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Project Title: |
Ariey Lane Minor Subdivision, Rezone, and Development Plan |
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County File(s): |
CDMS20-00010, CDRZ22-03264, & CDDP22-03002 |
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Applicant & Owner: |
MGJ Development LLC |
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Zoning: |
R-10, Single-Family Residential District |
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General Plan: |
SL, Single-Family Residential, Low Density; AL, Agricultural Lands |
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Site Address/Location: |
85 Ariey Lane in the unincorporated Lafayette area (Assessor’s Parcel Number: 167-010-017) |
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California Environmental Quality Act (CEQA) Status: |
An Initial Study and Mitigated Negative Declaration was prepared indicating that no significant environmental impacts will be created by the proposed project with the implementation of mitigations. |
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Project Planner: |
Syd Sotoodeh, Senior Planner; (925) 655-2877; syd.sotoodeh@dcd.cccounty.us |
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Staff Recommendation: |
Approve (See Section II for Full Recommendation) |
I. PROJECT SUMMARY
The applicant requests approval of a vesting tentative map to subdivide a 6.18-acre property into three lots resulting in an approximately 2.86-acre Parcel A, an approximately 2.48-acre Parcel B, and an approximately 0.84-acre Parcel C, a rezone from an R-10 Single-Family Residential District to a P-1 Planned Unit District, and a final development plan for the construction of a new single-family residence and retaining walls over three feet and up to eight feet in height on each of the new lots. Site improvements include extending Ariey Lane (a private road) from an existing bridge, installing new utilities and infrastructure, and constructing stormwater and drainage infrastructure. The applicant requests an exception to County Title 9, Division 914 standards for the construction of approximately 945 feet of private road improvements including curbs and road-supporting retaining walls (if needed) within the creek structure setback (CSS), and permission to construct these improvements within the CSS easement where development rights have been grant-deeded to the County. The applicant also requests approval of a tree permit for the removal of fourteen code-protected trees (one Aleppo pine, three incense cedar trees, three Arizona cypress trees, and seven coast live oak trees), and for work within the driplines of fifteen code-protected trees (one valley oak tree, two California bay trees, and twelve coast live oak trees) for ±3,500 cubic yards (CY) of cut and ±3,100 CY of fill for a net 400 CY of grading, construction of retaining walls, drainage improvements, and other site improvements, and construction of the new residences on each proposed parcel. The Planning Commission will consider and make recommendations to the Contra Costa County Board of Supervisors for the proposed project.
II. RECOMMENDATION
The Department of Conservation and Development, Community Development Division (CDD) staff recommends that the County Planning Commission:
A. OPEN the public hearing on the 85 Ariey Lane project (Project), RECEIVE testimony, and CLOSE the public hearing.
B. RECOMMEND that the Board of Supervisors:
a. FIND that the Initial Study/Mitigated Negative Declaration document prepared for the 85 Ariey Lane 3-Lot Subdivision, Rezoning, and Final Development Project adequately analyzes the project’s environmental impacts, that there is no substantial evidence that the project will have a significant impact on the environment, and that the mitigated negative declaration reflects the County’s independent judgement and analysis.
b. ADOPT the Mitigated Negative Declaration (SCH 2024080688) and Mitigation Monitoring and Reporting Program prepared for the Project, and specify that the Department of Conservation and Development (located at 30 Muir Road, Martinez, CA) is the custodian of the documents and other materials, which constitute the record of proceedings upon which this decision is based;
c. ADOPT an ordinance rezoning the approximately 6.18-acre project site and adjacent public right-of-way to a P-1 Planned Unit District (P-1) (County File #CDRZ22-03264);
d. APPROVE the Vesting Tentative Map for the Project (County File #CDMS20-00010);
e. APPROVE the Final Development Plan to construct residential improvements and single-family residences (County File #CDDP22-03002);
f. AUTHORIZE an exception to the requirements and regulations of County Code Title 9, County Code Division 914, for construction of road improvements within a creek structure setback;
g. APPROVE AND AUTHORIZE, under the terms of the Grant Deed of Development Rights conveyed to the County (Recorder’s Series # 02-303003) for a creek structure setback easement, the applicant to conduct site improvements, including the removal of trees, grading, and construction of roadway improvements;
h. APPROVE the Tree Permit to allow the removal of fourteen (14) code-protected trees and work within the driplines of fifteen (15) code-protected trees;
i. APPROVE the findings in support of the Project;
j. APPROVE the Project conditions of approval;
k. APPROVE the 85 Ariey Lane 3-Lot Subdivision, Rezone, and Final Development Plan Project; and,
l. DIRECT the Department of Conservation and Development to file a CEQA Notice of Determination with the County Clerk.
III. GENERAL INFORMATION
A. General Plan: As of November 5, 2024, the subject property is located within the RVL, Residential Very Low-Density and an RC, Resource Conservation General Plan land use designations (2045 General Plan). When the applications were deemed “complete” for processing on April 10, 2023, the property was in two General Plan land use designations, SL, Single-Family Residential - Low Density (approximately 4.33 acres) and AL, Agricultural Lands (approximately 1.86 acres).
B. Zoning: The subject property is located within an R-10, Single-Family Residential District.
C. California Environmental Quality Act (CEQA) Compliance: An Initial Study and Mitigated Negative Declaration (IS/MND) identified potentially significant impacts in the areas of aesthetics, biological resources, cultural and tribal cultural resources, geology and soils, hydrology and water qualify, wildfire, and mandatory findings of significance, and identified mitigation measures to reduce such impacts to less-than-significant levels. The IS/MND and corresponding documents were posted for public review on August 15, 2024. The public comment period for accepting comments on the adequacy of the environmental documents extended from August 16, 2024, through September 16, 2024, during which three comment letters were received via email.
In response to comments received from the California Department of Fish and Wildlife (CDFW) the applicant revised the project’s drainage and stormwater control plans to further avoid and minimize impacts to the riparian corridor, and the County refined the analysis and mitigation measures for Biological Resources and Hydrology and Water Quality. Therefore, the IS/MND was revised, and corresponding documents including a response to CDFW comments and additional or revised mitigations were recirculated for public review on July 13, 2026. The public comment period for accepting comments on the adequacy of the revised environmental documents extended from July 13, 2026, through August 11, 2026, during which three comment letters were received via email or U.S. mail. Two additional letters were received after the commenting period. The comments received on the revised IS/MND and staff’s responses to those comments do not substantially alter the findings regarding significant project-related impacts or require new or substantially revised mitigation measures. The letters received are discussed in further detail in the CEQA Public Comment section of this report.
