Ottawa River


The Ottawa River is a river in the Canadian provinces of Ontario and Quebec. It is named after the Algonquin word "to trade", as it was the major trade route of Eastern Canada at the time. For most of its length, it defines the border between these two provinces. It is a major tributary of the St. Lawrence River and the longest river in Quebec.

Geography

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.
From Lake Timiskaming, the river flows southeast to Ottawa and Gatineau, where it tumbles over Chaudière Falls and further takes in the Rideau and Gatineau rivers.
The Ottawa River drains into the Lake of Two Mountains and the St. Lawrence River at Montreal. The river is long; it drains an area of, 65 per cent in Quebec and the rest in Ontario, with a mean discharge of. It has a maximum depth of at the Carillon Reservoir and is wide at its widest part.
The average annual mean waterflow measured at Carillon dam, near the Lake of Two Mountains, is, with average annual extremes of. Record historic levels since 1964 are a low of in 2010 and a high of in 2017.
The river flows through large areas of deciduous and coniferous forest formed over thousands of years as trees recolonized the Ottawa Valley after the ice age. Generally, the coniferous forests and blueberry bogs occur on old sand plains left by retreating glaciers, or in wetter areas with clay substrate. The deciduous forests, dominated by birch, maple, beech, oak and ash occur in more mesic areas with better soil, generally around the boundary with the La Varendrye Park. These primeval forests were occasionally affected by natural fire, mostly started by lightning, which led to increased reproduction by pine and oak, as well as fire barrens and their associated species. The vast areas of pine were exploited by early loggers. Later generations of logging removed hemlock for use in tanning leather, leaving a permanent deficit of hemlock in most forests. Associated with the logging and early settlement were vast wild fires which not only removed the forests, but led to soil erosion. Consequently, nearly all the forests show varying degrees of human disturbance. Tracts of older forest are uncommon, and hence they are considered of considerable importance for conservation.
The Ottawa River has large areas of wetlands. Some of the more biologically important wetland areas include, the Westmeath sand dune/wetland complex, Mississippi Snye, Breckenridge Nature Reserve, Shirleys Bay, Ottawa Beach/Andrew Haydon Park, Petrie Island, the Duck Islands and Greens Creek. The Westmeath sand dune/wetland complex is significant for its relatively pristine sand dunes, few of which remain along the Ottawa River, and the many associated rare plants. Shirleys Bay has a biologically diverse shoreline alvar, as well as one of the largest silver maple swamps along the river. Like all wetlands, these depend upon the seasonal fluctuations in the water level. High water levels help create and maintain silver maple swamps, while low water periods allow many rare wetland plants to grow on the emerged sand and clay flats. There are five principal wetland vegetation types. One is swamp, mostly silver maple. There are four herbaceous vegetation types, named for the dominant plant species in them: Scirpus, Eleocharis, Sparganium and Typha. Which type occurs in a particular location depends upon factors such as substrate type, water depth, ice-scour and fertility. Inland, and mostly south of the river, older river channels, which date back to the end of the ice age, and no longer have flowing water, have sometimes filled with a different wetland type, peat bog. Examples include Mer Bleue and Alfred Bog.

