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National Dam Safety Program. Desoto Mining Co. Pit and Plant 'A' Dam (MO 30468), Mississippi - Kaskaskia - St. Louis Basin. Washington County, Missouri. Phase I Inspection Report.

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Final rept.,

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The St Louis District, Corps of Engineers, has classified this dam as a high hazard dam. The estimated potential damage zone extends approximately 21 mi downstream of the dam. Pit and Plant A Dam is in the intermediate size classification based on its maximum height of 76 ft and maximum storage capacity of approximately 2670 ac-ft. The dam is in fair to good condition. There is no designed spillway at this dam. This is considered a deficiency. Runoff from the dam crest roadway is directed toward the downstream face of the dam and has caused some minor erosion on the face of the embankment. The downstream face of the dam appears excessively steep and would be severely eroded if the dam were overtopped. Hydraulichydrologic analyses indicate the informal spillway at the southeast end of the dam will pass the PMF without overtopping the embankment. It is recommended a periodic inspection and monitoring program be initiated at this dam. This program should include Inspection of the embankment to identify areas of slope instability such as slumps, and erosion of the face of the dam. Monitoring seepage at the left abutment and near the toe of the dam to identify changes in the volume of flow or in the turbidity of the seepage water. It is further recommended that static and seismic stability analyses and seepage analyses be conducted by an experienced engineer to meet the standards set forth in the recommended guidelines.

Subject Categories:

  • Hydrology, Limnology and Potamology
  • Civil Engineering

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