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This article was published 18/2/2017 (485 days ago), so information in it may no longer be current.
When the Canadian Forces came to help Manitoba cope with the 1997 Flood of the Century, officers schooled in dealing with fast-moving water disasters initially were shocked by the volumes rolling this way.
But, the story goes, they were told not to panic; it would take about three weeks for that water to arrive.
Flash floods and landslides are events not normally associated with flooding on the bald, flat prairies. However, a new normal is emerging, particularly in western Manitoba.
In late January, for example, a large section of the Souris River’s bank slid into the river near Wawanesa, weighed down by heavy snow on top of saturated soil. The incident severed a cable providing Internet and phone services for residents. It warned of things to come as the spring thaw unfolds.
Municipal officials fear the wet weather and soaked soil that plagued last year’s harvest has combined with a heavy snow load this winter to set the stage for another road-ripping spring.
Bouts of unseasonably warm temperatures, in late January and again this month, are helping mitigate that risk. The best-case scenario would be dry weather and a slow, steady thaw that maximizes the potential for evaporation.
Forecasters however, are predicting above-normal precipitation for the next few months.
"A combination of above-normal winter snowfall, unusually high river levels and the potential for ice jams will lead to a major flood risk in low-lying areas near rivers and streams from southeastern Saskatchewan into portions of northwestern Ontario," AccuWeather’s Brett Anderson said in a spring forecast issued last week. "A wetter-than-normal spring can exacerbate flooding issues in this region."
Red River floods are a force to be reckoned with, but people have a pretty good idea what to expect. Communities and rural properties are now largely protected by ring dikes and local officials have flood management down to a routine.
When floods do happen, they spread logically over a gradually widening base as the volume of water moving through increases.
The situation in western Manitoba and eastern Saskatchewan is much less predictable, as demonstrated by overland flooding in the spring of 2011 and then again after a heavy rainfall in July 2014.
The drainage system in that region is less developed and the rolling landscape means that even small changes in the volume can be enough to cause breakouts that dramatically change how that water flows.
The elimination of tree bluffs and potholes has changed the pace at which water moves through the system, intensifying the havoc. Rural residents who never before had experienced serious flooding found themselves scrambling for higher ground.
Mitigating the risk means first understanding the scope of the problem. Is it changes in drainage, changes in the landscape design, climate change — or all of the above?
Toward that end, the Assiniboine River Water Commission was formalized in 2015 and brings the basin’s stakeholders into a common discussion forum. As well, the Saskatchewan government has moved to study and regulate farmland drainage in that province, some of which is believed to contribute to Manitoba’s flooding issues. But those efforts are meeting with strong resistance from farmers, who see better drainage as key to improving their farms’ productivity.
The federal and provincial governments are supporting a watershed modelling and analysis project, known as Aquanty, which is managed by the Manitoba Forage and Grassland Association.
The project collects data from millions of points across the basin and analyzes the interactions between surface, soil and ground water to provide a better picture of the basin’s hydrology. It’s expected the project will help define how forage and grasslands and other management practices might help reduce both the risk and magnitude of flooding.
It’s important research with far-reaching implications.
Whereas the solutions for the Red River basin have historically involved heavy investments in drainage and dikes, similar approaches may have only limited success in the Assiniboine basin.
Biological approaches that better manage how humans interact with the landscape are likely to play a bigger role in future flood management.
Laura Rance is editorial director for Farm Business Communications. She can be reached at email@example.com or 204-792-4382
Laura Rance is editorial director at Farm Business Communications.
Updated on Saturday, February 18, 2017 at 7:50 AM CST: Photo added