Variable runoff expected across the Southwest this spring

The Southwest will experience a wide range of spring runoff amounts according to the Spring Runoff Report for 2023 released by the Water Security Agency.

The Water Security Agency notes that a variety of snowpack conditions as of March 1 has resulted in forecasts of below normal to well below normal runoff for the majority of the Southwest. However, the extreme Southwest corner of the province has a well above normal snowpack, which will result in above normal runoff in that region.

Overall, after generally dry moisture conditions at freeze-up in 2022, when combined with below normal snowfall totals over the winter months, the Southwest is not expecting flood-related issues during this year’s runoff. The lower spring runoff forecast was also impacted by warmer than seasonal winter temperature which resulted in a near complete melt of the snowpack over areas north of the Cypress Hills and over a large area of southern Saskatchewan.

The Water Security Agency forecast also cautions that several reservoirs in the Southwest are not expected to fill from snowmelt runoff, including Thomson Lake and Cypress Lake.

“Without significant late winter precipitation, it is likely that surface water supply shortages will be experienced in the Southwest in 2023,” the report notes. “Most reservoirs in the Big Stick Lake Basin near Maple Creek are not expected to fill in spring 2023 unless there is significant late season precipitation.”

Other specific runoff outlook forecasts are as follows:

Old Wives Lake

Snowmelt runoff is expected to be well below normal for most of the Old Wives Lake Basin. This is a result of dry conditions at freeze-up and below normal snow accumulations throughout most of the basin. As such, minimum spring runoff is expected in the Wood River. Thomson Lake is expected to fill based on current conditions in the basin.

Frenchman River

Snowmelt runoff yields within the Frenchman

River Basin are generally expected to be below normal in 2023. With current conditions, and the expectation of normal conditions going forward, it is anticipated that Eastend, Huff and Newton reservoirs will fill in spring 2023.

Battle, Middle, Lodge Creeks

Although soil moisture conditions were dry going into the fall, an above normal snowpack exists in southeastern Alberta and in the southwestern corner of Saskatchewan. Altawan Reservoir, Middle Creek Reservoir and Cypress Lake levels have been declining over the past two years with low inflows, so a high runoff response will be required for these reservoirs to reach their full supply levels.

Big Stick Lake Basin

In the Big Stick Lake Basin near Maple Creek, the snowpack is generally well below normal due to mid-winter melt events. This has resulted in well below normal inflows expected at all reservoirs in the basin (Downie, Harris,

Mcdougald and Junction) in the spring. At this time, it is unlikely that the larger reservoirs in the basin will fill this spring, potentially leading to a third consecutive year of reduced irrigation deliveries in the basin.

Swift Current Rush Lake Creeks and

The Swift Current Creek Basin was drier than normal at freeze-up in 2022 and has received near normal precipitation this winter. As such, a below normal runoff is expected. Although dependent on melt conditions, Reid Lake will likely fill from the snowmelt runoff this spring. Highfield Reservoir is approximately 55 per cent full and, based on the snow cover currently existing in the Rush Lake Creek drainage basin, there is a chance that Highfield Reservoir may fill during the snowmelt period.