends that a qualified Archaeologist who meets the Secretary of Interior’s Professional Qualification Standards for Archaeology be present to monitor during the clearing and grubbing phases of ground disturbance within the limit of disturbance areas east of El Charro Road to check for the inadvertent exposure of cultural materials. In the event exposed soils indicate cultural materials may be present, this may be followed by regular or periodic archaeological monitoring as determined by the Archaeologist, but full-time archaeological monitoring is not recommended at this time.

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ADDENDUM
100 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Implementing Measure for MM CUL-2a
In addition to the WEAP training prescribed in MM CUL-2a, upon annexation of the proposed project into the City of Pleasanton (City), a qualified Archaeologist who meets the Secretary of Interior’s Professional Qualification Standards for Archaeology shall be present to monitor during the clearing and grubbing phases of ground disturbance within the limit of disturbance areas east of El Charro Road to check for the inadvertent exposure of cultural materials. In the event exposed soils indicate cultural materials may be present, the qualified Archaeologist shall determine if regular or periodic archaeological monitoring is required and shall monitor as determined necessary.

MM CUL-2b In the event that buried cultural resources are discovered during construction, operations shall stop within a 100-foot radius of the find and a qualified Archaeologist shall be consulted to determine whether the resource requires further study. The qualified Archaeologist shall make recommendations to the Lead Agency on the measures that shall be implemented to protect the discovered resources, including but not limited to excavation of the finds and evaluation of the finds in accordance with CEQA Guidelines Section 15064.5. Potentially significant cultural resources consist of, but are not limited to, stone, bone, fossils, wood, or shell artifacts or features, including hearths, structural remains, or historic dumpsites. Any previously undiscovered resources found during construction within the project area should be recorded on appropriate California Department of Parks and Recreation (DPR) forms and evaluated for significance in terms of CEQA criteria.

If the resources are determined to be unique historic resources as defined under Section 15064.5 of the CEQA Guidelines, mitigation measures shall be identified by the Archaeological Monitor and recommended to the Lead Agency. Appropriate mitigation measures for significant resources could include avoidance or capping, incorporation of the site in green space, parks, or open space, or data recovery excavations of the finds.

No further grading shall occur in the area of the discovery until the Lead Agency approves the measures to protect these resources. Any archaeological artifacts recovered as a result of mitigation shall be donated to a qualified scientific institution approved by the Lead Agency where they would be afforded long-term preservation to allow future scientific study.

MM CUL-3 In the event of an accidental discovery or recognition of any human remains, Public Resource Code Section 5097.98 must be followed. In this instance, once projectrelated earthmoving begins and if there is accidental discovery or recognition of any human remains, the following steps shall be taken:

1. There shall be no further excavation or disturbance of the site where human remains are discovered and/or any nearby area reasonably suspected to overlie adjacent human remains until the County Coroner is contacted to determine

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ADDENDUM
FCS 101
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2. Where the following conditions occur, the landowner or his/her authorized representative shall rebury the Native American human remains and associated grave goods with appropriate dignity either in accordance with the recommendations of the MLD or on the project area in a location not subject to further subsurface disturbance:
• The NAHC is unable to identify an MLD, or the MLD failed to make a recommendation within 48 hours after being notified by the commission. • The descendant identified fails to make a recommendation; or • The landowner or his authorized representative rejects the recommendation of the descendant, and the mediation by the NAHC fails to provide measures acceptable to the landowner.

Conclusion
There is no new information of substantial importance, changes in the project, or changes in circumstances under which it will be undertaken, identifying new significant effects, nor is there a substantial increase in the severity of previously identified significant impacts related to cultural resources and TCRs. The conclusions from the Prior FEIR remain unchanged when considering the implementation of the proposed project. No further environmental review is required.

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ADDENDUM
102 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Environmental Issue
Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
VI. Energy
Would the project:
a) Result in potentially
significant
environmental
impact due to
wasteful, inefficient,
or unnecessary
consumption of
energy resources,
during project
construction or
operation?
Less than
significant
impact
No No No NA
b) Conflict with or
obstruct a State or
local plan for
renewable energy
or energy
efficiency?
Less than
significant
impact
No No No NA
Discussion
a) Energy Use
Would the project: Result in potentially significant environmental impact due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation?
Prior FEIR Conclusions
Construction
According to the Prior FEIR, the County Project would result in the consumption of approximately 208,890 gallons of diesel fuel over the entire construction duration and a combined approximately 153,833 gallons of gasoline and diesel for vehicle travel during construction. However, compliance with California Code of Regulations, Title 13, Sections 2449(d)(3) and 2485, which limit idling from both on-road and off-road diesel-powered equipment, would result in fuel savings. Additionally,

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ADDENDUM
FCS 103
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Operation
According to the Prior FEIR, the County Project's operation would consume an estimated 1,729,121 kWh of electricity and an estimated 8,967,053 kilo-British Thermal Unit (kBTU) of natural gas on an annual basis. For comparison, the County’s total electricity consumption in 2022 was approximately 10,395,384,395 kWh. Therefore, the County Project’s electrical consumption represents approximately 0.017 percent of the County’s total 2022 electric consumption. The Prior FEIR found that the County’s total natural gas consumption in 2022 was approximately 37,730,978,800 kBTU.

Therefore, the County Project’s natural gas consumption represents approximately 0.023 percent of the County’s total 2022 natural gas consumption. Thus, the Prior FEIR determined that the County Project would represent a nominal percentage of the County’s total electrical and natural gas consumption during operation.

The County Project would also be required to include solar in compliance with Alameda County Municipal Code Title 15, Buildings and Construction; Alameda County Municipal Code Chapter

15.08.010 indicates the County adopted California Code of Regulations Title 24, Part 6 (Energy Code) standards for residential buildings. Title 24 standards include a broad set of energy conservation requirements that apply to the structural, mechanical, electrical, and plumbing systems in a building. For example, the Title 24 Lighting Power Density requirements define the maximum wattage of lighting that can be used in a building based on its square footage. Title 24 standards, widely regarded as the most advanced energy efficiency standards, would help reduce the amount of energy required for lighting, water heating, and heating and air conditioning in buildings and promote energy conservation. Compliance with these policies would ensure that building energy consumption would not result in the use of energy in a wasteful, inefficient, or unnecessary manner.

According to the Prior FEIR, based on energy use estimations contained within the CalEEMod output files used to estimate the County Project’s generation of GHG emissions, County Project-related vehicle trips would result in approximately 6 million Vehicle Miles Traveled (VMT) and consume an estimated 226,453 gallons of gasoline and diesel combined, annually.

The Prior FEIR determined that the County Project would not result in wasteful or inefficient energy use as detailed more fully therein and summarized as follows. During construction, energy would be consumed primarily through fuel use in construction equipment and vehicles. The County Project would comply with applicable energy efficiency regulations, including California Building Code Title 24 and California Green Building Standards Code (CALGreen) standards. Operational energy use would include electricity and natural gas for residential units, lighting, and water infrastructure. The project

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ADDENDUM
104 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx design incorporates energy-efficient appliances, lighting, and building materials. Additionally, the County Project would include pre-wiring for future conversion to all-electric systems. Further, alternative transit options in the project vicinity would encourage the reduction of personal vehicle fuel consumption. With respect to Alternative 2, energy use associated with construction and operation would be reduced due to the elimination of off-site utility improvements, though the residential component would remain unchanged. Direct energy impacts of Alternative 2 would be slightly less than those of the County Project. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.5-13, 6-14).

Proposed Project Analysis and Conclusion
Construction
The proposed project would involve a similar construction duration and would result in similar, if not slightly reduced, construction intensity as compared to the County Project, as it would reduce the amount of proposed dwelling units and the scope and nature of off-site improvements. The proposed project would also require substantially the same construction equipment and practices as the County Project. It is reasonable to assume that the overall construction schedule and process would be designed to be as efficient as commercially practicable to avoid excess monetary costs. This assumption is consistent with established principles in construction and project management, which emphasize schedule optimization and cost control through techniques such as critical path method and resource allocation.28 For example, private development considerations such as coordination for the use of equipment and fuel take into account efficiency opportunities due to the added expense associated with inefficient, duplicative, and/or wasteful renting, maintaining, and fueling equipment.

Therefore, the opportunities for further future efficiency gains during construction are limited.

Accordingly, consistent with the impact conclusions of the Prior FEIR, it is anticipated that the construction activities associated with the proposed project would not result in wasteful, inefficient, and unnecessary consumption of energy.

Similar to the County Project, the proposed project would involve the use of construction lighting, field services (office trailers), and electrically driven equipment such as pumps and other tools during construction. However, similar to the conclusions of the Prior FEIR, the proposed project’s use of such equipment would not be wasteful, as construction of the proposed project would be limited to the permitted City hours of 8:00 a.m. to 5:00 p.m. Monday through Friday per the City’s Standard Specifications and Details.
29 Therefore, similar to the County Project and the impact conclusions of the Prior FEIR, the proposed project would result in less than significant energy impacts related to construction.

Operation
The proposed project would be substantially similar to the County Project, though with fewer proposed dwelling units and a substantial reduction in the nature and scope of off-site improvements.

As such, it is likely that the proposed project would result in substantially similar, if not slightly less, 28 Daniel W. Halpin., & Bolivar A. Senior. (2010). Construction Management (4th edition). John Wiley & Sons. 29 This construction schedule is consistent with the air quality modeling.

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ADDENDUM
FCS 105
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In addition, City Municipal Code Chapter 20.08 adopts by reference the then-current edition of the California Code of Regulations Title 24 Parts 1 through 12, which includes Part 6 (Energy Code) standards for residential buildings and Part 11 (CALGreen Standards). Similar to the County Project, the proposed project would be required to comply with applicable Title 24 standards, which would help reduce the amount of energy required for lighting, water heating, and heating and air conditioning in buildings and promote energy conservation. Compliance with these State and local laws and regulations would ensure that building energy consumption under the proposed project would not result in the use of energy in a wasteful, inefficient, or unnecessary manner. Operational energy would also be consumed during vehicle trips associated with the proposed project. Fuel consumption would be primarily related to vehicle use by residents and visitors associated with the proposed project. Given the reduced scope of development contemplated by the proposed project, it is reasonable to conclude that it would result in substantially similar, if not slightly reduced, VMT and gasoline and diesel consumption as compared to the County Project.

