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U.S. Fish & Wildlife Service National Fish Passage Program: Truckee River

The Numana Diversion Dam was constructed in 1971 to divert Truckee River water for agricultural purposes to the Pyramid Lake Paiute Tribe Reservation. The dam is located about 12 miles upstream from the Pyramid Lake shoreline. The dam is a lowhead diversion and includes a fish ladder on the east abutment. On the opposite side of the river, water is diverted through a headgate and is filtered through three electrical powered revolving screens. This screen system is designed to prevent entrainment of adult fish and debris into the irrigation system, and conveys fish back to the river via a culvert. The fish ladder and screens were retrofitted in 1976 to facilitate fish passage. By 2000, the screens were badly corroded and not functional.

Project Status: In 2001, the Service partnered with the Bureau of Reclamation to assess the integrity of the screens. The structural frameworks of the screens were found corroded beyond repair and it was recommended to rebuild the screen system with stainless steel rather than high carbon steel. Currently, funds have been expended to replace a hoist, cables, and the trolley framework, and bids are being circulated to estimate the cost for complete renovation.

Benefits: Renovating the fish screens will maintain the endangered cui-ui lakesucker and threatened Lahontan cutthroat trout within 24 miles of its native habitat.