National Dam Safety Program. Old Viburnum Tailings Dam (MO 30342), Mississippi - Kaskaskia - St. Louis Basin, Iron County, Missouri. Phase I Inspection Report.

Old Viburnum Tailings Dam was constructed over a rock-fill starter dam. The main embankment was constructed of cyclone-deposited tailings, apparently maintaining a constant dam crest centerline over the starter dam. The decant system which passed water from the reservoir to the downstream toe was sealed with grout when operations on this dam ended in 1972. The embankment was covered with a thin mantle of soil, and grass was planted to control erosion. However, the vegetation has not become well established and substantial erosion gullies have developed. The most prominent gullies are along the abutments where overland runoff flows onto the tailings embankment. The spillway is about 900 ft southwest of the dam axis and consists of a cut through the ridge which forms the southeast side of the reservoir and right abutment of the dam. The excavation for the spillway extends into weathered bedrock and little or no erosion in the spillway is anticipated during flood flows. Hydraulic and hydrologic analyses including multiple dam analyses of the significant upstream dams indicate the dam will not be overtopped by 100 percent of the PMF.