Dave Sauchyn spent a summer looking at rings of 900-year-old tree stumps in the Jasper area and found a startling record of 36 long droughts that caused the Athabasca River levels to drop significantly. 

Water levels during those long droughts were much lower than any time in the past 60 years, said Sauchyn, senior research scientist at the Prairie Adaptation Research Collaborative at the University of Regina. 

That means we haven't seen the worst that can happen since industry started drawing water from the river in the 1960s. 

Such a prolonged drought will happen again, with implications for the oilsands industry that relies on the river, he noted. 

Concerns about the low-flow levels in the big northern river erupted just last summer when the Alberta Energy Regulator put restrictions on water withdrawals by some oilsands companies. 

But those low-flow rules are based on short-term, 60-year data that underestimate the problem and don't include the 1930s drought which was "about as bad as it gets," says Sauchyn. Government did not record the flow levels at the time. 

The historic, 900-year record established for the first time in Sauchyn's study shows the river level can drop much lower for years at a time. 

"Every century had a drought," he said. 

When the Athabasca River level runs low, government can restrict industry withdrawals, from some, but not all companies, to keep a minimum level to to sustain fish and other aquatic life. 

Government low flow rules also do not take into account the impact of climate change which is already causing lower volumes of water in the river, Sauchyn added. 

"So in the future, these prolonged droughts will recur in a much warmer climate," he said. 

"So they might want to take a look at those rules take into account the impact of climate change which is already reducing the water flow." 

The study, funded by Environment Canada, states: "Current and projected surface water allocations from the Athabasca River for oilsands exploitation are based on the untenable assumptions" of shortterm, 60 year data. 

The levels were surprising low at times. In one period, 1790 to 1806, there were 17 years of below average water levels in the Athabasca River due to drought. 

That drought also caused such low water levels in the nearby North Saskatchewan River that fur trade canoes got stuck at Fort Edmonton and trade temporarily halted. 

The oilsands industry is allocated 4.4 per cent of annual flow from the Athabasca. But in decades-long drought, when the river level is very low, industry withdrawals would make up a much larger percentage of the water, said Erin Flanagan of the Pembina Institute. 

"We think the policy should be based on the best data," she said. 

Also, under proposed oilsands expansion, industry will more than double the water it can take from the river, 505 million cubic metres from the 187 million cubic metres used in 2012, according to the research paper published in Proceedings of the National Academy of Sciences. 

The industry is committed to reduced the amount of fresh water it uses to produce in each barrel of oil 30 per cent by 2022, said Nick Brown of the Canada's Oilsands Innovation Alliance." 

spratt@edmontonjournal.com

Credit: Sheila Pratt; Edmonton Journal