D. Tribal Cultural Resources: In accordance with Section 21080.3.1 of the California Public Resources Code, on July 26, 2024, Notices of Opportunity to Request Consultation were mailed to the Wilton Rancheria, Cultural Preservation Department, and to the Confederated Villages of Lisjan Nation. These are the two California Native American tribes that have requested notification of proposed projects. Pursuant to Section 21080.3.1(d), there was a 30-day time period for each of the tribes to either request or decline consultation in writing for this project. No response was received from the Wilton Rancheria or Confederated Villages of Lisjan Nation during the 30-day time period. However, on October 17, 2024, an email from the Confederated Villages of Lisjan Nation was received, in which the Cultural Resource Manager requested copies of the Sacred Lands File, Environmental Review document (IS/MND), and the final California Historical Resources Information System (CHRIS) letter prepared for the project. The available information in our records was provided. Also, on July 13, 2026, a Notice was sent to the Tribal Chair on the availability of a revised IS/MND. As of the writing of this Staff Report, neither Wilton Rancheria nor the Confederated Villages of Lisjan Nation have requested consultation. Therefore, consultation with Native American tribes has not occurred in relation to this project.
E. Lot Creation: The subject property was created as Lot 7 of Subdivision Tract 7410 (446M28, filed in August 2002).
F. Prior County Files Related to the Property:
a. SD89-7410: A tentative map to subdivide a 9.48-acre parcel and establish 16 new lots, approved October 23, 1990.
b. SD89-7410: An amended tentative map to subdivide a 9.48-acre parcel into seven parcels for the development of up to six single-family residences (one residence exists), approved October 24, 2000.
c. CDTP19-00039: A tree permit for the removal of four code-protected trees removed without a permit, approved with conditions on October 21, 2019.
d. CDTP23-00034: A tree permit for the removal of five code-protected trees and for work within the driplines of three code-protected trees for the purpose of prescriptive emergency grading to repair a land slide on the property, approved with conditions on July 31, 2023.
IV. SITE/AREA DESCRIPTION
The subject property is bounded by a perennial creek (Grayson Creek) and single-family residences to the south, the Oakmont Memorial Park and Mortuary to the north and northeast, and the Queen of Heaven Catholic Cemetery & Mortuary to the west. Other nearby landmarks include Briones Regional Park, approximately 0.75 miles west of the property, and Briones Park trailheads located about 0.25 miles to the south and west of the project site. As designated by the U.S. Census Bureau urban area reference map, the subject property is located within the Concord-Walnut Creek urbanized area, however, there is an element of suburban/rural character along the small roads and lanes of the residential area in the vicinity. Developments in the surrounding unincorporated area are within a variety of zoning districts including single-family residential (R-10, R-15, R-20, or R-65), Planned Unit (P-1) districts, and General Agriculture (A-2). Reliez Valley Road located approximately 300 feet south of the subject property provides access to Taylor Boulevard approximately 0.75 miles to the east. Nearby town centers include Pleasant Hill, Lafayette, and Walnut Creek.
The subject property is an undeveloped, approximately 6.18-acre, triangular lot located at 85 Ariey Lane (a private road) within the R-10, Single-Family Residential zoning district. Located within a hilly area of unincorporated Lafayette, the property has steep topography, with an approximately 206-foot elevation change, rising towards the north from an elevation of 228 feet at the southeastern property line to 434 feet at the northern property line. Slopes where the proposed development site is located at the approximate center of the property range from approximately 15% to 26% in grade. The development rights of approximately 1.98 acres of the northern portion of the subject property where slopes exceed 26% grade have been granted to the County as a scenic easement (OR-303002, recorded 2002). Development rights of approximately 1.34 acres along the southern boundary of the property have also been granted to the County as a creek structure setback (CSS) easement for Grayson Creek (OR-303003, recorded 2002). Forty trees on the subject property measuring between 6 inches and 42 inches in diameter, or with multiple stems ranging between 5 inches and 18 inches diameter per stem, including California bay laurel, coast live oak, valley oak, incense cedar, Aleppo pine, and Arizona cypress, were inventoried by the project arborist, and an additional three oak trees and two bay laurel trees are shown on the site plans. Of the forty-five trees, thirty-nine are considered to be code-protected due to their size and location on an undeveloped lot. Additional trees in the northern and eastern area of the property and located within the scenic easement were not inventoried for the project.
V. PROJECT DESCRIPTION
The applicant is requesting approval of a vesting tentative map to subdivide a 6.18-acre parcel into three new parcels, resulting in an approximately 2.86-acre (gross) Parcel A, an approximately 2.48-acre Parcel B, and an approximately 0.84-acre Parcel C. Access would be from Ariey Lane, a private road, via an existing bridge that crosses Grayson Creek. Proposed site improvements include extending Ariey Lane from the bridge as a 20-foot-wide private road within a 25-foot private access easement, with slopes up to a 20% gradient. No improvements are proposed for the existing bridge. Water, electricity, telecommunication, and other utility extensions, as needed, would be attached beneath the bridge using an existing utility trapeze. Curbs, gutters, four bioretention basins and two energy dissipator outfalls (61 linear feet and 165 linear feet, respectively) would be installed for drainage and stormwater control. The dissipator outfalls would discharge treated water to the uplands north of the creek via overland sheet flow. In addition, approximately 15 retaining walls over three feet and up to eight feet in height would be constructed. Approximately ±3,500 cubic yards (CY) of cut and ±3,100 CY of fill for a net 400 CY of grading is anticipated for the future road and residential foundation pads.
The applicant also requests a rezone of the property from R-10, Single-Family Residential to a site-specific P-1, Planned Unit District (P-1) to correct inconsistencies with the SL, Single-Family Residential - Low Density and the AL, Agricultural Lands General Plan land use designations of the property, and approval of a Final Development Plan for development of each parcel. Up to five dwelling units are proposed, including two attached accessory dwelling units (ADU). Future approval of any ADU will require a separate ministerial application. The proposed development of each parcel is described as follows:
• Parcel A: 6,244-square-foot, two-story, single-family residence up to 26 feet in height, an 886-square-foot garage, driveway, and seven retaining walls ranging between 1 foot and 6 feet in height.
• Parcel B: In addition to a driveway and five retaining walls ranging between 1 foot and 6 feet in height, a single-family residence, garage, and attached ADU with an approximately 5,275-square-foot building footprint is shown on the final development site plan; however, the applicant has not submitted architectural drawings for the residence.
• Parcel C: 4,424-square-foot, two-story split-level, single-family residence stepping up the existing grade with a height up to 28 feet, an approximately 747-square-foot attached ADU, a 974-square-foot garage, driveway, and three retaining walls ranging between 2 feet and 8 feet in height.
