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• 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

One of the greatest concerns about climate change is the expected increase in climate variability and in extreme weather, causing floods, droughts and storms.

South Nation WatershedSurface water and groundwater quality can be influenced by factors such as the terrain, the time of year, and the type of sewage treatment plants and industry in the surrounding watershed. Common sources of groundwater pollution may include landfills, improper use and disposal of pesticides, agricultural and residential fertilization, improper disposal of animal wastes and industrial leaks and spills.

Reservoirs and Dams

Northern Pike/Grand Brochet

Small Mouth Bass/L'achigan à petite bouche

Quebec - Ottawa Bird's-eye viewThe well being of any water body is strongly tied to the watershed that surrounds it. A watershed (or catchment) is an area of land from which surface runoff, including water, sediments, nutrients and contaminants, drain into a common water body, such as a lake, river, stream, creek or estuary. Watersheds include all water and water-dependent land features, including wetlands, forests, towns, humans and other living things. Land use is a way of classifying the expected activities occurring around a watershed that can affect its well being.

Land use can contribute all major classes of pollutants to receiving waters, i.e., pathogens, nutrients, and toxic materials. These pollutants may enter waters either via groundwater or surface flows. The relative contribution of pollutants from land use depends upon the pollutant and may depend upon the distance from the receiving waters.

A key component of local land use planning is the identification of critical areas for protection. Escalating growth patterns place stress on these critical resource areas, and the stress is often proportional to growth. Identification of these areas will provide communities with a planning tool to begin answering questions of where to allow development, how much of it can occur, and how best to regulate potentially detrimental future land uses.

Read more: Types of Land Use

Read Local: Land Use in My Watershed

Adapted from Pollution Probe's Source Water Protection Primer and Land Use Management in Buzzards Bay

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.