Ottawa River WatershedThe Ottawa River watershed, shown on the image to the right, is a secondary (second-order) watershed. The five watersheds within are tertiary (third-order) watersheds. All of these watersheds are included within the primary watersheds (will open in a new window).

Kitche-sippi, the Great River, was the original name given by Algonquin First Nations people who lived on its banks. The river was the first highway for the Algonquin people, giving them access to the resources of the wilderness and the means to trade them.

The Ottawa River is the second largest river the Eastern Canada. It stretches for 1271km and drains an area of 146,300km2. The Ottawa River watershed is a part of the Great Lakes St Lawrence watershed - the largest freshwater ecosystem in the world! The Ottawa River is the largest tributary of the St Lawrence River, and so the health of the Ottawa River directly effects the health of the St Lawrence River.

The Ottawa River begins deep in Québec just outside La Vérendrye Wildlife Refuge, flowing from here into Lake Temiskaming, then it runs all the way to the St Lawrence in the East along the border of Québec and Ontario until it reaches Montreal. 

• Municipal wastewater pollution, including stormwater flowing from across the cities of Ottawa and Gatineau into the Ottawa River
• Lack of water data and information on the Ottawa River
• Industrial pollution
• Lack of integrated management for the protection of the Ottawa River between the two provinces
• Agricultural pollution, mostly non-point source polution such as fertilizers, manure, pesticides and herbicides
• Dams on the Ottawa River act as barriers to species migration, causing puttingspecies at risk and reducing biodiversity in the river

Lady Evelyn Lake

Major Tributaries

Upper Ottawa River: Camachigama, Capitachouane, Chochouane, Darlens, Kinojéris, Blanquet and Wabi Creek.

From Lake Temiscaming to the mouth: Kipawa, Montreal, Mattawa (43 km), Petawawa (187 km), Bonnechere (145 km), Madawaska (230 km), Mississipi (169 km), Rideau (146 km), South Nation (161 km), Rigaud, Maganasipi, Dumoine (129 km), Noire, Coulonge (217 km), Gatineau (386 km), du Lièvre (330 km), Blanche, Petite Nation (97 km) and Rouge (185 km).

Water quality in the Ottawa River basin is considered good overall as a result of the high velocity of the water and the numerous wastewater treatment plants that have been established. Most problem areas are localized, such as around densely urbanized areas. The Ottawa River’s many tributaries affect the overall water quality of the river itself. Despite localized problems, the majority of the Ottawa River is considered suitable for recreational uses such as swimming and fishing.

Ottawa River WatershedSurface water gauges collect water level data and stream flow data on rivers, creeks, and lakes. Level data is typically collected on lakes and reservoirs. Flows are collected where rating curves have been established on rivers and creeks. Surface water gauges are operated by a division of Environment Canada called Water Survey of Canada (WSC), Parks Canada, the Conservation Authorities, the City of Ottawa and several private companies.

WSC own and operate six surface water gauges on the Ottawa River and some of its tributaries within the jurisdiction of Mississippi Valley Conservation (MVC) and Rideau Valley Conservation Authority (RVCA) and outside the boundaries of the Mississippi and Rideau River Watersheds. The gauge on Sawmill Creek is a historic WSC gauge that was recently reinstated by the City of Ottawa.

Click the map to see the location of the gauges and graph water flow data.

Skating on the Rideau CanalIndustry

Some land is used for industrial purposes along the Ottawa River, and many of industries rely on the river’s water for their operations. Atomic Energy Canada Limited (AECL) has its major research facility, Chalk River Laboratories, on the Ontario shore of the river. A Canadian forces base lies between AECL and Petawawa. Bryson and Portage-du-Fort have pulp and paper mills. The town of Braeside, with its Tembec mill, is a major water user. Industries between Chaudiere Falls and Chats Falls include Goldie Mohr Construction and M.G. MacDonald.

Ottawa River WatershedThe Ottawa River is home to many different ecosystems, each playing an important role in sustaining Canada’s biodiversity. More than 300 species of bird have been inventoried along the river. Of these, about half are migratory species that use the Ottawa River region as one of the continent’s most important migratory halts. Along the river, 33 species of reptiles and amphibians, 53 species of mammals, and 85 species of fish can also be observed. Among these, several are rare or at risk.