In addition, the applicant requests approval of a tree permit for project-related impacts to twenty-nine code-protected trees, including the removal of fourteen code-protected trees and construction, trenching or grading work within the driplines of fifteen code-protected trees located on the subject property, as described in the table below:
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Tree # |
Species |
Diameter |
Remove/ Dripline Impact |
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52 |
Aleppo pine (Pinus halepensis) |
12.5 |
Remove |
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62 |
Arizona cypress (Hesperocyparis arizonica) |
19 |
Remove |
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64 |
Arizona cypress (Hesperocyparis arizonica) |
16.5 |
Remove |
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65 |
Arizona cypress (Hesperocyparis arizonica) |
10.5 |
Remove |
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46 |
Coast live oak (Quercus agrifolia) |
12.5 |
Remove |
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47 |
Coast live oak (Quercus agrifolia) |
18.5 |
Remove |
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48 |
Coast live oak (Quercus agrifolia) |
19.5 |
Remove |
|
50 |
Coast live oak (Quercus agrifolia) |
17.5 |
Remove |
|
51 |
Coast live oak (Quercus agrifolia) |
31.5 |
Remove |
|
54 |
Coast live oak (Quercus agrifolia) |
19.5 |
Remove |
|
80 |
Coast live oak (Quercus agrifolia) |
18 |
Remove |
|
53 |
Incense cedar (Calocedrus decurrens) |
14 |
Remove |
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171 |
Incense cedar (Calocedrus decurrens) |
Multistem 80.5" circumference |
Remove |
|
(none) |
Incense cedar (Calocedrus decurrens) |
10 |
Remove |
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73 |
California bay (Umbellularia californica) |
16 |
Dripline Impact |
|
179 |
California bay (Umbellularia californica) |
Multistem, 83.25" circumference |
Dripline Impact |
|
41 |
Coast live oak (Quercus agrifolia) |
15 |
Dripline Impact |
|
66 |
Coast live oak (Quercus agrifolia) |
Multistem, 100.5" circumference |
Dripline Impact |
|
67 |
Coast live oak (Quercus agrifolia) |
10.5 |
Dripline Impact |
|
70 |
Coast live oak (Quercus agrifolia) |
17 |
Dripline Impact |
|
74 |
Coast live oak (Quercus agrifolia) |
18 |
Dripline Impact |
|
75 |
Coast live oak (Quercus agrifolia) |
12 |
Dripline Impact |
|
76 |
Coast live oak (Quercus agrifolia) |
8 |
Dripline Impact |
|
77 |
Coast live oak (Quercus agrifolia) |
15.5 |
Dripline Impact |
|
78 |
Coast live oak (Quercus agrifolia) |
13 |
Dripline Impact |
|
79 |
Coast live oak (Quercus agrifolia) |
14 |
Dripline Impact |
|
175 |
Coast live oak (Quercus agrifolia) |
47.5 |
Dripline Impact |
|
181 |
Coast live oak (Quercus agrifolia) |
42 |
Dripline Impact |
|
180 |
Valley Oak (Quarcus lobata) |
9 |
Dripline Impact |
The project arborist recommended removal of some trees due to poor health or condition (e.g., tree #171), however, most project impacts to trees would be due to the trees’ location within the footprint of site improvements or new residential structures.
As a result of two existing easements on the property, development is limited to less than half of the property’s gross acreage. The scenic easement area in the northern corner of the property will remain undeveloped. The applicant is seeking approval of an exception to County Code Division 914 and to construct approximately 945 square feet of access road, curbs, and road-supporting retaining walls (if needed) within the CSS easement and permission to construct these improvements within the CSS easement where development rights have been grant-deeded to the County. No changes are proposed that would reduce the size of either easement.
VI. AGENCY COMMENTS
Agency comments received by staff are included in Attachment 4. Following are summaries of the agency comments received:
A. Central Contra Costa Sanitary District (Central San): In correspondence dated January 4, 2021, Central San staff indicated that the project site is located within Central San’s service area and sanitary sewer service is available to the project site. Central San staff also indicated that the project is not expected to produce an unmanageable added capacity on the wastewater system or interfere with existing public facilities and advised that the applicant would be responsible for submitting plans to Central San for review prior to receiving a sewer permit and residential connection to the sewer system. Please refer to the attached correspondence for the details of their comments.
B. Contra Costa County Department of Conservation and Development, Advance Planning: In correspondence dated January 15, 2021, Advance Planning staff commented on the applicant’s original proposal for a 4-lot subdivision and indicated that a rezoning is required as R-10 is inconsistent with the SL and AL General Plan land use designations for the property. Advance Planning staff advised that the applicant does not get acreage credit for the portion of the property under grant deed of development rights which should be excluded from the density calculations, and that the property is in a high fire hazard zone with a significant portion of the property having a slope of 26 percent or greater which should decrease density according to the General Plan. Please refer to the attached correspondence for the details of their comments.
C. Contra Costa Mosquito & Vector Control District: On an Agency Comment Request form dated January 20, 2022, staff of the Mosquito & Vector Control District indicated that the applicant should employ measures to ensure that there is no creation or maintenance of a public nuisance including producing, harboring, or maintaining disease vectors as part of the project or property conditions.
D. Contra Costa County Fire Protection District (CCCFPD): Staff of the Contra Costa County Fire Protection District provided multiple sets of project comments as they worked with the applicant to achieve a project design that meets applicable standards. In correspondence dated February 2, 2022, Fire District staff indicated that development on any parcel of the subdivision would be subject to review and approval by the Fire District, and the applicant would be required to comply with requirements for fire department access, water supply, fire hydrants, automatic fire sprinkler systems for the homes, fire abatement measures including removal of weeds and other growth capable of being ignited, and developing a fire prevention plan for all phases of construction. In additional email correspondence received on February 2, 2022, Fire District staff indicated that the applicant would need to widen the existing bridge to 20 feet. However, on October 10, 2022, Fire District staff indicated in an email to staff that the applicant had submitted an Application for Alternative Materials and Methods (AMM) which was approved and thus the Fire District would accept the existing 16-foot width of the bridge if all structures are constructed to upgraded Chapter 7A (SFM) construction with certification, and an approved vegetation management plan is approved by the Fire Marshal prior to final inspection. CCCFPD’s recommendations for a vegetation management plan and other measures related to wildfire have been included as mitigation measures in FIRE-1 through FIRE-3 in the IS/MND and as conditions of approval (COA #56 through #58). Please refer to the attached correspondence for the details of their comments.
E. East Bay Municipal Utility District (EBMUD): In correspondence dated February 2, 2022, EBMUD staff advised that the applicant should contact EBMUD’s New Business Office to request a water service estimate, and that engineering and installation of water mains and services may require a substantial lead time. EBMUD also indicated that water meters are not allowed to be located in driveways and that EBMUD’s Water Service Regulations require applicable water-efficiency measures to be installed at the project sponsor’s expense for the provision of new or expanded water services. EBMUD indicated that due to their limited water supply, all customers should plan for shortages in time of drought. Please refer to the attached correspondence for the details of their comments.
