National Dam Inspection Program. Clear Lake Dam (NDI ID Number PA-175 DER ID Number 20-3), Ohio River Basin, East Branch Oil Creek, Crawford County, Pennsylvania. Phase I Inspection Report

摘要

Inspection and review of data of the Clear Lake Dam did not reveal any problems which require emergency action. The dam appeared to be in poor condition and poorly maintained. The Clear Lake Dam is a high hazard-small size dam. The spillway design flood (SDF) for a dam of this size and classification is in the range of the 1/2 PMF to the PMF. The PMF has been selected as the spillway design flood based on the downstream potential for loss of life. The spillway and reservoir are capable of controlling approximately 6% of the PMF. Based on criteria established by the Corps of Engineers, the spillway is termed seriously inadequate. Clear Lake Dam is classified as an unsafe non-emergency dam. A detailed stability and seepage analysis should be conducted by a registered professional engineer knowledgeable in dam design and construction and should be conducted in conjunction with a hydrologic and hydraulic analysis of the structure to increase spillway capacity and the stability of the structure. The method used to block the penstock should be investigated by a registered professional engineer knowledgeable in dam design and construction. Repairs should be conducted accordingly.