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Project Title: |
Withers Avenue 3-Lot Residential Subdivision |
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County File: |
#CDMS22-00011 |
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Applicant/Owner: |
Pallav Chatterjee / Jeanette Sorensen Trust |
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Zoning/General Plan: |
R-20, Single-Family Residential District / SL, Single-Family Residential - Low Density |
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Site Address/Location: |
2.56-acre property located at the corner of Wither Avenue and Pleasant Hill Road in the unincorporated Lafayette area of Contra Costa County (APN: 166-160-034) |
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California Environmental Quality Act (CEQA) Status: |
Mitigated Negative Declaration, SCH 2026060678 |
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Project Planner: |
Dominique Vogelpohl, Senior Planner (925) 655-2880 Dominique.Vogelpohl@dcd.cccounty.us |
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Staff Recommendation: |
Approve (See Section II for Full Recommendation) |
I. PROJECT SUMMARY
A request for approval of a Vesting Tentative Map to subdivide a 2.56-acre site into 3 new residential parcels to be accessed by a new private road from Withers Avenue. The project also includes: a request to remove 20 trees and work within the dripline of 24 other trees, 1,200 cubic yards of grading (600 cubic yards of cut and 600 cubic yards of fill), and 4 exception requests (1. 96-10 - requirement to underground utilities, 2. Division 914 to construct the access road within the creek structure setback, 3. Division 914 to construct the bio retention basin within the creek structure setback, and 4. 96-14.002 requirement to construct frontage improvements).
II. RECOMMENDATION
Department of Conservation and Development, Community Development Division (CDD) staff recommends that the Zoning Administrator:
A. FIND that the mitigated negative declaration prepared for County File #CDMS22-00011 adequately analyzes the project’s environmental impacts, that there is no substantial evidence that project will have a significant effect on the environment, and that the June 12, 2026, Mitigated Negative Declaration prepared for this project reflects the County’s judgement and analysis;
B. ADOPT the June 12, 2026, Mitigated Negative Declaration (MND) and mitigation monitoring and reporting program (MMRP) prepared for this project;
C. APPROVE the Vesting Tentative Map for the Withers Avenue 3-Lot Minor Subdivision (County File #CDMS22-00011), including the Tree Permit for the removal of twenty (20) code protected trees and construction work within the driplines of an additional twenty-four (24) code-protected trees, and grant exceptions to County Code Sections 96-10 (Underground Utilities) and 96-14.002 (Improvement of County Streets), and Division 914 (Drainage), based on the attached findings and subject to the attached conditions of approval.
D. DIRECT staff to file a Notice of Determination with the County Clerk.
III. GENERAL INFORMATION
A. General Plan: SL, Single-Family Residential - Low Density.
B. Zoning: R-20, Single-Family Residential District.
C. California Environmental Quality Act (CEQA): A draft Mitigated Negative Declaration/Initial Study (MND) was prepared and published for the application. The State and public review period for the draft MND started on July 29, 2025, and ended on August 28, 2025. Comments were received from the California Department of Fish & Wildlife (CDFW), the Confederated Villages of Lisjan Nation (CVLN), the East Bay Municipal Utility District (EBMUD), and the general public.
A revised draft Mitigated Negative Declaration/Initial Study (MND) was prepared to revise mitigation measures under Biological Resources and Tribal Cultural Resources per CFFW and CVLN comments. The State and public review period for the revised draft MND started on June 12, 2026, and ended on July 13, 2026, and the State review period extended to July 14, 2026. Additional comments were received from CVLN and the general public.
A final MND has been prepared that includes the written comments received on the draft MND and revised draft MND, responses to the comments received, and staff-initiated text changes. The final MND is attached to this report.
A Mitigation Monitoring Program was prepared based on the mitigation measures recommended in the revised draft MND. The Mitigation Monitoring and Reporting Program (MMRP) is attached to this staff report. If approved, the MND mitigation measures would apply to the Minor Subdivision as Conditions of Approval.
