The Ashland Dam (PADEP No. 54-75) in Butler Township, PA impounds 331 acre-feet of water and is owned and operated by the Ashland Area Municipal Authority (AAMA) for municipal water supply. The Pennsylvania Department of Environmental Protection (PADEP) categorizes the dam as a Hazard Category 1 (High), Size Class B-1 structure. The existing spillway did not have sufficient capacity to safely pass the required spillway design flood (SDF) without overtopping the dam’s embankment.
PADEP required action to minimize the risk for dam overtopping and/or failure by increasing storage and spillway capacities, therefore reducing the risk of downstream flooding. Improvements to rehabilitate the dam included construction of a concrete parapet and earthfill raising the dam six feet which allowed for greater storage capacity and to allow the spillway to safely pass the SDF. Benesch was involved with alternatives analysis, funding acquisition, design and construction completion for this project.