On June 4, Baykeeper advocated before the Bay Conservation and Development Commission (BCDC) for changes in San Francisco Bay dredging to reduce erosion of Bay and coastal shorelines and better protect endangered species. However, BCDC voted to issue permits for the continuation of maintenance dredging by the U.S. Army Corps of Engineers without changes until 2017. BCDC’s decision may represent the last step in the regulatory approval of dredging practices that have accelerated the pace of coastal erosion and harmed imperiled fish.
The Army Corps regularly dredges the Bay floor to keep shipping channels and harbors deep enough to accommodate large ocean-going ships traveling to and from ports and shipping terminals around the Bay and farther up the Delta. The Corps is responsible for approximately 70% of Bay dredging.
Baykeeper advocated for permit improvements that include requiring sand dredged from the Bay to be used to restore wetlands and protect shorelines from sea level rise. In addition, we recommended that whenever possible, dredged materials should not be dumped deep in the ocean—an outdated and wasteful disposal method. We also urged BCDC to immediately phase out dredging methods that kill endangered species of fish.
San Francisco Bay is a dynamic and shallow water body that rapidly fills shipping lanes, marinas and harbors with sand, silt and mud. Each year, three to four million cubic yards of sediment—or enough to fill the Transamerica Building ten times—is dredged from the Bay. Two methods are used: suction dredges, which vacuum the sediment off the Bay floor, and clamshell buckets, which grab sediment in the way a backhoe would dig a pit.
Over the last decade, scientists from the United Stated Geological Survey and elsewhere have correlated Bay dredging and sand mining with coastal erosion at Ocean Beach and other areas just outside of the Golden Gate, which are experiencing the fastest rates of erosion on the West Coast. However, environmental documentation prepared in support of the Army Corps’ permits failed to consider the impacts of disposing dredged sediment in the ocean, which robs the Bay of a resource that could otherwise replenish coastal beaches, improve flood protection, and build up wetlands in the face of sea level rise.
In addition to erosion, Baykeeper is greatly concerned about impacts to endangered fish. We urged BCDC to immediately phase out a method of dredging called hydraulic hopper suction dredging. This dredging method kills large numbers of two Bay fish species that are on the brink of extinction, delta smelt and longfin smelt. According to the Army Corps’ own analysis, in 2011, their dredging killed up to 29% of the delta smelt population and 8% of the longfin smelt population.
Baykeeper will continue advocating for San Francisco Bay dredging methods that reduce erosion of Bay and coastal shorelines and better protect endangered species.