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Water Quality Conditions Monitored at the Corps' Big Bend Project in South Dakota during the 3-Year Period 2008 through 2010

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Special rept.

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The U.S. Army Corps of Engineers Corps Big Bend Project consists of Big Bend Dam and Big Bend Reservoir i.e., Lake Sharpe. Big Bend Dam is located on the Missouri River at River Mile RM 987, near the town of Fort Thompson, South Dakota about 20 miles upstream i.e., northwest from Chamberlain, South Dakota. The reservoir and dam are authorized for the uses of flood control, recreation, fish and wildlife, hydroelectric power production, water supply, water quality, navigation, and irrigation. Lake Sharpe is an important recreational resource. Water quality monitoring was conducted at the Big Bend Project by the Omaha District District over the 3-year period of 2008 through 2010. The water quality monitoring conducted included 1 continuing long-term, fixed-station monitoring in the reservoir at a near-dam deepwater location 2 monthly sampling and continuous monitoring i.e., hourly of water quality conditions in the powerplant of water discharged through Oahe and Big Bend Dams and 3 intensive water quality surveys in 2008, 2009, and 2010. The results of this monitoring were used to assess the existing water quality conditions at the Big Bend Project. Water quality conditions in Lake Sharpe vary longitudinally from the dam to the reservoir s upstream reaches, and vertically from the reservoir surface to the bottom. Water quality monitoring indicated that the reservoir is probably discontinuous polymictic with a hypolimnion only forming on an irregular basis. The trophic status of Lake Sharpe is mesotrophic to moderately eutrophic in the area near the dam, eutrophic in the middle reaches, and eutrophic to borderline hypereutrophic in the upper reaches of the reservoir. The phytoplankton community of Lake Sharpe was dominated by diatoms and no concentrations of the cyanotoxin microcystin above 1 ugl were measured.

Subject Categories:

  • Hydrology, Limnology and Potamology
  • Water Pollution and Control

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