F. California Historic Resources Information System (CHRIS): In correspondence dated February 4, 2022, staff of the CHRIS indicated that Study #22714 (Self and Wills 2000) covering approximately 90 percent of the proposed project area identified no cultural resources; therefore, the proposed project has a low possibility of containing unrecorded archeological sites. Staff of CHRIS recommended that the Lead Agency contact the local Native American tribe(s) and that if the project area contains any building or structure that is 45 years or older, a qualified professional conduct a formal CEQA evaluation. Pursuant to the recommendations made by CHRIS, mitigation measures CUL-1 through CUL-3 for Cultural Resources have been included in the MND, and also in the conditions of approval as part of staff’s recommendations (COA #44 through #46). Please refer to the attached correspondence for the details of their comments.
G. Contra Costa Health Services (CCEH): In correspondence dated received on March 21, 2022, CCEH staff provided comments regarding new or existing wells and septic systems, hazardous construction and demolition materials, debris from construction or demolition, and other waste materials. CCEH staff recommended that the project be served by public sewer and public water services. Please refer to the attached correspondence for the details of their comments.
H. Contra Costa County Department of Conservation and Development, Transportation Planning: In correspondence dated April 11, 2022, Transportation Planning staff indicated they have no comments on the proposed project. Please refer to the attached correspondence for the details of their comments.
I. County Peer Review Geologist: Darwin Meyers Associates (DMA) provided multiple sets of project comments as the applicant worked to achieve a project that meets preliminary applicable standards, submitted multiple geotechnical reports or letters, and made project revisions. In correspondence dated October 30, 2022, DMA noted that they reviewed the preliminary geotechnical reports, studies, and letters by Gray Geotech and by Bear Engineering Group Inc., the preliminary VTM and project plans, and a preliminary Stormwater Control Plan prepared for the proposed project. DMA also indicated that they had reviewed the pertinent geology reports, maps, and soil surveys for the Contra Costa County area. DMA acknowledges that there are steep slopes above the project site and that there has been a landslide on the subject property. According to DMA, the geotechnical assessments provided sufficient data and indicated that Bear Engineering Group Inc. presented a comprehensive plan to stabilize the portion of the proposed for residential development. Thus, DMA advised that there was enough information to deem the application complete. The peer-review geologist’s recommendations for the applicant to provide a design-level geotechnical report prior to issuance of a building permit and to have monitoring work performed during grading and construction have been included as mitigation measures GEO-1 through GEO-5 in the IS/MND and also as conditions of approval (COA #47 through #52). Please refer to the attached correspondence for the details of their comments.
J. Contra Costa County Public Works Department, Engineering Services: The County Public Works Department, Engineering Services Division provided multiple sets of project comments as they worked with the applicant to achieve a project design that met applicable standards. In their most recent correspondence and staff report dated October 9, 2025, Public Works staff provided comments and recommended conditions of approval for the project relating to traffic and circulation, drainage and stormwater control management, floodplain management, lighting district annexation, area of benefit fees and drainage area fee and creek mitigation, and support for the requested exception to Title 9 requirements for creek structure setback. Public Works' recommendations have been included in the conditions of approval as part of staff’s recommendations (COA #59 through #81). Please refer to the attached correspondence for the details of their comments.
K. Additional Agencies: Comments were solicited from the Contra Costa Couty Building Inspection Division and the Contra Costa County Grading Inspection Division. No comments were received from Building Inspection prior to the preparation of this report. Grading Inspection provided comments during the CEQA noticing period which are discussed further in the CEQA Public Comments section of this report.
VII. CEQA PUBLIC COMMENTS
A CEQA Initial Study was prepared indicating that, with mitigations, no significant environmental impacts would be created by the proposed project. The proposed rezone, three-lot minor subdivision, grading and site improvements, and residential development may affect the quality of the environment. However, the impacts would be reduced to less than significant levels with the adoption of the recommended mitigation measures as specified in the Mitigation Monitoring and Reporting Program (MMRP; Attachment 8). Mitigation measures in the areas of aesthetics, biological resources, cultural and tribal cultural resources, geology and soils, hydrology and water quality, and wildfire have been added as conditions of approval for the project and will be implemented to reduce project impacts to less than significant levels.
An Initial Study and Mitigated Negative Declaration (IS/MND) for the proposed project was posted for public review on August 15, 2024. The public comment period for accepting comments on the adequacy of the environmental documents extended from August 16, 2024, through September 16, 2024. During that time three comment letters were received from the East Bay Municipal Utility District (EBMUD), Contra Costa County Department of Conservation and Development Grading Inspection Division, and the California Department of Fish and Wildlife (CDFW).
Based on project revisions and a refinement to the analysis and mitigation measures for Biological Resources and Hydrology and Water Quality, a revised IS/MND was posted for public review on July 13, 2026. The public comment period for accepting comments on the adequacy of the revised environmental documents extended from July 13, 2026, through August 11, 2026. During that time three comment letters were received from the SF Bay Regional Water Quality Control Board, the Central Contra Costa Sanitary District (Central San), and Allexia Everlong of Top Action Property Management on behalf of residents of Ariey Lane Homeowner’s Association. Additional comments were received from Roger and Yumi Chelemedos and from Philip M. Barton after the commenting period ended.
Staff has prepared a Final IS/MND for the project, including staff-initiated text changes to correct typographical errors. The text changes are not the result of any new avoidable, significant effect and do not alter the effectiveness of any mitigation included in the pertinent section. None of the mitigations identified in the IS/MND circulated on July 13, 2026, have been revised and no new mitigations have been added. All mitigation measures identified in the MMRP have also been included in the conditions of approval as part of staff’s recommendations.
Below is a summary of the comments that address environmentally related issues discussed in the MND, and staff’s responses to those comments.
A. Letter from the East Bay Municipal Utility District (EBMUD), received September 9, 2024
1. Comment: EBMUD advises that the project would be served by the EBMUD Colorados Pressure Zone, that water service is available, and that a water main extension will be required. EBMUD provided information on how to request water service when development plans are finalized. In addition, EBMUD indicates that they own and operate an 8-inch distribution pipeline in an EBMUD right-of-way in Ariey Lane and any proposed construction in the right-of-way would be subject to terms and conditions determined by EBMUD to maintain the integrity of the pipeline. EBMUD also notes that the project presents an opportunity to incorporate water conservation measures including those required by State Assembly Bill 325 (Model Water Efficient Landscape Ordinance).
Staff Response: In general, comments received from EBMUD during the CEQA notification period provided additional guidelines that apply to the proposed project but did not challenge the adequacy of the environmental document. The majority of the comments received on September 9, 2024, are similar to comments provided to the CDD in response to an Agency Comment Request during the project review period. The project would be required to comply with the County’s Model Water Efficient Landscape Ordinance if new or renovated landscaping is proposed and as such would comply with State Assembly Bill 325.
