What is a lock canal?

A lock canal is an artificial waterway designed to improve navigation by allowing vessels to move between bodies of water at different levels through water-filled chambers with gates and sluices. Originally, the canal at Coteau-du-Lac had three locks, but only two remained after major repair work in the early 19th century. This lock canal made it possible to overcome a drop of approximately 2 m in the water level of the St. Lawrence. As a vessel traveled up the St. Lawrence toward the Great Lakes, it entered the lower lock while the gates between the two locks were closed, then water from the upper lock was released into the lower one until both were at the same level, allowing the vessel to move into the upper lock, and finally water in the upper lock was raised to the level of the canal’s upper entrance so the vessel could reenter the river.

Quebec · Canada