Weber Reservoir Fish Passage
When the Bureau of Reclamation discovered that Walker River Dam was constructed on a seismic fault, fixing the dam became a high priority safety issue. Upon further review of the dam, U.S. Fish and Wildlife noted that the original 1930s construction did not include a fish passage. Without a fish passage, the Lohontan cutthroat trout, an endangered species, could not pass through the dam for spawning. Before repairing the dam for seismic safety, U.S. Fish and Wildlife mandated a plan for inclusion of a fish passage in the revised design.
Restricted from filling the reservoir to full capacity, the Northern Paiute people of the Walker River Paiute Reservation lost their ability to irrigate alfalfa crops, a main source of subsistence. The dam, originally constructed with the purpose of impounding river water to be used by the reservation for irrigation and flood control, was no longer approved to be at full capacity. Located in rural Schurz, Nevada, this left the Paiute with limited resources, resulting in a stagnant economy for the tribe. Based on needs outlined in an environmental impact statement, HDR was hired to perform design services for the fish passage and accompanying bridge that would return Walker Reservoir to full capacity. The renovated structure features a roughened channel fishway that employs boulder weirs for energy dissipation and a vertical slot fishway structure to accommodate a wide range of water surface elevations. The roughened channel required extensive excavation to achieve the required slope to connect to Walker River downstream of the dam while highly erosive soil materials required careful attention to erosion control.
Highways US 95 and US 95 Alternate frame Walker Lake, the lake formed by the reservoir, with an additional road spanning the top of the dam. During redesign of the dam, a fishway channel was added, eliminating the efficient road across the dam. With this road serving as a critical path for emergency vehicles and preferred path for residents, HDR designed and erected a prefabricated bridge over the channel to provide vehicle access over the fishway channel. Though HDR was contracted by the Northern Paiute Tribe, the Walker Reservoir project was funded by the U.S. Department of Interiors, Bureau of Indian Affairs (BIA) and carried out by the BIA's Safety of Dams office in Phoenix, Arizona.