Bloede's Dam was a hydroelectric dam on the Patapsco River in Maryland. Built in 1906, it was the first submerged hydroelectric plant—that is, the power plant was housed under the spillway. It was also one of the earliest dams constructed of reinforced concrete. Its site is now part of Patapsco Valley State Park upstream from the Orange Grove area. The dam w…Bloede's Dam was a hydroelectric dam on the Patapsco River in Maryland. Built in 1906, it was the first submerged hydroelectric plant—that is, the power plant was housed under the spillway. It was also one of the earliest dams constructed of reinforced concrete. Its site is now part of Patapsco Valley State Park upstream from the Orange Grove area. The dam was breached in 2018, with removal complete by 2019.