Emergency Swing Bridge Dam / Barrage tournant de secours

Built by the Dominion Bridge Company of Montreal in 1896, the Emergency Swing Bridge Dam was modeled on the American Sault Canal dam but modified in a Canadian design and built entirely of steel. Intended for emergencies, it was tested in 1909 when a ship rammed and dislodged the lower gates while two vessels were locking through. The rush of water through the lock carried away the main gates and flushed the two vessels through the lock, damaging the lock floor and submarine electric cables. The superintendent ordered the dam swung into position across the canal, and within a few hours it was secured while workers lowered its 23 wickets one by one into the rushing water. Their internal shutters extended fully and came to rest against the underwater sill at the canal bottom, forming a dam that slowed the flow enough to allow one set of gates to be closed and control of the lock to be regained. Twelve days later new gates were in place, the floor and cables were repaired, and the canal was back in operation. The success of this operation demonstrated the superiority of the design, similar structures were later built on the Panama Canal, and the Sault Canal's Emergency Swing Bridge Dam is one of the last remaining dams of its type in the world.

Ontario · Canada