Mallard Slough Rehabilitation Project

Mallard Slough Rehabilitation Project

The proposed project is a maintenance project to dredge accumulated mud and sediment in a 3,000-ft long by 40-ft wide (bottom width) trench along the length of the intake channel. The proposed project depth to negative six feet mean lower low water (MLLW)^1 with a two-ft overdredge is most similar to a previous maintenance dredge event in 1968, and would excavate ~ 41,600 cubic yards (cy) of sediment (which includes a 25% buffer) from the pump station intake channel. Figure 3 outlines the dredge limits from 1968 and 1987 along with the limits for the proposed project. On September 20, 2010 the Dredge Material Management Office (DMMO) advised that 26,000 cubic yards of sediment (which includes a 25% buffer) be disposed of in open water (SF-9) and that 15,600 cubic yards (which includes a 25% buffer) be disposed of at an approved upland location.

Pittsburg

Contra Costa

Air Resources Board, Major Industrial Projects, California Department of Fish and Wildlife, Bay Delta Region 3 (CDFW), California Department of Parks and Recreation, California Department of Transportation, District 4 (DOT), California Native American Heritage Commission (NAHC), California Public Utilities Commission (CPUC), California Regional Water Quality Control Board, Central Valley Sacramento Region 5 (RWQCB), California State Lands Commission (SLC), Caltrans, Division of Aeronautics, Central Valley Flood Protection Board, Delta Protection Commission, Department of Toxic Substances Control, Department of Water Resources, Office of Historic Preservation, Resources Agency, San Francisco Bay Conservation and Development Commission (BCDC), State Water Resources Control Board, Division of Water Quality

Water Facilities (for Mallard Slough Station Total acres: 2.75)(Type Intake Channel)

Operations & Maintenance Activity

Biological Resources, Cultural Resources, Hazards & Hazardous Materials, Hydrology/Water Quality