FY 22/23 Gravity Sewer Improvements Project

FY 22/23 Gravity Sewer Improvements Project

The Ross Valley Sanitary District (RVSD) Fiscal Year 2022/2023 Gravity Sewer Improvements Project (#953) (Project) entails the construction and rehabilitation, within the existing alignment, of sanitary sewer mains and related appurtenances within the unincorporated community of Sleepy Hollow, the Town of San Anselmo, the unincorporated communities of Greenbrae and Kentfield, and the City of Larkspur, located within the County of Marin. The Project site encompasses approximately 0.12 acres and the total area disturbed would be approximately 5,403 square ft. The Project would include rehabilitation of sanitary sewer mains in the following area: Sleepy Hollow: Replacing approximately 1,554 linear ft of existing 6-inch (in.) vitrified clay pipe (VCP) with 8-in. high-density polyethylene (HDPE) pipe via pipe bursting methods. No work would occur on the bridge located at Deer Hollow Road. Work would include: • Baltus Lane segment: Removing one existing sanitary sewer cleanout and replacing it with a new sanitary sewer manhole. • Deer Hollow Road segment: Constructing one new manhole in order to pipe burst downstream of the Deer Hollow Bridge, towards Butterfield Road. No work would occur on the bridge, and pipe bursting would continue upstream of the bridge until the end of the segment. Additionally, one existing sanitary sewer cleanout would be removed and replaced with a new sanitary sewer manhole. San Anselmo: Replacing approximately 2,125 linear ft of existing 6-in. VCP with 8-in. HDPE pipe via pipe bursting methods. Additional work would include: • The Alameda segment: Removing five existing sanitary sewer cleanouts and replacing four of the cleanouts with new sanitary sewer manholes. • Greenbrae: Replacing approximately 1,219 linear ft of existing 6-in. VCP with 8-in. HDPE pipe via pipe bursting methods. Kentfield: Replacing approximately 1,575 linear ft of existing 6-in. VCP with 8-in. HDPE pipe via pipe bursting methods. Additional work would include: • Oak Avenue segment: Removing two existing sanitary sewer cleanouts and replacing one of the cleanouts with a new sanitary sewer manhole. • Larkspur: Replacing approximately 120 linear ft of existing 6-in. VCP with 6-in. HDPE pipe via pipe bursting methods. Rehabilitation of all of sanitary sewer mains would occur within the existing alignment. Work would also include the rehabilitation of existing sanitary sewer manholes. Depth of excavation is projected to range from approximately 5 to 12 ft. The primary objective of this Project is to relieve hydraulic and structural deficiencies and reduce groundwater infiltration associated with aging RVSD infrastructure.

community of Sleepy Hollow, Kentfield, Greenbrae, Larkspur, San Anselmo

Marin

Northern California, San Francisco Bay Area, Unincorporated

Marin