The Chilcotin River /tʃɪlˈkoʊtɪn/ located in Southern

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

is a long tributary of the

Fraser River The Fraser River is the longest river within British Columbia, Canada, rising at Fraser Pass near Blackrock Mountain in the Rocky Mountains and flowing for , into the Strait of Georgia just south of the City of Vancouver. The river's annual d ...

. The name Chilcotin comes from Tŝilhqot’in, meaning "ochre river people," where ochre refers to the mineral used by Tŝilhqot’in Nation and other Indigenous communities as a base for paint or dye. The Chilcotin River,

Chilko River The Chilko River is a river in the Chilcotin District of the Central Interior of British Columbia, Canada, flowing northeast from Chilko Lake to the Chilcotin River. Its main tributary is the Taseko River. The Chilko is the Chilcotin River's mai ...

and Lake, and

Taseko River The Taseko River or Dasiqox in the original Chilcotin, is a tributary of British Columbia's Chilko River, a tributary of the Chilcotin River which joins the Fraser near the city of Williams Lake. The Taseko has its origins at Taylor Pass in ...

and Lake make up the Chilcotin River watershed. This watershed drains the

Chilcotin Plateau The Chilcotin Plateau is part of the Fraser Plateau, a major subdivision of the Interior Plateau of British Columbia. The Chilcotin Plateau is physically near-identical with the region of the same name, i.e. "the Chilcotin", which lies between t ...

which reaches north to south from the

Nechako Plateau The Nechako Plateau is the northernmost subdivision of the Interior Plateau, one of the main geographic regions of the Canadian province of British Columbia. It spans the basin of the Nechako River and its tributaries the Stuart River and Endako ...

to Bridge River county and east to west from Fraser River to the

Coast Mountains The Coast Mountains (french: La chaîne Côtière) are a major mountain range in the Pacific Coast Ranges of western North America, extending from southwestern Yukon through the Alaska Panhandle and virtually all of the Coast of British Columbia ...

. It is also one of twelve watersheds that make up the Fraser River Basin. Made up of seven major tributaries, Chilcotin River starts northeast of Itcha Mountain, flowing southeast until it joins the Fraser River south of Williams Lake, upstream from

Gang Ranch A gang is a group or society of associates, friends or members of a family with a defined leadership and internal organization that identifies with or claims control over territory in a community and engages, either individually or collectivel ...

. The geological processes that created this region support its diverse history, climate, and ecology. This diversity is also illustrated by the presence of biogeoclimatic zones and a rich population of fish. Canadian Fisheries and many communities within the region such as:

Alexis Creek Alexis Creek is a creek in the Chilcotin District of British Columbia, Canada, flowing southeast from its source in Alexis Lake into the Chilcotin River a short distance upstream from the town of Alexis Creek. Name origin The name was conferr ...

, Hanceville, and the Tŝilhqot’in Nation depend on the diversity of Chilcotin River. In recent years, its diverse history, climate, and ecology has been impacted by a number of environmental concerns such as: increases in flooding, changes in water quality, declines in

steelhead trout Steelhead, or occasionally steelhead trout, is the common name of the anadromous form of the coastal rainbow trout or redband trout (O. m. gairdneri). Steelhead are native to cold-water tributaries of the Pacific basin in Northeast Asia and N ...

populations, and an increase in

mountain pine beetle The mountain pine beetle (''Dendroctonus ponderosae'') is a species of bark beetle native to the forests of western North America from Mexico to central British Columbia. It has a hard black exoskeleton, and measures approximately , about the siz ...

outbreaks.

Natural Landscape & Climate

Geology

Rocks that form the valley walls suggest that the southward course of the Chilcotin River may have formed during the Late

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

s. The lower reach of the Chilcotin River is home to th
Wineglass assemblage
and

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

which is enclosed by older rocks from the

Cache Creek terrane The Cache Creek Terrane (alternately known as Cache Creek Melange ) is a geologic terrane in British Columbia and southern Yukon, Canada. The Cache Creek Terrane consists of Carboniferous to Lower Jurassic volcanic rocks, carbonate rocks, coarse c ...

. The assemblage is made up of

Late Permian Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

tonalitic rock cut through Late Permian

volcanic rock Volcanic rock (often shortened to volcanics in scientific contexts) is a rock formed from lava erupted from a volcano. In other words, it differs from other igneous rock by being of volcanic origin. Like all rock types, the concept of volcanic r ...