The proposed project is located in an urbanized area that is well supported by public transit. Regional and local access to the project site is provided via Busch Road, which is adjacent to the south of the project site. Furthermore, LAVTA provides bus transit services through the Wheels bus service.

Wheels operates Routes 10R, 605, and 608 within 0.5 mile of the project site.30,31 However, Routes 605 and 608 provide only morning and afternoon school services._ The closest bus stops to the project site are Martin Avenue and Mohr Avenue, and Stanley Boulevard and Valley Avenue, approximately 0.3 mile northwest and 0.45 mile southwest of the project site, respectively. The ACE Rail is a regional rail transit service that runs approximately 0.33 mile south of the project site and provides connections throughout the County from San José to Stockton.32 The Pleasanton ACE Rail station is located approximately 2.10 miles southwest of the project site at 4950 Pleasanton Avenue.

Finally, BART is a regional rail transit service that operates within the County and provides 30 Livermore-Amador Valley Transit Authority (LAVTA). 2025. Wheels System Map. Website:
https://www.wheelsbus.com/wp-content/uploads/2025/10/System-Map-Brochure-2025-CIRCA-production-MC2-WEB.pdf.

Accessed March 10, 2026.
31 Although certain transit stops are located within approximately 0.5 mile of the project site when measured as a straight-line (“as-the-crow-flies”) distance, the actual pedestrian travel distance exceeds 0.5 mile due to the absence of direct walking routes and the need to follow the existing street and path network. 32 ACE Rail. 2026. Schedules. Website: https://acerail.com/schedules/. Accessed March 10, 2026.

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ADDENDUM
106 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx connections to Contra Costa, San Francisco, and San Mateo counties. The Dublin/Pleasanton BART Station is approximately 2.60 miles northwest of the project site. These available and readily accessible alternative transit options would further encourage the reduction of VMT and the related personal vehicle fuel consumption. Thus, transportation fuel consumption would not be wasteful, inefficient, or unnecessary. Consistent with the impact conclusions in the Prior FEIR, impacts would be less than significant.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
b) Energy Efficiency and Renewable Energy Standards Consistency Would the project: Conflict with or obstruct a State or local plan for renewable energy or energy efficiency?
Prior FEIR Conclusions
The Prior FEIR found that the County Project would not conflict with any State or local energy plans.

The County Project would be required to comply with the applicable Title 24 Energy Efficiency Standards and CALGreen requirements as adopted under Alameda County Municipal Code Title 15.

The County Project would incorporate energy conservation features and comply with applicable energy efficiency standards, and the electricity provider, PG&E, meets the State’s current objectives for renewable energy sources. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.5-17, 6-14).

Proposed Project Analysis and Conclusion
The proposed project would be substantially similar to the County Project, though with fewer proposed dwelling units and a substantial reduction in the scope and nature of off-site improvements.

Similar to the County Project, the proposed project would be required to comply with the applicable Title 24 Energy Efficiency Standards and CALGreen requirements—for example, and among others, EV charging infrastructure and solar requirements as adopted by Municipal Code Chapter 20.08.

Ava Community Energy (Ava) would provide electricity generation services for the proposed project, while PG&E would provide transmission and delivery services. In 2024, Ava obtained 62 percent of its electricity from renewable energy sources, while the remaining electricity was sourced from large hydroelectric (34 percent), and fossil fuels (4 percent).33 Ava also offers a Renewable 100 option that sources 100 percent of its power mix from eligible renewable energy sources.

The proposed project’s electricity provider is required to meet the State’s mandate that electricity retail sellers procure a minimum of 33 percent of their retail electricity sales from eligible renewable energy resources, as required by the Renewables Portfolio Standard (RPS) provisioned in SB 350, as 33 California Energy Commission (CEC). 2024. Power Content Label. Website:
https://www.energy.ca.gov/filebrowser/download/9427. Accessed April 14, 2026.

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ADDENDUM
FCS 107
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provider would also be required to meet the State’s future objective of 60 percent of in-State electricity sales being generated from renewable energy sources by 2030. As such, the proposed project would not conflict with or obstruct the applicable plan for renewable energy or energy efficiency. Impacts would be less than significant.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

Zone 7 Stormwater Option
The Zone 7 Stormwater Option would not result in any new or more severe impacts related to energy use compared to those previously analyzed since it was previously considered in the Prior FEIR.

Under this option, construction of the detention basin, pump facilities, and storm drain force main would be eliminated (as compared to the City Stormwater Option), thereby reducing constructionrelated energy consumption associated with grading, equipment operation, and material transport. In addition, the option would avoid the ongoing energy demand associated with the operation of pump facilities. Accordingly, consistent with the impact conclusions in the Prior FEIR, the Zone 7 Stormwater Option would not increase energy consumption or conflict with applicable energy conservation plans, and energy impacts would remain less than significant and consistent with the conclusions of the Prior FEIR.

Mitigation Measures
None.

Conclusion
There is no new information of substantial importance, changes in the project, or changes in circumstances under which it will be undertaken, identifying new significant effects, nor is there a substantial increase in the severity of previously identified significant impacts related to energy. The conclusions from the Prior FEIR remain unchanged when considering the implementation of the proposed project. No further environmental review is required. 34 Note that the percentages above do not reflect compliance with the Renewables Portfolio Standard (RPS), which measures the use of tracking instruments called Renewable Energy Credits over the course of multi-year compliance periods. Renewable Energy Credits that are purchased separately from the renewable energy can be used for RPS compliance, but they do not factor into the power mixes or GHG emissions intensities above.

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ADDENDUM
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Area
Conclusion in
Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring
New Analysis
or
Verification?
Mitigation
Measures
VII. Geology, Seismicity, and Soils
Would the project:
a) Directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury, or death involving:
i) Rupture of a
known
earthquake
fault, as
delineated on
the most recent
Alquist-Priolo
Earthquake
Fault Zoning
Map issued by
the State
Geologist for
the area or
based on other
substantial
evidence of a
known fault?
Refer to
Division of
Mines and
Geology
Special
Publication 42.

Less than
significant
impact with
mitigation
incorporated
No No No MM GEO-1
ii) Strong seismic
ground
shaking?
Less than
significant
impact with
mitigation
incorporated
No No No MM GEO-1
iii) Seismic-related
ground failure,
Less than
significant
impact with
No No No MM GEO-1

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ADDENDUM
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Area
Conclusion in
Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring
New Analysis
or
Verification?
Mitigation
Measures
including
liquefaction?
mitigation
incorporated
iv) Landslides? Less than
significant
impact with
mitigation
incorporated
No No No MM GEO-1
b) Result in
substantial soil
erosion or the loss
of topsoil?
Less than
significant
impact
No No No NA
c) Be located on a
geologic unit or
soil that is
unstable, or that
would become
unstable as a
result of the
project, and
potentially result in
on- or off-site
landslide, lateral
spreading,
subsidence,
liquefaction or
collapse?
Less than
significant
impact with
mitigation
incorporated
No No No MM GEO-1
d) Be located on
expansive soil, as
defined in Table
18-1-B of the
Uniform Building
Code (1994),
creating
substantial direct
Less than
significant
impact with
mitigation
incorporated
No No No MM GEO-1

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ADDENDUM
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Area
Conclusion in
Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring
New Analysis
or
Verification?
Mitigation
Measures
or indirect risks to
life or property?
e) Have soils
incapable of
adequately
supporting the use
of septic tanks or
alternative
wastewater
disposal systems
where sewers are
not available for
the disposal of
wastewater?
Less than
significant
impact
No No No NA
f) Directly or
indirectly destroy a
unique
paleontological
resource or site or
unique geologic
feature?
Less than
significant
impact with
mitigation
incorporated
No No No MM GEO-6

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ADDENDUM
FCS 111
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a-d) Earthquake Hazards; Erosion; Unstable Soils or Geologic Units; Expansive Soils Would the project: a) Directly or indirectly cause potential substantial adverse effects, including the risk of loss, injury or death involving: (i) Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault; (ii) Strong Seismic Ground Shaking; (iii) Seismic-related ground failure, including liquefaction; or (iv) Landslides?
b) Result in substantial soil erosion or the loss of topsoil? c) Be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and
potentially result in on- or off-site landsliding, lateral spreading, subsidence, liquefaction, or collapse?
d) Be located on expansive soil, creating substantial direct or indirect risks to life or property?
Prior FEIR Conclusions
Earthquake Hazards (Threshold (a)(i-iv))
The Prior FEIR found that the project site is not located within an Alquist-Priolo Earthquake Fault Zone (EFZ), and no evidence of active or historic faulting was observed on or near the project site.

The nearest active fault is the Calaveras Fault, approximately 4.4 miles to the southwest. While the project site is in a seismically active region, the preliminary geotechnical reports concluded that the project site is suitable for development with appropriate design measures. Liquefaction potential is considered negligible due to soil type and groundwater depth (at least 45 feet below ground surface), although Association of Bay Area Governments (ABAG) mapping identifies moderate susceptibility.

Landslide risk is low, with no mapped landslides or landslide zones on or near the project site.

MM GEO-1 requires a design-level geotechnical study to address site-specific hazards and incorporate recommendations into project design and construction. With respect to Alternative 2, the Prior FEIR determined that soil disturbance and grading would be reduced by approximately 38 acres compared to the County Project, lowering the potential for geotechnical impacts. Required mitigation for geotechnical hazards would still apply, but overall impacts would be less. Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.6-17, 6-14).

