Completion Report Lemhi River L-44 Irrigation Diversion 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, entrapping juvenile fish in the unscreened diversions as they migrate downstream, and impeding upstream migration of adult fish. The primary objective of the L-44 irrigation diversion replacement project and subsequent modification was to implement actions to improve the passage of adult and juvenile salmon and steelhead in the Lemhi River. 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 (NMFS), 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.