Sunset Weir and Pumps Fish Passage Project

Sunset Weir and Pumps Fish Passage Project

The California Department of Water Resources (DWR) proposes the Sunset Weir and Pumps Fish Passage Project (Proposed Project), which would consist of the removal of Sunset Weir and the restoration of unimpeded flow and fish passage conditions for the Feather River channel; replacement of the Sunset Pump Station to operate at a lower surface water elevation; rehabilitation of existing pump discharge pipelines; installation and operation of new fish screens at the Sunset Pump Station; bank stabilization downstream of the weir; and modification of up to seven upstream irrigation diversions (within the existing weir backwater area) to address lowered water surface elevations after weir removal. The weir is operated and maintained by the Sutter Extension Water District (SEWD) to maintain hydraulic head for SEWD’s Sunset Pump Station. SEWD currently operates the Sunset Pump Station to supplement flows from Thermalito Afterbay, made necessary due to lack of capacity in the Sutter Butte Main Canal. The Pump Station also acts as a buffer to offset periodic flow delivery inconsistencies in the Main Canal and ensure that they can meet obligations to customers. The final grade of the restored Feather River channel would be designed to provide a stable transition from upstream to downstream, reduce scour downstream, and provide channel stability. The fish passage component of the Proposed Project would be achieved by removing the weir and restoring the channel to match the natural grade. Passage improvements are intended to benefit all species; however, designs would focus on passage for Central Valley fall-run and spring-run Chinook salmon, Central Valley steelhead, and southern distinct population segment green sturgeon. The materials comprising the weir would be degraded (or removed) and the weir footprint would be restored to match the existing natural channel bed. Suitable portions of the weir material and material imported for the construction of temporary access and work areas may be used to stabilize the banks and partially backfill scoured areas immediately downstream of the current weir configuration, e.g., the deep hole in the river at the downstream edge of the weir. Following the removal of the weir, the banks adjacent to the weir may be graded so the channel cross-section is similar to the geometry of the channel upstream and downstream. Disturbed areas at the channel banks, and other areas determined to be at risk of erosion following removal of the weir, would be protected with rock slope protection. All other areas disturbed by construction and above the channel waterline would be protected by the establishment of non-woody vegetation. Additionally, the Sunset Pump Station would be substantially modified such that the pumps operate optimally under free-flowing riverine conditions and allow SEWD to continue to divert water and meet their existing water supply obligations. This would involve replacing the pumps and replacing or slip-lining associated piping (as needed), constructing a new wet well and pump support structure, and installing contemporary fish screens that meet current state and federal fish protection criteria. SEWD would operate and maintain the modified Sunset Pump Station, fish screens, and related appurtenances into the future. To construct the facilities, a temporary cofferdam would be installed within the Feather River, dewatering of the cofferdam would occur (with discharge of pumped flows returned to the Feather River), and a temporary pumping system would be installed within the Feather River and discharge to the Main Canal in order to maintain uninterrupted service to SEWD’s customers.

Live Oak

Sutter

Unincorporated

California Air Resources Board (ARB), California Department of Fish and Wildlife, North Central Region 2 (CDFW), California Department of Parks and Recreation, California Department of State Parks, Division of Boating and Waterways, California Department of Toxic Substances Control (DTSC), California Department of Transportation, District 3 (DOT), California Department of Water Resources (DWR), California Highway Patrol (CHP), California Native American Heritage Commission (NAHC), California Natural Resources Agency, California Regional Water Quality Control Board, Central Valley Sacramento Region 5 (RWQCB), California State Lands Commission (SLC), Central Valley Flood Protection Board, Office of Historic Preservation, State Water Resources Control Board, Division of Water Quality, State Water Resources Control Board, Division of Water Rights, State Water Resources Control Board, Divison of Financial Assistance

Other (Weir Removal)

Weir Removal

Aesthetics, Agriculture and Forestry Resources, Air Quality, Biological Resources, Cultural Resources, Cumulative Effects, Drainage/Absorption, Energy, Flood Plain/Flooding, Geology/Soils, Greenhouse Gas Emissions, Growth Inducement, Hazards & Hazardous Materials, Hydrology/Water Quality, Land Use/Planning, Mandatory Findings of Significance, Mineral Resources, Noise, Population/Housing, Public Services, Recreation, Schools/Universities, Septic System, Sewer Capacity, Solid Waste, Transportation, Tribal Cultural Resources, Utilities/Service Systems, Vegetation, Wetland/Riparian, Wildfire