Final phase of stormwater basin moving forward despite bridge project issue
The Marin County Flood Control and Water Conservation District is wrapping up plans for the final phase of the Sunnyside Stormwater Detention Basin and the project is expected to open for contractor bids this summer.
The basin, located at 3000 Sir Francis Drake Boulevard near Fairfax, is a key component of the San Anselmo Flood Risk Reduction (SAFRR) project, which will improve public safety for properties along Fairfax Creek / San Anselmo Creek in Ross Valley.
The first phase of the basin project was completed in mid-November 2020, about a month ahead of schedule. The work included demolition of the old nursery site’s deteriorated structures, extracting and storing gravel and topsoil to be reused for future aspects of the project, and excavation and hauling of approximately 20,000 cubic yards of earthen material.
The final phase of the work, expected to commence in July 2021, will complete the excavation of the basin as well as construct embankments around the basin. The $6 million basin project, budgeted as part of the SAFRR project, is expected to be completed by late summer 2021.
The next steps in the SAFRR project include removal of the concrete foundation at 634-636 San Anselmo Avenue and stabilization of the creek banks at that location. The concrete foundation obstructs the natural flow of San Anselmo Creek, which for decades has substantially aggravated overbank flooding of the downtown area of San Anselmo and certain residential areas of Ross.
Timing of the Flood District’s work, as well as creek restoration and subsequent creation of a public park at that location by the Town of San Anselmo, hinges on removal and reconstruction of the Winship Bridge downstream in the Town of Ross. However, the timelines of those steps are being reevaluated considering a recent federal funding shortfall for Ross’ bridge project.
The Town of Ross was planning to begin construction of the approximately $2 million Winship Bridge replacement project in summer 2022. The project, which is functionally linked to other Flood District projects such as SAFRR, was expected to be fully covered by federal funding through the Metropolitan Transportation Commission’s (MTC) Highway Bridge Program (HBP), but that has now been indefinitely delayed. In a recent announcement from MTC, the agency is reassessing all HBP allotments.
Due to the federal funding issue, the Town of Ross is pursuing alternative funding sources in order to get the bridge project underway as soon as possible. As a result, the Flood District will delay the start of the foundation removal until the Town of Ross has secured alternative funding and construction is underway.
For the Town of San Anselmo, the delayed timeline has created an opportunity to extend the public input phase for the creekside park design, allowing residents to refine the vision. The creek park has been an important aspect for residents as they work together to fill the vacant downtown space with a communal environment for public enjoyment.
Changes in the timeline are expected for the overall San Anselmo Project, which is being funded by an $8.7 million state grant from the Department of Water Resources and the remainder using Flood Control Zone 9 funds. While the extent of the potential changes is unknown at this time, Flood District staff are reviewing current grant funding requirements to identify any possible time constraints that may result from the Winship Bridge funding delay.
“The Flood District is approaching the potential delay from all angles, working together with the different agencies involved and are optimistic that we will find a beneficial solution for our community,” said Hugh Davis, Flood District Project Manager for SAFRR. “While things are uncertain right now with federal funding, any speculation on funding alternatives is premature at this time, but our goal is to be back on track with this project by 2022.”