Below-normal water level expected for Last Mountain Lake

Last Mountain Lake’s water level is expected to be lower than normal this summer.

In a media release Monday, the Water Security Agency said dry conditions dating back to 2019 and below-normal snowmelt in 2021 could leave the water level in the lake well below its normal range.

“At current levels, the lake would need above-average precipitation this spring to reach near-normal levels by the summer,” the WSA said.

According to the agency, the elevation of Last Mountain Lake currently is 489.72 metres; the normal summer operating range is between 489.66 and 490.27m.

The WSA plans to increase releases from Lake Diefenbaker at the Qu’Appelle River Dam to raise the levels of downstream lakes.

That’s expected to change the elevation of the lakes by 15 centimetres by late July, but vegetation growth and evaporation will keep Last Mountain Lake from reaching its desired elevation this summer unless there’s significant rainfall.

“In 2020, WSA also diverted water from Lake Diefenbaker to improve downstream lake levels,” the agency said in its release. “However, levels at Last Mountain Lake dropped by about 33 cm from late July to freeze-up in November 2020 because of dry conditions.

“WSA understands the importance of recreational lake levels to the public and will continue to utilize the tools within its capacity to manage this situation.”

The agency added it’s monitoring the water levels at other lakes and reservoirs in southern Saskatchewan, including Rafferty Reservoir, Boundary Reservoir, Nickle Lake and Thomson Lake.