National Dam Safety Program. Horners Dam (Inventory Number VA 19305) Rappahannock River Basin, Westmoreland County, Virginia. Phase I Inspection Report.

Horners Dam is an earthfill embankment 16.7 feet high and approximately 600 feet long. The dam, is located approximately 8.8 miles southeast of Oak Grove, Virginia is used for recreation. Horners Dam is a small size - significant hazard structure as defined by the Recommended Guidelines for Safety Inspection of Dams. The dam and appurtenant structures were found to be in fair overall condition at the time of inspection. Past maintenance of the dam has been inadequate. The principal spillway, located at the left abutment, is a rectangular-shaped, broad-crested reinforced concrete weir 19.4 feet wide. A 10 foot wide vegetated earth emergency spillway is cut into the right abutment. There are no facilities for dewatering the reservoir. Using the Corps of Engineers' screening criteria for initial review of spillway adequacy, the 100-year flood was selected as the spillway design flood (SDF). The spillway is capable of passing up to 6 percent of the Probable Maximum Flood (PMF) or 32 percent of the SDF without overtopping. Based on the present unoccupied status of the house located within the downstream channel about 200 feet downstream of the spillway, a dam failure from overtopping would not significantly increase the hazard to loss of life downstream from the dam over that which would exist just before overtopping failure. However, overtopping flows are considered detrimental to the embankment. Therefore, the spillway has been adjudged as inadequate, but not seriously inadequate.