The Lake Ondawa Dam is an earthfill dam, 50 feet long and 18 feet high. The dam is located on a tributary to Bentley Creek, approximately 0.3 mile northwest of the Village of Big Pond, Springfield Township, Bradford County, Pennsylvania. The inspection consisted of: Visual inspection of the retaining structure, abutments and toe; Examination of the spillway facilities, exposed portion of any outlet works and other appurtenant works; Observations affecting the runoff potential of the drainage basin; and Evaluation of the downstream area hazard potential. The dam appeared to be in fair condition. From a brief survey conducted during the inspection, it was noted that the low spot on the top of dam existed adjacent to either edge of the spillway on the retaining walls. The earthen embankment section rises gently from the spillway to either abutment.

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.

Based on visual inspection, available records, calculations and past operational performance, and according to criteria established for these studies, Summit Lake Dam is rated as unsafe, nonemergency, because the spillway capacity is seriously inadequate. The existing spillway can pass 26 percent of the Probable Maximum Flood (PMF) without overtopping of the dam. The failure of the dam would cause an increased hazard to loss of life downstream. As a whole, the dam is judged to be in fair condition. If the top of the dam were raised 0.1 foot to its design elevation, the spillway could pass 27 percent of the PMF. The spillway capacity would still be rated as seriously inadequate. There is no evidence of stability problems with the embankment. The masonry gravity section of the embankment has no significant deviations from the OCE guideline for stability, since the toe pressure is well below the allowable.

Based on the evaluation of the existing conditions, the condition of Cooks Pond Dam is considered to be unsafe/nonemergency due to the seriously inadequate spillway capacity and structural deficiencies. The condition of the embankment is considered to be poor. The dam is old and in a general state of disrepair. The crest of the dam is irregular and the center of the dam appears to have settled. The stone wall along the downstream toe is irregular and bulging. The toe of the wall is swampy, caused by a general underseepage. In view of these observations, the overall stability of the dam is considered to be questionable, requiring further investigation and implementation of measures to improve the stability of the dam. The spillway capacity was evaluated according to the recommended procedure and was found to pass less than 10 percent of the Probable Maximum Flood (PMF) without overtopping the embankment. This capacity is less than the required spillway capacity of one-half PMF relative to the size and hazard classification of the dam. Because the spillway capacity is less than 50 percent of the PMF and it is estimated that failure of the dam due to overtopping would significantly increase the downstream hazard of loss of life compared to that which would exist just before failure, the spillway is considered to be seriously inadequate, and consequently the condition of the dam is considered to be unsafe/nonemergency.