Fraser River: Map

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For other uses of this name see Fraser River .

The Fraser River ( ) is the longest river within British Columbia

, Canada

, rising at Fraser Pass

near Mount Robson

in the Rocky Mountains and flowing for 1,375 km (870 mi), into the Strait of Georgia

at the city of Vancouver

. It is the tenth longest river in Canada. The river's volume at its mouth is 112 km³ (27 cu mi) each year (about 800,000 gal/s or 3550 cubic metres per second), and it dumps 20 million tons of sediment into the ocean.

Geography

The Fraser drains a 220,000 km² (85,000 sq mi) area. Its headwaters are just northwest of Fraser Pass

, which forms the first part of its course before its descent at Valemount

to the Rocky Mountain Trench

through which it runs northwest via a region known as the Robson Valley. After running northwest past 54° north, it makes a sharp turn to the south at Giscome Portage, meeting the Nechako River at the city of Prince George

, then continuing south, progressively cutting deeper and deeper into the Fraser Plateau

to form the Fraser Canyon

from roughly the confluence of the Chilcotin River, near the city of Williams Lake

, southwards. It is joined by the Bridge and Seton Rivers

at the town of Lillooet

, then by the Thompson River at Lytton

, where it proceeds south until it is approximately 40 km (25 mi) north of the 49th parallel, which is Canada's border with the United States

. From Lytton southwards it runs through a progressively deeper canyon between the Lillooet Ranges of the Coast Mountains

on its west and the Cascade Mountains on its east. At Yale

, at the head of navigation on the river, the canyon opens up and the river is wider, though without much adjoining lowland until Hope

, where the river then turns west and southwest into a lush lowland valley, known as the Fraser Valley, past Chilliwack

and the confluence of the Harrison and Sumas Rivers, bending northwest at Abbotsford

and Mission

, turning southwest again just east of New Westminster

, where it splits into a North Arm, which is the southern boundary of the city of Vancouver, and the South Arm, which divides the City of Richmond

from the Corporation of Delta. Richmond is on the largest island in the Fraser, Lulu Island

and also on Sea Island, which is the location of Vancouver Airport; the eastern end of Lulu Island is within the City of New Westminster and is called Queensborough

. Also in the lowermost Fraser, among other smaller islands, is Annacis Island

, an important industrial and port area, which lies to the southeast of the eastern end of Lulu Island (Sea, Lulu and Annacis Islands lie between the North and South Arms. Other notable islands in the lower Fraser are Barnston Island

, Matsqui Island

, Nicomen Island

and Sea Bird Island

.` Other islands lie on the outer side of the estuary, most notably Westham Island

, a wildfowl preserve, and Iona Island, the location of the main sewage plant for the City of Vancouver.

After 100 kilometres (about 60 mi), it forms a delta where it empties into the Strait of Georgia

between the mainland and Vancouver Island

. The lands south of the City of Vancouver, including the cities of Richmond

and Delta sit on the flat flood plain. The islands of the delta include Iona Island, Sea Island

, Lulu Island

, Annacis Island

, and a number of smaller islands. While the vast majority of the river's drainage basin lies within British Columbia, a small portion in the delta area lies across the international border in Washington

in the United States, namely the upper reaches of the tributary Chilliwack and Sumas Rivers. Though not part of the Fraser drainage basin, other than the headwaters of the Sumas northeast of Everson, Washington

, most of lowland Whatcom County, Washington

is part of the Fraser Lowland and was formed also by sediment deposited from the Fraser.

Similar to the Columbia River Gorge

east of Portland, Oregon

, the Fraser exploits a topographic cleft between two mountain ranges separating a more continental climate (in this case, that of the British Columbia Interior) from a milder climate near the coast. In winter, modified arctic air often pushes through this weakness, producing uncharacteristically low temperatures in these areas, often accompanied by strong winds known as outflow winds.

The estuary at the river's mouth is a site of hemispheric importance in the Western Hemisphere Shorebird Reserve Network.

Discharge

With an average flow at the mouth of about , the Fraser is the largest river by volume flowing into the Pacific seaboard of Canada and the fifth largest in the country. The average flow is highly seasonal; summer discharge rates can be ten times larger than the flow during the winter.

The Fraser's highest recorded flow, in June 1894, is estimated to have been at Hope

. It was calculated using high water marks near the hydrometric station at Hope and various statistical methods. In 1958 the Fraser River Board adopted the estimate for the 1894 flood. It remains the value specified by regulatory agencies for all flood control work on the river. Further studies and hydraulic models have estimated the maximum discharge of the Fraser River, at Hope during the 1894 flood, as within a range of about .

