Saturday, December 13, 2008

Harbor dredging

According to BEACON, average sand bypassing at Ventura County harbors is almost 600,000 cubic yards at Ventura Harbor and over 1 million cubic yards at Channel Island harbor. Their report illustrates how littoral drift transports sand downcoast, where it accumulates in sediment traps designed to keep the harbor entrance open for navigation. Because downcoast beaches depend on a steady supply of sand, these harbor sand traps need to be dredged annually to keep the sand moving down the coast.

Here the dredge is operating at Channel Islands Harbor, depositing sand on Silver Strand Beach in Oxnard. The dredge basically sucks up the sand behind the breakwater and sends it through a pipe along the beach where it spews out 'nourishing' the beach. While this may seem benign, the discharge from the slurry contains fine sediment and potentially hazardous organic debris that accumulates at the harbor entrance over the year. Surfing while the dredge is operating puts you out in smelly black water, where ear infections or worse are to be expected...

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