Erosion (Threshold (b))
The Prior FEIR determined that while construction activities could disturb soils and potentially lead to erosion, the County Project would be subject to compliance with the National Pollutant Discharge Elimination System (NPDES) permit requirements. A SWPPP would be implemented, including BMPs

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ADDENDUM
112 FCS
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Unstable Soils or Geologic Units (Threshold (c))
The Prior FEIR found that the project site includes deep fill materials from past quarry operations, with depths ranging from 22 to 162 feet depending on location. These materials vary in stiffness and density, and some areas contain loose or soft soils. However, the preliminary geotechnical reports concluded that the potential for liquefaction and other ground failures is low. MM GEO-1 would ensure that site-specific engineering recommendations are incorporated into project design and construction to address any instability risk. Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, p. 3.6-20).

Expansive Soils (Threshold (d))
The Prior FEIR identified that the lean clay fill on the project site has moderate to high expansion potential. Expansive soils can cause damage to foundations and infrastructure due to volume changes with moisture fluctuations. MM GEO-1 would require design-level recommendations to address expansive soils, including foundation design and ground improvement techniques, to be incorporated into the project design and construction. Implementation of this mitigation measure would also ensure that development associated with the County Project would be designed in compliance with the recommendations provided in a Design-level Geotechnical Report, to appropriately address any potentially significant impacts related to expansive soil. Therefore, the Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, p.

3.6-21).

Proposed Project Analysis and Conclusion
The project site location and boundaries of the proposed project would be consistent with the project site and off-site areas evaluated in the Prior FEIR. Therefore, the geologic and soil features in the Prior FEIR for the County Project would be the same for the proposed project. For purposes of potential erosion impacts under Threshold (b), consistent with the analysis in the Prior FEIR, the proposed project would be required to adhere to all applicable laws and regulations, including without limitation, those relating to compliance with NPDES permitting and preparation and implementation of an approved SWPPP, including BMPs to control erosion and sedimentation during construction.

Compliance with the County’s grading and erosion control ordinance would further reduce potential impacts. Therefore, based on compliance with applicable laws and regulations, and consistent with the Prior FEIR’s impact conclusions, impacts in this regard would be less than significant.

With respect to the items under Thresholds (a), (c), and (d), consistent with the analysis and conclusions set forth in the Prior FEIR for the County Project, the proposed project would be required to implement MM GEO-1, which would ensure that the proposed structures adhere to the implementation of site-specific engineering measures recommended by a Design-level Geotechnical Report, reducing potential impacts to less than significant. The Design-level Geotechnical Report

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ADDENDUM
FCS 113
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx prepared for the proposed project by ENGEO Incorporated can be found in Appendix A; it contains site-specific recommendations for project design and construction that the proposed project would be required to implement. Additionally, ENGEO Incorporated prepared a response to geotechnical peer review comments provided by the City (Appendix A). No new geologic hazards were identified as a result of the peer review process. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
e) Septic Tanks
Would the project: Have soils incapable of supporting the use of septic tanks or other alternative wastewater disposal systems where sewers are not available?
Prior FEIR Conclusions
The Prior FEIR confirmed that the County Project would include the development of a WWTP on approximately 1 acre. The WWTP would be a package membrane bioreactor WWTP that would treat approximately 50,000 gallons per day (gpd) of wastewater. The WWTP would include an influent pump station, a headworks facility, odor control, a membrane bioreactor facility, ultraviolet disinfection, an effluent and recycled water pump station and pipelines, solids handling, a chemical facility, administration, laboratory, operations, and maintenance. The proposed WWTP would not rely on subsurface disposal and would produce disinfected tertiary recycled water as defined in California Code of Regulations, Title 22, Section 60301.230. All recycled water discharged from the WWTP would be treated pursuant to applicable State laws and regulations, and the project applicant would be required to file a Notice of Intent under the Statewide General Recycled Water Order. With respect to Alternative 2, the Prior FEIR determined that construction of the WWTP would not occur because Alternative 2 would connect to the City’s sanitary sewer system, reducing any potential impacts related to alternative wastewater disposal systems. Therefore, the Prior FEIR concluded that impacts associated with the County Project and Alternative 2 would be less than significant. (Draft EIR, pp.

3.6-22, 6-14).

Proposed Project Analysis and Conclusion
In contrast to the County Project, sanitary sewer services for the proposed project would be provided by the City, and the off-site WWTP and associated improvements would not be constructed. As such, the proposed project would have no impact related to the use of septic tanks or alternative wastewater disposal systems. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those analyzed in the Prior FEIR.

No additional analysis is required.

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ADDENDUM
114 FCS
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Prior FEIR Conclusions
The Prior FEIR found that the project site is underlain by Holocene- and Pleistocene-age deposits.

While Holocene deposits have low potential for paleontological resources, deeper Pleistocene layers have high potential. The University of California Museum of Paleontology (UCMP) database identified five vertebrate fossil localities within 3 miles of the project site. Therefore, given the foregoing, and the possibility of inadvertent discovery during construction, the Prior FEIR concluded there would be a potentially significant impact and identified MM GEO-6, which requires a qualified Paleontologist to conduct WEAP training, monitor excavations deeper than 6 feet, and implement fossil salvage procedures if resources are encountered. The Prior FEIR concluded that impacts would be less than significant with mitigation incorporated. (Draft EIR, pp. 3.6-22, 6-14).

Proposed Project Analysis and Conclusion
Consistent with the impact conclusions set forth in the Prior FEIR for the County Project, the proposed project would have a potentially significant impact in this regard due to potential inadvertent discovery and, thus, would be required to implement MM GEO-6, which would ensure that potential impacts related to any unique paleontological resources and unique geologic features would be less than significant. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

Zone 7 Stormwater Option
The Zone 7 Stormwater Option would not result in any new or more severe impacts related to geology, seismicity, or soils because it was described and considered in the Prior FEIR. By eliminating construction of the detention basin, pump facilities, and storm drain force main (as contemplated in the City Stormwater Option), this option would incrementally reduce grading and soil disturbance and would not increase exposure to seismic hazards, erosion, liquefaction, expansive soils, or other geologic risks. In addition, reduced subsurface disturbance would lessen the potential to encounter paleontological resources, and all previously adopted inadvertent discovery procedures would continue to apply; therefore, impacts would remain less than significant and consistent with the Prior FEIR.

Mitigation Measures
MM GEO-1 Design-Level Geotechnical Study
Prior to issuance of building and grading permits, an updated design-level geotechnical exploration and assessment shall be performed by a qualified

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ADDENDUM
FCS 115
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Geotechnical Engineer. The design-level exploration and reporting shall include (but would not be limited to) the following items:
• Hollow-stem auger borings, including matched-pair borings. • Soil sample collection at depths relevant to building-specific foundation design. • Laboratory testing, including (but not limited to) moisture content, unit weight, gradation, Atterberg Limits, strength, consolidation, and corrosivity testing. • Design-level assessment of geologic and geotechnical hazards, including (but not limited to) the following:
- Characterization of subsurface conditions.
- Consolidation of compressible soil based on in situ structural loading. • Design recommendations for foundation system design.
• Design-level subexcavation, ground improvement, and/or surcharging recommendations.
• Foundation constructability recommendations.
• Design-level earthwork and improvement design and construction recommendations.
• Design-level features required for landslides.

The recommendations included in the Design-level Geotechnical Report shall be implemented during construction activities, including grading and excavation.

MM GEO-1 has been partially satisfied via the preparation of a Design-level Geotechnical Report prepared by ENGEO and included herein. In accordance with the analysis, and to demonstrate full compliance with MM GEO-1, prior to the issuance of building and grading permits, the applicant shall incorporate the recommendations included in the Design-level Geotechnical Report in all application materials and plan check submittals and shall thereafter implement the same during project construction.

MM GEO-6 Prior to the start of any ground-disturbing activity, a qualified Paleontologist meeting Society of Vertebrate Paleontology (SVP) standards and best practices shall be retained to prepare and conduct a project-wide Worker Environmental Awareness Program (WEAP) training. The WEAP shall contain unanticipated discovery measures to be followed in the event that paleontological resources are encountered while the qualified Paleontologist or qualified Paleontological Monitor is not present (i.e., during excavations within the first 6 feet below the existing grade). The WEAP shall be conducted by a qualified environmental trainer, under the supervision of a qualified Paleontologist. In the event construction crews are phased in, additional training shall be conducted for new construction personnel. The training session shall focus on the recognition of the types of paleontological resources that could be encountered within the proposed project site and the procedures to be followed if they are found.

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ADDENDUM
116 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Paleontological monitoring shall be conducted by a qualified Paleontological Monitor meeting SVP standards and best practices, under the supervision of the qualified Paleontologist. Monitoring would be required for excavations at the project site that exceed 6 feet below the existing grade east of El Charro Road, in previously undisturbed deposits. Full-time monitoring shall be required for all excavation into previously undisturbed Pleistocene-age deposits. If earth-disturbing constructionrelated activities uncover any paleontological resources (i.e., bones or teeth), those activities shall be diverted at least 15 feet away from the discovery until a qualified Paleontologist is brought on-site to assess the find for possible salvage, consistent with the standards and best practices set by the SVP. Construction workers shall not attempt to remove such finds. Depending on the conditions encountered, full-time monitoring can be reduced to part-time inspections or ceased entirely if determined adequate by the qualified Paleontologist.

In the event that paleontological resources are encountered while monitoring is not occurring (i.e., during excavations within the first 6 feet below the existing grade), excavations within 50 feet of the find shall be temporarily halted or diverted until the qualified Paleontologist can assess the find and determine its significance.

Depending on the conditions encountered, monitoring activities may be increased at the discretion of the qualified Paleontologist if he or she deems it appropriate. The qualified Paleontologist may spot check the excavation on an intermittent basis and recommend whether the depth of required monitoring should be revised based on his/her observations.

The qualified Paleontologist shall document the discovery as needed and assess the significance of the find under the criteria set forth in CEQA Guidelines Section 15064.5. Salvaged fossils should be deposited in an appropriate repository (i.e., University of California Museum of Paleontology [UCMP]), where they will be properly curated and made available for future research. The qualified Paleontologist shall notify the appropriate agencies to determine procedures that would be followed before construction activities are allowed to resume at the location of the discovery. If the applicant determines that avoidance is not feasible, the qualified Paleontologist shall prepare an excavation plan for mitigating the effect of construction activities on the discovery.