History

On June 14, 1792, the Spanish explorers Dionisio Alcalá Galiano and Cayetano Valdés entered and anchored in the north arm of the Fraser River, becoming the first Europeans to find and enter it. The existence of the river, but not its location, had been deduced during the 1791 voyage of José María Narváez, under Francisco de Eliza.

The upper reaches of the Fraser River were first explored by Sir Alexander Mackenzie in 1793, and fully traced by Simon Fraser in 1808, who confirmed that it was not connected with the Columbia River.

In 1828 George Simpson visited the river, mainly to examine Fort Langley

and determine whether it would be suitable as the company's main Pacific depot. Simpson had believed the Fraser River might be navigable throughout its length, even though Simon Fraser had described it as non-navigable. Simpson journeyed down the river and through the Fraser Canyon

and afterwords wrote "I should consider the passage down, to be certain Death, in nine attempts out of Ten. I shall therefore no longer talk about it as a navigable stream". His trip down the river convinced him that Fort Langley could not replace Fort Vancouver

as the company's main depot on the Pacific coast.

Much of British Columbia's history has been bound to the Fraser, partly because it was the essential route between the Interior and the Lower Coast after the loss of the lands south of the 49th Parallel with the Oregon Treaty of 1846. It was the site of its first recorded settlements of Aboriginal people (see Musqueam, Stó:lō, St'at'imc, Secwepemc and Nlaka'pamux), the route of multitudes of prospectors during the Fraser Canyon Gold Rush and the main vehicle of the province's early commerce and industry.

This river has been designated a Canadian Heritage River for its natural and human heritage.

Uses

The Fraser is heavily exploited by human activities, especially in its lower reaches. Its banks are rich farmland, its water is used by pulp mills, and a few dams on some tributaries provide hydroelectric power. The main flow of the Fraser has never been dammed partly because its high level of sediment flows would result in a short dam lifespan, but mostly because of strong opposition from fisheries and other environmental concerns. In 1858, the Fraser River and surrounding areas were occupied when the gold rush came to the Fraser Canyon and the Fraser River.

The delta of the river, especially in the Boundary Bay

area, is an important stopover location for migrating shorebirds

The Fraser Herald, a regional position within the Canadian Heraldic Authority is named after the river.

Flooding

After European settlement, the first disastrous flood in the Fraser Valley occurred in 1894. With no protection against the rising waters of the Fraser River, Fraser Valley communities from Chilliwack downstream were inundated with water.

After the 1894 flood, a dyking system was constructed throughout the Fraser Valley. The dyking and drainage projects greatly improved the flood problems, but unfortunately over time, the dykes were allowed to fall into disrepair and became overgrown with brush and trees. With some dykes constructed of a wooden frame, they gave way in 1948 in several locations, marking the second disastrous flood.

1894 June, the Fraser River flooded Chilliwack and the Fraser Valley. The high water mark at Mission reached 25.75’.

1948 saw massive flooding in Chilliwack and other areas along the Fraser River. The high water mark at Mission rose to 24.7’.

Timeline of 1948 flood

Throughout the May 24 long weekend, the waters of the Fraser were rising steadily, but only a few thought any real danger lay ahead.
On May 28, 1948, the Semiault Creek Dyke broke.
On May 29, 1948, dykes near Glendale (now Cottonwood Corners) gave way and in four days, of fertile ground were under water.
On June 1, 1948, the Cannor Dyke (east of Vedder Canal near Trans Canada Highway) broke and released tons of Fraser River water onto the Greendale area, destroying homes and fields.
In June 3, 1948, the steamer Gladys supplied flood-stricken Chilliwack with tents and provisions as well as moving people and stock onto high ground.

Reasons for the flood of 1948

Cool temperatures during March, April and early May had delayed the melting of the heavy snowpack that had accumulated over the winter season. Several days of hot weather and warm rains over the holiday weekend in late May hastened the thawing of the snowpack. Rivers and streams quickly swelled with spring runoff, reaching heights surpassed only in 1894.

At the height of the 1948 flood, stood under water. Dykes broke at Agassiz, Chiliwack, Nicomen Island, Glen Valley and Matsqui. By the time the flood waters receded a month later, 16,000 people had been evacuated, damages totaled $20 million.

Due to record snowpacks on the mountains in the Fraser River catch basin which began melting, combined with heavy rainfall, water levels on the Fraser River rose in 2007 to a level not reached since 1972. Low-lying land in areas upriver such as Prince George

suffered minor flooding. Evacuation alerts were given for the low-lying areas not protected by dikes in the Lower Mainland