Thompson River

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Thompson River
North Thompson River.jpg
A CN railway crossing of the North Thompson River in Kamloops
ThompsonRiverBritishColumbia Location.png
A map of the Thompson River's watershed
Country Canada
Province British Columbia
Physical characteristics
SourceConfluence of the North & South Thompson Rivers
  location Kamloops
  coordinates 50°40′49″N120°20′36″W / 50.68028°N 120.34333°W / 50.68028; -120.34333
  elevation345 m (1,132 ft)
Mouth Fraser River
50°14′07″N121°35′00″W / 50.23528°N 121.58333°W / 50.23528; -121.58333 Coordinates: 50°14′07″N121°35′00″W / 50.23528°N 121.58333°W / 50.23528; -121.58333 [1]
195 m (640 ft)
Length489 km (304 mi) [2]
Basin size56,000 km2 (22,000 sq mi) [3]
  location Spences Bridge
  average773 m3/s (27,300 cu ft/s)
  minimum171 m3/s (6,000 cu ft/s)
  maximum4,200 m3/s (150,000 cu ft/s)

The Thompson River is the largest tributary of the Fraser River, [3] flowing through the south-central portion of British Columbia, Canada. The Thompson River has two main branches, the South Thompson River and the North Thompson River. The river is home to several varieties of Pacific salmon and trout. The area's geological history was heavily influenced by glaciation, and the several large glacial lakes have filled the river valley over the last 12,000 years. Archaeological evidence shows human habitation in the watershed dating back at least 8,300 years. The Thompson was named by Fraser River explorer, Simon Fraser, in honour of his friend, Columbia Basin explorer David Thompson. Recreational use of the river includes whitewater rafting and angling.



South Thompson River

The South Thompson originates at the outlet of Little Shuswap Lake at the town of Chase and flows approximately 55 kilometres (34 mi) southwest through a wide valley to Kamloops where it joins the North Thompson. Highway 1, the Trans-Canada Highway and the mainline of the Canadian Pacific Railway parallel the river. Little Shuswap Lake is fed by the Little River, which drains Shuswap Lake, which is fed by several rivers and creeks.

North Thompson River

The North Thompson originates at the toe of the Thompson Glacier [4] in the Cariboo Mountains west of the community of Valemount and flows generally south towards Kamloops and the confluence with the South Thompson. For most of its length, the river is paralleled by Highway 5, and the Canadian National Railway (both of which cross the river a couple times). The North Thompson passes by several small communities, the most notable being Blue River, Clearwater & Barriere.

The North Thompson picks up the Clearwater River at the town of Clearwater. The Clearwater, the North Thompson's largest tributary, drains much of Wells Gray Provincial Park.

A notable feature along the North Thompson is Little Hells Gate, a mini-replica of the much larger rapid on the Fraser downstream from the mouth of the Thompson. About 17.4 kilometres (10.8 mi) upstream from the small town of Avola, the river is forced through a narrow chute only about 30 feet (9.1 m) wide creating a rapid that resembles the Fraser's famous rapid.


The darker waters of the Thompson meet the Fraser at Lytton. Fraser joins Thompson River at Lytton.JPG
The darker waters of the Thompson meet the Fraser at Lytton.

At Kamloops, the combined Thompson River river flows 15 kilometres (9.3 mi) from the confluence of the North and South Thompson Rivers before reaching Kamloops Lake, which is roughly 30 kilometres (19 mi) in length, ending at the town of Savona. From there it flows in a meandering course westwards through a broad valley area. At Ashcroft, the Thompson Canyon begins and the river turns southwestward to its confluence with the Fraser. The river is paralleled by the Trans-Canada Highway, the Canadian Pacific Railway and the Canadian National Railway.

From Ashcroft to Lytton, the river is completely confined within Thompson Canyon, making for spectacular scenery. The Thompson River joins the Fraser River in Lytton. There is a striking stretch of dark black cliffside just downstream from Ashcroft and visible from the Logan Lake-Ashcroft highway is officially named the Black Canyon. Just below the town of Spences Bridge was the site of a major rail disaster in the early 20th Century. Communities along this section are Bighorn, Shaw Springs, and Goldpan.


