Southern Saskatchewan bracing for potential flooding with high spring runoff

REGINA - A higher than normal snowpack means people in southern Saskatchewan may need to keep rubber boots and, in some cases, sandbags handy this spring.

The Water Security Agency is calling for above normal or well above normal spring runoff in almost all of the southern half of the province — and it could be worse for some areas. The agency's March forecast calls for very high runoff in areas between Indian Head and Moose Jaw, including Regina, and between Saskatoon and Prince Albert.

"Everyone in Saskatchewan should be concerned," Ken Cheveldayoff, minister responsible for the agency, said Monday.

"We should look back at what happened in 2011 and we should learn from those lessons."

There was widespread flooding in southern Saskatchewan in 2011, but the southeast was hardest hit.

The causes behind the high flow and flooding in the region that year started in the summer of 2010 with wet conditions on the Prairies. Precipitation was 200 per cent above normal immediately upstream of Lake Diefenbaker. More rain that fall led to soil that was at or near saturation at freeze-up, which meant the ground couldn't absorb the subsequent spring runoff.

Mountain snowpacks were also higher than average by spring 2011.

John Fahlman, director of hydrology and groundwater services with the Water Security Agency, said there are three factors to consider this year: the fall soil condition, the amount of snow and how fast it melts.

There were relatively dry conditions going into winter, which means the ground can absorb more water.

But snowfall is a big issue.

A precipitation map shows that a wide area circling Regina and Moose Jaw, and a smaller area around Saskatoon, had 2 1/2 times more snow than normal between Nov. 1 and March 10. The rest of southern Saskatchewan had 1 1/2 times to twice as much snowfall than average.

"It's no secret to anybody in the cities that there's a lot of snow out there," said Fahlman.

He could not say when the peak runoff might take place.

"Our maps are based on normal precipitation going forward 'til melt. Well, if you get some major snowstorms it's going to change. If we get a rapid late melt it means more risk for flooding than a nice, slow gradual melt."

Fahlman said the good news is that areas expecting a very high runoff are smaller than they were two years ago.

"The potential for flooding this year is, although it's still high, it's a lot less than it was in 2011," he said.

"Regina was in the very high in 2011 also. We're expecting similar things in Regina as it was in 2011, but they're well prepared."

Fahlman said the big snowfall that year filled reservoirs, but he's not expecting that this time. He also noted that much of the flooding in 2011, especially in the Souris River Basin in the southeast, came because "it kept raining and raining and raining" well after the snow melt.

Heavy rainfall during that spring overwhelmed reservoirs and the province said it had to release water to preserve the integrity of the structures.

There was nowhere for the water to go but downstream, so parts of southeast Saskatchewan were flooded, But Minot, N.D., was hardest hit. More than 10,000 people were forced from their homes and 4,100 houses, along with hundreds of businesses, were damaged.

North Dakota Gov. Jack Dalrymple said in February 2012 that there was nothing Saskatchewan could have done to stop the flooding. He said the way the dams were managed was exactly according to plan.

That far southeastern corner of Saskatchewan, including the city of Estevan, is expected to have near normal spring runoff this year.

Cheveldayoff said roughly 580 flood protection projects, such as clearing drainage channels, have been undertaken by communities over the last couple of years, so that should mitigate the risk.

Agency officials are meeting with communities to talk about preparedness efforts. Sandbags and equipment will also be ready, if needed.

"We're asking everyone to take it serious and everyone has a responsibility," said Cheveldayoff.

"You know homeowners can take snow and move it away from their foundations, can clear paths to the public drainage ways. We want everyone to be responsible for themselves. We want communities to be responsible, but more important we want them to know that they have the expertise of the Water Security Agency to back them up."