Bow River flowing at half of its normal rate: researcher

Calgary’s Bow River is flowing at half of its normal rate, and a researcher is warning that lower water levels can hurt ecosystems and cities that rely on its supply.

“If we didn’t have the snows that we’re hoping for this winter, and a fairly dry spring, we would, the low river levels would be devastating,” said Canada Research Chair John Pomeroy, with Water Resources and Climate Change from the University of Saskatchewan in Canmore, Alberta.

Pomeroy explains the Bow River is down about 30 cubic meters per second from its normal flows at this time of year.

In basic terms, he says a cubic metre of water weighs roughly a tonne, and there are 30 of those per second missing right now.

“This has been developing since mid-July when flows have been exceptionally low and it’s really a manifestation of last summer’s drought,” he explained

“The early snow-melt and the heat, the hot weather, the relatively low precipitation, this dried out the mountains through July and August.

In Alberta, Saskatchewan, and Manitoba, this water is extremely important.

Pomeroy says low water levels can affect trout and their survival, leave our treated sewage less diluted, and reduce the flow available for hydroelectricity generation and irrigation.

Snow that falls in the mountains isn’t melting now, but Pomeroy says mountain snow and snow-melt are what will get us out of this situation.

“That snowpack is going to keep building up over the winter and through the spring in the Rockies and start to melt in April, and May and June,” and that’s when he says the groundwater recharges and the river-flow peaks.

“We also tend to get a rainy season that time of year as well and that’s also very, very helpful.”

Over the winter, the Bow River level will continue to drop, slowly fading away but not completely drying out.

“Then what happens in the spring will depend on the snowfall that we’ll get, which is still uncertain at this point,” said Pomeroy.