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Proactive disclosure Print version   | |  The winds of change: Climate change in Prairie Provinces Rivers in flux
Impacts depend on location Overall, climate change is expected to bring about more variation in the size of extreme flows in prairie rivers. This could cause large flows to increase in size, but also cause low flows to decrease. The impacts for a given river, however, will depend on the location and the source of water for the river. Potential impacts Mountain-source rivers: Greater risk of extreme flooding in small rivers of the interior Cordillera and southeastern slopes of the Rocky Mountains. Prairie-source rivers: Lower but more variable flows, and possibility of larger extreme flows. Northern plains rivers: Greater risk of damaging floods from changing runoff characteristics because of the thawing of permafrost. Southern shield and Hudson Plain rivers: Runoff controlled by lake and wetland storage; rivers on bedrock are stable, but sections of rivers that flow within sediments may be sensitive to erosion. Too much ... or too little water?
Flooding in low-lying areas adjacent to rivers affects many communities. During years of very low flow rates there may be water shortages in the summer. The Red River Flood of 1997 The 1997 flood along the Red River was a major Canadian disaster. The flood cost more than $800 million and more than 7000 military personnel helped relocate 25 500 evacuees and prevent further flood damage. Ring-dikes prevented flood damage in most of the towns in the flood zone south of Winnipeg. The town of Morris looked like an island.
A century of change on the Red River The Red River flows northward from the United States into southern Manitoba. Each spring the flow of the river rises. Over the last century there has been a marked increase in the size of the spring flows. Between 1892 and 1945, only two historic peak flows exceeded 2000 cubic metres per second. But between 1945 and 1999 this level has been exceeded eleven times.
References Ashmore, P. and Church, M., in press: The impact of climate change in rivers and river processes in Canada; Geological Survey of Canada, Bulletin 555.
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