Green Valley Road Rezone and Two-Lot Minor Subdivision (County File CDRZ23-03271 and CDMS23-00005)

Green Valley Road Rezone and Two-Lot Minor Subdivision (County File CDRZ23-03271 and CDMS23-00005)

The applicant is requesting approval of a vesting tentative map to subdivide the subject 2-acre property into two parcels, resulting in a 0.95-acre (gross) Parcel A and a 1.05-acre (gross) Parcel B. The project proposes one approximately 16- to 30-foot private access and utility easement. Access to both lots would be from Green Valley Road through an existing driveway within the new private access easement. The project proposes to remove and replace the existing driveway onto Green Valley Road. The new and wider driveway will take a 90-degree turn, providing direct access to a proposed residence on Parcel B and branching onto the existing drive to the existing residence on Parcel A that is to remain. Site improvements also include three bioretention filters, a concrete ditch, and trench inlets/drains for stormwater control/drainage. Six retaining walls are proposed, ranging between zero and approximately nine feet in height. It is anticipated that the project will entail ±330 cubic yards (CYS) of cut and ±540 CYS of fill for a net 210 CYS of grading for site and residential improvements, primarily on proposed Parcel B. New development for proposed Parcel B includes demolishing a barn and constructing a new 3,496-square-foot, two-story, single-family residence with a 553-square-foot garage, 315-square-foot main floor deck, and 383-square-foot lower floor concrete patio in approximately the same location as the barn. New development proposed for Parcel A consists of the installation of two bioretention filters for stormwater control. No changes to the existing residence or driveway on Parcel A are proposed. The applicant also requests a rezone of the property from A-2, General Agricultural District to R-40, Single-Family Residential district. The applicant has requested the following variances to the requirements of the R-20 zoning district for the construction of two retaining walls over three feet in height: • 0-foot front setback (where 25 feet is required) and 8-foot side yard (where 20 feet is required) for “Wall No. 1”; and • 5-foot front setback (where 25 feet is required) for “Wall No. 3”. In addition, the applicant is requesting an exception from the requirements of Title 9, Chapter 96-10, of the County Ordinance Code related to the undergrounding of existing overhead utility services along the subject property’s Green Valley Road frontage. Water, sewer, electrical, and other utilities extending to the proposed residence on Parcel B would be installed underground. Trenching for those utilities, as well as drainage improvements, would be performed as part of grading. The applicant also requests approval of a tree permit for project-related impacts to code-protected trees located on the subject property, including the removal of eight trees (three valley oaks, one coast live oak, three coast redwoods, and one ash with a combined diameter of 149 inches), and work including construction, trenching or grading within the driplines of five trees (one black walnut, one valley oak and three coast live oaks with a combined diameter of 100 inches). Up to seventeen non-code- protected trees (thirteen valley oak, two coast redwood, one black walnut, and one fan palm) located within the public right-of-way may also be removed or potentially altered due to work within their driplines. Project impacts to the trees include being located within the footprint of site improvements, the new residential structure, or accessory structures such as retaining walls.

Alamo

Contra Costa

Countywide, San Francisco Bay Area

California Air Resources Board (ARB), California Department of Conservation (DOC), California Department of Fish and Wildlife, Bay Delta Region 3 (CDFW), California Department of Forestry and Fire Protection (CAL FIRE), California Department of Parks and Recreation, California Department of Resources Recycling and Recovery, California Department of Toxic Substances Control (DTSC), California Department of Transportation, District 4 (DOT), California Department of Water Resources (DWR), California Fish and Game Commission (CDFGC), California Governor's Office of Emergency Services (OES), California Highway Patrol (CHP), California Native American Heritage Commission (NAHC), California Natural Resources Agency, California Regional Water Quality Control Board, San Francisco Bay Region 2 (RWQCB), California State Coastal Conservancy (SCC), Delta Protection Commission, Delta Stewardship Council, Office of Historic Preservation, San Francisco Bay Conservation and Development Commission (BCDC), State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Water Quality

Residential (Single-Family Residential)(Units 2, Acres 2.004)

Rezone, Land Division (Subdivision, etc.)

Biological Resources, Cultural Resources, Geology/Soils, Mandatory Findings of Significance, Tribal Cultural Resources, Wildfire