How did locks move boats through changes in elevation on the Erie Canal?

To move boats through changes in elevation, the Erie Canal utilized a series of 83 stone locks. A lock functions as an enclosed basin with gates at both ends, allowing the water level within the chamber to be raised or lowered to match the level of the adjacent canal section.1

The process operates as follows:
* To raise a boat: The boat enters the lock chamber from the lower level. The downstream gates are closed, and the chamber is filled with water until it reaches the level of the upper section. Once equalized, the upstream gates are opened, allowing the boat to exit at the higher elevation.1
* To lower a boat: The boat enters the chamber from the higher level. The upstream gates are closed, and water is drawn out of the chamber until the level matches the lower section. The downstream gates are then opened to allow the boat to proceed.1

These locks were designed to be operated by a single person, and in areas with significant elevation changes, such as the Niagara Escarpment, engineers constructed staircase-like series of locks to overcome the barrier.2