Holtwood Dam is the oldest of three major dams built across the lower Susquehanna River, and the middle location of the three. The Holtwood Hydroelectric Plant produces 109 Megawatts of power, using 10 turbine driven generators. The dam consists of a main concrete dam, which is mostly one continuous spillway, with a power house at the eastern end. A fish lift is located near the power house to lift American shad and other migratory fish species. ANAMAR provided technical assistance for a multibeam survey that was conducted in the forebay area above the fish lift and power house to determine post-blasting conditions associated with plant expansion.