Tributaries

Major tributaries include:
Communities along the Ottawa River include :
  • Kitcisakik Anicinape Community
  • Long Point First Nation
  • Moffet, Quebec
  • Angliers, Quebec
  • Notre-Dame-du-Nord, Quebec
  • Timiskaming First Nation
  • Temiskaming Shores, Ontario
  • Ville-Marie, Quebec
  • Témiscaming, Quebec
  • Thorne, Ontario
  • Mattawa, Ontario
  • Deux Rivières, Ontario
  • Rapides-des-Joachims, Quebec
  • Rolphton, Ontario
  • Deep River, Ontario
  • Sheenboro, Quebec
  • Petawawa, Ontario
  • Pembroke, Ontario
  • Westmeath, Ontario
  • Waltham, Quebec
  • Davidson, Quebec
  • Fort-Coulonge, Quebec
  • La Passe, Ontario
  • Campbell's Bay, Quebec
  • Bryson, Quebec
  • Portage-du-Fort, Quebec
  • Bristol, Quebec
  • Norway Bay, Quebec
  • Braeside, Ontario
  • Arnprior, Ontario
  • Fitzroy Harbour, Ontario
  • Quyon, Quebec
  • Constance Bay, Ontario
  • Aylmer, Quebec
  • Ottawa, Ontario
  • Gatineau, Quebec
  • Masson-Angers, Quebec
  • Cumberland, Ontario
  • Rockland, Ontario
  • Thurso, Quebec
  • Wendover, Ontario
  • Plaisance, Quebec
  • Papineauville, Quebec
  • Montebello, Quebec
  • Fassett, Quebec
  • L'Orignal, Ontario
  • Grenville, Quebec
  • Hawkesbury, Ontario
  • Carillon, Quebec
  • Pointe-Fortune, Quebec
  • Saint-André-Est, Quebec
  • Rigaud, Quebec
  • Saint-Placide, Quebec
  • Kanesatake
  • Hudson, Quebec
  • Oka, Quebec
  • Vaudreuil-sur-le-Lac, Quebec
  • L'Île-Cadieux, Quebec
  • Vaudreuil-Dorion, Quebec
  • Terrasse-Vaudreuil, Quebec
  • Pincourt, Quebec
  • Pointe-des-Cascades, Quebec

    Islands

Ontario

  • Alexandra Island
  • Aylmer Island
  • Basil Island
  • Bate Island
  • Beacon Island
  • Beckett Island
  • Bell Island
  • Big Island
  • Big Elbow Island
  • Bruyère Island
  • Burnt Island
  • Butternut Island
  • Carl Island
  • Cedar Island
  • Chapman Island
  • Chartrand Island
  • Chenaux Island
  • Christie Island
  • Clarence Island
  • Coreille Island
  • Corinne Island
  • Cornelius Island
  • Cotnam Island
  • Crab Islands
  • Cunningam Island
  • Cushing Island
  • Daisy Island
  • Davis Island
  • Deep River Islet
  • Demers Island
  • Dow Island
  • Dunlop Island
  • Dupras Island
  • Dutch Island
  • Ellis Island
  • Evelyn Island
  • Farr Island
  • Fish Island
  • Fraser Island
  • Fury Island
  • Gibraltar Island
  • Green Island
  • Gutzman Island
  • Hamilton Island
  • Haycock Island
  • Hazel Island
  • Hazelton Island
  • Hen Island
  • Hog Island
  • Houston Island
  • Île Chénier
  • Île du Chenail
  • Île Ste-Rosalie
  • Île Young
  • Irving Island
  • Jamieson Island
  • John Joe Island
  • Kate Island
  • Kedey's Island
  • King Edward Island
  • Latour Island
  • Lemieux Island
  • Lillian Island
  • Lorne Island
  • Louise Island
  • Lower Duck Island
  • Lumpy Denommee's Island
  • Mackie Island
  • Man Island
  • Meadow Island
  • Merrill Island
  • Metcalf Island
  • Miller Island
  • Morris Island
  • Nichol's Island
  • Oak Island
  • O'Meara Island
  • Parker Island
  • Pearl Island
  • Petrie Island
  • Pink Island
  • Poker Island
  • Princess Island
  • Ramsey Island
  • Randolph Island
  • Rempnouix Island
  • Riopelle Island
  • Rocher Capitaine Island
  • Ruby Islet
  • Sack's Island
  • Sandbar Island
  • Santa Island
  • Sawlog Island
  • Shoal Island
  • Short Turn Island
  • Steamer Island
  • Snake Island
  • Sullivan Island
  • Upper Duck Island
  • Victoria Island
  • Wabewawa Island
  • Willson Island
  • Windsor Island

