County of Marin - News Releases - San Anselmo Flood Project

For Immediate Release
May 15, 2018

Draft Report for San Anselmo Project Released

Opportunity to provide comment on flood risk project’s environmental impacts

San Rafael, CA – The draft environmental impact report (EIR) for the San Anselmo Flood Risk Reduction Project has been released. The key report presents an analysis of the environmental impacts of potential flood mitigation projects.

Muddy flood waters in Corte Madera Creek get close to flood level near buildings in downtown San Anselmo.Muddy flood waters in Corte Madera Creek get close to flood level above 634-636 San Anselmo Avenue.
The proposed project is intended to improve public safety and protect residential and business properties along Fairfax and San Anselmo creeks in the Ross Valley. The draft is available for review online, as well as in hardcopy at local libraries including the Fairfax, San Anselmo, College of Marin and Marin Civic Center locations.

A public hearing will be on the afternoon of May 22 during the Marin County Flood Control and Water Conservation District’s Board of Supervisors session in Suite 330 of the Marin County Civic Center in San Rafael.

The public has 45 days to comment on the report’s findings, from May 17 to July 2. Feedback received during that stage will be addressed in the final project EIR, which will be prepared following the close of the public comment period. The final project EIR is expected to be brought before the Flood District Board of Supervisors in August for certification and to recommend a project.

Ross Valley has been hit by significant flooding events for decades. To alleviate this, the flood district has been working with the towns in the Ross Valley since 2011 to develop and design an overall flood mitigation strategy. District staff sought input during 40 meetings with various community stakeholders, neighbors, public EIR scoping sessions, the Zone 9 Flood Advisory Board and the San Anselmo Town Council. Project recommendations gathered from these public engagement activities has been included in the draft EIR.

The San Anselmo project is a component of the Ross Valley Watershed Flood Risk Reduction Program, which looks at broader flood mitigation measures for Corte Madera Creek and its tributaries within the 28 square-mile watershed. An EIR for the entire program is underway in parallel with the project EIR.

EIRs require public agencies to document and consider the potential environmental implications of their actions. The San Anselmo Project EIR contemplates a proposed project comprised of two complementary parts. A basin to temporarily divert and store floodwater is proposed at the former Sunnyside Nursery site at 3000 Sir Francis Drake Boulevard, about a mile north of downtown Fairfax. The basin would be coupled with the anticipated acquisition and removal of a building at 634-636 San Anselmo Avenue that obstructs the creek’s natural flow. The flood risk reduction project is proposed to be funded by a $8.7 million state grant and $8.7 million in local match funds coming from Ross Valley property owners’ stormwater fee.

The San Anselmo project would result in a net reduction in flooding for about 530 parcels for the 10-year and 25-year flood events. However, the project would result in some minor new flooding downstream of the project area, north of the Sir Francis Drake Bridge in Ross and east of Sir Francis Drake Boulevard, and upstream of the Nursery Basin site, during the 25-year storm event. The impact can be mitigated with the installation of flood barriers in Ross and San Anselmo. Replacing the Winship bridge would also reduce flood flows in the area. A discussion of these impacts can be found in the draft EIR, chapter 4.9.

Businesses at 634-636 San Anselmo Avenue have continued to operate during the preparation of the project EIR and will do so until a project decision is made by the District Board of Supervisors following the certification of the final EIR. The district is working with the tenants on a relocation plan for their businesses should the final project approved encompass removal of the building.

Learn more about the San Anselmo Flood Risk Reduction Project on the Ross Valley Watershed program website.


Liz Lewis
Water Resources Manager
Public Works

3501 Civic Center Drive
Suite 304
San Rafael, CA 94903
(415) 473-7226
Email: Liz Lewis
Public Works website