Last summer, rivers ran low. This summer, they could be lower.
Water scientists are sounding the alarm that snowpack levels in the mountain headwaters of rivers crucial for southern Alberta are some of the lowest ever recorded.
Low Snowpack, Early Melt
Winter started slowly. Then a January warm spell took a bite out of an already low snowpack.
“This snowpack has been low really all winter,” Tricia Stadnyk, a University of Calgary civil engineer and water modeling expert, told CBC News. “And people also need to remember that we’ve had a very early warm period. We also had a midwinter warm back in January that many Calgarians enjoyed. But the consequence of that is that we lost a lot of our snowpack very early on.”
Despite pulses of winter weather in late March and early April, and another over the Easter long weekend, the snowpack was still playing catch-up.
Some Relief for Farmers
As of April 11, the provincial government had issued 33 water shortage advisories in eight river basins: the Hay, Peace, Athabasca, North Saskatchewan, Battle, Red Deer, Bow, Milk and Oldman.
Still, rain has helped ease the pressure in some watersheds. The Oldman Watershed Council is reporting that La Niña delivered enough precipitation to put soil moisture and reservoirs in good shape. It’s short term relief for a long term drought.
“We are going into the year with full reservoirs, which is nice, especially since the snowpack in the mountains is still in that lower quartile,” Alex Ostrop, chair of the Alberta Irrigation Districts Association told the Alberta Farmer Express.
Ostrop is a farmer in Grassy Lake, which falls just outside the Oldman Watershed. He says that the snowpack is “very similar to last year, but the biggest difference is last year we went into the season with empty reservoirs, and this year we’re going in with full reservoirs.”
Snowpack Feeds Drinking Water Reserves
The Oldman Watershed Council is nevertheless recommending a conservative approach to water use in the Oldman River Basin in anticipation of stingy snowmelt and run-off. Last year’s rains may have filled many underground aquifers, but rivers are filled by snow melt, not rain.
The snowpack in the upper watershed is lower than last year. This doesn’t bode well for summer drinking water levels. In August of 2024, Pincher Creek’s reservoir, the Oldman Dam, was so low that the municipal district had to truck in water to keep the taps flowing. Trucking water in cost $7,500 per day.
This spring is looking equally dire. One hydrological station in the Oldman headwaters is measuring 59 percent of historical snowpack averages.
According to a recent Oldman Watershed Council update, “mountain runoff forecast is predicted to be below average, and snowmelt substantially impacts filling our reservoirs, lakes, and other waterways for the summer/fall season,”
In an interview with CBC News, John Pomeroy said snowpacks in the headwaters of the Oldman, Bow, North Saskatchewan and Red Deer rivers are some of the lowest he’s ever seen.”Our most recent diagnosis using hydrological models suggests that the snowpack is about 80 per cent of the stream flow volume that Calgary sees,” said Pomeroy, director Global Water Futures at the University of Saskatchewan. “So it’s extremely important. Most of those rains recharge soil moisture. It’s a snowmelt that generates stream flow.”