The Thompson River valley has existed in some form for at least 50 million years; however, for much of its history, it did not drain to the southwest into the Pacific Ocean as it does today. [5] Geologists believe water from the river flowed northward, through the Cariboo region, eventually entering what is the modern-day Peace River drainage basin and ending up in the Arctic Ocean. [6] This flow direction is estimated to have ended approximately 2 million years ago, as the Pleistocene era of heavy glaciation began. [6]

Glacial lakes

During the era of massive glaciers in the Thompson River valley, water from the area likely drained eastward, through the Shuswap Lake area into what is now the Columbia River drainage. This flow direction was influenced by large ice buildups in the Thompson valley, which created extensive glacial lakes. Two large glacial lakes, Glacial Lake Thompson and Glacial Lake Deadman, occupied much of the modern river's course from 13,000 BCE to 10,000 BCE. These deep, narrow, ribbon-shaped lakes held large volumes of water; Glacial Lake Thompson held nearly 84 cubic kilometres (20 cu mi) at its highest point. The lake stretched from Spences Bridge in the west to the eastern reaches of Shuswap Lake, as well as far up the northern reaches of the North Thompson river valley. [7] The last large glacial lake, Lake Deadman, was drained by a catastrophic ice dam failure, called a jökulhlaup, in about 10,000 BCE. This event released as much as 20 cubic kilometres (4.8 cu mi) of water southwest into the Fraser River system, possibly depositing sediments as far away as the Salish Sea, more than 250 kilometres (160 mi) away. From this point, the Thompson waters stopped flowing eastward into the Columbia River system, and the river became a tributary of the Fraser. [7]


Remnants of a landslide near the railway in the lower Thompson River valley Maintenance vehicles on the Canadian National (5999043481).jpg
Remnants of a landslide near the railway in the lower Thompson River valley

Because of large deposits of glacial silt, sand, and gravel in the lower Thompson River valley, large landslides are common. [8] The area downstream from the town of Ashcroft is prone to landslide events; eight major events between 1880 and 1982 have been recorded. Several of them have obstructed the river, and caused large, temporary lakes. An 1880 slide caused the formation of a short-lived lake over 14 kilometers long with a maximum depth of 18 meters. These slides have caused major damage to the rail lines and farming operations in the river valley. Heavy irrigation has been blamed for some of the events. [8]


Aboriginal peoples

The Interior region of British Columbia was first populated after the retreat of the continental ice sheets of the last ice age. The ice moved out of the Thompson River region approximately 11,000 BCE, and migration by the ancestors of the Nlaka'pamux and Secwepemc people is thought to have occurred soon after. [9] Some of the older archaeological sites on the lower Thompson include the Drynoch Slide site, near Spences Bridge, with artifacts dating to about 7350 BCE, and the Landels site, near Ashcroft, which dates to older than 8000 BCE. [10] Archaeologists theorize early settlers lived in small groups, beginning with nomadic bands hunting ungulates on the plateaus around the river, who then established more permanent dwellings along the river benches as their fishing techniques developed. [11]

The South Thompson has the watershed's oldest dated evidence of human habitation, at the Gore site near Pritchard. The human remains date to 8250 BCE, and bone analysis suggests the person was a hunter with small amounts of his protein coming from salmon. [12] Archaeological investigation in the North Thompson has been sparse, but artifacts near Bridge Lake to the west of the river have been dated to 3000 BCE, while pieces found near the tributary Clearwater River are possibly as old as 6000 to 7000 BCE. [12]

