Rideau Falls, Natural waterfall in Ottawa, Canada

Rideau Falls is a waterfall in Ottawa where the Rideau River empties into the Ottawa River, dropping about 11 metres. Green Island splits the river into two branches before the falls, and a stoplog dam spans each branch at the crest. The water pours over a curved, stepped ledge between dark concrete piers, turning white and foamy in the plunge pool.

Samuel de Champlain, a French explorer, documented these falls in the early 1600s and noted their substantial width and power. The location became an important reference point for those exploring and settling the region afterward.

Samuel de Champlain named the falls in 1613; the French word rideau, meaning curtain, described the sheet of water. The Rideau River and later the Rideau Canal took their names from the falls. The canal, finished in 1832, was built so boats could bypass the falls and Hog's Back Falls.

The falls are easily reached on foot from Sussex Drive, with multiple viewing platforms positioned at different angles along the pathways. Each spot offers a different perspective on the cascading water and the power of the flow.

The stoplog dams above each branch were rebuilt at different times: the eastern dam in 1968, the western one in 1999. They still regulate the river's flow and must be coordinated with the municipality's spring ice blasting on the Rideau. The crest in the photo, split by dark concrete piers, is this dam structure rather than bare rock.