Mallard Slough Rehabilitation Project


SCH Number
Lead Agency
Contra Costa Water District
Document Title
Mallard Slough Rehabilitation Project
Document Type
MND - Mitigated Negative Declaration

Document Description
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.

Contact Information
Mark Seedall
Contra Costa Water District
P.O. Box H20
Concord, CA 94524-2099

(925) 688-8119


Contra Costa
Cross Streets
Suisun Ave at Poinsella Ave
Total Acres
Parcel #
096-100-017 and 018
State Highways
SR 4
Buchanan Field
Mallard Slough/Suisun Bay
Other Location Info
City/Nearest Community:Bay Point

Notice of Completion

Review Period Start
Review Period End
Development Type
Water Facilities (for Mallard Slough Station Total acres: 2.75)(Intake Channel Type)
Local Action
Other Action Other Action: Operations & Maintenance Activity
Project Issues
Water Quality Toxic/Hazardous Biological Resources Archaeologic-Historic
Reviewing Agencies
Air Resources Board, Major Industrial Projects California Department of Parks and Recreation California Public Utilities Commission Caltrans, District 4 Caltrans, Division of Aeronautics Central Valley Flood Protection Board Delta Protection Commission Department of Fish and Wildlife, Region 3 Department of Toxic Substances Control Department of Water Resources Native American Heritage Commission Office of Historic Preservation Regional Water Quality Control Bd., Region 5 (Sacramento) Resources Agency San Francisco Bay Conservation and Development Commission State Lands Commission State Water Resources Control Board, Division of Water Quality
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