National Dam Safety Program. Deer Lake Dam (NDI Number PA 01139, PennDER Number 26-53), Ohio River Basin, Fayette County, Commonwealth of Pennsylvania, Phase I Inspection Report,

Deer Lake Dam is a Significant hazard - Small size dam owned and operated by the Deer Lake Improvement Association. The dam was found to be in poor overall condition at the time of inspection. Hydraulichydrologic evaluations, performed in accordance with procedures established by the Baltimore District, Corps of Engineers, for Phase I Inspection Reports, revealed that the spillways will not pass the spillway design flood SDF without overtopping the dam. An SDF in the range of the 100-year flood to the 12 Probable Maximum Flood 12 PMF is required for Deer Lake Dam. The 12 PMF was chosen because the dam is on the high side of the Small size category based on storage capacity. During the 12 PMF, the dam is overtopped by a maximum of 1.71 feet for a duration of 11.50 hours. The spillways are capable of passing only 15 percent of the PMF before overtopping begins. The spillways are therefore considered inadequate. It is recommended that the owners immediately initiate an engineering study to further evaluate the total capacity of the spillways and develop recommendations for remedial measures to reduce the overtopping potential of the dam. Due to the velocity of seepage through the embankment, the presence of relatively large piping holes, and the under-cutting of the toe of the embankment, the dam is classified as being in an Unsafe - Non-emergency condition. The inspection revealed certain items of remedial work which should be immediately performed by the owners. Items 1 through 7 below should be completed under the direction of a qualified professional engineer experienced in the design and construction of earth dams and appurtenant structures.