Ethel Springs Dam is owned and operated by the Borough of Derry Municipal Water Authority. The dam is classified as a 'High' hazard - 'Intermediate' size dam. The dam was found to be in poor overall condition at the time of inspection. Hydraulic/hydrologic evaluations, performed in accordance with procedures established by the Baltimore District, Corps of Engineers, for Phase I Inspection Reports, revealed that the spillway will pass approximately 40 percent of the Probable Maximum Flood (PMF) before overtopping will occur. A spillway design flood (SDF) equal to the PMF is required for Ethel Springs Dam. Additional analyses were performed to assess whether or not the dam would fail under 1/2 Probable Maximum Flood (1/2 PMF) conditions. Since the duration and depth of overtopping under the 1/2 PMF (6.0 hours and 0.28 feet, respectively) do not exceed the limiting criteria assumed for failure of the dam (8.0 hours and 1 foot), it has been estimated that failure of the dam under 1/2 PMF conditions is not likely. The spillway is therefore considered 'inadequate' but not 'seriously inadequate.' The owner should immediately initiate an engineering study to further evaluate the spillway capacity and to develop recommendations for remedial measures to reduce the overtopping potential of the dam. The possibility of movement of the upstream slope and the uncertainties of construction of the dike and downstream slope are causes for concern for the continued stability and safety of this dam. It is recommended that a detailed overall investigation of this dam be performed.