MARIN CITY, CALIFORNIA
CONTINUING AUTHORITIES PROGRAM, SECTION 205
FLOOD RISK MANAGEMENT FEASIBILITY STUDY
The U.S. Army Corps of Engineers San Francisco District (USACE), in collaboration with the Marin City Community Services District as our non-federal sponsor, is studying alternatives for improving floodwater conveyance in the lower Marin City watershed.
PROJECT LOCATION AND DESCRIPTION
The study area is in Marin City, a small, unincorporated community in Marin County, California. Home to approximately 3,000 people, this small watershed is a “bowl turned on its side” (2020 U.S. Census). With steeps hills on one side and Richardson Bay on the other, Marin City is vulnerable to both fluvial and coastal flooding. Stormwater flowing to the bay is blocked by Highway 101 (Figure 1). There is a privately-owned pond, connected to the bay through a single, manually-operated tidal gate. During storms, the water from the gate backs up and floods the highway interchange and Donahue Street. This is the only route in and out of Marin City, so when severe storms hit the county in 2017 and 2021, residents could not enter or leave Marin City. Those needing to get into or out of Marin City were forced to wade through dangerous floodwaters. Flood related impacts include trapping residents in and out of Marin City, away from their homes, jobs, medical access, emergency services and more. In addition, it is believed that flood waters contain contaminants threatening public health and local ecosystems.
TOTAL FUNDING
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TOTAL COST
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$15,000,000
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FEDERAL COST
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$15,000,000
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NON-FEDERAL COST
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$0
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FY 2025-2026 SUNK COST (Federal Interest Determination and Feasibility)
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$700,000
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FY 2026-2028 BUDGET (Feasibility)
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$2,300,000
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FY2028-2032 (Design and Implementation)
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$12,000,000
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FY25-26 ACCOMPLISHMENTS
- June 9, 2025 – Feasibility Cost Share Agreement with Marin City CSD executed
- November 13, 2025 – Planning Charrette #1
FUTURE MILESTONES
- April 2026 – Public Meeting
- February 2027 (tentative) – Identify Tentatively Selected Plan
- December 2027 (tentative) – Conduct Public Meeting; release Draft NEPA Report for public and agency review
- August 2028 (tentative) – Approve Final Report
- December 2028 (tentative) – Execute Project Partnership Agreement
- December 2028 – July 2030 (tentative) – Design
- September 2030 – January 2031 (tentative) – Construction contract procurement
- February 2031 – September 2032 (tentative) – Construction
ISSUES AND OTHER INFORMATION
- Marin City Community Services District is the Non-Federal Sponsor (NFS).
CONGRESSIONAL INTEREST
- 2nd District, Rep. Jared Huffman
POINT OF CONTACT
- Deputy for Project Management, Thomas R. Williams, 415-503-6560
Updated on 23 December 2025