The plan shall be submitted to the appropriate repository and to the County for review and approval prior to implementation. The applicant shall adhere to the recommendations in the approved plan.

Implementing Measure for MM GEO-6
Upon annexation of the proposed project into the City of Pleasanton (City), the applicant shall submit all documents, plans, and materials required under MM GEO-6 to the City for review and approval, in lieu of the County.

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ADDENDUM
FCS 117
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There is no new information of substantial importance, changes in the project, or changes in circumstances under which it will be undertaken, identifying new significant effects, nor is there a substantial increase in the severity of previously identified significant impacts related to geology and soils. The conclusions from the Prior FEIR remain unchanged when considering the implementation of the proposed project. No further environmental review is required.

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ADDENDUM
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
VIII. Greenhouse Gas Emissions
Would the project:
a) Generate
greenhouse gas
emissions, either
directly or indirectly,
that may have a
significant impact
on the
environment?
Significant
and
unavoidable
impact
No No No MM GHG-1,
MM GHG-2
b) Conflict with any
applicable plan,
policy or regulation
adopted for the
purpose of reducing
the emissions of
greenhouse gases?
Significant
and
unavoidable
impact
No No No MM GHG-2
Discussion
a-b) Greenhouse Gas Emissions; Greenhouse Gas Emissions Reduction Plan Conflict Would the project: a) Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment?
b) Conflict with any applicable plan, policy or regulation of an agency adopted for the purpose of reducing the emissions of greenhouse gases?
Prior FEIR Conclusions
The Prior FEIR found that the County Project would result in both construction and operational GHG emissions. These emissions include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from sources such as vehicle trips, energy use, and infrastructure development. The Bay Area Air District thresholds require projects to demonstrate consistency with either Criterion A (e.g., all-electric design, will not result in any wasteful, inefficient, or unnecessary energy use, and 15 percent VMT reduction) or Criterion B (compliance with a qualified GHG reduction plan).

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ADDENDUM
FCS 119
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As detailed more fully therein, the Prior FEIR evaluated consistency with the California Air Resources Board (ARB) Scoping Plan, Plan Bay Area 2050, and the Bay Area Air District 2017 Clean Air Plan.

Although the County Project includes some measures to reduce emissions to the extent feasible (e.g., traffic calming and bicycle infrastructure under MM TRANS-2), it does not fully align with the design elements required under the Bay Area Air District’s CEQA Guidelines, as described above.

Therefore, the Prior FEIR concluded there would be a significant impact in this regard.

MM GHG-1 and MM GHG-2 require pre-wiring for future all-electric retrofits and the purchase of carbon offsets to mitigate emissions from natural gas use. However, even with these measures, the Prior FEIR determined that the County Project would still exceed the Bay Area Air District thresholds because it would not demonstrate a 15 percent VMT reduction. Under Alternative 2, GHG emissions would be slightly reduced due to the smaller development footprint, but the residential component would still involve the use of natural gas and exceed the City’s per capita GHG threshold, resulting in a significant and unavoidable impact. The reduction in GHG emissions under Alternative 2 would not be sufficient to avoid a significant impact. (Draft EIR, pp. 6-15–6-16). Therefore, the Prior FEIR concluded that impacts would be significant and unavoidable. (Draft EIR, pp. 3.7-22, 6-15–6-16).

Proposed Project Analysis and Conclusion
Similar to the County Project, the proposed project would be required to comply with the applicable Title 24 Energy Efficiency Standards and CALGreen requirements—for example, and among others, EV charging infrastructure and solar requirements as adopted by Municipal Code Chapter 20.08.

The City’s CAP 2.0 is considered a qualified GHG reduction strategy pursuant to CEQA Guidelines Section 15183.5(b). Therefore, for purposes of this Addendum, the proposed project is analyzed pursuant to the Bay Area Air District’s current GHG significance thresholds under Criterion B:
consistency with a local GHG reduction strategy that meets the criteria under CEQA Guidelines Section 15183.5(b).

GHG emissions associated with the development of the proposed project would occur over the shortterm from construction activities, consisting primarily of emissions from equipment exhaust and worker and vendor trips. There would also be long-term operational emissions associated with vehicular traffic within the project vicinity, energy and water usage, and solid waste disposal. The proposed project would be largely the same as the County Project, only with fewer proposed dwelling units and a substantial reduction in the nature and scope of off-site improvements. As such, the proposed project would result in a similar, if not lower, amount of GHG emissions during construction and operation.

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ADDENDUM
120 FCS
Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx To assess whether the proposed project’s emissions would result in a significant impact, the proposed project is evaluated for consistency with the City’s CAP 2.0. As shown in the proposed project’s CAP

2.0 checklist (Appendix B), the proposed project would incorporate most applicable measures required under CAP 2.0; however, the proposed project would not include two listed features: (1) an all-electric building design and (2) a battery-storage system to support on-site solar generation.

Because the proposed project does not comply with all applicable listed CAP 2.0 measures, it is considered inconsistent with CAP 2.0. Accordingly, the proposed project would result in a significant and unavoidable GHG impact, consistent with the impact conclusions set forth in the Prior FEIR.

The proposed project would nevertheless be required to comply with the applicable 2022 CALGreen Code and Title 24 Building Energy Efficiency Standards, which, among other things, mandate highefficiency plumbing fixtures, water-efficient irrigation systems, and compliance with current energy efficiency performance standards. Compliance with these State-level codes ensures consistency with applicable State and federal plans, policies, and regulations that govern GHG emissions.

Despite compliance with these Statewide requirements and the proposed project’s compliance with most of the City’s CAP 2.0 applicable measures, because the proposed project does not include two of the above-referenced measures, it would be treated as inconsistent with the City’s CAP 2.0 for purposes of this GHG assessment. Therefore, its GHG emissions impact would continue to be significant and unavoidable. Consistent with the Prior FEIR’s analysis of the County Project, the proposed project would implement MM GHG-1 and MM GHG-2 to reduce GHG emissions to the extent feasible.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

Zone 7 Stormwater Option
The Zone 7 Stormwater Option would not result in any new or more severe greenhouse gas emissions since it was previously considered in the Prior FEIR. Moreover, because it would eliminate construction and operation of the detention basin, pump facilities, and storm drain force main (as contemplated by the City Stormwater Option), this would reduce construction-related emissions as compared to the City Stormwater Option without altering the project’s long-term operational GHG profile.

Mitigation Measures
MM GHG-1 Prior to issuance of building permits, the project applicant shall provide documentation (e.g., site plan) to the County to demonstrate that the proposed residential units would include pre-wiring so that each building is ready for a future retrofit to all-electric (e.g., such that electric space heating, water heating, drying, and cooking appliances) could be installed.

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ADDENDUM
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Prior to issuance of building permits, the applicant shall provide documentation (e.g., site plan) to the City of Pleasanton (City) demonstrating that all proposed residential units include pre-wiring to allow future retrofit to all-electric appliances (e.g., electric space heating, water heating, drying, and cooking).

MM GHG-2 Prior to issuance of building permits, the applicant shall provide documentation to the County to demonstrate purchase of carbon offsets that reduce the project’s greenhouse gas (GHG) emissions due to natural gas use, which is estimated to be 478 metric tons carbon dioxide equivalent (MT CO2e), if no other on-site measures are implemented to further reduce emissions. Based on estimated project life of 30 years, total credits needed to offset emissions below the applicable thresholds would be 14,341 MT CO2e for the life of the proposed project (or a reduced amount estimated based on implementation of other measures or preparation of refined emission modeling).

The project developer or its designee may purchase and retire carbon credits that have been issued by a recognized and reputable, accredited carbon registry in a quantity equal to the operational GHG emissions from natural gas use. For an offset to be considered viable, it must exhibit “permanence.” To adequately reduce emissions of GHGs, carbon offsets must be able to demonstrate the ability to counterbalance GHG emissions over the lifespan of a project or “in perpetuity.” The purchase of GHG credits through voluntary participation in an approved registry must meet the following criteria:
• Real—represent reductions actually achieved (not based on maximum permit levels),
• Additional/Surplus—not already planned or required by regulation or policy (i.e., not double counted),
• Quantifiable—readily accounted for through process information and other reliable data,
• Enforceable—acquired through legally-binding commitments/agreements, • Validated—verified through accurate means by a reliable third party, and • Permanent—will remain as GHG reductions in perpetuity.

Implementing Measure for MM GHG-2
Prior to issuance of building permits, the applicant shall provide documentation to the City of Pleasanton (City) demonstrating purchase and retirement of carbon offsets from a recognized and reputable, accredited carbon registry in a quantity sufficient to offset the proposed project’s greenhouse gas (GHG) emissions from natural gas use, as specified in MM GHG-2. Documentation

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ADDENDUM
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Conclusion
There is no new information of substantial importance, changes in the project, or changes in circumstances under which it will be undertaken, identifying new significant effects, nor is there a substantial increase in the severity of previously identified significant impacts related to GHG emissions. The conclusions from the Prior FEIR remain unchanged when considering the implementation of the proposed project. No further environmental review is required.

