International Dredging Review

International Dredging Review

The San Francisco District released the Draft Integrated Feasibility Report and Environmental Impact Statement/Environmental Impact Report for a deepening project at the Port of Redwood City California to improve navigation. The report was prepared by Hydro-Plan LLC and Moffatt and Nichol and released in June 2015.

The recommended project will deepen the Redwood City Harbor and San Bruno Shoal Channels from -30 feet MLLW to -32 MLLW and slightly realign the Redwood City Harbor Channel to avoid sensitive environmental features of Bair and Greco Islands.

Redwood City Harbor is located on the southwest side of San Francisco Bay approximately 18 miles south of San Francisco California. The study was authorized by Congress in 2008. The study area includes the existing Federal navigation channel and turning basins at Redwood City Harbor extending from the mouth of Redwood Creek to deep water in the San Francisco Bay. The Federal navigation channel at San Bruno Shoal in San Francisco Bay is also included in the study area having been added to the Federal project by the 1945 authorizing legislation. It is located north of Redwood City and lies within the corporate boundaries of the cities of both Brisbane and South San Francisco California. Both channels are currently authorized to be maintained at -30 feet MLLW.

The recommended plan would dredge 1.4 million cubic yards and place that at the San Francisco Deep Ocean Disposal Site (SFDODS).

The average sedimentation rate for the Redwood City Harbor Channel is about 183000 cubic yards per year. The Corps has scheduled the channel for maintenance dredging on a two-year cycle since 1965 when it receives adequate federal funds for the project.

Recent maintenance dredging done in 2004 2005 2008 2012 and 2014 was done with a clamshell dredge. According to the study the existing navigation project channels at Redwood City Harbor and San Bruno Shoal do not allow for a large majority of vessels calling at the port that have design drafts greater than the authorized channel depth of 30 feet.

The projected costs for the deepening of the channels and ancillary work described in the plan is $53.4 million with the federal government paying 75 percent ($39887000) and the Port the balance $13514000.