European exploration and settlement

Explorer of the Fraser River and North West Company employee Simon Fraser named the river, after passing its mouth on the Fraser in 1808. [13] He named the river after his colleague, David Thompson, who had mapped much of western Canada and was at the time exploring the Columbia River basin to the east. Thompson never visited the river that bears his name. [13] The first documented traverse of the Thompson from Kamloops to Lytton was by Hudson's Bay Company governor George Simpson in 1828. [14] More Europeans entered the Thompson River valley in the early to mid 1800s, drawn by the fur trade and small gold rushes. Others started farming on the fertile benches of the river, and a North West Company trading fort at the confluence of the North and South rivers became the city of Kamloops, now the largest human population center in the watershed. [13]


Sockeye salmon during the salmon run, Tsutswecw Provincial Park SockeyeSpawn inAdams.JPG
Sockeye salmon during the salmon run, Tsútswecw Provincial Park

The Thompson River supports 24 fish species, including two considered endangered. It also hosts carp, which are not native to the watershed. The river is home to large populations of Pacific salmon, including coho, sockeye, pink and chinook. Through its tributary, the Adams River, the Thompson has one of the largest sockeye salmon runs in the world. [15] Pink salmon spawn mostly below Kamloops Lake, while coho spawning beds are found in 40 of the Thompson watershed's streams and rivers. Coastal rainbow trout (Oncorhynchus mykiss irideus), including an anadromous variety called steelhead, are found in the river along with a local strain the Kamloops rainbow trout which occurs in Kamloops Lake at the Thompson River headwaters and other nearby lakes. Other fish species include round whitefish, largescale sucker, bridgelip sucker, northern pikeminnow, longnose dace, and slimy sculpin. [16]

Several bird species are found in Thompson River environments, including osprey, merganser, wood ducks, and dippers. Golden eagles are found near the confluence with the Fraser, [17] and Bald eagles congregate on the river during the salmon run. Trumpeter swans use the South Thompson on their migratory route. Rattlesnakes are found in the dry sagebrush regions of the lower river. Aquatic insects found in the river system are dominated by three groups: mayflies, midges, and caddisflies. Many of these species emerge with the spring snowmelt, which greatly increases the volume of flow on the river. [15]

Conservation and recreation

The Thompson River and its two branches are mostly unprotected through parks or reserves. Small sections of the river are within provincial parks, including Steelhead, Juniper, Goldpan, and North Thompson Provincial Parks. Some of its tributaries, such as the Clearwater, are more protected through large parks like Wells Gray. However, unlike major river systems to the north and east like the Columbia and Nechako, the Thompson has no hydroelectric dams or major man-made water diversions. [13] Under the British Columbia Fish Protection Act of 1997, the Thompson cannot be considered for future dam construction. [18]

Conservation of the Thompson's fisheries, especially its salmon population, has been a focus of provincial, federal, and international bodies, such as the Department of Fisheries and Oceans (DFO) and the Pacific Salmon Commission.

Hwy 5 bridge, first crossing of N. Thompson River after emerging from the Cariboo Mountains N Thompson River bridge.jpg
Hwy 5 bridge, first crossing of N. Thompson River after emerging from the Cariboo Mountains


From the 1950s through the early 1990s the Thompson River was considered one of the premier steelhead angling destinations in North America. The river hosted large runs of both summer and winter run anadromous coastal rainbow trout (Oncorhynchus mykiss irideus). In the late 1980s the runs were estimated at over 10,000 fish. [19] The river attracted anglers from around the world seeking powerful Thompson River steelhead. In 1982, the average male winter run Thompson River steelhead was 16 pounds (7.3 kg). [20] By the late 1990s, steelhead populations began to decline due to a wide variety of adverse environmental conditions and overfishing by commercial and First Nations gill netters. In 2016, annual steelhead numbers entering the Thompson were estimated to be less than 400 fish. Low numbers have prompted conservation organizations and sportsman’s associations to petition Committee on the Status of Endangered Wildlife in Canada (COSEWIC), for Canada's Species At Risk Act (SARA) protections. [21] The river is subject to catch and release angling only for steelhead and has severely restricted seasons to protect the wild stocks of remaining steelhead. [22]

Whitewater rafting

The rapids of the lower Thompson are used for recreational whitewater rafting. The first commercial rafting operation on the river began in the 1970s, based out of Spences Bridge. [23] Notable whitewater features on the lower river include the Frog, named for a frog-shaped rock formation, and the Jaws of Death, named by CPR engineers. [5] Rapids on the river reach up to Class 5 on the International Scale of River Difficulty.