D. Tribal Cultural Resources: In accordance with Section 21080.3.1 of the California Public Resources Code, a Notice of Opportunity to Request Consultation was sent on June 13, 2024, to the Confederated Villages of Lisjan Nation (CVLN) and the Wilton Rancheria, the California Native American tribes that have requested notification of proposed projects within unincorporated Contra Costa County. Pursuant to section 21080.3.1(d), there is a 30-day time period for the Wilton Rancheria and/or the Confederated Villages of Lisjan Nation to either request or decline consultation in writing for this project. To date, no response has been received from the Wilton Rancheria, but the Confederated Villages of Lisjan Nation did request consultation and a project specific cultural resources report be prepared that includes a confidential search that is done through the California Historical Resources Information System and Sacred Lands File request be carried out through the Native American Heritage Commission (NAHC). A cultural recourses report with the requested information was prepared by FirstCarbon Solutions and provided to the Lisjan Nation on April 25, 2025, and a meeting between staff, the project sponsor, the property owner, and representatives of the Lisjan Nation was held on July 23, 2025. At that meeting, the CVLN asked about specifics regarding the proposed grading plan, but the project civil engineer was not present to provide a response with technical expertise that could suitably address their concerns. The project civil engineer has since responded, which resulted in the CVLN recommending specific Tribal cultural resources mitigation measures, which have been included under the Tribal Cultural Resources section of the initial study.
IV. SITE/AREA DESCRIPTION
The subject site is located just west of the Withers Avenue and Pleasant Hill Road intersection, in the unincorporated Lafayette area. The site is bound by single-family residential properties on all sides. The City of Pleasant Hill boundaries are immediately to the east.
The project site is currently vacant and is steeply sloped. The site contains numerous trees of various species and sizes. A lined drainage channel is located along the southeasterly property line, at the base of the southeastern slope.
V. PROJECT DESCRIPTION
A Vesting Tentative Map to subdivide a 2.56-acre site into 3 new residential parcels to be accessed by a new private road from Withers Avenue. The project scope includes a request to remove 20 trees and work within the dripline of 24 other trees, and 1,200 cubic yards of grading (600 cubic yards of cut and 600 cubic yards of fill), for the necessary private road and drainage improvements.
The minor subdivision application includes four exception requests to Title 9 of the County Code that relate to undergrounding of overhead utilities, the construction of frontage improvements, and the placement of a bioretention basin and access road in the creek structure setback:
1. Code Section 96-10 - Undergrounding Utilities: An exception request to not require undergrounding existing overhead lines along Withers Avenue.
2. Code Division 914 - Drainage: An exception request to allow construction of the entry portion of the access road within the creek structure setback.
3. Code Division 914 - Drainage: An exception request to allow construction of the bioretention basin within the creek structure setback.
4. Code Section 96-14.002 - Improvement of County Streets: An exception request to not require frontage improvements along Withers Avenue.
VI. BACKGROUND
The initial project submission envisioned a subdivision of the property into four lots; however, given the significant topographical challenges presented by the steep terrain in the western portion of the site, staff requested a comprehensive slope analysis. This evaluation was conducted to precisely delineate areas where the property’s slope exceeds thresholds of 15% and 26%. The findings of this assessment are included as an attachment to this staff report.
The analysis determined that the western half of the property exhibits slopes greater than 26%, necessitating a revision of the project to a three-lot subdivision. The proposed development sites have been strategically relocated as far east as practicable, thereby avoiding encroachment into the mandatory creek structure setback located along the eastern boundary. This adjustment significantly mitigates hillside excavation, decreasing the estimated grading requirements from 1,500 cubic yards of cut to 600 cubic yards, and ensures that the retaining walls will not exceed a height of three feet, as opposed to the original plan which contemplated retaining walls up to six feet tall.
VII. AGENCY COMMENTS
A. Public Works Department, Engineering Services Division (PW): In a memo dated June 29, 2026, PW provided their analysis of the project conditions of approval (COAs). All COAs have been incorporated as COAs for this project.
B. Conservation and Development, Transportation Planning Division: In a memo dated September 16, 2022, Transportation provided analysis on projected Vehicle Miles Traveled (VMT) and Level of Service (LOS) and determined that a VMT analysis or an LOS review will not be required.
C. Contra Costa County Fire Protection District (CCCFPD): In a letter dated September 16, 2022, the Fire District stated development must be compliant with the fire and building codes, and local and County Ordinances and adopted standards. These requirements are present in the Vesting Tentative Map attached to this Staff Report, and approval from the Fire District is required prior to issuance of a building permit for residential construction to ensure compliancy with all applicable codes and ordinances.
