Increased flows prompt calls for caution near South Sask. River in coming days

The Saskatchewan River will be on the rise after the opening of the Gardiner Dam spillway on Sunday, and people in Saskatoon are being urged to use lots of caution around the fast-moving waterway.

The Water Security Agency says opening the spillway is expected to increase the river’s flow from around 280 cubic metres per second up to about 700 cubic metres per second. The release is expected to cause the river to rise about 1.4 metres in the Moon Lake area and about 0.6 m in Saskatoon.

Shawn Jaques, president and CEO of the agency, said the move is necessary after the significant rainfall Alberta received over the past week, combined with an above-normal snow pack that is melting and increasing flows on the river.

Read more:

• Prairie Lily riverboat to set sail in Saskatoon on Friday
• VIDEO: Central Saskatchewan dealing with extreme flooding as snow melts
• Spring runoff outlook mixed across Saskatchewan: Water Security Agency

“A number of dams and reservoirs in Alberta are already full, and they’ve started to release water out of them as well, because of the rising waters,” Jaques said in an interview on Wednesday.

He said the last time the agency operated the spillway was in 2020. It hasn’t needed to be opened since then due to drought conditions, Jaques said.

Peak flows due to the opening of the spillway are expected on Thursday. The agency said it will monitor water flow to decide when to close the spillway again, potentially about a week later, depending on conditions.

Jaques said about 400 cubic metres of water can flow through the dam every second. This time of year, the normal flow into Lake Diefenbaker is about 600 cubic metres per second, with typical flows through Saskatoon at about 160 cubic metres per second.

“This is significantly above,” Jaques said, “and we haven’t seen this kind of outflow since 2020.”

He said more than 1,000 cubic metres of water is flowing into Lake Diefenbaker every second, a rate that would fill Mosaic Stadium to the top in about two hours.

“We’ve been talking a lot about this this spring, because we’ve seen a lot of significant flows throughout Saskatchewan with the rapid snow melt and the heavy snow pack in the north, and we saw some of these levels of flows on much smaller rivers and channels than the Saskatchewan River, so they had quite an impact,” Jaques explained.

Any water released from the dam goes through the power turbines, he said. If higher flows are needed, the spillway gates at Gardener Dam will need to be opened.

“Residents will see a rise in the river,” Jaques said, though the City of Saskatoon noted that the increased flow rate is not high enough to cause flooding in areas along the river’s banks, like the Meewasin Valley Trail.

The past number of years have brought lower flows on the river, Jaques added.

“If it wasn’t for Lake Diefenbaker, we would have seen even lower levels on the Saskatchewan River,” he said.

He said there’s no doubt that low flows of water have an impact on sediment in the river channel, referencing troubles Saskatoon’s Prairie Lily riverboat has had in recent years, with sandbars forcing the ship to stay at its dock throughout the past season.

No out-of-bank flooding is expected, according to the agency’s calculations. Jaques said the agency will be watching to see how sand and silt respond to the increased flow along the river.

“Because we’re seeing an increased flow in the velocity of water coming through the city… should move that sand, but it is something that we’re going to monitor and see the impact of this,” he said.

The city said Saskatoon Water is prepared for the greater flows.

“While expecting more sediment and cloudiness in the river, processes are in place to handle extra clarification that may be needed,” the city release stated.

“Water service (in Saskatoon) is not expected to be impacted by the rising river levels.”

Safety urged for recreational river users

While the increased flow won’t limit recreational activities, Jaques said keeping safety in mind is always the best course of action.

“We’re cautioning and urgently urging the public to be cautious around Gardner Dam and stay away from the structure, because we are going to be flowing water over the spillway,” he shared.

“We’re also saying there’ll be an increase in flow through Saskatoon, increase in velocity on the Saskatchewan River, so we want people just to be cautious around the water at this time of year.”

The Saskatoon Fire Department is also advising extra caution as the flow rate rises.

“This represents a significant increase and with that, there’s an increase in the potential dangers on or around the river,” said fire department deputy chief Sean Thody.

In a statement, Thody urged anyone spending time around the river and along the riverbank to “keep their distance” from the water, adding that swimming in the river is prohibited in Saskatoon under a city bylaw.

“Although the river may provide a tempting option to cool down on hot days, the South Saskatchewan is unpredictable,” Thody said. “Aside from the changing, dangerously fast currents and unstable bottom, it will have many additional hazards right now such as fallen branches, hidden material like broken concrete and floating debris that will pose a threat to anyone in or near the water.”

Guidelines for recreational river uses shared by the city suggest that only expert paddlers with whitewater experience should head out on the water during the period of increased flow (600-800 cubic metres per second). At 800 cubic metres per second, river speeds are considered dangerous.

The fire department said it cannot put rescue divers into the water when the flow rate rises above 450 cubic metres per second due to the safety risk posed by those conditions.

Should someone witness a person in distress in the river, the fire department said to call 911 immediately and share any details about the person and the situation. Callers were advised to track recognizable landmarks where the person was first seen in distress, and to try to coach the person from shore to stay calm and keep their head above water.

Anyone who falls into the river was advised to remove any heavy or bulky clothing and to move with the current as they make their way towards the shore, rather than fighting against it.

Neither bridges nor construction projects are expected to be impacted by the higher river flow rate.

Residents were reminded to only view the weir from a safe distance, while pet owners were reminded to keep a close eye on their animals, especially in off-leash areas.

“The best advice is to avoid these areas for the coming days,” the city stated in a release.

– with files from 650 CKOM’s Brent Bosker