Sunset Weir and Pumps Fish Passage Project

The Proposed Project consists of removal of the Sunset Weir and restoration of natural, volitional passage conditions for protected migratory fish species; replacement and upgrade of the Sunset Pump Station to operate at a lower surface water elevation and rehabilitation of existing pump discharge pipelines; installation of new fish screens that meet current State and federal standards for protecting fish; and stabilization of eroded Feather River left bank downstream of the weir, incorporating bioengineering techniques. Removal of the Sunset Weir would restore unimpeded passage so that migratory fish could access the 28.5 miles of the Feather River from the Sunset Weir (River Mile 38.5) upstream to the existing Feather River Fish Barrier Dam (River Mile 67). Weir removal would also allow for a more natural riverine morphology with variable and distinct habitat types (e.g., deep pools and shallow riffles) as compared to the current backwatered and more slough-like conditions that persist for miles upstream of the existing weir; in this way, weir removal would restore natural fish passage conditions for the Feather River channel. Concurrent with weir removal and river restoration, the Sunset Pumps would be replaced and upgraded to be able to operate under the lowered riverine hydraulic conditions to meet existing water supply obligations. This would involve replacing the pumps and motor units and slip-lining or replacing associated discharge piping, constructing a new cast-in-place concrete structure (i.e., wet well) that would house the pumps and motor units, and installing contemporary fish screens that meet current criteria. Bank stabilization work on the left bank of the Feather River would be implemented as part of the Proposed Project. The work would involve flattening the eroding bank to a 3 horizontal to 1 vertical slope and protecting most of it against further failure and erosion using vegetated rock slope protection and bioengineering methods. The toe and lower portion of the vegetated rock slope protection would be stabilized with rock slope protection up to the ordinary high-water mark, with longitudinal peak stone toe protection, and with willow pole baffles planted perpendicularly to the flow. The left bank stabilization area below the ordinary high-water mark would be allowed to fill in naturally over time, with the final grade designed to benefit native fish as potential off channel refugia for out-migrating salmon and sturgeon during their seasonal migration periods at higher flows.