On October 15, 2025, residents from Santa Venetia learned about a proposal from the Marin County Flood Control District (MCFCD)
that could reduce the risk of floods caused by intense, global warming-induced storm surges over the next 50 years.
It involves replacing the timber reinforced berm (TRB) that currently sits atop an earthen levee that runs along Vendola Drive with a proposed flood wall made of composite sheet piling.
“The timber reinforced berm is now more than 40 years old, and it is wood, and we are seeing more and more of it at any given time has reached a level of deterioration that requires replacement,” said Marin County Senior Civil Engineer Hannah Lee during the community meeting. “We also have concerns about seepage, so water can actually go under the timber reinforced berm—through the earth. This tends to be exacerbated by rodents.”
Lee said almost 700 homes in Santa Venetia would be at risk of flooding from Las Gallinas Creek, if the existing TRB were to fail.
It’s the Tides
While residents appeared worried, some asked whether it would be more cost effective to simply repair the TRB or dredge Las Gallinas Creek.
“We are really threatened by tides,” said Robert Stevens, president and CEO of consulting firm CSWST2, “so when the tides come in, and the tides get to seven, eight feet, that is where we have a huge risk, so dredging’s not going to fix that problem.”
Stevens, who has been working with the County of Marin to study the feasibility of building a new flood wall, said one made of composite sheet piling can resist corrosion and withstand harsh environmental conditions.
“In November of 2022, we actually. . .installed a section of the composite sheets. The next day, we actually pulled on them to 21,000 pounds, and we held that for over an hour, which simulated the worst-case flood load on it, and then we measured the deflection of the sheet piles, and there was minimal deflection, almost none. . .so we know that, given the geotechnical conditions and the potential flood conditions, a composite sheet pile will work in this condition.”
Paying for Protection
Replacing the TRB with a proposed flood wall could cost around $25 million, which includes construction costs, planning work, construction management, inspection services, and right-of-way costs.
“If we build a flood wall, the flood control district, Zone 7, saves up to $400,000 a year that it’s currently spending repairing the reinforced timber berm,” said Stevens. “This option that we’re talking about tonight extends the service life of the flood wall for at least 50 years.”
According to Lee and Stevens, one way of financing the new flood wall could be through the creation of a benefit assessment district that residents could pay over 10 to 30 years through their property taxes.
A federal grant could also help to subsidize the cost, but Stevens pointed out that obtaining one was no guarantee, and that a 25% local contribution would still be needed.
“We can’t really do this alone,” said Stevens. “We’ve got to do this as a community.”
Right of Way
Another prerequisite for construction of a proposed flood wall in Santa Venetia is the ability of the MCFCD to obtain easements from the 111 homeowners along Vendola Drive whose properties abut Las Gallinas Creek.
“Easements are necessary to both operate and build a flood wall,” said Stevens. “We cannot build a piece of critical infrastructure, unless the District has the underlying right to operate and maintain that piece of infrastructure.”
An easement is a non-ownership interest in a property that allows the easement holder to access that property for specific purposes.
“Since taking office, I’ve been focused on advancing this project and securing the funding needed to make it happen,” said Marin County Supervisor Mary Sackett. “I’m committed to working with you [Santa Venetia residents] and with our local, state, and federal partners to make sure Santa Venetia has the flood protection it deserves.”
As the meeting concluded, attendees were informed about additional opportunities where they can provide feedback and learn about the proposed flood wall.
These include a(n):
- November 19th meeting for property owners along Las Gallinas Creek on easements and right-of-way issues;
- Informational flyer and questionnaire delivered to homeowners in winter 2025 with information about funding options for the proposed flood wall;
- December 3rd Flood Zone 7 Advisory Board meeting; and
- Open house in spring 2026 with a financial analysis and opportunities for community input.
More information