This report was prepared under the National Program of Inspection of Non-Federal Dams. This report assesses the general condition of the dam with respect to safety, based on available data and on visual inspection, to determine if the dam poses hazards to human life or property. (Author).

The purpose of Dresser No. 4 Dam is to impound tailings from a barite separation and beneficiation operation. The dam completely encircles the impoundment except for a 300-foot wide breach at the north (up-stream) end where the structure failed in 1975. The dam cannot retain water in its present state because of this breach in the dam. This dam is classified as large. The U.S. Corps of Engineers has classified it as having a high downstream hazard potential to indicate that failure of this dam could threaten life and property. The damage zone, estimated by the U.S. Corps of Engineers, extends about 6 miles downstream of the dam. Since the embankment cannot retain water, the overtopping potential of the embankment was not analyzed. Instead, studies were made to estimate the amount of flow that could occur in the diversion ditch (located to the west and south of the impoundment) under different flood conditions. It was calculated that the diversion ditch could pass a 100-year flood probably without significant erosion of the ditch or adjacent embankment toe. However, it was estimated that the ditch cannot pass 50 percent of the Probable Maximum Flood without significant erosion of the ditch and adjacent embankment materials.

This report was prepared under the National Program of Inspection of Non-Federal Dams. This report assesses the general condition of the dam with respect to safety, based on available data and on visual inspection, to determine if the dam poses hazards to human life or property. (Author).

This report was prepared under the National Program of Inspection of Non-Federal Dams. This report assesses the general condition of the dam with respect to safety, based on available data and on visual inspection, to determine if the dam poses hazards to human life or property. (Author).