Souris Basin runoff outlook
Precipitation well below normal
The first Spring Runoff Outlook for the Souris River Basin issued by the Water Security Agency in Saskatchewan says current expectations are for a very limited runoff this spring.
The report is based on a variety of factors, including the amount moisture on the ground throughout the Saskatchewan portion of the Souris River drainage last fall and the depth of the current snowpack, data that is supported by airborne gamma surveys flown by the National Weather Service.
According to the WSA, winter precipitation has averaged 60-85 percent below average across the Saskatchewan portion of the Souris River Basin. Aerial surveys were flown Jan. 12-13 and the snowpack cover was confirmed by satellite imagery Jan. 29. Current conditions, which are subject to change with several weeks of winter remaining, result in the projection of a very limited runoff season for the Souris.
Due to current conditions, concludes the WSA, “it would take well above average precipitation in February, March and April to produce an above average spring runoff with most areas” of Saskatchewan. Souris River impoundments at Estevan, Rafferty Reservoir, and at Oxbow, Grant Devine Lake, were below their required drawdown levels prior to Feb.1 and no additional drawdown of those reservoirs are expected to occur this year.
The entire Souris River drainage in southern Saskatchewan is considered to be in the “below normal” category for spring runoff. The outlook notes that dry conditions last fall have resulted in “significant wetland storage available” in many areas of the province, which includes the Souris River Basin. Specifically, says the outook, “runoff yields are expected to be below median at all forecast points” along the Souris.