2. Comment: EBMUD cited the Geology and Soils section of the IS/MND which states that landslides have been mapped throughout the proposed development area and indicated that when the project sponsor applies for water service, they will need to provide EBMUD with proposed landslide mitigation measures for the proposed development to avoid landslide hazard impacts to proposed water main extensions.
Staff Response: As discussed in Section 7 - Geology and Soils of the Initial Study, potentially significant impacts were identified due to the potential risk of slope failure, and a mitigation measure related to Geology and Soils has been included in the MMRP (GEO-1) and related conditions of approval have been included as part of staff’s recommendations requiring a final, design-level geotechnical design recommendations to reduce any potentially significant geologic/geotechnical impacts including landslides.
B. Email from the Contra Costa County, Department of Conservation and Development Grading Inspection Division, received September 12, 2024
1. Comment: Grading Inspection staff provided the following comments on the project:
• The plans should show the as-built slide repair as an overlay with the proposed subdivision plans;
• The plans should include erosion and sediment control;
• Grading activities should be restricted to April 15 through October 15 due to the creek below the project;
• An updated letter or new geotechnical report should be provided with new recommendations based on the as-built landslide repair;
• Hydrology calculations should be provided showing pre- and post-runoff for the project and where surface water will drain from the bioretention basins to the creek.
Staff Response: The applicant provided updated plans, new or updated geotechnical letters/reports, and new our updated hydrology letters/reports for the preparation of the revised IS/MND. Project impacts including erosion, sediment, and runoff were evaluated in revised Section 10 - Hydrology and Water Quality, and mitigation measure have been included in the MMRP (BIO-11, HYD-1 through HYD-3). Staff has not recommended as a condition of approval a restriction on grading activities to April 15 through October 15 as the applicant would be required to comply with the relevant regulations for a grading permit pursuant to County Code Division 716 - Grading, in which Section 716-8.1002 allows the county official to prohibit grading during rainfall months.
C. Letter from Erin Chappell, Regional Manager Bay Delta Region, California Department of Fish and Wildlife (CDFW), received September 16, 2026
1. Comment: The CDFW provided multiple comments challenging the adequacy of the analysis and mitigation measures included in the draft Initial Study circulated for public review on August 15, 2024, related to the following topics: riparian encroachment, impacts to stream hydrology, habitat loss and fragmentation (oak woodland, riparian woodland communities), Alameda Whipsnake habitat loss, and pre-construction wildlife, avian, and bat surveys.
Staff Response: In response to comments received from the CDFW the applicant revised the project’s drainage and stormwater control plans to further avoid and minimize impacts to the riparian corridor, and the County refined the analysis and mitigation measures for Biological Resources and Hydrology and Water Quality. The revised IS/MND was recirculated for public review, and no additional comments were received from the CDFW. Mitigation measures have been included in the MMRP (BIO-1 through BIO-11, HYD-1 through HYD-3).
D. Email from Katie Hart, SF Bay Regional Water Quality Control Board, received July 20, 2025
1. Comment: The project will require a permit from the Water Board
Staff Response: As discussed in Section 4 - Biological Resources of the Initial Study, several agencies including the Regional Water Quality Control Board regulate activities in wetlands and other waters through the Clean Water Act. The Initial Study also disclosed that jurisdictional waters potentially regulated under the authority of these agencies are present on the property. Therefore, a mitigation measure related to jurisdictional permits has been included in the MMRP (BIO-10).
2. Comment: The revised ISMND does not provide details for the proposed dissipator that would discharge treated stormwater runoff including the location of the dissipators, their location relative to Grayson Creek or the ephemeral creek noted on Parcel B, the expected overland path or extent of overland flow, and if a pipe to a constructed outfall would be a better option. There is a concern that these types of discharges (dissipators) typically cause erosion, and it has not been demonstrated that impacts to water quality or beneficial uses will not occur.
Staff Response: In response to comments received from the CDFW on the draft Initial Study circulated for public review August 15, 2024, the applicant revised the project’s drainage and stormwater control plans to further avoid and minimize impacts to the riparian corridor. The initial preliminary stormwater control plan proposed allowing stormwater to filter through three bioretention basins to ultimately discharge to a proposed outfall that would have been constructed in the creek bank adjacent to the bridge with rip rap placed within the creek bed. While the project is not subject to the County’s 2045 General Plan policies, Policy 8-78 encourages existing natural waterways to be protected and preserved in their natural state, thus discouraging the use of rip rap in streams.
According to the preliminary SWCP, stormwater runoff will be collected and treated on-site via four bioretention basins, which would then be discharged through two energy dissipators located upland of the creek. The location of each dissipator is shown on the revised Vesting Tentative Map, received on June 11, 2025, that was attached to the draft IS/MND for public review. A hydraulic analysis was performed by Wildscape Engineering, Inc. (January 20, 2025) indicating that the dissipators would be low energy sheet flow. In addition, the project was peer reviewed for the CDD by Monk & Associates (March 26, 2026) who in their response letter to the CDFW provided additional mitigations to reduce any potential impacts due to erosion within the creek and creek banks, rivulets, soil loss, and habitat loss to less than significant levels. Potential impacts due to erosion including any impacts that could potentially be caused by the proposed drainage and stormwater control plans were discussed in Sections 4 - Biological Resources, 7 - Geology and Soils, and 10 - Hydrology and Water Quality of the Initial Study, based on the revised preliminary stormwater control plan (SWCP; drainage) and Vesting Tentative Map. As such, mitigation measures have been included in the MMRP (BIO-9 through BIO-11, HYD-1 through HYD-3).
3. Comment: Previous grading on the southern portion of the property for landslide remediation appears to have potentially filled waters of the State, where aerial photos indicate the potential presence of an ephemeral creek within the graded footprint. Retroactive permitting for this work would need to address fill of State waters and assess whether the existing surface discharge of collected subdrain water is causing erosive conditions on the slope to Grayson Creek or within Grayson Creek due to increased flows. Photos of the area from pre-grading time frames and information about landforms present before the work was initiated is requested.
