OAKLAND, Calif. (CN) – The Army Corps of Engineers’ dredging of 11 navigation channels in San Francisco Bay will erode the shore and put endangered fish at risk, an environmental group claims in court.
San Francisco Baykeeper seeks writ of mandate compelling the San Francisco Region of the California Regional Water Quality Control Board to set aside its approval of the project.
The dredging project – “Maintenance Dredging of the Federal Navigation Channels in San Francisco Bay, Fiscal Years 2015-2015” – allows maintenance dredging by the Army Corps of Engineers.
The Corps of Engineers regularly dredges the Bay floor to keep shipping channels and harbors deep enough for oceangoing vessels in the Bay and farther up the Delta.
Three million to 6 million cubic yards of sediment must be dredged every year to maintain navigation in and around San Francisco Bay. The Corps of Engineers is responsible for about 70 percent of Bay dredging.
The process involves suction dredges that vacuum sediment off the Bay floor, or clamshell buckets that grab sediment in the same way that a backhoe digs a pit.
The Corps of Engineers project – for which the water board certified a final environmental impact report on May 13 – involves dredging six channels annually and dredging five channels less frequently.
The 11 channels have a combined surface area of 5,699 acres – 2.22 percent of the surface area of San Francisco Bay.
The first five years of the project would dredge up to 12.4 million cubic yards in San Francisco Bay, and up to another 2.5 million cubic yards in the San Francisco Harbor Main Ship Channel, west of the Golden Gate Bridge.
San Francisco Baykeeper claims that in the past decade scientists have correlated Bay dredging and sand mining with some of the fastest rates of coastal erosion on the West Coast.
Scientists documented erosion of the San Francisco Bar, an underwater sand bar at the Bay’s mouth that influences water flows and sediment movement in and out of the Bay, much of which has been attributed to dredging, Baykeeper says.
The dredging will also result in wetland loss, sea level rise adaptation, and nutrient over enrichment, Baykeeper says.
Half of the dredged material is to be disposed at in-Bay disposal sites and half at the San Francisco Deep Ocean Disposal Site, about 55 miles off the Golden Gate.
“The Army Corps has committed to the beneficial reuse of dredged material only when it represents the least costly disposal alternative,” Baykeeper says.
The environmental impact report does not consider the impacts of disposing dredged sediment in the ocean, which robs the Bay of sediment that could replenish beaches and improve flood protection, Baykeeper says.
The Corps of Engineers dredging are also hurt imperiled fish species, the Delta smelt and longfin smelt in particular, according to the complaint.
A 2013 Corps of Engineers analysis found that in 2011 its dredging killed 3 percent o 29 percent of the Delta smelt population and up to 8 percent of longfin smelt, Baykeeper says.
“Recent population numbers for these fish have been at historic lows, putting them on the brink of extinction,” Baykeeper says in the lawsuit.
Baykeeper urged the water board to stop the hydraulic hopper suction dredging immediately, which kills large numbers of the two fish species, but the board approved permits for it.
Baykeeper claims the water board certified the project’s environmental impact report without adequately analyzing the direct and indirect impacts of the dredging.
It wants the water board’s approval of the project set aside, including its certification of the final environmental impact report, until the project is brought into compliance with the California Environmental Quality Act and California Endangered Species Act.
Baykeeper is represented by George Torgun, who did not respond to a request for comment.
The water board did not respond to a request for comment.