San Francisco’s Ocean Beach is eroding at an increasing rate, threatening a major sewer line and the Great Highway. One proven cause is sand mining and dredging in San Francisco Bay.
There’s a better chance of controlling the erosion, Baykeeper recently told California officials, if management plans cover the ocean shoreline and the Bay together. Currently, the two areas are being considered separately.
Baykeeper made our recommendations to a working group from various state agencies that is developing a new Coastal Regional Sediment Management Plan. The plan covers sand and sediment resources along the coast between the Golden Gate and Pacifica, but does not currently include the Bay.
San Francisco has tried to prevent further Ocean Beach erosion in a haphazard manner, by periodically placing rock and debris at the beach. However, this is unsustainable in the long term. So the city is also considering a plan for Ocean Beach, referred to as managed retreat, which will likely require rerouting a major sewer main, along with part of the Great Highway.
Researchers from the U.S. Geologic Survey and nearby universities have painstakingly documented how sand mining and dredging in central San Francisco Bay have altered wave patterns, playing a large role in Ocean Beach’s erosion.
If regulators fail to consider how management decisions inside the Bay effect conditions along the outer coast, costly and unsustainable management strategies will be developed for both areas.
For example, the California State Lands Commission is preparing to renew sand leases for mining operations in San Francisco Bay, which would allow sand extraction at much higher rates than in the past.
Increased sand mining could further exacerbate erosion at Ocean Beach. The reduction in sand from the Bay reaching the coast could eventually erode significant portions of San Francisco, especially if sea level rise—caused by climate change—adds to the problem.
Baykeeper joined with Surfrider San Francisco and Citizens Committee to Complete the Refuge in urging the planners to manage the Bay and coast in a concerted manner. This could result in cost-effective strategies that will not only better protect Ocean Beach, but also ensure the region’s sand resources are managed more sustainably.