. It is unique because its structure and composition correlates to other assemblages
Kutcho and Sitlika assemblages
across British Columbia. The assemblages share similar

lithology The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lit ...

, an

unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

overlain with sedimentary sequences from the Triassic-Jurassic Periods, and a structural relationship with the overlying Cache Creek Complex. Chilko_River,_Lava_Canyon

Course

From its headwaters, Chilcotin River has many branches. Some branches are headed towards the western part of Chilcotin Plateau. Approximately 80 km (50 mi) from the Coast Range at altitudes of 3,500 to 4,200 feet, water is gathered from small creeks and lakes. The river flows slightly below the upland region of Punkutlaenkut Lake, then westerly towards the Chezakut where the Clusko comes from the north, flowing southwest and south of Chilcotin Lake. The Chilcotin River flows southwest through a deepening valley where it is met by the outlet of

Puntzi Lake Puntzi Lake is a lake in the Chilcotin District of the British Columbia Interior, Central Interior of British Columbia. It is located on the western side of the upper Chilcotin River to the northeast of Tatla Lake, and is connected to the Chilcoti ...

s. This occurs at Redstone by Chilanko River. The confluence of

and its main tributary

meet the Chilcotin River between Redstone and Alexis Creek. At this point, the Chilcotin River is roughly 200 feet below the surface. The valley in this reach also widens and deepens. At Alexis Creek, the river flows towards a basin as it forms a divide with the Nazko. At this point, the river joins form the north and turns southeast towards Hanceville. The valley becomes more deep until it is 1,800 feet below the level of the plateau. At the Fraser-Chilcotin confluence, Chilcotin is 2,220 feet below plateau-level when it is joined by Big Creek Canyon. Between the confluence with its main tributary the Chilko River and its final confluence with the Fraser River, it is approximately 83 km. Through this reach, the Chilcotin River flows through Bull Canyon,

Farwell Canyon Farwell Canyon (known to the local Tsilhqot'in First Nation as Nagwentled - 'place of landslides') is a canyon on the Chilcotin River in the Chilcotin District of British Columbia, Canada, located around the confluence of Farwell Creek and the C ...

, and Big Creek Canyon. The Chilko-Taseko confluence attracts many visitors because the rivers are coloured differently. Taseko River has a milky appearance where as Chilko River has a clear blue appearance. This site is a recreation favourite as it is used for whitewater rafting.

Discharge

A hydrometric station in Chilcotin River between Big Creek and the Fraser River confluence reported a mean discharge of 102 m³/s between 1971 and 2018. There have been no active, government-operated hydrometric stations on the river since 2018. The majority of winter precipitation in the Chilcotin Watershed falls as snow, causing Chilcotin River to experience a pronounced spring and early summer

freshet The term ''freshet'' is most commonly used to describe a spring thaw resulting from snow and ice melt in rivers located in upper North America. A spring freshet can sometimes last several weeks on large river systems, resulting in significant in ...

, which is stream flooding due to melting snow. The highest average monthly discharge is nearly 10 times that of the month with the lowest discharge.

Protected Zones

The Chilcotin River runs along borders of

Bull Canyon Provincial Park Bull Canyon Provincial Park is a provincial park in British Columbia, Canada, protecting Bull Canyon on the Chilcotin River, which is below the confluence of the Chilko River with the Chilcotin. The canyon and park are located just west of the ...

, Big Creek Ecological Reserve, and Junction Sheep Range Provincial Park.

Major Tributaries

Chilcotin River is composed of seven major tributaries, the largest is Chilko River which is unique because it has a volume greater than the Chilcotin River. These tributaries are part of the Fraser River tributaries and the rivers in British Columbia.

Climate

The annual average temperature between 1951-1980 was 5.1 °C (41.18 °F) and between 1981-2010 was 6 °C (42.8 °F).Climate Data Canada
considered a high emissions scenario to identify annual average temperature projections. Between 2021-2050, temperatures were found to be 7.5 °C (45.5 °F), between 2051-2080 temperatures were found to be 9.5 °C (49.1 °F), and 10.9 °C (51.62 °F) for the remainder of this century. The average annual precipitation between 1951-1980 was 348mm (13.7 inches). Using the same high emissions scenario, annual average precipitation projections were found to be 4% higher for 2021-2050, 11% for 2051-2080m and 12% higher for the remainder of the century. The data collected does not reflect the entire river, therefore climate can vary across the entire river length.