Staff Response: The comments do not directly challenge the adequacy of the Initial Study but ask for retroactive permits and information to be submitted to the Water Board. In 2023/2024, the property owners performed prescriptive grading of an approximately 0.95-acre area adjacent to and north of Grayson Creek for the purpose of repairing a slope failure on the subject property. At the time, an evaluation of the slide was prepared by the project geotechnical engineer (Bear Engineering Group, May 22, 2023) which provided evidence to the CDD of additional soil movement in the vicinity of Grayson Creek due to excessive rain during the 2022/2023 winter season which caused subsurface water to travel through the soil. Thus, according to the assessment, the shear strength of the slide area had weakened such that there was an inherent risk of extreme earth movement due to any additional groundwater seepage through fractured rock, potentially blocking the adjacent creek during rain events. Cut and fill grading activities consisted of approximately 22,000 cubic yards of cut and 22,000 cubic yards of fill, for a net total of zero cubic yards of soil. Subdrains and an energy dissipator were installed as shown on the Vesting Tentative Map and a Slide Repair Exhibit, both of which are attached to this report as Attachment 9. The project was determined to be exempt under the California Public Resources Code (PRC), Section 21080(b)(4), and CEQA Guidelines, Section 15269(c), regarding “Emergency Projects” and pursuant to PRC Section 21080(b)(4) and Section 15296(c) of the CEQA Guidelines, the project to undertake specific grading actions necessary to prevent or mitigate an emergency due to a landslide impacting the adjacent creek area was deemed exempt and a Notice of Exemption was recorded on September 3, 2023. It is the applicant’s responsibility to obtain permits before performing work when required. The comments received from the Water Board were forwarded to the applicant for their information.
E. Letter from the Central Contra Costa Sanitary District (Central San), received July 31, 2026
1. Comment: Central San advised that public sewer service is available on Ariey Lane, the applicant will need to evaluate the feasibility of utilizing the existing bridge for sewer service of the three lots and if needed, a separate sewer creek crossing parallel to the existing bridge may be required. In addition, Central San advises that each lot will need its own connection to the public sewer main and permits from Central San are required.
Staff Response: In general, comments received from Central San during the CEQA notification period provided additional guidelines that apply to the proposed project but do not challenge the adequacy of the environmental document. The comments received on July 31, 2026, are similar to comments provided to the CDD in response to an Agency Comment Request during the project review period.
F. Letter from the Allexia Long, Top Action Property Management, on behalf of residents of Ariey Lane Homeowner’s Association, received by mail on August 7, 2026
1. Comment: The comments received from Allexia Long during the CEQA notification period did not specifically challenge the adequacy of the environmental document. Rather, comments were generally regarding topics including the project’s conformity with the Ariey Lane homeowner association’s Covenants, Conditions and Restrictions (CC&Rs), including primary dwelling quality and size, and costs and expenses of enforcement related to creek bank stabilization. On behalf of the property owners, Allexia Long includes a request to impose conditions precluding or mitigating the development of multi-family housing on the subject lots, either as part of the current proposal or any future development. Although the comments do not specifically challenge the adequacy of the environmental document, staff will briefly respond to each comment below. The comments have been included as an attachment to this staff report for review by County decision makers.
Staff Response - Primary Dwelling Quality and Size: Allexia Long indicates a concern that the proposed homes feature an ultra-modern architectural design that is inconsistent with the craftsman-style character of the existing residences on Ariey Lane, and which does not satisfy the requirements of the CC&Rs. The County is not subject to private CC&Rs and does not have enforcement rights for CC&Rs. Although the project does not include a design review, the proposed single-family residences have been designed to be consistent with the development standards of the existing and surrounding R-10 zoning district in which Ariey Lane is located. In addition, staff considers that the findings related to compatibility of the residential project with the uses authorized in the surrounding and adjacent districts to allow the rezone to a P-1 Planned Unit District exist, as discussed in the attached Findings section of this report.
Staff Response - Costs and Expenses of Enforcement: Allexia Long indicates that any and all costs incurred by the Owners in enforcing the CC&Rs shall be paid by the non-complying owner, and a concern that the creek located on the applicant’s property should be stabilized before any development proceeds. Specifically, there is a concern that the applicant’s former Chief Operating Officer had committed to creating a joint plan to move forward on creek erosion control mitigation with other Ariey Lane owners, but the applicant withdrew from those efforts. As stated above, the County is not subject to private CC&Rs and therefore does not have enforcement rights for CC&Rs. The applicant has not proposed improvements to or stabilization of the existing creek bank due to any existing creek bank erosion as part of this project. The project proposes drainage improvements for the residential project, and if the project is approved, the applicant would be required to comply with specific mitigation measures identified in the MMRP and related conditions of approval as recommended by staff related to erosion control before grading or building permits are issued, during construction, and during operation of the residential development.
Staff Response - Rezoning and Multi-Family Housing: Allexia Long indicates a concern that upon rezoning to a P-1 zoning district the applicants could develop multi-family housing on the subject property, whether as part of the current proposal or any future development application, and requested that the County impose conditions that preclude or mitigate the development of multi-family housing on the subject lots. The project does not propose multi-family housing, as shown on the Preliminary and Final Development Plan and Architectural Plans. The subject property and properties along Ariey Lane are in an R-10, Single-Family Residential zoning district. As recommended by staff, conditions of approval have been included requiring permitted uses to be consistent with the uses allowed in the R-10, Single-Family Residential district. Also, any future development will be subject to the County’s 2045 General Plan policies applicable to residential development within the current RVL, Residential Very Low-Density land use designation which requires a maximum density of less than or equal to 1 unit per net acre, with uses generally related to detached single-family residences on lots 1 acre or larger.
G. Additional letters received after Public Commenting period
Correspondence from two additional neighbors was received on August 12, 2026, after the Public Comment period on the revised IS/MND ended on August 11, 2026, including a letter from Roger and Yumi Chelemedos received by mail, and an email from Philip Barton. Their comments are generally related to concerns about the existing “severe” erosion of the Grayson Creek bank in the vicinity of Ariey Lane and the subject property and indicate that the condition of the creek bank has been exacerbated by the emergency repair work and subdrains previously installed by the applicant. Their correspondence indicates a concern that the applicant has withdrawn from a creek stabilization project that the neighbors have been working on for a few years, and request that the creek stabilization project be completed before approval of the subdivision and development plan. Their correspondence is included for the Planning Commission’s consideration.
VIII. STAFF ANALYSIS AND DISCUSSION
A. General Plan:
The subject applications were deemed “complete” for processing prior to the November 5, 2024, adoption date of the Contra Costa County 2045 General Plan by the County Board of Supervisors. Therefore, the County General Plan 2005-2020 applies as analyzed below.
