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National Dam Safety Program. Iron Mountain Lake Dam (MO 30057), Mississippi - St. Francis Basin, St. Francois County, Missouri. Phase I Inspection Report.

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Final rept.,

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This report assesses the general condition of the dam with aspect to safety, based on available data and on visual inspection, to determine if the dam poses hazards to human life or property. The St. Louis District SLD, Corps of Engineers, has classified this dam as having a significant hazard potential. Based on the visual inspection and analysis of available data, the dam is judged to be in very poor condition. This assessment is based primarily on the history of the recent breach and seepage which developed at this dam, possibly along piping paths resulting from decaying root systems. The size of the trees on the embankment and the number of stumps where trees have been cut down indicate that similar seepage areas will likely continue to appear and pose a hazard of dam failure. Hydraulichydrologic analyses of the dam and appurtenant structures indicate the dam will be overtopped by a flood greater than 10 percent of the Probable Maximum Flood PMF. The 1 percent probability-of-occurrence flood occurs on the average once every 100 years will overtop the dam by 0.7 ft. The relatively narrow embankment section and moderately erodible soil used in construction of the dam suggest overtopping would likely produce an effective breach of this dam. Seepage and stability analyses comparable to the requirements of the Recommended Guidelines for Safety Inspection of Dams were not available. This is considered a deficiency which should be rectified.

Subject Categories:

  • Hydrology, Limnology and Potamology
  • Civil Engineering

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