National Dam Safety Program. Dorlac Lake Dam (MO 30731). Mississippi - Kaskaskia - St. Louis Basin. Washington County, Missouri. Phase I Inspection Report.
Abstract
The St Louis District (SLD), Corps of Engineers, has classified this dam as having a high hazard potential. The dam is classified intermediate size based on its height of about 45 to 50 feet. The downstream face is steep, on the order of 33 to 35 degrees, is constructed of cohesionless sand gravel, and could be severely eroded if overtopped. Scattered large trees up to 12 in. diameter are growing on the downstream face of the dam. The reservoir storage volume is completely filled with fine tailings and storage of water is limited to two small ponds at the upstream end of the impoundment, and shallow, intermittent ponds on the surface of the tailings. Hydraulic/hydrologic analyses indicate the dam and informal spillway will pass the 1 percent probability-of-occurrence event (100-year flood) without overtopping the embankment. These analyses further indicate the dam will be overtopped by a storm which produces greater than 55 percent of the Probable Maximum Flood (PMF). Based on the inspection of the Dam, it is recommended that further study be conducted without undue delay, under the guidance of an engineer experienced in the design and construction of tailings dams.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1981
- Accession Number
- ADA106615
Entities
People
- Leonard M. Krazynski
- Richard G. Berggreen