D. Central Contra Costa Sanitary District: In an email dated September 14, 2022, the Sanitary District stated the project site is within their service area and sanitary sewer service is available to the project site and would not be expected to produce an unmanageable added capacity demand on the wastewater system, nor interfere with existing, public facilities. The developer will need to construct a set of on-site public main sewers and private laterals. The Sanitary District’s review and approval of all sewer improvements is required prior to construction.
E. East Bay Municipal Utility District (EBMUD): In a letter dated September 16, 2022, EBMUD stated water main extension will be required, and each parcel to be provided domestic service and its own service connection and meter will require EBMUD review and approval prior to water service, which will include all applicable water efficiency measures under Section 31 of EBMUD’s Water Regulations.
F. California Historical Resources Information System (CHRIS): In a letter dated September 29, 2022, CHRIS stated the project site has a possibility of containing unrecorded archaeological sites, and recommends further study be conducted. Based on this recommendation a cultural resources study was prepared for this project.
According to the Cultural Resources Report prepared by Taylor Love of FirstCarbon Solutions (FCS), dated April 4, 2025, a 0.5-mile radius beyond the project site boundary was conducted at the Northwest Information Center (NWIC) located at Sonoma State University in Rohnert Park, California. The results of the record search indicate that seven cultural resources (one pre-contact, six historic) have been recorded within the 0.5-mile search radius surrounding the project site; no resources are located within the project boundaries, however, resource P-07-000035 is located immediately southeast of the project site. Additionally, 18 area-specific survey reports are on file within the 0.5-mile radius of the project site, however, none address the project area. This indicates that the proposed project has not been previously surveyed for cultural resources. Taylor Love’s survey of the project site was conducted on March 31, 2025. While no indications of historic or pre-contact archaeological resources were encountered over the course of either pedestrian survey, FCS considers the potential for
the proposed project to have an adverse effect on historic or pre-contact cultural resources to be moderate due to its proximity to these known sites, and thus, have provided mitigation measures. Their recommended cultural resources mitigations, along with the CVLN Tribal Cultural Resources mitigations, are included in the project revised Draft MND and MMRP.
G. County Geologist, Darwin Myers Associates (DMA): In a letter dated November 17, 2023, DMA evaluated the adequacy of the project geotechnical report, and recommended Geology and Soils mitigation measures are included in the project revised Draft MND and MMRP.
VIII. STAFF ANALYSIS
A. General Plan Consistency: On November 5, 2024, the County Board of Supervisors adopted the Contra Costa County 2045 General Plan. County file #CDMS22-00011 was deemed “complete” for processing on June 13, 2024. Therefore, the County General Plan 2005-2020 applies.
The subject property is located within a Single-Family Residential, Low Density (SL) land use designation. Generally speaking, the purpose of the SL designation is to allow for the development of detached single-family residences and accessory buildings and structures, while also allowing for secondary uses that are considered to be compatible with low density homes (e.g., ADUs, churches, home occupations, small residential and child care facilities). The SL land use designation allows for a density of 1 to 2.9 units per net acre. According to Table 3-4 of the 2005-2020 County General Plan, “Net acreage includes all land area used exclusively for residential purposes, and excludes streets, highways, and all other public rights-of-way.” Due to the road dedication and access easement, the total net acreage of the approximately 2.56-acre project site is approximately 2.07 acres. This would allow for a minimum of two units and a maximum of 6 units. Therefore, the three-lot minor subdivision would result in a density within the range of units allowed. Thus, the project is consistent with the applicable general plan required by law.
B. Zoning Compliance: The subject property is located in the R-20, Single-Family Residential District, which requires a 20,000 square-foot minimum lot size, a minimum average lot width of 120 feet, and a minimum lot depth of 120 feet. No variances are being sought in connection with the subdivision project. Parcel A: 45,153 square-feet, Parcel B: 20,101 square-feet, and C: 34,378 square-feet, all comply with the minimum parcel area for the R-20 district. The project does not include any proposed residential development; however, the Vesting Tentative Map identifies building sites for future construction of single-family residences on the resultant vacant parcels that comply with setback and yard requirements of the R-20 District. Based on the above, the project is consistent with all applicable requirements for the R-20 District.
