The Fraser River is the longest river in British Columbia and the tenth longest river in Canada. It drains a 220,000 km² (85,000 sq mi) area and flows for 1,375 km (870 mi) into the Pacific Ocean in Vancouver. Its headquarters are in the Mount Robson Provisional Park in the Rocky Mountains, and it passes across the dry Fraser Plateau and through the coastal mountain ranges to the Pacific Ocean. It rumbles onward near the cities of Prince George, Williams Lake, Hope, Chilliwack, Abbotsford, and New Westminster. After about 100 km it forms a delta and discharges into the Georgia Strait between Vancouver and Vancouver Island.

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Image persmissions by Andrea McNeil at Parks Canada

The majority of the drainage basin of the Fraser lies in British Columbia. However, a small portion does pass into Washington state in the United States. The Fraser Basin system comprises the main Fraser River and a huge network of tributaries that drains more than a quarter of British Columbia before the river’s egress into the Pacific Ocean through Vancouver. The river and its tributaries provide habitat, migration routes, nutrients, and food sources to many ecosystems and communities that exist within the basin. The Fraser Basin is comprised of a mixture of mountainous terrain, interior plains, and inter-mountain valleys. The plains and the valleys are covered with glacial, alluvial, and lacustrine deposits, and the mountains are made up of colluvium and outcrop (predominantly metamorphic and igneous rocks). The Fraser River is naturally high in sediment load due to erosion as it passes through central plateau glacial deposits.

For more information, visit the BC Geological Survey.

Sources:
Rivers of North America (Arthur C. Benke, Colbert E. Cushing – 2005)
Wikipedia (Fraser River)