bloede’s dam

ca. 2014 – Patapsco Valley State Park, Avalon Area

Bloede’s Dam was a hydroelectric dam on the Patapsco River in Maryland. It was the first known instance of a submerged hydroelectric plant, where the power plant was actually housed under the spillway. It is also recognized as one of the earliest dams constructed of reinforced concrete. (wikipedia)

It was demolished September 2018.