Mahoning Creek Dam – Hydropower Plant

The Mahoning Creek Dam, a flood control structure, was constructed in 1941 to help protect the lower Allegheny River valley. Built by the US Army Corps of Engineers, this dam included forward-thinking features, such as two water conduits in the south abutment which allowed for this hydroelectric development.

The project involved connecting the existing dam water conduits via a 10-ft diameter penstock to feed a new powerhouse constructed downstream. Ruhlin constructed the powerhouse, the installation of the control room with skid-mount instrumentation controls and installed the two turbines (4 MW and 2 MW) with two vertical-shaft generating units. The new hydroelectric powerhouse provides 6MW of renewable power out to the grid which is expected to produce a long-term average generation of 19,243 MWh of electricity annually for 50 years, which is enough to power 1,850 homes.

Challenges overcome in this project included having to float and then sink a new steel intake structure, removal of the original 10’ long concrete plug in one of the water conduits, installation of 1000’ of 10’ buries penstock along the downstream shoreline and construction of the powerhouse beginning at 12’ below the tailwater.