National Dam Inspection Program. Renton Slurry Pond 3 (NDI Number PA 00838, Penn DER Number 2-50), Ohio River Basin, Tributary to Little Plum Creek, Allegheny County, Pennsylvania. Phase I Inspection Report

Abstract

Abstract : Based on a review of available information, visual observations of conditions as they existed on the date of the field inspections, and supporting engineering calculations, the general condition of the Pond 3 is considered to be fair. This assessment is based primarily on visual observations of embankment, spillway and seepage conditions and hydrology/hydraulic analyses of reservoir/spillway capacity. The structure is classified as a 'small' size, 'high' hazard dam. Corps of Engineers guidelines recommend 0.5 to one times the Probable Maximum Flood (PMF) as the Spillway Design Flood for a 'small' size, 'high' hazard dam. The Pond 3's Spillway Design Flood is the Probable Maximum Flood because of its height. Spillway capacity is 'inadequate' because the nonovertopping flood discharge was found, by using the HEC-1 computer program, to be 35 percent of the PMF. At 0.5 PMF, the embankment overtopping depth and duration would be 0.58 feet and eight hours and 40 minutes respectively. In the opinion of the evaluating engineer, this overtopping depth and duration would not cause a catastrophic failure of the embankment.