National Dam Safety Program. Lake Holly Dam (Inventory Number Va 03334). York River Basin. Caroline County, Commonwealth of Virginia. Phase I Inspection Report.

Lake Holly Dam is an earthfill embankment approximately 20.7 feet high and 365 feet long. The principal spillway is a corrugated metal pipe riser located near the center of the embankment. An emergency spillway is located on the right abutment. The dam, located about 14.5 miles west of Sparta, Virginia, is used for recreation. 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 89 percent of the SDF or 21 percent of the Probable Maximum Flood (PMF) without overtopping the dam. Overtopping velocities are not considered to be seriously detrimental to the dam. The spillway is adjudged as inadequate, but not seriously inadequate.