C. Undergrounding Utilities: Chapter 96-10 of the County Ordinance Code requires all new and existing utility distribution facilities to be installed underground. This requirement applies to the existing overhead lines along the site’s Withers Avenue frontage.
The project engineer delivered an exception request on October 27, 2023, from the requirement to underground existing overhead lines along Withers Avenue in accordance with the findings outlined in Chapter 92-6 of the County Ordinance.
D. Drainage: Division 914 of the County Ordinance Code requires that all storm water entering and/or originating on this property to be collected and conveyed, without diversion and within an adequate storm drainage system, to an adequate natural watercourse having a definable bed and banks or to an existing adequate public storm drainage system which conveys the storm water to an adequate natural watercourse. As noted, a tributary of Murderer’s Creek is located along the southeast portion of the property and would be considered adequate receiving water for the 10-year design flowrate required by the County Code.
The applicant should consider the creek structure setback requirements of the Code as it applies to future construction of improvements on the property. The Code requires development rights within the creek structure setback be dedicated to the County. A setback line is delineated on the tentative map, but additional information, i.e., cross sections, will be required to verify that the line as delineated meets Code requirements.
Per the tentative map, a portion of the proposed bioretention basin encroaches into the structure setback area. As that is part of the project’s drainage infrastructure and above the FEMA determined base flood elevation, this encroachment would be allowable. There is a small portion of the proposed private road serving the subdivision that also encroaches into the setback. According to Code requirements, the road would have to be relocated.The project engineer delivered an exception request on October 27, 2023, from the creek structure setback requirements in accordance with the findings outlined in Chapter 92-6 of the County Ordinance.
E. Traffic and Circulation: All access to the subject property is to come from Wither’s Avenue, a County maintained road. The internal private road shall consist of 20 feet of pavement within a 25-foot private access and utility easement as indicated on the tentative map.
Withers Avenue is a 24-foot road within a 40-foot right of way and is planned to be a 40-foot road in a 60-foot right of way. The County Ordinance Code will require a 10-foot right-of-way dedication along the entire Withers Avenue frontage. The Code would also require construction of frontage improvements along the entire frontage.
The project engineer delivered an exception request on March 29, 2023, from the requirement to construct frontage improvements in accordance with the findings outlined in Chapter 92-6 of the County Ordinance.
F. Tree Protection and Preservation Ordinance: The 3-lot subdivision with road and drainage improvements requires removal of 20 code-protected trees and work within the dripline of 24 code-protected trees, and could not be reasonably accommodated on another area of the lot.
The project Arborist Report prepared by registered consulting arborist Tony Wolcott (RCA#685) dated August 7, 2022, provides an inventory and evaluation of all trees on the project site that may be impacted by the proposed project. A total of 147 trees were surveyed, numbered, tagged, identified, measured, and evaluated. There were 9 tree species inventoried, but only 4 species are listed in the County Tree Ordinance under the indigenous species list: 120 Valley Oaks, 10 Coast Live Oaks, 4 Monterey Pines, 4 Claro Walnut trees, 2 Coastal Redwoods, 2 California Buckeyes, 2 Blue Gum trees, 2 Olive trees, and 1 Canary Island Pine.
The arborist report indicates these trees cannot be avoided and are not expected to survive, thus requiring removal. In addition, remaining trees that are proposed for preservation would be preserved through the implementation of the tree mitigation measures described in the attached conditions of approval, which will be required to be in place throughout the entire construction period.
IX. CONCLUSION
The proposed Minor Subdivision (County File #CDMS22-00011) is consistent with the SL, Single-Family Residential General Plan Land Use designation and with the regulations of the R-20 Single-Family Residential District. Staff recommends adopting MND SCH 2026060678 and the MMRP, granting the exceptions to Section 96-10 (Undergrounding Utilities), Division 914 (Drainage) for both the private road and bioretention basin, and Section 96-14.002 (Improvement of County Streets), and approving the Vesting Tentative Map for 3-Lot Minor Subdivision #CDMS22-00011, including the Tree Permit for removal of 20 code-protected trees and for construction work within the driplines of 24 code-protected trees, based on the attached findings and subject to the attached conditions of approval.