Holtwood Dam

Holtwood hydroelectric plant

The Holtwood Hydroelectric Plant produces 252 Megawatts of power, using 14 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. The water level is raised by wooden flash boards and inflatable dam sections.

The western end of the dam has the original, and ineffective, fish ladder. In the mid 1990s, construction started on a fish lift. The fish lift and dam were damaged by heavy rain and rapid snowmelt from the severe 1996 flood in January of that year. The new fish lift was completed in time for the 1997 season and began lifting american shad and other migratory fish species.

The Kingsbury thrust bearing of Holtwood's Generator No. 5 is designated an International Historic Mechanical Engineering Landmark. Previously used roller bearings would last about 2 months under the generator's 220 ton load, but the Kingsbury bearing has been in use since 1912.

The impounded water, Lake Aldred, was originally dredged for anthracite coal silt, or fines, washed downstream from the Coal Region of Pennsylvania. This coal was used in the adjacent Holtwood Steam Generator station. When Safe Harbor Dam was built upstream, its impoundment was then "mined" for coal as well. More efficient primary mining upstream reduced the availability of fines, and 1972 environmental laws made the dredging impractical, so coal was brought in by train.