Upper Fraser Valley

The Fraser Valley is the region of the Fraser River basin in southwestern British Columbia downstream of the Fraser Canyon. The term is sometimes used outside British Columbia to refer to the entire basin including the Fraser Canyon and up from there to its source, but in general British Columbian usage of the term refers to the stretch of the river downstream from the town of Hope, and includes all of the Canadian portion of the Fraser Lowland and areas flanking it.

After descending through the rapids of the Fraser Canyon, the Fraser River emerges almost at sea level at Yale, over 100 km inland. Although the canyon in geographic terms is defined as ending at Yale, Hope is generally to be considered the southern end of the canyon, partly because of the change in the character of the highway from that point , and perhaps also because it is at Hope that the first floodplains typifying the course of the Lower Fraser are found. Downstream from Hope, the river and adjoining floodplains widen considerably in the area of Rosedale, Chilliwack and Agassiz, which is considered the head of the Fraser Delta. From there the river passes through some of the most fertile agricultural land in British Columbia—as well as the heart of the Metro Vancouver region—on its way through the valley to its mouth at Georgia Strait.

During the last ice age, the area that would become the Fraser Valley was covered by a sheet of ice, walled in by the surrounding mountains. As the ice receded, land that had been covered by glaciers became covered by water instead, then slowly rose above the water, forming the basin that exists today. The valley is the largest landform of the Lower Mainland ecoregion, with its delta considered to begin in the area of Agassiz and Chilliwack, although stretches of floodplain flank the mountainsides between there and Hope.

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