WESTERN PRODUCER — The megadrought affecting the western United States has prompted a scientist to warn that Canada’s prairie provinces need to better plan how water is used across the entire Saskatchewan river system.
“A water expert from California we had up here a few years ago said that Alberta and Saskatchewan reminded him of California and Arizona around 1912,” said John Pomeroy, the Canada Research Chair in Water Resources and Climate Change at the University of Saskatchewan.
“We’re still getting by OK, we have pretty loose agreements, everybody’s getting along, it’s fine – but we have trouble ahead.”
The Saskatchewan river system includes the North and South Saskatchewan rivers, along with major tributaries such as the Bow and Oldman rivers in Alberta. Its headwaters are in the Eastern Slopes of the Rocky Mountains, providing water relied on by farmers and communities in Alberta and Saskatchewan.
About 80 percent of flow in the Saskatchewan River basin comes from the Eastern Slopes, with the main driver being the snowpack, so it is “very vulnerable to climate change,” said Pomeroy.
He used to think the impact on the system was decades in the future, “but after the drought this summer … I think it’s going to be very fast. We’re already in it.”
Record-breaking heat waves affected farmers and ranchers across much of Western Canada last year. Pomeroy said groundwater supplies dried up during the summer and fall, causing the Bow River’s November levels to reach about half of normal.
The Oldman River also dropped to less than half the usual flow during the summer, and some small tributaries in the mountains ran dry. A high snowpack will be needed over the winter for both rivers to generate enough flow to replenish irrigation and hydroelectric reservoirs, said Pomeroy.
Although recent precipitation boosted the snowpack feeding the Bow River to about twice what is normal for this time of year, it won’t be known until March or April if accumulated levels are high enough, he said.
Meanwhile, the snowpack as of Dec. 8 hadn’t built up in the Oldman River watershed “very much at all, and so they’ve got to keep an eye on it.” However, the rapid shift in B.C. from drought in the summer to flooding in November shows how quickly circumstances can change, he added.
Despite such considerations, Pomeroy said there is a link between the record-breaking hot weather that hit Western Canada in 2021 and the ongoing drought that has dominated the western U.S.
“And it’s been going on for over a decade. At that point, they call it a megadrought, but (in 2021), that megadrought sped from southern Mexico all the way up into Western Canada up into the southern Yukon, and then east all the way to Quebec and New Brunswick.”
He pointed to the Colorado River system, which provides water for nearly 40 million people across seven states, including Arizona, California, Colorado and Nevada. Users range from farmers to cities including Las Vegas and Los Angeles.
Pomeroy said Canada’s prairie provinces “could easily get into the trouble that the Americans have in the Colorado River right now where they over-allocated water years ago … and now they have vastly reduced snowpack in the mountains, and the reservoirs are dropping and not refilling them adequately every year.”
The crisis is forcing the U.S. to shut down irrigation districts relied on by farmers because there isn’t enough water to go around, he said.
“We don’t want to get into that situation.”
The snowpack in Alberta’s Eastern Slopes could melt as much as two months earlier than it does now, he said. It now melts in mid-June, in time to supply peak irrigation needs downstream.
“But if we end up with peak flow in April, then the lack of timing of the flows and the use will be something we’ll have to manage very carefully. Irrigators may need to increase the water storage capacity downstream.”
Canada must improve its forecast models to provide weekly forecasts and to create seasonal ones that look ahead three or even six months, said Pomeroy.
“A lot of the models have been developed at a research level at the universities, but they’re not in operation yet.”
Although scientists have conducted tests at smaller scales, it will likely take supercomputers and dedicated federal-provincial co-operation to make it work on a continental scale, he said.
Such information could help officials better decide whether to keep reservoirs full to deal with an expected drought or lower them to prepare for floods. It could also help farmers plan in midwinter for crop selection, he added.
Another problem is that the Prairie Provinces Water Board has an agreement it looks at only “very loosely.” The board involves the federal government as well as Alberta, Saskatchewan and Manitoba.
Water use isn’t really considered in terms of the impact on the entire system under climate change, said Pomeroy. During the past two years, Alberta launched a nearly $1-billion expansion of its irrigation system that is one of the largest of its kind in the province’s history.
The Alberta Wilderness Association said Nov. 15 “this large expansion of reservoirs, pipelines and irrigated lands (in the province) … has largely been presented as a foregone conclusion. It hasn’t undergone any public consultation and no environmental impact assessment of the project was conducted.”
Irrigated agriculture already takes up 78 percent of water allocations in the Bow and Oldman River basins, said the association.
“Approving expanded irrigation acres will only serve to intensify water use in basins that are over-allocated, rather than considering the needs for healthy aquatic ecosystems and the potential impact of the climate crisis on water availability.”
However, the Alberta government has said the expansion will increase irrigated acreage and primary crop production while improving water use efficiency through use of pipelines instead of open-water canals.
Objectives will be achieved within existing water licence allocations, said provincial Agriculture, Forestry and Rural Development Minister Nate Horner on Nov. 12. “I look forward to seeing more projects break ground over the coming years.”
Meanwhile, Saskatchewan started a 10-year, $4-billion project at Lake Diefenbaker in 2020 that will more than double the amount of irrigated land in that province.
Pomeroy said he hadn’t looked at Alberta’s expansion in detail, “but Saskatchewan is expanding as well, and it really means that we need the detailed study of the whole Saskatchewan River basin … to make sure there’s enough water for everyone because that water’s going on to Saskatchewan.”
The basin supplies about 70 percent of Saskatchewan’s population and its entire irrigation system, along with hydroelectricity, he said. It also supplies the Saskatchewan River delta at Cumberland House.
As the largest inland freshwater delta in North America, the area is “already suffering from low flows and ecological devastation – a very difficult situation for the Indigenous people there,” said Pomeroy.
Such consequences mean it’s “important to look at the whole thing before expanding irrigation in one part or managing it differently in another part, and we’re going to have to do that always with an eye to the mountains.”
The Alberta government has sought public input about potential open-pit coal mining in the Eastern Slopes to help create a new coal policy for the province.
Additional mining will add pressure on water use in the Saskatchewan River system and studies of the impact on water quality of existing open-pit coal mines in B.C. have detected toxic amounts of selenium in runoff in that province, said Pomeroy.
Researchers have found levels above those “that you could use to irrigate crops or give to livestock or to humans.” Such contamination is “very hard to clean up. The impacts last for hundreds if not thousands of years.”
During a previous interview, executive director Ian Urquhart of the Alberta Wilderness Association called for a comprehensive plan involving all uses of the Eastern Slopes, including forestry.
The need for integrated planning for the entire Saskatchewan River system is especially important because demand for food from Canada has continued to increase, said Pomeroy.
There is a danger that cities on the Prairies could overpower rural areas in terms of water use, he said.
“What became apparent looking at the U.S. and to Colorado is that when it comes to fighting over the water between cities and rural areas, the cities win … and so getting these protections in place early on would be advantageous.”
