As a condition for continued operation of the State Water Project and Central Valley Project under the Federal Endangered Species Act, California Department of Water Resources (DWR) is required to restore tidal habitats within the Delta as part of Reasonable and Prudent Alternative (RPA) actions identified in biological opinions by the US Fish and Wildlife Service and National Marine Fisheries Service. In response, the Fish Restoration Program Agreement was developed between California Department of Fish and Wildlife (CDFW) and DWR requiring DWR to restore a minimum of 8,000 acres of appropriate tidal habitat to support the federally listed fish species.
Stillwater Sciences is leading a team of subcontractors to provide DWR with assistance with this aquatic habitat restoration in hydrodynamic modeling, permitting and environmental compliance support, restoration design analysis and alternatives, and engineering support for several ongoing projects, including Prospect, Decker, Winter, and Chipps islands, among others. Restoration actions include selective levee breaching, invasive species control, excavation of tidal slough channels, creation of habitat berms and benches, and revegetation. As part of project planning, Stillwater is analyzing the feasibility of design alternatives, developing conceptual restoration plans, conducting pre-project assessment of site conditions (e.g., collecting tidal and bathymetric data, cultural resource and special-status and invasive plant surveys, and wetland delineations), and overseeing 2D hydrodynamic modeling to assess changes in regional flow, turbidity, salinity, water temperature, site productivity and export, and scour potential at breach locations. Stillwater is also preparing the revegetation design and supporting the mitigation and monitoring planning. The team has brought together a number of specialty subcontractors to support DWR over the last seven years. Stillwater is providing CEQA and permitting support including compliance strategy development, EIR preparation and support, federal and state permit applications and associated environmental documents, outreach planning, and interagency coordination.
Additional services are provided, as requested, to assist DWR in developing preliminary and engineering designs, construction inspection support, and post-project monitoring programs at Prospect Island and other restoration sites.