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ADDENDUM
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
IX. Hazards and Hazardous Materials
Would the project:
a) Create a significant
hazard to the public
or the environment
through the routine
transport, use, or
disposal of
hazardous
materials?
Less than
significant
impact
No No No NA
b) Create a significant
hazard to the public
or the environment
through reasonably
foreseeable upset
and accident
conditions involving
the release of
hazardous
materials into the
environment?
Less than
significant
impact
No No No NA
c) Emit hazardous
emissions or handle
hazardous or
acutely hazardous
materials,
substances, or
waste within onequarter mile of an
existing or
proposed school?
Less than
significant
impact
No No No NA
d) Be located on a site
which is included
on a list of
Less than
significant
impact
No No No NA

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ADDENDUM
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
hazardous
materials sites
compiled pursuant
to Government
Code Section
65962.5 and, as a
result, would it
create a significant
hazard to the public
or the environment?
e) For a project
located within an
airport land use
plan or, where such
a plan has not been
adopted, within two
miles of a public
airport or public use
airport, would the
project result in a
safety hazard or
excessive noise for
people residing or
working in the
project area?
Less than
significant
impact
No No No NA
f) Impair
implementation of
or physically
interfere with an
adopted emergency
response plan or
emergency
evacuation plan?
Less than
significant
impact
No No No NA

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ADDENDUM
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
g) Expose people or
structures, either
directly or indirectly
to a significant risk
of loss, injury or
death involving
wildland fires?
Less than
significant
impact
No No No NA
Discussion
a) Routine Transport, Use, or Disposal of Hazardous Materials Would the project: Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? Prior FEIR Conclusions
The Prior FEIR found that the construction and operation of the County Project would involve the use of common hazardous materials such as fuels, lubricants, paints, and cleaning agents, which could generate small amounts of hazardous waste. However, all activities would be subject to mandatory compliance with applicable federal, State, and local laws and regulations administered by agencies including the United States Environmental Protection Agency (EPA), Occupational Safety and Health Administration (OSHA), United States Department of Transportation (USDOT), California Department of Toxic Substances Control (DTSC), California Department of Transportation (Caltrans), California Highway Patrol (CHP), Alameda County Department of Environmental Health (ACDEH), and the Bay Area Air District. The Alameda County Fire Department (ACFD) and Building Department would review building permits to ensure compliance with hazardous materials requirements. Businesses storing hazardous materials above threshold quantities would be required to submit Hazardous Materials Business Plans (HMBPs), including contingency plans for accidental releases. Disposal would be regulated by ACDEH, ACFD, California Division of Occupational Health and Safety (Cal/OSHA), and DTSC. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.8-17, 6-16).

Proposed Project Analysis and Conclusion
Consistent with the County Project, the proposed project may utilize typical hazardous materials, such as fuels or solvents, during the construction phase of the proposed project. During the operations phase, residents may also routinely use commonly available hazardous substances, such

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ADDENDUM
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Would the project: Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment?
Prior FEIR Conclusions
Phase I Environmental Site Assessments (Phase I ESAs) were conducted for both the residential site and off-site improvement areas, and no Recognized Environmental Conditions (RECs) were identified. The Former Hanson Aggregate Radum Facility is classified as a Controlled REC (CREC), but nearby sites were evaluated and found not to pose a concern to the project site. The Prior FEIR found that, because the project site remains under active regulatory oversight with long-term management requirements, there is potential for exposure to impacted soil or groundwater if such materials are not properly handled. However, the County Project would be required to comply with the ACDEH-approved Soil Management Plan and Soil Import Management Plan, which establishes procedures for identifying, segregating, testing, and properly managing any impacted materials encountered during construction, which would ensure potential hazards to the project site and to the public are minimized. Additionally, vapor migration was also assessed and determined to be unlikely.

Areas of Concern (AOCs) 6 and 7 were evaluated through historical investigations and subsequent sampling; results indicated that subsurface conditions in both areas do not pose a risk to human health or the environment. None of the County Project’s on-site or off-site improvements would be constructed within these AOCs.

The County Project would comply with applicable health and safety laws and regulations to prevent accidental releases. As discussed above, construction activities would require the use of commercially available typical hazardous materials and may generate small amounts of hazardous waste.

The Prior FEIR disclosed that the use, storage, transportation, and disposal of hazardous materials at the project site could result in the accidental release of hazardous materials into the environment.

However, the County Project would be required to comply with applicable mandatory federal, State, and local laws and regulations, which would reduce the potential for an accidental release of hazardous materials. In the event of an accidental release, the ACFD and ACDEH would be notified

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ADDENDUM
FCS 127
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Proposed Project Analysis and Conclusion
The project site location and boundaries of the proposed project would be consistent with the project site and off-site areas evaluated in the Prior FEIR; therefore, the hazardous materials conditions of the project site and related analysis identified in the Prior FEIR would apply to the proposed project.

As determined in the Prior FEIR, no RECs have been identified for the project site. Consistent with the findings in the Prior FEIR, the proposed project would comply with all applicable federal, State, and local laws and regulations, including the General Plan, Titles 8 and 17 of the California Code of Regulations, and Cal/OSHA requirements. This would include, but not be limited to, requiring compliance with Pleasanton General Plan Public Safety Element Goal 5, which looks to “minimize the risks to lives and property due to potential exposure to hazardous materials.” If accidental release of hazardous materials did occur, the appropriate regulatory agencies would be notified to address the release. Accordingly, the proposed project’s impact in this regard would be less than significant, consistent with the impact conclusions of the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required. c) Exposure of Schools to Hazardous Materials or Emissions Would the project: Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school?
Prior FEIR Conclusions
The Prior FEIR found that the Montessori School of Pleasanton is located approximately 0.25 mile from the project site. However, as detailed above, the County Project would adhere to applicable federal, State, and local laws and regulations while utilizing typical commercial hazardous materials for construction. Given the foregoing, the County Project would not handle or emit hazardous materials that could result in a significant impact on the school within proximity to the project site.

Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.8- 21, 6-16).

Proposed Project Analysis and Conclusion
Similar to the conclusions of the Prior FEIR, while there is a school located within 0.25 mile of the project site, the proposed project would not handle or emit hazardous materials that could result in a significant impact to any schools because the proposed project, which would be reduced in scope to a certain degree and thus the amount of hazardous materials involved in construction and operation

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ADDENDUM
128 FCS
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Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
d) Hazardous Materials Sites
Would the project: Be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment?
Prior FEIR Conclusions
The Prior FEIR determined that the project site is located on a list of hazardous materials sites (the Cortese List). The Cleanup Program Site at the project site is currently open and is undergoing longterm management as of 2026. Long-term management refers to ACDEH’s continued oversight of the project site until it verifies that all soil import, restoration, and reporting requirements are fully satisfied and the case can be formally closed. The ACDEH has concluded that potential environmental impacts from former mining operations have been adequately investigated and delineated and found not to present an adverse risk to human health or the environment.

The Prior FEIR found that construction activities associated with the County Project could expose contaminants to workers, the public, or the environment if not properly managed. Compliance with COA HAZ-4a through COA HAZ-4e established by ACDEH and all applicable laws and regulations associated with development on hazardous materials sites would reduce any potential impact associated with the project site being located on a site included on the Cortese List. Additionally, the County Project would be subject to ongoing regulatory requirements. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.8-21, 6-16).

Proposed Project Analysis and Conclusion
The hazardous materials conditions of the project site and related analysis identified in the Prior FEIR for the County Project would apply to the proposed project as well. Because the project site is located on the Cortese List, the proposed project would be required to comply with COA HAZ-4a through COA HAZ-4e from ACDEH, which include coordinating with ACDEH prior to and during site development by submitting the soil management protocols, project schedule, soil import documentation, stockpile information, and soil excavation report. With the implementation of these COAs, as well as applicable provisions of the Pleasanton General Plan, as noted above, the proposed project would have less than significant impacts, consistent with the analysis and impact conclusions in the Prior FEIR. Therefore, the proposed project would not introduce new significant

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ADDENDUM
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e) Airports
Would the project: For a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project result in a safety hazard or excessive noise for people residing or working in the project area? Prior FEIR Conclusions
The Prior FEIR found that the Livermore Municipal Airport is located approximately 1.6 miles northeast of the project site. The project site is within the Airport Influence Area, however the project site is not within any established noise contours or airport safety zones as indicated by the Livermore Municipal Airport Land Use Compatibility Plan (ALUCP). As such, the County Project would not result in airport-related safety hazards or excessive noise, and the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.8-23, 6-16).

Proposed Project Analysis and Conclusion
Similar to the conclusions of the Prior FEIR, the project site is not located within any established noise contours or airport safety zones. Accordingly, the proposed project would not result in airportrelated hazards, and impacts would be less than significant, consistent with the impact conclusions of the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
f) Emergency Response and Evacuation
Would the project: Impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan?
Prior FEIR Conclusions
The County has developed an Emergency Operations Plan (EOP) that establishes policies and procedures and assigns responsibilities to ensure the effective management of emergency operations within the County. The County’s EOP does not list any specific evacuation routes throughout the County because these routes would be determined based on the location and nature of the emergency by the Alameda County Sheriff’s Office. Major roadway networks, including SR-84, I-580, and I-680, provide regional access to the project site and would likely be used as evacuation routes in the event of an emergency. Any road blockages during the construction phase would not interfere with these routes and would be temporary. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.8-23, 6-16).

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ADDENDUM
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Similar to the conclusions of the Prior FEIR, the proposed project would have adequate vehicle circulation, including adequate circulation for large vehicles such as fire trucks, all of which would be confirmed and implemented during the building permit process. The proposed internal roadways and access points would meet the applicable regulations for emergency vehicle widths.

The proposed project would also be required to comply with applicable goals and policies from the Public Safety Element of the General Plan. In addition, the proposed project would not interfere with guidelines set forth in the Pleasanton Comprehensive Emergency Management Plan and the Alameda County Disaster Plan, because the proposed project would provide adequate emergency access to the project site and would not obstruct major roadways in the City which may serve as evacuation routes, including Stanley Boulevard and I-680. The proposed project would also undergo review by Livermore-Pleasanton Fire Department (LPFD) to ensure its proposed emergency access adheres to all applicable standards and requirements. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required. g) Wildland Fires
Would the project: Expose people or structures, either directly or indirectly to a significant risk of loss, injury or death involving wildland fires? Prior FEIR Conclusions
The Prior FEIR found that the project site is not located in a Very High Fire Hazard Severity Zone (VHFHSZ) and not in or near a State Responsibility Area (SRA). However, it acknowledged that wildfire risk exists due to regional conditions such as wind and vegetation. Compliance with fire safety regulations, including the use of fire-resistant building materials and landscaping, would reduce risks.

Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.8- 25, 6-16).

