Click here for an animation of a barge going upstream. Large File: Please wait for download.
Click here for an animation of a barge going downstream.
Canal locks are a series of gates designed to allow a boat or ship to pass from one level of water to another. Here, after a boat has entered the lock and all gates are secured, the downstream sluices open and water flows through them. When the water level is equal on either side of the downstream gate, water stops flowing through the sluices; the downstream gate opens, and the boat continues on at the new water level.