Major Tributaries

The South Thompson River valley, near Monte Creek SouthThompson.jpg
The South Thompson River valley, near Monte Creek

North Thompson River

South Thompson River


See also


  1. "Thompson River". BC Geographical Names.
  2. Thompson River Archived 2005-05-10 at the Wayback Machine , The Columbia Gazetteer of North America
  3. 1 2 Thompson River,
  4. "Thompson Glacier". BC Geographical Names.
  5. 1 2 Fandritch 2013, p. 270.
  6. 1 2 Fandritch 2013, p. 271.
  7. 1 2 Johnsen, Timothy F.; Brennand, Tracy A. (2004). "Late-glacial lakes in the Thompson Basin, British Columbia: paleogeography and evolution" (PDF). Canadian Journal of Earth Sciences. National Research Council (Canada). doi:10.1139/E04-074.
  8. 1 2 Clague, John J. (August 1, 2003). "Geologic Framework of Large Historic Landslides in Thompson River Valley, British Columbia". Environmental & Engineering Geoscience. doi:10.2113/9.3.201.
  9. Rousseau 1993, p. 140.
  10. Rousseau 1993, p. 153.
  11. Rousseau 1993, p. 168.
  12. 1 2 Rousseau 1993, p. 156.
  13. 1 2 3 4 Benke & Cushing 2005, p. 708.
  14. Fandritch 2013, p. 7.
  15. 1 2 Benke & Cushing 2005, p. 710.
  16. Benke & Cushing 2005, p. 725.
  17. Fandritch 2013, p. 284.
  18. "BILL 25 -- 1997: FISH PROTECTION ACT". Retrieved 2016-11-30.
  19. Combs, Trey (1999). "Thompson River". Steelhead Fly Fishing. Heritage House Publishing Co. pp. 218–228. ISBN   9781895811728 . Retrieved December 5, 2016.
  20. Knap, Jerome J. (March 1982). "Fishing Across Canada". Field and Stream. LXXXVI (11): 138. Retrieved December 5, 2016.
  21. Wedeking, Brett (March 18, 2016). "At Risk Status Sought for Thompson Steelhead". The Drake ( Retrieved December 5, 2016.
  22. "Changes to Thompson River steelhead management". BC Gov News-Ministry of Forests, Lands and Natural Resource Operations. July 8, 2014. Retrieved December 5, 2016.
  23. Fandritch 2013, p. 186.

Related Research Articles

Savona is a small community located at the west end of Kamloops Lake, where the Thompson River exits it. It is approximately halfway between Kamloops and Cache Creek along the Trans-Canada Highway. The countryside surrounding the community is semi-arid grasslands and hills, which support cattle ranching and agriculture. Savona has about 2000 hours of sunshine and less than 12 inches of precipitation a year. It has a population of approximately 650.

Shuswap Lake lake in British Columbia, Canada

Shuswap Lake is a lake located in south-central British Columbia, Canada that drains via the Little River into Little Shuswap Lake. Little Shuswap Lake is the source of the South Thompson River, a branch of the Thompson River, a tributary of the Fraser River. It is at the heart of a region known as the Shuswap Country or "the Shuswap", noted for its recreational lakeshore communities including the city of Salmon Arm. The name "Shuswap" is derived from the Shuswap or Secwepemc First Nations people, the most northern of the Interior Salish peoples, whose territory includes the Shuswap. The Shuswap call themselves /ʃǝxwépmǝx/ in their own language, which is called /ʃǝxwepmǝxtʃín/, but the ethnonym's original meaning is now lost.