Land Use Element:
The subject property is located within two different General Plan land use designations, with approximately 1.86-acres of the north/northwestern area of the property in an Agricultural Lands (AL) land use designation and approximately 4.33-acres of the southern/southeastern area of the property in a Single-Family Residential, Low Density (SL) land use designation as shown in the attached General Plan map. As proposed, approximately 69% of the area of proposed Parcel B would be located in the AL land use designation. Parcels A and C would primarily be located within the SL land use designation with approximately 99.9% of Parcel A in SL, and approximately 80.7% of Parcel C in SL as shown in the chart below:
|
Proposed Parcel |
Proposed Gross Area in square feet |
Portion of Parcel in AL in square feet |
Portion of Parcel in SL in square feet |
Percent of Parcel in AL |
Percent of Parcel in SL |
|
Parcel A |
124,743 |
160 |
124,583 |
0.13% |
99.87% |
|
Parcel B |
107,891 |
73,963 |
33,928 |
68.55% |
31.45% |
|
Parcel C |
36,732 |
7,073 |
29,659 |
19.26% |
80.74% |
The purpose of the AL designation is to preserve and protect lands capable of and generally used for the production of food, fiber, and plant materials. The AL designation allows for secondary uses such as single-family residences, accessory dwelling units (ADU), and accessory structures. In addition, the AL designation allows for the subdivision of lands that conform with the requirements of the “ranchette policy” as outlined in the Agricultural Resources section of the County General Plan Conservation Element at a density of 0.2 units per net acre with a maximum of 1 dwelling unit per 5 acres.
The purpose of the SL designation is to allow for the development of detached single-family residences and accessory buildings and structures on lots as large as 43,560 square feet in area, while also allowing for secondary uses that are considered to be compatible with low density homes such as ADUs, churches, home occupations, small residential and childcare facilities. The SL land use designation allows for a density of up to 2.9 units per net acre while also allowing larger lot sizes due to unique environmental characteristics.
Existing scenic and CSS easements with development rights granted to the County restrict development on the project site. Thus, in addition to the proposed access easement, the total net acreage of the 6.18-acre subject property is approximately 2.60 acres. Combined, the maximum number of units allowed on the subject 6.18-acre lot is 6 units. The steep slopes of the property warrant larger lot sizes and a lower density; therefore, the project proposes three units which results in a total density of one unit per net acre which is at the lower end of the range of units allowed. Thus, the proposed subdivision of land will not alter or conflict with the density by allowing the potential for more residential units than is allowed for the project site.
Based on the proposed development plan site plan, if approved, the project would construct one single-family residence on Parcel B that is partially within both the AL and SL land use designations. The residences proposed for Parcel A and Parcel C would be located entirely within the SL designation. Although the proposed project would result in parcels partially located within the AL designation that are less than 5 acres in area, the project is consistent with the area requirements of the SL land use designation and the minimum area, minimum depth, and average width of the underlying R-10 zoning district. In addition, P-1 zoning is considered as consistent with the SL land use and could be consistent with the AL land use designation.
The General Plan Land Use Element contains specific policies that guide land use and development for specific geographic areas of the County. Based on Figure 3-2, “Unincorporated Communities with Adopted Area Policies,” the subject property is not located in an area with specific policies.
Upon the adoption of County’s 2045 General Plan (November 5, 2024), approximately 2.86-acre area of the property that is located outside of scenic and CSS easements was designated RVL, Residential Very-Low Density while the remaining, approximately 3.32 acres of the property was designated RC, Resource Conservation. The RVL designation is intended to be appropriate for transitional areas between urban development and agricultural or rural areas (or open space), or for constrained sites where reduced densities are justified. The RVL designation allows for single-family residential development on lots that are generally 1 acre in size, with a density of less than or equal to 1 unit per net acre. If approved, the project would result in three new lots (units) ranging between approximately 0.84 and 2.86 acres for an approximate density of 1 unit per net acre. P-1 zoning is consistent with RVL land use and each new lot would be developed with a single-family residence. The RC land use designation is generally applied to ecologically significant or environmentally sensitive areas that are not within publicly owned lands or otherwise constrained areas that are unsuitable for development, and other scenarios. Although urban development and subdivisions that would increase density are prohibited in RC designated lands, construction of public and semi-public infrastructure (e.g., roads) is allowed. Therefore, the project is substantially consistent with the new RVL designation and the extension of the private roadway from an existing bridge is consistent with the intent of the new RC designation. Although the P-1 zoning district is not considered to be consistent or potentially consistent with the RC designation, given that most of the development would be outside of the RC land use designation, the proposed rezoning from R-10 to P-1 would remain consistent with the 2045 General Plan Land Use Element.
The 3-lot minor subdivision does not involve an amendment to the General Plan land use designation, and the resultant parcels would remain residential in nature and use. The development of one new single-family residence on each proposed parcel would remain compatible with the predominantly residential development of the area.
Conservation Element:
The Conservation Element of the General Plan lists three overall conservation goals (8A-8C):
• Conservation Goal 8A: To preserve and protect the ecological resources of the County.
• Conservation Goal 8B: To conserve the natural resources of the County through control of the direction, extent, and timing of urban growth.
• Conservation Goal 8C: To achieve a balance of uses of the County’s natural and developed resources to meet the social and economic needs of the County’s residents.
According to Figure 8-1 of the County General Plan, although the project site is located near the Briones Hills area, it is not located within an area of known, significant ecological sensitivity. The project site has been previously disturbed due to emergency grading of an approximately 0.95-acre area for slope failure repair after significant rain events in winter 2022/2023 and ongoing maintenance of the vacant lot for vegetation management/wildfire fuel reduction. The project does not affect any known gas or mineral resources. With conditions of approval as recommended by staff and through the implementation of mitigation measures identified in the Initial Study and Mitigated Negative Declaration, the project would not significantly affect biological, geological, or cultural resources in Contra Costa County. In addition, more than half of the property in the steeper northern/northeastern area and in the southern creek area is restricted from development through existing grant deeds of development rights and would therefore be preserved as scenic, undisturbed open space.
B. Rezoning and Consistency with P-1 Zoning District: The subject property is located within a R-10, Single-Family Residential (R-10) zoning district. The R-10 district requires a minimum 10,000-square-foot lot area, an 80-foot average width, a 20-foot front setback for primary and accessory buildings/structures, a 10-foot side yard with a 20-foot side yard aggregate for primary buildings, and a 15-foot rear side yard. R-10 allows a 3-foot side yard for accessory building and structures with a minimum 50-foot front setback. Setbacks on lots that are larger than 40,000 square feet are measured from property lines and not the edge of existing or proposed access easements (County Code section 82-4.244(d)). Building heights are restricted to a 35-foot maximum and maximum 2-1/2 stories.