    Quebec

  • L'Île
  • Île Allen
  • Île aux Allumettes
  • Île Armstrong
  • Île Avelle
  • Bald Rock
  • Île Béique
  • Îles Benny
  • Île Bernard
  • Île Bernardin
  • Île Berry
  • Île à Bertrand
  • Île Boom
  • Île Bray
  • Île Brisseau
  • Île Brunet
  • Île Bryson
  • Île Cadieux
  • Île Cobb
  • Île de Carillon
  • Île du Centre
  • Île du Chef
  • Île du Chenal Blind
  • Île du Chicot
  • Îles à Cole
  • Île du Collège
  • Île de la Compagnie
  • Île à Cowley
  • Île à Crépault
  • Île D'Arcy
  • Île Davidson
  • Île Dog
  • Île Dubé
  • Île à Everill
  • Île Fer à Cheval
  • Île du Finlandais
  • Îles Finlay
  • Île Fitzpatrick
  • Île au Foin
  • Île Fox
  • Île Fox
  • Île French
  • Île Frigon
  • Île Gagnon
  • Rocher à Gillis
  • Rochers aux Goélands
  • Île Graham
  • Île du Grand Calumet
  • Île Green
  • Île Greene
  • Île à Griffin
  • Île Harbec
  • Île Hemlock
  • Île Henry
  • Île Hiam
  • Île Jacey
  • Île John-Park
  • Île Jones
  • Îles Jumelles
  • Île Kettle
  • Île Lafleur
  • Île Lafontaine
  • Île Lasalle
  • Île à Lawn
  • Île Leblanc
  • Île Lemoine
  • Île Leroux
  • Île Lighthouse
  • Île Lighthouse
  • Île Limerick
  • Petite île Limerick
  • Île Lorelei
  • Île Mann
  • Île Marcotte
  • Île à Marion
  • Île Mohr
  • Île Morrison
  • Île Mulligan
  • Île O'Connor
  • Île Oscar-Béchamp
  • Île Oster
  • Île Paquin
  • Île à Payne
  • Îles Pelley
  • Île Philemon
  • Île Pigs
  • Île aux Pins
  • Île des Quinze
  • Île Rainville
  • Île des Rapides
  • Île du Refuge
  • Île Reid
  • Île Reid
  • Île Rita
  • Île à Ritté
  • Île du Rocher Fendu
  • Île à Rouleau
  • Île à Roussin
  • Île de Sable
  • Petite île Sèche
  • La Semelle
  • Île Smith
  • Île Snake
  • Île des Soeurs
  • Île Soulier
  • Île Squelette
  • Île Submergée
  • Île Sunset
  • Île Todd
  • Île à Tom
  • Île à Tom-Simon
  • Île aux Tourtes
  • Île Verte
  • Île Victoria
  • Île Wickens
  • Île Winneway
  • Île Woods
  • Île Wight
  • Île Young
  • Île Young
  • Île Yvette-Naubert

    Geology

The Ottawa River lies in the Ottawa-Bonnechere Graben, which is a Mesozoic rift valley that formed 175 million years ago. Much of the river flows through the Canadian Shield, although lower areas flow through limestone plains and glacial deposits.
As the glacial ice sheet began to retreat at the end of the last ice age, the Ottawa River valley, which, along with the St. Lawrence River valley and Lake Champlain, had been depressed to below sea level by the glacier's weight, filled with sea water. The resulting arm of the ocean is known as the Champlain Sea. Fossil remains of marine life dating 12 to 10 thousand years ago have been found in marine clay throughout the region. Sand deposits from this era have produced vast plains, often dominated by pine forests, as well as localized areas of sand dunes, such as Westmeath and Constance Bay. Clay deposits from this period have resulted in areas of poor drainage, large swamps, and peat bogs in some ancient channels of this river. Hence, the distribution of forests and wetlands is very much a product of these past glacial events.
File:Ottawa River Stromatolite Bed.jpg|thumb|Ottawa River Stromatolite Bed, near the Champlain Bridge, with the Ottawa skyline in the background
Large deposits of a material commonly known as Leda clay also formed. These deposits become highly unstable after heavy rains. Numerous landslides have occurred as a result. The former site of the town of Lemieux, Ontario collapsed into the South Nation River in 1993. The town's residents had previously been relocated because of the suspected instability of the earth in that location.
As the land gradually rose again the sea coast retreated and the fresh water courses of today took shape. Following the demise of the Champlain Sea the Ottawa River Valley continued to drain the waters of the emerging Upper Great Lakes basin through Lake Nipissing and the Mattawa River. Owing to the ongoing uplift of the land, the eastward flow became blocked around 4000 years ago. Thereafter Lake Nipissing drained westward, through the French River which later became a link in the historic canoe route to the West.