National Dam Inspection Program. Ridgebury Lake Dam, (NDI I.D. Number PA-00727, PennDER I.D. Number 8-57) Susquehanna River Basin, Tributary to Fall Creek, Bradford County, Pennsylvania. Phase I Inspection Report,

Based on a visual inspection, operational history, and available engineering data, the facility is considered to be in good condition. The size classification of the facility is intermediate and its hazard classification is considered to be high. In accordance with the recommended guidelines, the Spillway Design Flood (SDF) for the facility is the PMF (Probable Maximum Flood). Results of the hydrologic and hydraulic analysis indicate the facility will pass and/or store only about 45 percent of the PMF prior to embankment overtopping. A breach analysis indicates that failure under less than 1/2 PMF conditions could lead to increased downstream damage and potential for loss of life. Thus, based on screening criteria provided in the recommended guidelines, the spillway is considered to be seriously inadequate and the facility unsafe, non-emergency. Calculations also indicate that if the spillway were constructed in accordance with available desing drawings, the facility could pass and/or store approximately 63 percent of the PMF.