Similar to the conclusions of the Prior FEIR, the project site is not located in a VHFHSZ and is not located in or near an SRA. Although construction of the proposed project would not occur within a Fire Hazard Severity Zone (FHSZ), the proposed project would be required to comply with applicable fire protection measures included in the policies and programs within the General Plan and the Municipal Code, such as General Plan Program 13.1, which requires the installation of building and fire code compliant fire-detection and alarm equipment in residential structures. Further, continued implementation of the Tri-Valley Local Hazard Mitigation Plan (LHMP) and review of architectural and development plans by LPFD would assist in protecting life and property in the event of a wildfire, further reducing risk in this regard. Accordingly, consistent with the impact conclusions in the Prior FEIR, the proposed project would have a less than significant impact with respect to wildfire.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

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ADDENDUM
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Under the Zone 7 Stormwater Option, as considered in the Prior FEIR, construction and operation of the detention basin, pump facilities, and storm drain force main (as contemplated under the City Stormwater Option) would be eliminated, thereby reducing the use, handling, and potential accidental release of fuels, lubricants, and other hazardous materials associated with construction equipment and mechanical infrastructure. Consistent with the impact conclusions in the Prior FEIR, this option would not introduce new hazardous materials uses or expose people or structures to additional risk.

Accordingly, impacts related to hazards and hazardous materials would remain less than significant and consistent with the conclusions of the Prior FEIR.

Mitigation Measures
The Prior FEIR determined that no mitigation measures are required. However, the following Conditions of Approval established by ACDEH were identified for implementation in the Prior FEIR and would be applicable to the proposed project.

Conditions of Approval
COA HAZ-4a During site redevelopment, the Applicant shall implement corrective actions and soil management protocols identified in the Final Soil Report submitted to the Alameda County Department of Environmental Health (ACDEH) for review and approval.

COA HAZ-4b Prior to the start of site grading, the Applicant shall submit the project schedule to the Alameda County Department of Environmental Health (ACDEH) for review and approval.

COA HAZ-4c Prior to the import of soil to the project site, the Applicant shall submit soil import documentation to the Alameda County Department of Environmental Health (ACDEH) for review and approval.

COA HAZ-4d Prior to the reuse of excavated stockpile material on the project site, the Applicant shall submit a Stockpile Characterization Sampling, Evaluation, and Reuse Plan to the Alameda County Department of Environmental Health (ACDEH) for review and approval.

COA HAZ-4e Prior to the beginning of construction, the Applicant shall submit a soil excavation report to the Alameda County Department of Environmental Health (ACDEH) for review and approval.

Conclusion
There is no new information of substantial importance, changes in the project, or changes in circumstances under which it will be undertaken, identifying new significant effects, nor is there a substantial increase in the severity of previously identified significant impacts related to hazards and hazardous materials. The conclusions from the Prior FEIR remain unchanged when considering the implementation of the proposed project. No further environmental review is required.

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ADDENDUM
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
X. Hydrology and Water Quality
Would the project:
a) Violate any water
quality standards or
waste discharge
requirements or
otherwise
substantially
degrade surface or
ground water
quality?
Less than
significant
impact
No No No NA
b) Substantially
decrease
groundwater
supplies or interfere
substantially with
groundwater
recharge such that
the project may
impede sustainable
groundwater
management of the
basin?
Less than
significant
impact
No No No NA
c) Substantially alter
the existing
drainage pattern of
the site or area,
including through
the alteration of the
course of a stream
or river or through
the addition of
impervious
surfaces, in a
Less than
significant
impact
No No No NA

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ADDENDUM
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
manner which
would:
(i) result in
substantial
erosion or
siltation on- or
off-site;
Less than
significant
impact
No No No NA
(ii) substantially
increase the
rate or amount
of surface runoff
in a manner
which would
result in flooding
on- or off-site;
Less than
significant
impact
No No No NA
(iii)create or
contribute runoff
water which
would exceed
the capacity of
existing or
planned
stormwater
drainage
systems or
provide
substantial
additional
sources of
polluted runoff;
or
Less than
significant
impact
No No No NA
(iv) impede or
redirect flood
flows?
Less than
significant
impact
No No No NA

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ADDENDUM
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
d) In flood hazard,
tsunami, or seiche
zones, risk release
of pollutants due to
project inundation?
Less than
significant
impact
No No No NA
e) Conflict with or
obstruct
implementation of a
water quality control
plan or sustainable
groundwater
management plan?
Less than
significant
impact
No No No NA
Discussion
a) Water Quality
Would the project: Violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or ground water quality?
Prior FEIR Conclusions
The Prior FEIR found that construction activities such as grading and excavation could introduce pollutants (e.g., sediment, fuel, concrete, litter) into stormwater runoff. However, the County Project would be subject to the California State Water Resources Control Board’s (State Water Board’s) NPDES General Permit for Construction Activities, requiring a SWPPP with site-specific BMPs. These measures would minimize erosion and control pollutant discharge. During operations, increased impervious surfaces could elevate urban runoff pollutants, but the County Project would comply with the County’s Municipal Regional Permit (MRP), which includes Low Impact Development (LID) standards and post-construction monitoring.

With respect to Alternative 2, the Prior FEIR determined that development would be located west of El Charro Road in the Federal Emergency Management Agency (FEMA) Flood Hazard Zone X, avoiding flood hazard areas and reducing potential impacts related to flooding and water quality. As such, impacts under Alternative 2 would be lower than those under the County Project, although the impact conclusions remained the same under both the County Project and Alternative 2. (Draft EIR, p. 6-16).

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ADDENDUM
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The Prior FEIR addressed comments from the City and other agencies regarding potential per- and polyfluoroalkyl substances (PFAS) concerns associated with wastewater treatment, effluent management, and water quality. As documented in the Prior FEIR’s Master Responses addressing wastewater treatment plant operation, effluent quality, and regulatory compliance, the County concluded that the County Project would comply with applicable State and federal PFAS regulations and would not result in significant impacts to groundwater or surface water quality (Final EIR, pp. 2- 34–2-35).

Proposed Project Analysis and Conclusion
Similar to the County Project, construction associated with the proposed project would include grading, excavation, and removal of vegetative cover that has the potential to result in runoff that contains sediment and other pollutants, such as fuel, grease, oil, and other fluids, that could degrade surface and groundwater quality, if not properly controlled. As construction of the proposed project would disturb more than 1 acre of land, compliance with the NPDES General Permit would be required, similar to the County Project. The General Permit would require the development and implementation of a SWPPP. The SWPPP would include site-specific BMPs, such as strategically placed silt fences and straw wattles to minimize erosion on-site and reduce or otherwise prevent conditions of erosion and stormwater runoff during construction. The proposed project would also be subject to the San Francisco Bay MRP, which includes LID standards and post-construction monitoring to encourage stormwater infiltration and retention.

The proposed project does not include the water storage and booster pump facility, WWTP, recycled water storage, and agricultural irrigation fields included under the County Project, removing potential water quality impacts associated with these types of development that were identified and evaluated in the Prior FEIR, such as PFAS. Furthermore, the proposed project includes stormwater drainage facilities as described in the Project Description, which would ensure that stormwater is treated, detained, and conveyed to the appropriate facilities to prevent potential impacts related to stormwater drainage on the nearby lakes. As such, impacts related to surface and groundwater quality would be less than those disclosed in the Prior FEIR, although the less than significant impact conclusion would be the same for the proposed project and the County Project. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

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ADDENDUM
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Would the project: Substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin? Prior FEIR Conclusions
The Prior FEIR determined that the project site is located within the Livermore Valley Groundwater Basin, managed under Zone 7’s Alternative Groundwater Sustainability Plan. The County Project would be served by the California Water Service (Cal Water) and would comply with all applicable groundwater management actions. No significant extraction or interference with recharge was identified, and the proposed WWTP would not adversely affect groundwater quality.

The Prior FEIR concluded that the County Project would not result in groundwater depletion or degradation. The County Project would not involve on-site groundwater extraction and would be served by municipal water supplies consistent with the Zone 7 Alternative Groundwater Sustainability Plan. Recycled water would be applied at agronomic rates and treated using membrane bioreactor technology that removes nitrogen, thereby avoiding nitrate loading to groundwater. Project-related salt contributions would be de minimis and would be managed through Zone 7’s basin-wide salt and nutrient management programs. Accordingly, the Prior FEIR determined that the County Project would not contribute to chronic lowering of groundwater levels, degradation of groundwater quality, land subsidence, or adverse effects on interconnected surface waters. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.9-27, 6-16; Final EIR, pp. 2- 37–2-51).

Proposed Project Analysis and Conclusion
During construction, similar to the County Project, the proposed project would comply with applicable stormwater requirements, including those found in Pleasanton Municipal Code Chapter 9.14 (Stormwater Management and Discharge Control) and would incorporate BMPs to address water quality and control runoff from the project site; therefore, construction runoff would not be absorbed into the groundwater supplies. While dewatering is not expected to be required during project construction, such actions, if required, would be temporary and would not substantially interfere with groundwater supplies, recharge, or management.

Water services for the proposed project would be provided by the City, which receives its water supply from Zone 7. Similar to the County Project, the proposed project could lead to an increased demand for water, which could lead to an increase in demand for groundwater production. However, the water demand for the proposed project would be slightly reduced compared to the County Project due to the reduction in dwelling unit count. The City receives 100 percent of its water from Zone 7. 35,36
35 City of Pleasanton. 2026. About our Water. Website: https://www.cityofpleasantonca.gov/our-government/pleasantonwater/about-our-water/. Accessed March 10, 2026. 36 While the City previously obtained a portion of its supply from City-owned groundwater wells, those wells are no longer in

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ADDENDUM
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Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx Approximately 20 percent of Zone 7’s water supplies come from groundwater, with the rest coming from surface water sources.37 Groundwater supply is pumped from the Livermore Valley Groundwater Basin. The basin is not adjudicated and is not considered to be critically overdrafted; it is instead considered a medium-priority groundwater basin. As such, the basin is regulated under the Sustainable Groundwater Management Act (SGMA), and the preparation and implementation of a Groundwater Sustainability Plan (GSP) is required. Zone 7 has an approved GSP for the Livermore Valley Groundwater Basin, which identifies projects, practices, and goals related to management of groundwater supplies.
38 Adherence to the applicable objectives and sustainability goals provided in the GSP would reduce impacts to groundwater quality within the City. Further, the proposed project would not include any on-site wells that would draw groundwater for proposed project operations.

