National Dam Inspection Program. Colyer Lake dam (NDS ID Number PA-00448, PennDER ID Number 14-112), Susquehanna River Basin, Sinking Creek, Centre County, Pennsylvania. Phase I Inspection Report.

Colyer Lake Dam is a zoned earth embankment approximately 38 feet high and 700 feet long. Including the spillway system, the length of the facility is approximately 780 feet. The dam is provided with an ungated concrete rectangular spillway and plunge pool located on the right abutment. The spillway consists of a 69-foot wide trapezoidal weir section aside a 10-foot wide rectangular flume section inside dimensions, separated by a concrete wall. The outlet works consist of a 4-foot square reinforced concrete outlet connected to a rectangular vertical riser. Discharge through the outlet is controlled by stop logs that are set in grooves within the riser. The visual inspection, operational history, and hydrologichydraulic analysis indicate the facility is in good condition. Based on the recommended guidelines, the Spillway Design Flood SDF for this facility is the Probable Maximum Flood PMF. Hydrologic and hydraulic calculations performed for this Phase I study indicate that the dischargestorage capacity of the dam can accommodate a flood of magnitude equal to about 77 percent of the PMF prior to overtopping of the dam. Therefore, the spillway system is considered to be inadequate.