The City of San Francisco has recently obtained an emergency permit from the CA Coastal Commission to place sandbags along the shoreline of the Sloat region of Ocean Beach. This permit is intended to protect the Great Highway and Lake Merced Tunnel from potentially significant bluff retreat during the winter storm season. As seen throughout the last decade, storms can cause major bluff retreat at Ocean Beach and impacts infrastructure built too close to the coast, such as the Great Highway and Lake Merced Tunnel.
Unlike in previous years, however, San Francisco has opted to implement a relatively softer bluff protection measure. Sandbags are flexible, easily installed and easily removed, and do not have the same destructive impacts as rock and concrete revetments.
According to the design report, the Great Highway and Lake Merced tunnel will be temporarily protected from winter storm events by large sandbags that will be placed along the bluff toe and slope. Approximately 375 tan-colored, geo-textile sandbags will be used as bluff protection. The bags would be deposited in a 4-foot-wide by 70-feet long toe trench that would be excavated to a depth sufficient for 2 bags to be embedded.
While sandbags are indeed a step in the right direction from the destructive armoring strategies that the City has implemented in the past, it is important to urge San Francisco officials to move away from coastal armoring altogether and to adopt strategic relocation (a.k.a managed retreat), which is a more sustainable bluff protection and erosion control strategy.
Click here to watch a video of the sandbag placement, courtesy of Tom Prete/Ocean Beach Bulletin.
Here are photos taken in early January of the work:
Photos: Save The Waves Coalition