Therefore, impacts related to groundwater recharge and supply would be less than significant, consistent with the analysis and impact conclusions in the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required. c) Drainage
Would the project: Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would:
i) result in substantial erosion or siltation on- or off-site; ii) substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site;
iii) create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff.

Prior FEIR Conclusions
The Prior FEIR found that construction activities within the project site could result in substantial erosion or siltation, leading to drainage pattern alteration and the increased potential for polluted runoff to enter nearby water bodies. However, the County Project would be required to comply with the regulations of its NPDES permit. Additionally, the County Project would be required to comply with construction-phase BMPs and requirements for erosion and sedimentation control plans. The County Project would be required to design and implement a SWPPP to ensure that erosion, siltation, and operation. The City is actively evaluating future supply alternatives, including potential joint groundwater wells in coordination with Zone 7; however, at present, all water supplies are purchased from Zone 7. 37 Zone 7 Water Agency (Zone 7). 2021. 2020 Urban Water Management Plan. June. 38 Zone 7 Water Agency (Zone 7). 2021. Alternative Groundwater Sustainability Plan for the Livermore Valley Groundwater Basin. December.

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ADDENDUM
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From an operational standpoint, stormwater on the project site would be captured in two bioretention areas designed in accordance with all applicable standards with adequate capacity to accommodate stormwater flows at the project site. Because stormwater would be treated through bioretention areas to ensure that there would be no net increase in off-site stormwater flow, the County Project would not result in an exceedance of storm drain capacity. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.9-28, 6-16).

Proposed Project Analysis and Conclusion
Similar to the County Project, the proposed project could result in erosion or siltation, as well as increased risk of flooding and additional sources of polluted runoff during construction. However, the proposed project would be required to comply with the regulations of its NPDES permit. Additionally, the proposed project would be required to comply with construction-phase BMPs and requirements for erosion and sedimentation control plans. The proposed project would be required to design and implement a SWPPP to ensure that erosion, siltation, and flooding are prevented or minimized to the maximum extent feasible during construction.

Similar to the County Project, stormwater runoff from the project site during operation would be drained by storm gutters located on the sides of the proposed internal streets. Stormwater would flow into 18-inch to 24-inch pipes located under the streets and then be drained off the project site using two proposed pipes. The first pipe would be a 24-inch diameter pipe that would be constructed to connect to an existing City-owned 54-inch diameter storm drainpipe in Mohr Avenue. The proposed 24-inch storm drainpipe would follow the same alignment as the proposed water line, extending from the northwest corner of the project site, following the existing utility road, to Mohr Avenue (Exhibit 9c).

The second pipe would be constructed to extend from the intersection of Street A and Loop A, across the adjacent vacant land to the east of the project site, to a proposed bioretention area and detention basin approximately 0.45 mile east of the project site, adjacent to El Charro Road (Exhibit 9b). The bioretention area would meet all applicable regulatory requirements and would include a treatment area of approximately 1 acre, a discharge pump, and a detention basin, with layers of bioretention soil mix and permeable rock, protected by an approximately 8-foot berm. The stormwater improvements would be designed and constructed to applicable City of Pleasanton Standard Specifications and Details. As discussed in the Prior FEIR, the proposed bioretention area and detention basin would have sufficient capacity to serve the project site pursuant to applicable regulatory standards, which would further ensure that the proposed project would not result in a net increase of off-site stormwater flow, or a significant impact related to flooding or exceedance of the capacity of the City’s existing stormwater infrastructure. As such, impacts related to erosion or siltation, flooding, and runoff would be less than significant, consistent with the impact conclusions in the Prior FEIR.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

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ADDENDUM
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Prior FEIR Conclusions
The proposed residential development area is located within a Flood Hazard Zone X, an area of minimal flood hazard, which is outside of the 0.2 percent Annual Chance Flood Hazard Area. The Prior FEIR determined that the County Project’s design would not impede or redirect flood flows because stormwater would be captured in bioretention areas off-site, which would be designed in accordance with all applicable standards with adequate capacity to accommodate the County Project during storm events to ensure no net increase in off-site flow of stormwaters.

Some of the off-site improvements would be located in a FEMA Flood Hazard Zone A, which is an area with a 1 percent annual chance of flooding. The Prior FEIR determined that it would be unlikely that 100-year flood levels would inundate the County Project’s off-site utilities, and the County Project would be required to comply with FEMA guidelines for development within a flood zone. Furthermore, as part of the County’s deliberations and approval, the agricultural irrigation fields were moved west of El Charro Road, into an area designated by Flood Hazard Zone X, which would reduce potential impacts. Therefore, the Prior FEIR concluded that impacts would be less than significant.

Proposed Project Analysis and Conclusion
The proposed residential development area would remain in an area of minimal flood hazard, as designated by FEMA.

Similar to the County Project, the proposed project has been designed to ensure it would not impede or redirect flood flows. Stormwater would be captured in bioretention areas off-site, which would be designed in accordance with all applicable standards to ensure there is adequate capacity to accommodate the project site during storm events to ensure no net increase in off-site flow of stormwater. In addition, for extreme storm events that exceed the capacity of the bioretention system, an overland release in the form of an emergency spillway would safely convey flows in accordance with Zone 7 Flood Control standards and historic drainage patterns as described in the Project Description. As such, impacts would be less than significant, consistent with the conclusions in the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
d) Risk of Pollutant Release Due to Inundation
Would the project: In flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation?
Prior FEIR Conclusions
The Prior FEIR evaluated flood hazard risks using the FEMA’s Flood Insurance Rate Maps (FIRMs) and found that the proposed residential development area would be located within Flood Hazard Zone X, an area of minimal flood hazard. Portions of the off-site utility infrastructure (i.e., water storage and booster pump facility and a bioretention area) required for the County Project would be

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ADDENDUM
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The Arroyo Lago Off-site Utility Flood Study, prepared by Schaaf and Wheeler, dated March 13, 2024, indicates that the off-site improvements would not be inundated during a 100-year storm event because it is unlikely that the 100-year water surface elevation would be above ground at the location for the off-site improvements and that any spills that occur from the nearby lakes would be contained into the quarry ponds. Additionally, the water storage and booster pump facility would be designed in accordance with FEMA-published guidelines for development occurring within a 100-year Flood Hazard Zone.

The WWTP and other infrastructure would be constructed above inundation zone elevations.

Compliance with applicable FEMA standards and RWQCB Basin Plan requirements would ensure protection from flood-related pollutant release.

The project site is located immediately south of Lake I of the Zone 7 Chain of Lakes, which could be susceptible to a seiche. However, the County Project would comply with all applicable regulations and requirements from the ECAP, Municipal Code, and NPDES to ensure protection from flood-related pollutant release. Additionally, the project site is approximately 16.4 miles east of the San Francisco Bay and 35.7 miles east of the Pacific Ocean. The project site would not be at risk of inundation from a tsunami. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.9-32, 6-16).

Proposed Project Analysis and Conclusion
Similar to the conclusions of the Prior FEIR, the project site is approximately 16.4 miles east of the San Francisco Bay and 35.7 miles east of the Pacific Ocean. Given this distance from the ocean, the project site would not be at risk of inundation from a tsunami.

As discussed in the Prior FEIR, the project site is located immediately south of Lake I of the Zone 7 Chain of Lakes, which could be susceptible to a seiche. However, the proposed project would comply with all applicable regulations and requirements from the City’s General Plan, Municipal Code, and NPDES, which would allow for the adequate sizing of storm drainage systems, preserve areas with percolation abilities, and minimize sedimentation and erosion. Therefore, consistent with the impact conclusions in the Prior FEIR, impacts related to a tsunami and inundation from a seiche would be less than significant.

As also evaluated at length in the Prior FEIR, potential pollutants stored on-site during construction would be stored in a manner consistent with the proposed project’s NPDES-mandated SWPPP, as well as applicable regulations including, without limitation, those by OSHA, Department of Hazardous Substances and Materials, which help to prevent pollutant release.

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ADDENDUM
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Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx The proposed project stormwater drainage system, including the bioretention area and detention basin, would have sufficient capacity to serve the proposed project. The stormwater system would be designed in accordance with all applicable standards, including those set out in Pleasanton Municipal Code Chapter 9.14 (“Stormwater Management and Discharge Control”) with adequate capacity to accommodate the project site during storm events and ensure no net increase in off-site flow of stormwater. Consistent with Pleasanton General Plan Public Safety Policy 15, residential development would be located outside of the 100-year flood hazard area, while limited off-site utility infrastructure proposed within Flood Hazard Zone A would be designed to meet applicable FEMA and local flood control standards. In addition, the proposed project includes a controlled overland release in the form of an emergency spillway to safely convey extreme storm flows in accordance with Zone 7 Flood Control standards and historic drainage patterns.

Moreover, the proposed project includes residential land uses, which do not represent the type of use that would otherwise degrade water quality (e.g., industrial land uses that utilize hazardous materials that could adversely affect water quality). Anticipated and potential pollutants generated by the proposed project would be limited to household items and normal and expected materials for the proposed land uses and include sediment, nutrients, pesticides, metals, pathogens, oil, and grease.

These materials would be limited to personal use quantities. Thus, impacts would be less than significant, consistent with the impact conclusions of the Prior FEIR.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.
e) Water Quality Control or Sustainable Groundwater Management Plans Consistency Would the project: Conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan?
Prior FEIR Conclusions
Particularly given the project site’s location and the scope of off-site utility improvements, the Prior FEIR conducted a robust analysis to consider whether the County Project would conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan.

