R655-10-5A. Hazard Classification -- Criteria

  The hazard classification analysis should include a determination of the threat to human life and property damage in the event of the failure of a dam. In some cases the classification can be assigned by observance of the downstream development in relationship to the location of the dam. In other cases it will be necessary to prepare inundation maps to determine the downstream consequences of failure. When using maps for hazard classification determination, the inundation boundary, as well as the depth and velocity of flow, will be considered. In preparing the inundation maps, the following criteria relative to the dam should be used.

  1. No concurrent flooding conditions exist.

  2. The reservoir level is at the spillway crest.

  3. The low level outlet is discharging at capacity.

  4. The breach times and geometric parameters used to simulate the dam failure should be acceptable to the State Engineer and consistent with accepted practices.

  5. The inundation study should be carried downstream to a point that the breach flows are contained within the banks of the natural channel or a downstream reservoir.