The Saskatchewan Water Security Agency (WSA) released its 2020 Conditions at Freeze-Up report on Friday, showing a mixed picture for moisture conditions across the province entering winter.
In combination with the winter snowpack, this forecast becomes the initial conditions for the spring snowmelt runoff.
Most agricultural areas of the province entered the winter drier than normal, particularly the area east of Gravelbourg and south of Yorkton, where severe dry conditions exist.
In the extreme southwest and northern portions of the grain belt, conditions at freeze-up were near normal.
In the Souris River Basin, Grant Devine Lake (formerly Alameda Dam) and Rafferty Dam are both below their prescribed Feb. 1 maximum levels. As such, winter releases are not occurring.
Beginning on Feb. 1, 2021, spring runoff forecasts for the Souris River Basin will be prepared in consultation with U.S. partners for both reservoirs on a semi-monthly basis.
The reservoirs may be drawn down further in advance of spring runoff, if warranted by these forecasts, in accordance with the 1989 Canada-U.S. Agreement on Water Supply and Flood Control in the Souris River Basin.
While most larger water supply reservoirs in the south have adequate supplies, surface water users who rely on smaller reservoirs or dugouts have been impacted by the dry conditions. This includes both diminished supplies and quality.
Over northern areas of the province, well above normal rainfall in late spring and throughout the summer has resulted in conditions at freeze-up that are wetter than normal. This is particularly true for the Churchill River Basin where flows at the end of October were at or near record levels for that time of year.
Winter flows within northern areas are expected to remain above normal throughout the season.
Wet conditions in the north will increase the risk of above normal runoff in spring 2021.
Compared to the south where conditions at freeze-up were much drier, the infiltration capacity of the soils and storage capacity within wetland areas will be higher, reducing the risk of above normal runoff come spring. Over these southern areas, above normal snowfall would likely be needed to result in sufficient runoff to replenish surface water supplies in spring 2021.
Current long-range forecasts and climate indices suggest above normal precipitation and below normal temperature over the winter months.
The WSA will release their initial spring runoff outlook in early February.