Cultural Significance

The Chilcotin River and its tributaries, most notably the Chilko and Taseko Rivers, are significant for the Indigenous people of the Tŝilhqot’in Nation. The annual migration of salmon in these rivers are relied upon by the Tŝilhqot’in to sustain their communities year round; as a food resource, cultural staple, and economic subsidy. To ensure salmon come back after every fishing season, the Tŝilhqot’in National Government (TNG) and the Canadian Department of Fisheries and Oceans (DFO) practice sustainable harvesting and monitor the rivers regularly. However, progressively smaller harvesting outcomes in recent years followed by an assessment done by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has prompted the TNG to shut down their fishery operations for 2021 and presently, fishing in the Chilcotin River has seized.

Ecology & Environment

Biogeoclimatic Ecosystem Classification

Sub-Boreal Pine-Spruce biogeoclimatic zone covers 40% of the Chilcotin River watershed. The headwaters of the Chilcotin River are in a Montane-Spruce zone, and the lowest reach where it confluences with the Fraser River is dominated by Bunchgrass. The river also passes through a zone of Interior Douglas-Fir. Over 40% of the watershed area is covered by pine tree species.

Biodiversity

Salmon

The Chilcotin River supports populations of

coho The coho salmon (''Oncorhynchus kisutch;'' Karuk: achvuun) is a species of anadromous fish in the salmon family and one of the five Pacific salmon species. Coho salmon are also known as silver salmon or "silvers". The scientific species name is ...

, chinook, and

sockeye The sockeye salmon (''Oncorhynchus nerka''), also called red salmon, kokanee salmon, blueback salmon, or simply sockeye, is an anadromous species of salmon found in the Northern Pacific Ocean and rivers discharging into it. This species is a P ...

salmon, the first two of which are considered threatened by COSEWIC. Salmon are an important cultural, food, and economic resource for the Tŝilhqot’in Nation.

Steelhead Trout

The Chilcotin River hosts a genetically distinct population of

(''Oncorhynchus mykiss''). It migrates from the

Bering Sea The Bering Sea (, ; rus, Бе́рингово мо́ре, r=Béringovo móre) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasses on Earth: Eurasia and The Ameri ...

to the Chilcotin River headwaters every other autumn to spawn, making it one of the longest migrating

anadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousan ...

trout in Canada. The Chilcotin River steelhead has been classified as

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...

and at extreme risk of extinction by COSEWIC. COSEWIC conducted a rarely-used emergency fast-track assessment of the Chilcotin River steelhead in February 2018, after only 58 individuals returned to their spawning grounds in the previous fall, representing a decline of 81% and an all-time low. Despite this, the recommendation to add them to the Government of Canada's

List of Wildlife Species at Risk The List of Wildlife Species at Risk currently has more than 800 entries for Canadian wild life species considered vulnerable; including 363 classified as endangered species, —190 threatened species, —235 special concern, and 22 extirpated ( ...

was not approved, and the Chilcotin steelhead remain unprotected by the Species at Risk Act (SARA). Population declines are a result of factors such as interception by fisheries and competition with hatchery species while out at sea, as well as predation by

pinniped Pinnipeds (pronounced ), commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant families Odobenidae (whose only living member is the walru ...

s. Declining habitat quality and interference in spawning pathways by landslides are other contributors.

Disturbance

Flooding

In July 2019, the Chilcotin River and surrounding communities experienced extreme rainfall. Subsequent flooding led to mudslides, inundated roadways and the destruction of culverts. Residents were cut off, leaving over 300 people stranded and 120 properties destroyed.

Water Quality

Water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...

is complicated and stressors such as climate change and human development can have adverse impacts. Recently, the Chilcotin River monitoring site has seen increases in metal concentrations. There is not a lot of human development in this area but scientists are investigating the cause or driver of this change, noting that increases in sediments because of changes in streamflow could be an element.

Mountain Pine Beetles

British Columbia experiences recurring outbreaks of

(MPB) populations, with the largest infestations occurring in central BC. MPB cause widespread tree mortality that also raise the risk of

wildfire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire ...

occurrence and poses a substantial threat to the timber supply industry. Within central BC, the

has already experienced two major MPB outbreaks, first in the mid 1970s - 1980s, and the second in the early 2000s ending in 2010. A team of researchers studying post-MPB infested forests in the Chilcotin Plateau found that although the dominant tree species weren't eradicated, MPB outbreaks in the future would make forests unusable for the timber industry in the long term.

References

{{Authority control Canyons and gorges of British Columbia Tributaries of the Fraser River Rivers of the Chilcotin Rivers of British Columbia Lillooet Land District