The proposed 3-lot minor subdivision project is consistent with the criteria for lot size and average width, and each proposed single-family residence is consistent with the setbacks, heights, and permitted land uses within the R-10 zoning district. However, as the existing R-10 zoning district is inconsistent with the SL General Plan land use designation for the subject property, and none of the single-family residential districts are consistent with the AL General Plan land use designation, the applicant requested a rezoning of the property to a P-1, Planned Unit District (P-1). The purpose of the P-1 district is to provide for a diversification in the relationship between various uses, buildings, structures, lot sizes, and open space and to allow flexible regulations for developing special sites of concern or large-scale developments. The intent is to ensure substantial compliance with the General Plan and the county code regarding adequate standards for public health, safety, and general welfare. Approval of Preliminary and Final Development Plans are required by the P-1 district before any construction. Thus, the applicant has requested approval of a Final Development Plan for the construction of new single-family residences and approximately fifteen retaining walls over three feet and up to eight feet in height. The residences have been designed for consistency with the R-10 zoning. Therefore, staff has recommended conditions of approval permitting land uses within the site specific P-1 zoning district to be consistent with the uses permitted in the R-10 zoning district, and, except as modified by the conditions of approval and project entitlements, future development to be based on R-10 zoning district development standards as the guide with all development subject to the review of the CDD prior to issuance of a building permit (COA #12 through #14). The project also proposes an ADU attached to the proposed primary residences on proposed Parcels B and C. Pursuant to the County’s ADU ordinance, ministerial approval of separate ADU applications for any future ADUs would be required.
The proposed 3-lot minor subdivision project and proposed residential improvements are consistent with the permitted residential land uses within the R-10 zoning district, and the proposed P-1 zoning district is consistent with the underlying SL and AL General Plan land use designations and would be consistent with the County’s 2045 General Plan RVL land use designation.
C. Tree Permit: The Contra Costa County Tree Protection and Preservation Ordinance (Tree Ordinance) provides for the protection of certain trees by regulating tree removal and alteration while allowing for reasonable development of private property and tree maintenance. On any property proposed for subdivision and development approval, the Tree Ordinance requires tree alteration or removal to be considered as part of the project application. According to the Arborist Report prepared for the project, the project site contains trees that are considered protected trees under the Tree Ordinance due to their size (greater than 6.5 inches diameter) and location on a vacant lot. The project proposes to remove a portion of these code-protected trees, or to work within the driplines of (alter) code-protected trees, to extend the private access road, construct new residences on each new parcel resulting from the minor subdivision, and construct new retaining walls or bioretention (drainage) facilities. In addition, the consulting arborist has recommended the removal of several code-protected trees that are outside the footprint of development but are in poor condition or health. Thus, a tree permit for the removal of fourteen (14) code-protected trees and for the alteration of fifteen (15) code-protected trees due to potential drip line encroachment is requested with the proposed project. With conditions of approval as recommended by staff, the tree permit would require restitution of any tree approved for removal including planting replacement trees, protection of remaining trees where work may occur within the drip lines of the trees, and implementation of the tree protection measures from the project's arborist report. As a condition of approval, staff has recommended that the applicant be required to plant 28 replacement native trees (a 2:1 restitution ratio) under the Tree Ordinance. As a result of CDD staff applying the Tree Protection and Preservation Ordinance to the proposed project, there would be no conflict with the Tree Ordinance.
D. Traffic and Circulation: The subject site is located to the north of Reliez Valley Road, a publicly maintained road. Access to the subdivision would be provided by Ariey Lane, a private road constructed with subdivision 7410. The proposed project would construct a new road and further extend Ariey Lane. The applicant proposes a 20-foot road within a 25-foot private access easement, with a paved turnaround at the end of the road which is subject to the review of the Fire District. The proposed road would be at a 16% gradient, requiring grooved concrete or open-graded asphalt surface for increased vehicle traction. As the proposed road width is less than 28 feet, parking would be prohibited along both sides of the road. The applicant will be required as a condition of approval to install “No Parking” signs along the road, subject to the review and approval of the Public Works Department. Staff of the Public Works Department recommended conditions of approval regarding traffic and circulation (COA #59 to #81).
E. Creek Structure Setback/Exception Request: The applicant is proposing to construct portions of the extension to Ariey Lane and a supporting retaining wall within the creek structure setback area for Grayson Creek, which spans the entire southern boundary of the subject property. Section 914-14.014 of the County Ordinance prohibits any permanent structure within the creek structure setback other than drainage structures. On behalf of the applicant, the project engineer submitted an exception request relative to Section 914-14.014 - “Structures and encroachments within structure setback areas”, relative to road improvements to tie into the existing bridge, citing the unique topographic constraints of the site and responding to the other required findings necessary for the granting of the exception. As the Board of Supervisors accepted the Grant Deed of Development Rights on behalf of the County, the allowance of the encroachment into the restricted development area rests with the Board.
The road is necessary to provide future property owners with access to the project site. The retaining wall supporting the roadway is necessary to conform to the existing bridge constructed as part of the prior subdivision 7410. These walls and improvements are located well above both the top of bank of the creek and the 100-year floodplain elevation. It is the opinion of staff of the County Public Works Department that this work will not impede or be subject to exposure to flood flows.
Considering the unique situation posed by this project site, Public Works is not averse to the granting of the encroachments, provided the applicant provides the technical analyses to verify the stability of the creek banks and underlying foundation design. Staff of the Public Works Department recommended conditions of approval regarding encroachment into the creek structure setback (COA #72 and #73).
F. Underground Utilities: Chapter 96-10 of the County Ordinance Code requires all new and existing utility distribution facilities to be installed underground. Staff of the Public Works Department recommended a condition of approval regarding the undergrounding of utilities (COA #68).
G. Drainage/Stormwater Management and Discharge Control: Division 914 of the County Ordinance 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. Grayson Creek runs along the southern portion of the subject property. Based on the vesting tentative map, runoff from the site will be routed through storm drains and eventually outfall into Grayson Creek. A Preliminary Stormwater Control Plan (SWCP) prepared by the Humann Company (January 2025), was submitted for review, and was determined by staff of the County Public Works Department to be “preliminarily complete” in compliance with the Stormwater Management and Discharge Control Ordinance (§1014), and the County’s Municipal Separate Storm Sewer System (MS4) National Pollutant Discharge Elimination System (NPDES) Permit. Staff of the Public Works Department recommended conditions of approval regarding drainage and stormwater management (COA #69 to #71 and #75 to #81). Mitigation measures as specified in the attached Mitigation Monitoring and Reporting Program (MMRP) related to erosion control (BIO-11) and drainage, the addition of impervious surfaces, and the potential alteration of a course of a stream or river (HYD-1 through HYD-3) due to the project have also been included as conditions of approval (COA #53 to #55).
IX. CONCLUSION
With Conditions of Approval, the proposed residential project is consistent with applicable policies and standards of the General Plan. The residential project is appropriate for the area and satisfies the requirements of Titles 8 and 9 of the County code. In addition, an environmental analysis of the project was completed and found that the proposed project would not have a significant impact on the environment with the incorporation of specific mitigations. Therefore, staff recommends approval of County Files #CDMS20-00010, CDRZ222-03264, and CDDP22-03002 based on the attached findings and subject to the attached conditions of approval.