National Dam Safety Program. Potters Falls Dam (Inventory Number N.Y. 378), Oswego River Basin, Tompkins County, New York. Phase I Inspection Report,
METCALF AND EDDY OF NEW YORK INC NY
Pagination or Media Count:
Visual inspection of this dam and engineering analyses which have been performed revealed that several deficiencies exist on this structure. The worst of these deficiencies was the localized spalling and erosion of the gunite covering the dam. This was observed in three areas on the downstream face and toe. A more thorough examination of the gunite when there is no discharge over the spillway is needed to evaluate the extent and cause of this deterioration. If the gunite is not repaired, the interior concrete of the dam will become exposed to erosion. Using the Corps of Engineers Guidelines for the initial review of spillway adequacy, it has been determined that the structure would be overtopped by all storms exceeding 31 percent of the Probable Maximum Flood PMF. During a one-half PMF storm, the abutments of the dam would be overtopped by 3.4 feet. The dam is a concrete arch-gravity structure with bedrock at both abutments. While overtopping is not likely to induce failure from erosion, a stability analysis indicates that the factor of safety is below the recommended level during the one-half PMF storm. If the dam were to fail, it would increase the degree of flooding in downstream residential areas. Therefore, the spillway is assessed as seriously inadequate.
- Hydrology, Limnology and Potamology
- Civil Engineering