Vedder River river in Washington state, US and British Columbia, Canada

The Vedder River, called the Chilliwack River above Vedder Crossing, is a river in the Canadian province of British Columbia and the U.S. state of Washington.

Secwepemc people in Canada

The Secwépemc, known in English as the Shuswap people, are a First Nations people residing in the Canadian province of British Columbia. Secwepemcúĺecw, their country, ranges from the eastern Chilcotin Plateau and the Cariboo Plateau southeast through the Thompson Country to Kamloops and the Shuswap Country, and spans the Selkirk Mountains and Big Bend of the Columbia River to include the northern part of the Columbia Valley region. The country's traditional territory covers approximately 145,000 square kilometres. They relied heavily on hunting, trading and fishing to support their communities. The Secwepemc are perhaps the most numerous of the Interior Salish peoples of British Columbia if based upon the numbers who speak their language.

Clearwater River (British Columbia) river in Canada

The Clearwater River is the largest tributary of the North Thompson River, joining it at the community of Clearwater, British Columbia. The Clearwater rises from glaciers in the Cariboo Mountains and flows in a mostly southerly direction for 201 km (125 mi) to the North Thompson. Its entire course, except the last 5 km (3 mi), is within Wells Gray Provincial Park. Its confluence with the North Thompson is protected by North Thompson River Provincial Park.

North Thompson River river in British Columbia, Canada

The North Thompson River is the northern branch of the Thompson River, the largest tributary of the Fraser River, in the Canadian province of British Columbia. It originates at the toe of the Thompson Glacier in the Premier Range of the Cariboo Mountains, west of the community of Valemount. The river flows generally south through the Shuswap Highland towards Kamloops where it joins the South Thompson River to form the main stem Thompson River.

South Thompson River river in Canada

The South Thompson River is the southern branch of the Thompson River, the largest tributary of the Fraser River, in the Canadian province of British Columbia. It originates at the outlet of Little Shuswap Lake at the town of Chase and flows approximately 58 kilometres (36 mi) southwest and west through a wide valley to Kamloops where it joins the North Thompson River to form the main stem Thompson River.

Thompson Plateau Intermontane plateau in British Columbia, Canada and Washington, United States

The Thompson Plateau, also known as the Okanagan-Thompson Plateau, forms the southern portion of the Interior Plateau of British Columbia, Canada, lying to the west of Okanagan Lake, south of the Thompson River and east of the Fraser River. At its most southern point the plateau is squeezed by the mountainous terrain of the Cascade Range abutting closer to the Okanagan Valley. Its southwestern edge abuts the Canadian Cascades portion of that extensive range, more or less following the line of the Similkameen River, its tributary the Tulameen River, and a series of passes from the area of Tulameen, British Columbia to the confluence of the Thompson River with the Nicoamen River, a few miles east of Lytton, British Columbia, which is in the Fraser Canyon. Its northeastern edge runs approximately from the city of Vernon, British Columbia through the valley of Monte Creek to the junction of the same name just east of the city of Kamloops. Northeast of that line is the Shuswap Highland.

The Big Bend Gold Rush was a gold rush on the upper Columbia River in the Colony of British Columbia in the mid-1860s.

The British Columbia Interior, BC Interior or Interior of British Columbia, usually referred to only as the Interior, is one of the three main regions of the Canadian province of British Columbia, the other two being the Lower Mainland, which comprises the overlapping areas of Greater Vancouver and the Fraser Valley, and the Coast, which includes Vancouver Island and also including the Lower Mainland.

The Thompson Country, also referred to as The Thompson and in some ways as the Thompson Valley and historically known as the Couteau Country or Couteau District, is a historic geographic region of the Southern Interior of British Columbia, more or less defined by the basin of the Thompson River, a tributary of the Fraser and focused on the city of Kamloops.

