Fraser River: History in a Changing Landscape

Abstract

The Fraser River of British Columbia is among the longest montane rivers in the world. Draining a mainly wildland catchment, its hydrology is dominated by the annual snowmelt freshet and sediment yield by material recruited along the banks of the river from Pleistocene valley fills. The upper course of the river was captured from arctic drainage in late Quaternary time. Another Quaternary legacy is one of the world’s greatest salmonine fisheries. As it approaches the sea, gradient declines and the gravel load of the river is deposited, creating a wandering-braided channel zone that supports an exceptionally rich aquatic ecosystem. But it also presents a potentially escalating flood hazard to settlements along the river and to major arteries of communication. In the sand-bed deltaic reach of the river, persistent dredging for navigation has created the reverse problem of riverbed degradation and loss of sand recruitment to the delta front. Natural history and human development are intertwined in complex ways along the lower course of this river.