National Dam Safety Program. Wallace Lake Dam (MO 31263), White River Basin, Carter County, Missouri. Phase I Inspection Report.

Wallace Lake Dam was inspected to make an assessment of the general condition of the dam with respect to safety, based upon available data and visual inspection, in order to determine if the dam poses hazards to human life or property. The dam is in the small size classification, since it is less than 40 ft high, and the maximum storage capacity is greater than 50 ac-ft but less than 1,000 ac-ft. Our inspection and evaluation indicates that the spillway does not meet the criteria set forth in the guidelines for a dam having the above size and hazard potential. The spillway will pass 37 percent of the Probable Maximum Flood without over-topping. The Probable Maximum Flood is defined as the flood discharge that may be expected from the most severe combination of critical meteorologic and hydrologic conditions that are reasonably possible in the region. The guidelines require that a dam of small size with a high downstream hazard potential pass 50 to 100 percent of the PMF. Considering the height of dam (25 feet) and the maximum storage capacity (63 acre-feet), 50 percent of the PMF has been determined to be the appropriate spillway design flood. The 100-year flood (1 percent probability flood) will not overtop the dam. The 1 percent probability flood is one that has a 1 percent chance of being exceeded in any given year.