Napa River Salt Marsh Restoration Project. Volume 1: Environmental Impact Statement

Abstract : The California State Coastal Conservancy (Coastal Conservancy), U.S. Army Corps of Engineers (Corps), and California Department of Fish and Game (DFG) (project sponsors) are proposing a salinity reduction and habitat restoration project for the 94569,460-acre Napa River Unit of the Napa-Sonoma Marshes Wildlife Area (NSMWA) (Napa River Unit). The parcel was purchased with funds from the Shell Oil Spill Settlement, State Lands Commission, Wildlife Conservation Board, and the Coastal Conservancy. The Napa River Unit is located at the northeast edge of San Pablo Bay, adjacent to the Napa River (Figure 5-1). The Napa River Unit was first diked off from San Pablo Bay during the 1850s for hay production and cattle grazing. Dike construction continued for several years and much of the land was converted to salt ponds in the 1950s for salt production through the solar evaporation of bay water. In the early 1990s, Cargill Salt Company stopped producing salt in the ponds on the west side of the Napa River and sold the evaporator ponds to the State of California, which assigned ownership and management to DFG. The site consists of 7,190 acres of salt ponds and levees and 2,266 acres of fringing marsh and slough. For the purpose of this document, Ponds 1, 1 A, 2, 3, 4, 5, 6, and 6A will be referred to as the lower ponds. Ponds 7, 7A, and 8 will be referred to as the upper ponds. The lower ponds are located south of Napa Slough; the upper ponds are located north of Napa Slough. Detailed site topography was collected and used for the project as described in Chapter 3, "Hydrology." Additional pond salinity and water quality information is provided in Chapter 4, "Water Quality."