National Dam Inspection Program. Glenwood Lake Dam (NDI ID Number PA- 00327, DER ID Number 35-143), Susquehanna River Basin, Covey Creek, Lackawanna County, Pennsylvania. Phase I Inspection Report

Abstract

Based on visual inspection, past performance, field surveys and calculations, Glenwood Lake Dam is judged to be in poor condition. The recommended Spillway Design Flood (SDF) for the size (small) and hazard classification (high) of the dam is between the one-half Probable Maximum Flood (1/2 PMF) and the full PMF. Based on the small size and storage capacity, it is judged that the SDF of 1/2 PMF is appropriate for the Glenwood Lake Dam. Under the present conditions, the spillway will pass approximately 10 percent of the PMF without overtopping the dam. Overtopping depths of 1.1 feet and 2.12 feet were calculated for flood magnitudes of 20% and 50% of the PMF, respectively. It was judged that the dam will begin to fail under an overtopping depth of one- foot. Because the present spillway capacity would not pass the SDF without overtopping the dam and failure of the dam would increase the downstream hazard to life and property, the spillway is rated as seriously inadequate and the dam is rated as unsafe, non-emergency. The facility is not properly maintained, as evidenced by the extensive growth of trees on the embankment and the condition of the outlet works valve pit. There is no warning system and evacuation plan in effect at the present time.