From
www.nature.nps.gov:
Along the Potomac River, adjacent to C&O Canal, numerous dams were constructed,
including several built to produced backwater for recharging the canal at various locations (Feeder Dams). The following is a list of these dams; (1) Feeder Dam 1 (approx. CHOH milepost 5.5)... A recent breaching of Feeder Dam 1, at Little Falls, opened 10 miles of river habitat upstream to Great Falls. The breaching provided a new fish passage at the 12-foot-high dam designed to meet the needs of shad and other regional migratory fish.