Lock 20 was a lift-lock on the Original Erie Canal, where lift-locks allowed boats to climb or descend the 565-foot difference between the Hudson River and Lake Erie. The first Erie Canal had 83 lift-locks, each 90 feet long and 15 feet wide, and each provided a lift of 6 to 12 feet; Lock 20 raised or lowered boats 6 feet. A lift-lock worked like an elevator, with two large doors at each end and two sides forming an enclosed lock chamber. When the doors were shut, small gates at the bottom of each door could be opened or closed to raise or lower the water level inside the chamber, lifting a boat to the water level above the lock or lowering it to the water level below. Lock 20 was later adapted as part of a feeder canal that brought new water from Schoharie Creek into the Enlarged Erie, and the possibility of collapse required an emergency gravel fill of Lock 20 in 1980.
