National Dam Safety Program Riss Lake Dam Mo 10926 Missouri Kansas City Basin Platte County Missouri Phase I Inspection Report PDF Download

The purpose of this inspection was 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 inspection and evaluation indicates the spillways do not meet the criteria set forth in the guidelines for a dam having the above size and hazard potential. The spillways will pass 55 percent of the probable maximum flood, which is greater than the 100-year flood, without over topping the dam. The spillway design flood recommended by the guidelines is the probable maximum flood. 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. Deficiencies visually observed by the inspection team were minor seepage through the spillway weir wall, erosion on the upstream embankment, minor deterioration of the concrete weir, separation of riprap, brush growth on both faces of the structure, and a slide area on the downstream face. There were no observed deficiencies or conditions existing at the time of the inspection which indicated an immediate safety hazard. Future corrective action and regular maintenance will be required to correct or control the described deficiencies.