As detailed more fully therein, the Prior FEIR confirmed that the County Project would comply with the RWQCB Basin Plan and Zone 7’s Alternative GSP. During construction, the County Project would be required to comply with the terms of the Construction General Permit, which requires the preparation and implementation of a SWPPP that includes BMPs to ensure reduction of pollutants from construction activities potentially entering surface waters.

During operation, the County Project would be served by Cal Water Livermore District, which derives its water supply from a combination of groundwater and surface water purchased from Zone 7. The County Project complies with the Zone 7 Alternative GSP by demonstrating that its groundwater use would have an insignificant impact on basin conditions and would not interfere with Zone 7’s ability to maintain the Livermore Valley Groundwater Basin within its sustainable yield. The Prior FEIR

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ADDENDUM
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Furthermore, the WWTP would be designed and required to produce disinfected tertiary recycled water per Title 22 standards and be regulated during operations under Water Reclamation Requirements (Order WQ 2016-0068-DDW). A Notice of Intent would be filed with the RWQCB for Waste Discharge Requirements (WDRs), further ensuring consistency with applicable water quality plans. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp.

3.9-34, 6-16).

Proposed Project Analysis and Conclusion
As described in the Prior FEIR, the RWQCB has established regulatory standards and objectives for water quality in its Basin Plan. Consistent with the analysis of the Prior FEIR, the proposed project would not conflict with the Basin Plan or the County’s NPDES program. Given that proposed construction would disturb more than 1 acre of land, the proposed project would be required to comply with the terms of the Construction General Permit, which require the preparation and implementation of a SWPPP that includes BMPs to ensure reduction of pollutants from construction activities potentially entering surface waters. Therefore, consistent with the impact conclusions in the Prior FEIR, construction impacts related to a water quality control plan or groundwater management plan consistency would be less than significant.

As described above, any groundwater used by the City to serve the proposed project comes from the Livermore Valley Groundwater Basin through contracts with Zone 7, which is considered a mediumpriority groundwater basin. While the City previously obtained a portion of its supply from City-owned groundwater wells, those wells are no longer in operation. The City is actively evaluating future supply alternatives, including potential joint groundwater wells in coordination with Zone 7; however, at present, all water supplies are purchased from Zone 7. The Basin is regulated under SGMA, and the preparation and implementation of a GSP is required. Adherence to the objectives and sustainability goals provided in the GSP would reduce impacts to groundwater quality within the City. Thus, the proposed project would not interfere substantially with groundwater supply. Furthermore, the proposed project would not include the construction of the WWTP included under the County Project, further reducing the potential for any significant impacts. Therefore, impacts related to sustainable groundwater management would be less than significant.

Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

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The Zone 7 Stormwater Option would not result in any new or more severe hydrology or water quality impacts since it was considered in the Prior FEIR. Stormwater would continue to be treated through the proposed bioretention facilities in full compliance with applicable water quality standards and regulatory requirements, and the alternative would not introduce new pollutant sources or violate WDRs. Regarding groundwater, the option would not increase groundwater extraction or interfere with groundwater recharge, as stormwater management would remain consistent with the approved project design and applicable groundwater management plans. In terms of drainage patterns and runoff, this option would allow treated stormwater to discharge and drain naturally toward Cope Lake, rather than being conveyed through a detention basin, pump facilities, and storm drain force main; however, this change would not increase runoff volumes, alter drainage patterns in a manner that would cause erosion or flooding, or exceed the capacity of downstream drainage systems. This option would not increase flood risk or impede flood flows, as stormwater flows would remain within the hydrologic conditions evaluated in the Prior FEIR and would be subject to applicable erosion control and post-construction stormwater requirements. Finally, this option would not conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan, as it would remain subject to all applicable City, RWQCB, and Zone 7 requirements, as discussed in the Prior FEIR. Accordingly, hydrology and water quality impacts associated with the Zone 7 Stormwater Option would remain less than significant and consistent with the conclusions of the Prior FEIR.

Mitigation Measures
None.

Conclusion
There is no new information of substantial importance, changes in the project, or changes in circumstances under which it will be undertaken, identifying new significant effects, nor is there a substantial increase in the severity of previously identified significant impacts related to hydrology and water quality. The conclusions from the Prior FEIR remain unchanged when considering the implementation of the proposed project. No further environmental review is required.

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ADDENDUM
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Area
Conclusion
in Prior FEIR
Do the
Proposed
Changes
Involve New or
More Severe
Impacts?
New
Circumstances
Involving New
or More Severe
Impacts?
New
Information
Requiring New
Analysis or
Verification?
Mitigation
Measures
XI. Land Use and Planning
Would the project:
a) Physically divide an
established
community?
No impact No No No NA
b) Cause a significant
environmental
impact due to a
conflict with any land
use plan, policy, or
regulation adopted
for the purpose of
avoiding or
mitigating an
environmental
effect?
Less than
significant
impact
No No No NA
Discussion
a) Division of an Established Community
Would the project: Physically divide an established community? Prior FEIR Conclusions
As stated in the Prior FEIR, the physical division of an already established community typically refers to construction of a linear feature, such as an interstate highway, railroad tracks, or the removal of a means of access that would impact mobility within an existing community and an outlying area. The County Project would include the development of market-rate single-family homes, junior ADUs, and certain off-site improvements, including a WWTP, a recycled water storage facility, a water storage and booster pump facility, agricultural irrigation fields, and two bioretention areas. For the reasons detailed in the Prior FEIR, the County Project is consistent with the surrounding land uses and would not physically divide an established community since it would not involve the construction of a linear feature or the removal of a means of access that would impact mobility within the County. Similarly, as discussed under Alternative 2, the residential development would be consistent with City land use plans and would not divide an established community. Impacts would be similar to the County Project.

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ADDENDUM
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3.10-8, 6-16).

Proposed Project Analysis and Conclusion
The proposed project includes the construction of 189 single-family homes and 48 junior ADUs on an approximately 30-acre project site, in addition to related improvements including a bioretention area and stormwater detention basin to be located approximately 0.45 mile east of the project site, adjacent to El Charro Road. The project site and associated off-site improvement areas are currently vacant with no structures or existing development.

The development of the proposed project would not involve the construction of any type of linear feature that would impair mobility within an existing community, nor would it remove a means of access in a manner that would impede travel or otherwise constitute division of an established community. Rather, the proposed project would be designed in accordance with the relevant City General Plan’s policies that encourage a cohesive, integrated site and circulation plan. As such, consistent with the impact conclusion of the Prior FEIR, the proposed project would have no impact related to dividing an established community. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required. b) Conflict with Applicable Land Use Plans, Policies, or Regulations Would the project: Cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect?
Prior FEIR Conclusions
The Prior FEIR determined that the proposed residential project is consistent with the MDR land use designation in the ECAP, which allows for 4.1 to 8.0 du/acre. Although the project site is currently zoned A, the zoning is inconsistent with the ECAP designation. Under Government Code Sections 65589.5(j)(4) and 65905.5(c)(2), the County Project does not require rezoning if it complies with objective general plan standards. The proposed density of 7.3 du/acre aligns with the applicable MDR standards set forth in the ECAP and supports County housing goals and Regional Housing Needs Allocation (RHNA) targets. The Prior FEIR also found that the County Project’s off-site improvements would be consistent with the applicable Water Management (WM) and LPA General Plan land use designations. Therefore, the Prior FEIR concluded that impact would be less than significant. (Draft EIR, p. 3.10-9, 6-16).

Proposed Project Analysis and Conclusion
The proposed project includes annexation of the approximately 30-acre project site into the City, and includes a General Plan Amendment to redesignate the project site from the County MDR land use to the City’s MDR land use. According to the City’s General Plan, the proposed project would be consistent with the City’s MDR land use designation, which allows for 2 to 8 du/acre and supports any housing type (detached and attached single-family homes, duplexes, townhouses, condominiums,

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The proposed project would be designed in accordance with the City General Plan and Zoning Ordinance and would be consistent with the development standards and allowed uses of the MDR designation and the PUD-MDR zone. Consistent with the impact conclusion of the Prior FEIR, the proposed project would not conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect. The proposed project would comply with applicable provisions of the CBC and General Plan policies designed to protect the environment.

Additionally, please refer to Appendix C for a consistency analysis of applicable policies from the General Plan.

The City has also established noise land use compatibility standards for new land use development.

For new single-family residential development, the City’s “normally acceptable” standard is 60 Aweighted decibel (dBA) Ldn for exterior noise in private or shared outdoor use areas excluding front yards. This means that the specified land use would be considered satisfactory for that noise environment, based upon the assumption that any buildings involved are of normal conventional construction, without any special insulation requirements. As noted in the noise analysis prepared for this project, the measured existing ambient noise levels are 59 dBA CNEL next to roadway segments adjacent to the project site.
39 Furthermore, the project site is located well outside the 55, 60, and 65 dBA CNEL noise contours shown in the ALUCP. Therefore, the existing ambient noise environment meets the City’s “normally acceptable” standard noise land use compatibility standard of 60 dBA Ldn for single-family residential development as measured at any point on the project site and no additional noise insulation would be required beyond compliance with standard CBC requirements to meet the interior noise standard of 45 dBA Ldn. As such, consistent with the conclusion in the Prior FEIR, impacts would be less than significant. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required.

Zone 7 Stormwater Option
The Zone 7 Stormwater Option would not result in any new or more severe land use impacts because it would not change approved land uses, land use designations, or zoning, nor introduce new development or intensify existing uses, and was considered in the Prior FEIR. Discharging treated stormwater to land east of El Charro Road would not physically divide an established community or 39 CNEL is the Community Noise Equivalent Level, which is a weighted average that applies a 5 dBA penalty to noise between 7:00 p.m. and 10:00 p.m. and a 10 dBA penalty between 10:00 p.m. and 7:00 a.m. Ldn is the day/night equivalent noise level average that only applies a 10 dBA penalty to noise between 10:00 p.m. and 7:00 a.m. CNEL and Ldn are within one dBA of each other and are normally interchangeable.