Ottawa River drainage basin
The Ottawa River drainage basin is the drainage basin in northern North America where surface water empties into the Ottawa River and adjoining waters. Spanning an area of about , it is the 12th largest drainage basin in Canada, occupying the Canadian provinces of Ontario and Quebec. It accounts for about 11% of the total Saint Lawrence River drainage area.
Rideau Falls
The Rideau Falls are two waterfalls located in Ottawa, Ontario, Canada, where the Rideau River empties into the Ottawa River. The falls are divided by Green Island, with Ottawa's Old City Hall just to the south. To the west of the falls is the headquarters of the National Research Council while to the east are the Canada and the World Pavilion and the French Embassy. The falls were named by the early French for their resemblance to a curtain, or "rideau" in French. The Rideau River was later named after the falls. The Rideau Canal was constructed to bypass these falls and the Hog's Back Falls.