About
The Marin County Flood Control District is proposing a project to build a new floodwall along the top of an existing earthen levee in the Santa Venetia community.
The proposed Santa Venetia Floodwall Project is designed to reduce the risk for 600 homes in the Santa Venetia community from tidal flooding along 1.5 miles of Las Gallinas Creek. It would reduce the flood risk for up to 100-year tide events, which are severe floods that have a 1% chance of occurring in any given year, by replacing the aging Timber-Reinforced Berm with a floodwall constructed of durable composite sheet pile to resist corrosion and withstand harsh environmental conditions.
Why a floodwall
Santa Venetia is an unincorporated community in a low-lying area near San Pablo Bay. The development was built on filled marshland in the lower Gallinas Creek Watershed and experienced significant flooding in the early 1980s, prompting construction of the Timber Reinforced Berm (TRB) to protect homes from high tides in Las Gallinas Creek.
Currently, the berm and an earthen levee sit behind homes on Vendola Drive, forming the main line of defense against high tide flooding. More than 40 years later, the berm has exceeded its design life. Timber deterioration, worsened by rising sea levels and sinking land elevations, threatens the berm’s ability to protect against severe flooding.
Project history
The Marin County Flood Control and Water Conservation District previously proposed a major timber-reinforced berm upgrade, but the original project scope was revised in 2022 after cost estimates exceeded available funding. This prompted a re-evaluation of project alternatives to achieve a more effective design.
The new design was presented in March 2023 to the District Board of Supervisors who authorized staff to complete an environmental assessment in compliance with the California Environmental Quality Act (CEQA). The District has since been working to also extend the design to tie into higher ground beyond Santa Margarita Island, which delayed adoption of CEQA recognizing additional information would be required for the extended design.
A map of the proposed project can be found here. An elevation map of the area’s floodplain can be found here.
To learn about Gallinas Creek dredging, which is separate from but coordinated with the Proposed Santa Venetia Floodwall Project, please review the County Service Area 6 webpage.
Project timeline
Fall 2025 - Spring 2026
Timeline is subject to change.
Fall 2025
- 9/24 – Flood Zone 7 Advisory Board Meeting
- 10/8 – Creekside Property Owners Meeting
- 10/15 – Community Open House #1
- Regular Timber Reinforced Berm Maintenance
- FEMA Grant Application Migration (BRIC to HMGP)
Winter 2025/2026
- Date TBD – Flood Zone 7 Advisory Board Meeting
- Community Questionnaire #1
- Date TBD - Community Open House #2
- Public Comment Period for CEQA Certification
- Draft Financial Plan
Spring 2026
- Date TBD – Flood Zone 7 Advisory Board Meeting
- CEQA Certification
- Community Questionnaire #2
- Date TBD - Update at District Board of Supervisors Meeting
Project cost
The preliminary estimated cost of the project is $25 million. This figure is expected to change based on construction year and evolving building costs.
Funding Status
The project is funded through the design phase, including finalization of the CEQA documents which detail the project’s potential impacts and how they can be mitigated. The District is seeking federal, state and local funding to implement the project.
A $300,000 expenditure authorized by the Marin County Board of Supervisors supports District communications and outreach with the Santa Venetia community, evaluation of right-of-way costs and pursuit of additional funding mechanisms. The District intends to prepare a draft finance plan as soon as the end of 2025 to determine additional funding needs.
- Funded Project Phases
- Environmental: The CEQA Initial Study/Mitigated Negative Declaration will be updated this summer and finalized as soon as late 2025. This document will explain the project’s potential impacts and show how any significant effects can be reduced or avoided.
- Design: The final design is complete pending any minor changes that may occur during project permitting and easement acquisition.
- Unfunded Project Phases
- Right-of-Way: Easement needs are being re-evaluated in summer 2025 to align with the current project design. Funding has not yet been identified to pursue easement acquisition.
- Construction: Funding has not been secured to pursue construction at this time.
