Completion Report Lemhi River L-35A Fish Screen and Headgate Replacement. Lemhi River Subbasin Salmon, Idaho

摘要

Throughout the Lemhi River subbasin, irrigation diversions, combined with other domestic uses of water, have negatively affected salmonids by reducing water flow and entrapping juvenile fish in the unscreened diversions as they migrate downstream. In 2001, the Idaho Department of Fish and Games (IDFG) Anadromous Fish Screen Shop (Screen Shop) requested the Bureau of Reclamations (Reclamation) assistance with replacement of an outdated fish screen in a diversion ditch on the Lemhi River. The dilapidated fixed plate wiper screen located in the L-35A diversion ditch (cover photos), was replaced with a solar powered, point-of-diversion (POD) fish screen. The POD screen, which allows for delivery and control of diverted irrigation water, screens migratory and resident fish from entry into the irrigation ditch, and meets fish screening criteria as set forth by the National Marine Fisheries Service (NMFS). The primary objective of this project was to implement actions to prevent the entrainment of adult and juvenile salmon and steelhead in the Lemhi River at the L-35A irrigation diversion. The Lemhi River provides habitat for several species of fish listed as either threatened or endangered under the Endangered Species Act (ESA), as well as resident fish. Section 7(a)(2) of the ESA requires that all Federal agencies consult with the National Marine Fisheries Service or the U.S. Fish and Wildlife Service (USFWS), to ensure that any action authorized, funded, or carried out by such agency is not likely to jeopardize the continued existence of any endangered or threatened species or result in adversely modifying their critical habitat. The NMFS oversees the implementation of the ESA for certain listed species including anadromous salmon and steelhead. Currently, there are 12 listed anadromous evolutionarily significant units (ESU) and one ESU proposed for listing within the Columbia River. Consultation with NMFS was completed on these ESUs and a Biological Opinion (BiOp) was issued in 2002 and a subsequent BiOp issued on November 30, 2004.1 This consultation contained an Updated Proposed Action by the action agencies including a Tributary Habitat Program.