Thompson River

Thompson River
River
A CN railway crossing of the North Thompson River in Kamloops
Country	Canada
Province	British Columbia
Source	Confluence of the North & South Thompson Rivers
- location	Kamloops
- elevation	1,113 m (3,652 ft)
- coordinates
Mouth	Fraser River
- location	Lytton
- elevation	472 m (1,549 ft)
- coordinates
Length	489 km (304 mi)
Basin	56,000 km2 (21,622 sq mi)
Discharge	for Spences Bridge
- average	773 m3/s (27,300 cu ft/s)
- max	4,200 m3/s (148,000 cu ft/s)
- min	171 m3/s (6,039 cu ft/s)
A map of the Thompson River's watershed

For the river in the United States, see Thompson River (Montana).

The Thompson River is the largest tributary of the Fraser River, flowing through the south-central portion of British Columbia, Canada. The Thompson River has two main branches called the South Thompson River and the North Thompson River. The Thompson was named by Fraser River explorer, Simon Fraser, in honour of his friend, Columbia Basin explorer David Thompson.

Geography

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 & creeks.

North Thompson River

The North Thompson originates at the toe of the Thompson Glacier 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 km upstream from the small town of Avola, the river is forced through a narrow chute only about 30 feet wide creating a rapid that resembles the Fraser's famous rapid.

Mainstream

The darker waters of the Thompson meet the Fraser at Lytton.

At Kamloops, the combined Thompson River river flows 15 km from the confluence of the North and South Thompson Rivers before reaching Kamloops Lake, which is roughly 30 km 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.

History

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. 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. The first documented traverse of the Thompson from Kamloops to Lytton was by Hudson's Bay Company governor George Simpson in 1828. 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.

Ecology

The Thompson River supports 24 fish species, including two that are 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. Pink salmon spawn mostly below Kamloops Lake, while coho spawning beds are found in 40 of the Thompson watershed's streams and rivers. Rainbow trout are common, and a subspecies, Kamloops trout, is found in Kamloops Lake and nearby water bodies. Other fish species include round whitefish, largescale sucker, bridgelip sucker, northern pikeminnow, longnose dace, and slimy sculpin.

Several bird species are found in Thompson River environments, including osprey, merganser, wood ducks,and dippers. Trumpeter swans use the South Thompson on their migratory route. 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.

Major Tributaries

North Thompson River

• Albreda River
• Thunder River
• Mud Creek
• Blue River
• Mad River
• Raft River
• Clearwater River
• Barrière River

South Thompson River

• Little River (via Little Shuswap Lake from Shuswap Lake)
• Chase Creek
• Monte Creek

Mainstream

• Tranquille River (via Kamloops Lake)
• Deadman River
• Bonaparte River
• Oregon Jack Creek
• Nicola River
• Murray Creek
• Skoonka Creek
• Nicoamen River
• Botanie Creek

See also

• List of tributaries of the Fraser River
• List of British Columbia rivers
• List of crossings of the Thompson River

External links

• Media related to at Wikimedia Commons