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Final Independent External Peer Review Report for the Intake Diversion Dam Modification Lower Yellowstone Project, Montana Draft Supplement to the 26 April 2010 Environmental Assessment and Appendices

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The Intake Diversion Dam is located along the Lower Yellowstone River, approximately 18 miles downstream from the City of Glendive, Dawson County, Montana. The project site includes the dam and diversion structure, the upper 3,000 feet of the Lower Yellowstone Project Main Canal, and the area extending from about 3 miles downstream of the Dam to about 5 miles upstream of the Dam. The Intake Dam itself is a low-head timber and rock-filled weir dam owned by the U.S. Bureau of Reclamation that was originally constructed from 1905 to 1906. The dam is approximately 12 feet high and spans the entire width of the Yellowstone River, about 700 feet. The purpose of the proposed project is to modify features of the U.S. Bureau of Reclamation s Lower Yellowstone Project Intake Diversion Dam and canal headworks to improve passage and reduce entrainment for endangered pallid sturgeon and other native fish in the Lower Yellowstone River. The U.S. Fish and Wildlife Service listed the pallid sturgeon as endangered under the Endangered Species Act ESA in 1990. The wild population of pallid sturgeon inhabiting the Yellowstone River and the Missouri River between Fort Peck Dam, Montana, and Lake Sakakawea, North Dakota, are anticipated to be extirpated by 2018 if reproduction and recruitment of young fish do not improve. The best available science suggests that the Intake Diversion Dam impedes upstream migration of pallid sturgeon and their access to spawning and larval drift habitats. In addition, previous entrainment studies on other native fish in the Yellowstone River suggest that once passage is provided, pallid sturgeon may be entrained in the Main Canal if left unscreened. An Environmental Assessment EA and Finding of No Significant Impact FONSI were completed on April 26, 2010, and a contract was awarded for construction of the first phase entrainment protection in the fall of 2010.

Subject Categories:

  • Biology
  • Hydrology, Limnology and Potamology
  • Civil Engineering

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