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The river rises at Lac des Outaouais, north of the Laurentian Mountains of central Quebec, and flows west to Lake Timiskaming. From there its route has been used to define the interprovincial border with Ontario.
3 days ago · Ottawa River, river in east-central Canada, the chief tributary of the St. Lawrence River. It rises in the Laurentian Plateau of western Quebec and flows swiftly westward to Lake Timiskaming and then southeastward, forming for most of its course the Quebec– Ontario provincial border before it joins the St. Lawrence west of Montreal.
- The Editors of Encyclopaedia Britannica
- Course
- Geology
- Flora
- Fauna
- Environmental Concerns
- Conservation
- Indigenous History Before 1600
- Algonquin-French Alliance, 1600–1763
- British Colonization
- 19Th-Century Timber Trade
The source of the Ottawa River is Lake Capimitchigama in the Laurentian Mountains, approximately 240 km north of Ottawa and 290 km northwest of Montreal. The river traces a westward arc through lakes and reservoirs including Dozois Reservoir, Grand lac Victoria, Lac Granet, Decelles Reservoir, Lac Simard and Lake Timiskaming. From Lake Timiskaming,...
The retreat of the Laurentide Ice Sheet some 10,000 years ago exposed land that had been depressed under the glacier’s weight (see also Glaciation). Because of its low elevation, the area now occupied by Lake Nipissing and the Mattawa River became an outlet for waters from the prehistoric upper Great Lakes. These waters flowed into the Ottawa Valle...
The deep lakes and fast-flowing waters of the Ottawa River support few plant species. However, algae and larger aquatic plants commonly grow in its wetlands. Invasive species that grow in the Ottawa River include European frog-bit and Eurasian water‐milfoil. The dense mats of vegetation they form on or under the surface of the water stifle other aq...
The Ottawa River area provides habitats for many animals, despite it being one of the country’s most threatened landscapes. Dams, wastewater from municipalities and industry, and urban development all threaten the biodiversity of its ecosystems. The river’s waters are home to many species of fish (between 85 and 96 species, depending on the source)...
Pollution has been a problem since the 19th-century timber tradeon the Ottawa River. The large volumes of sawdust dumped into the river from the sawmills at Chaudière Falls, directly upstream from Parliament Hill, created a very visible blight on the nation’s capital. Contamination of the river with untreated sewage from the cities of Ottawa and Ga...
Because the Ottawa River supports many different species, including local human populations that rely on it for drinking water, people have made significant efforts to protect it. In 2001, concerned citizens formed Ottawa Riverkeeper, a member organization of the international Waterkeeper Alliance. Ottawa Riverkeeper works to protect aquatic life a...
The Ottawa River watershed is the traditional territory of the Algonquin people, who trace their roots back to the first occupants of the land. Indigenous people have inhabited the region since roughly 6500 BCE. Archeologists call this first era the Paleo-American period. The cultures of the peoples that followed are known broadly as the Laurentian...
The French were the first known Europeans to have contact with the Algonquin people. This took place when the two peoples began trading around the turn of the 17th century at Tadoussac. The trade relations between the Algonquin and the French grew into an alliance. French explorers and traders began to venture further inland to Algonquin territory....
The British did not keep their guarantee, made in the Royal Proclamation of 1763, to protect First Nations’ lands from appropriation by settlers. After the American Revolutionary War (1775–83), they responded to the influx of Loyalists in the colony by buying up land in individual sales with other nations. Some of these sales included Algonquinland...
Log rafts descended the Ottawa even before it ceased to be the prime route of the fur trade. Philemon Wright showed that the route was feasible in 1806, and the British demand for pine grew. In 1854, the Reciprocity Treaty secured free access for Canadian lumberinto the US market. The timber trade pervaded the social life of the valley. Armies of m...
5 days ago · Levels and flows are above normal for this time of year in most locations along the main stem of the Ottawa River due to recent rainfall runoff. With no significant rainfall event in the forecast, levels and flows are expected to decline over the coming week.
The Ottawa River is the second largest river in eastern Canada. It flows through east-central Canada for 790 miles (1,271 kilometers). The river is the chief tributary of the Saint Lawrence River.
The Ottawa River starts at Lake Capimitchigama in Quebec. It flows west to Lake Timiskaming, where it begins to define the border between Ontario and Quebec. From Lake Timiskaming the river flows southeast to Ottawa and Gatineau where it tumbles over the Chaudière Falls.
The Ottawa River flows from Quebec’s Laurentian Mountains west into Ontario and then southeast to Montreal and the St. Lawrence River. For 580 kilometres the river forms the border separating Ontario and Quebec.