Kamloops Transit System

Kamloops Transit operates the public bus transit system in the City of Kamloops in south central British Columbia, Canada. The system consists of 18 regularly scheduled routes, one Sunday route, several school specials and handyDART customized service for those with a disability. Funding is provided through a partnership between the City of Kamloops and BC Transit, the provincial agency which plans and manages municipal transit systems. Operations are contracted out to FirstCanada ULC. The transit system began development in 1975 after the Province of British Columbia began offering subsidies to help operate local transit systems in local communities.

Adams River (British Columbia) river in Canada

The Adams River is a tributary to the Thompson and Fraser Rivers in British Columbia, Canada. Beginning in the Monashee Mountains to the north, the Upper Adams River flows mainly southward and eventually reaches Adams Lake. The Lower Adams River begins at the southern end of the lake and flows into the extreme western end of Shuswap Lake. The river is one of the most important sockeye salmon breeding areas in North America. The run occurs in mid-October and can bring millions of fish to a concentrated area near the river mouth. Excavations of Secwepemc villages on the river have shown a long tradition of habitation and salmon fishing in the area. The river also served as an important transportation route for early logging operations in the watershed.

North Fork Clearwater River river in the United States of America

The North Fork Clearwater River is a major tributary of the Clearwater River in the U.S. state of Idaho. From its headwaters in the Bitterroot Mountains of eastern Idaho, it flows 135 miles (217 km) westward and is dammed by the Dworshak Dam just above its mouth in north-central Idaho. Draining a rugged watershed of 2,462 square miles (6,380 km2), the river has an average flow of over 5,600 cubic feet per second (160 m3/s), accounting for a third of the discharge from the Clearwater basin. The river drains parts of Clearwater, Shoshone, Latah, and Idaho counties. Most of the watershed is managed by the U.S. Forest Service. Some of the fish of the river include westslope cutthroat trout, rainbow trout, mountain whitefish, and the threatened bull trout It also is host to an annual kokanee salmon run over Labor Day weekend. The North Fork also lays claim to grizzly bears, cougars, deer, moose, black bear, elk, grey wolves, and ospreys. The river used to hold a prosperous steelhead run before the implementation of Dworshak Dam. The North Fork of the Clearwater is located within the Clearwater National Forest

Wells Gray Provincial Park provincial park

Wells Gray Provincial Park is a large wilderness park located in east-central British Columbia, Canada. The park protects most of the southern, and highest, regions of the Cariboo Mountains and covers 5,250 square kilometres. It is British Columbia's fourth largest park, after Tatshenshini, Spatsizi and Tweedsmuir.

The Barrière River is a tributary of the North Thompson River, one of the main tributaries of the Fraser River, in the Canadian province of British Columbia. It flows through the Shuswap Highland region north of Kamloops. Its name in Secwepemctsín is St́yelltsecwétkwe.

The Raft River is a tributary of the North Thompson River, one of the main tributaries of the Fraser River, in the Canadian province of British Columbia. It flows through the Shuswap Highland region southeast of Wells Gray Provincial Park. Most of the Raft River's watershed lies outside the boundaries of Wells Gray, except for some of the headwaters of the West Raft River tributary.

Scotch Creek is a stream in the British Columbia Interior of Canada, located on the north side of Shuswap Lake. It is part of the Thompson River watershed, which is a tributary to the Fraser River. It flows from the Shuswap Highlands into Shuswap Lake just west of the community of Scotch Creek. It was named for Scottish gold prospectors who worked the creek with placer mining operations in the 1860s. The creek's headwaters are near Pukeshun Mountain, and flow southwest and south for 56.5 kilometres (35.1 mi). The creek supports sockeye salmon, which breed in the creek during a small salmon run in the autumn.

The Perry River, sometimes referred to as the North Fork of the Eagle River, is a mountain river in the interior of British Columbia, Canada. It flows out of the Monashee Mountains and joins the Eagle River near the town of Malakwa. It is part of the Thompson River system, which drains into the Fraser River. The river's watershed area is 43,646 hectares (169 sq mi), and major tributaries to the river include Bews and Rocky creeks.