Floods upend the world we know, our habits and our homes. Things are taken away, foundations shift and the power goes out. Lives are lost. Many southern Albertans know about this in a visceral way that I do not. As the water begins to recede on the Bow River this week, however, many people understandably search for meaning. One way to do that is to think about flooding in historical perspective.
Although the 2013 flood will go down as the largest flood in living memory with the widest social impacts, the Bow has risen throughout its history. Float a canoe east of Calgary and you pass high cut banks, dotted with holes for nesting birds, which reveal the outlines of past surges of water and sediment that carved the valley over centuries.
For much of its human history, the Bow figured as an obstruction for the people of the plains, a place to be crossed. The high waters made this difficult and the best fords became central locations along indigenous trails, places for meeting, rendez-vous and crossing. Calgary was established around one of these fords. Treaty Seven was signed at Blackfoot Crossing, another significant ford further downstream, now at the centre of the Siksika reserve.
The old Centre Street Bridge partly washed out by the flood of 1915. (Glenbow Archives, NA 671-8)
As people built ranches, settlements and cities along the Bow, they began to live with the risks of flooding. One of the largest floods ever recorded occurred in June 1897, when the Bow flooded after several days of intense rainfall. In the fledgling city of Calgary, bridges were torn out and buildings flooded. Some floated away. Sixty families had to relocate to higher ground. Downstream, ranchers with homesteads on the river had to get out quickly. When the river flooded again the following year, rancher Lachlin McKinnon recorded in his diary, “The spring of 1898 arrived and with it another stab in the back by the Bow River.”
Other floods followed and with time, engineers and government surveyors established gauges and complex instrumentation to measure river flow, assess its seasonal rhythms and forecast the likely flood threat. Significant floods continued to occur in the early twentieth century, but none matched the big event of 1897. Still, early Calgarians had plenty of experience with the Bow’s capacity to burst its banks. After mid-century, however, big summer floods didn’t happen as often. Some assumed that the river had been tamed. Perhaps the hydro dams upriver had shaved off the flood threat? Perhaps settlement itself had succeeded in changing river flow? Hydrologists who built models of stream flow came to a different conclusion. They determined that historical floods were associated with heavy rainfall in the foothills in the early summer, which saturated the ground, followed by intense bursts of high precipitation. Those conditions might return one day, they warned, though for most of the late twentieth century they didn’t.
Calgarians worried much more about winter floods in the middle decades of the twentieth century. A series of events from the late 1930s to the late 1940s witnessed ice jams in the dead of winter, often around bridges, followed by massive surges of slushy water into low-lying sections of the city. Many people blamed the power company and its dams upstream for the problem, though government officials found this difficult to credit. Winter floods also had a long history. What had changed was the built environment along the river which placed houses and businesses in the line of danger where formerly pastures had stood. Nevertheless, after a Royal Commission on the flood problem in 1952, a dam was built at the western edges of the city at Bearspaw to reduce the water flow through the city during the winter months. Like a vast ice trap, the dam lowered the volume of ice through the urban sections of the river and lowered the threat of ice jams and the accompanying floods. Dikes were also built and obstructions like the Eau Claire weir were removed. Winter floods became rare.
In the late 1960s, the City of Calgary decided to revisit the flood threat and hired the Montreal Engineering Company to analyze the risk and make recommendations to meet it. Against prevailing assumptions, the consultants noted that the conditions which gave rise to earlier floods remained. As a result the city expanded its purchase of riverbank lands, dredged the main channel and built up the banks. When government workers cleared trees around St George’s Island in 1973, however, local citizen groups reacted to the blunt aesthetic consequences of flood control work. In response to the uproar the province and city established a Bow River Study Committee to recommend a future course on river management. Many community groups spoke in favour of accepting a measure of flood risk with a view to preserving the natural beauty of the river and its valley bottom. After public meetings and consultants reports, a policy emerged to guide future management, emphasizing park development along the river as well as pathway construction.
As in so many cities of the western world, a river which had once been conceived as a hard-working river, a source of drive, a log transport system and power generator, had come to be understood as a recreational amenity. It still supplied water for power and water for drinking. It still washed away wastes and sewage, but it was nevertheless reconceived as a site of enjoyment and beauty. Where once industrial parks and timber mills had been located, new shopping areas, office towers and condominiums emerged. The urban river lay at the centre of it all as a parkland and recreational space. The threat of the century flood was not forgotten entirely, but nor was it at the forefront of thinking about urban planning.
Recent events bring us full circle to the flood of 1897 but in a radically changed geography of human settlement. Moving forward, the imagination of the river and the human decisions about how to relate to its changing course will be fundamentally altered. Calgary will change. And no doubt the river will be changed as well.
Matthew Evenden is an Associate Professor in the Department of Geography, University of British Columbia, and a member of the NiCHE Executive. The material for this blog entry draws from Christopher Armstrong, Matthew Evenden and H.V. Nelles, The River Returns: An Environmental History of the Bow (Montreal and Kingston: McGill-Queen’s University Press, 2009). The 1915 photo and others available at http://mqup.tumblr.com/post/53929525483/top-picture-flooding-in-calgary-…. See also Stéphane Castonguay and Matthew Evenden, eds. Urban Rivers: Remaking Rivers, Cities and Space in Europe and North America (Pittsburgh: University of Pittsburgh Press, 2012)