Winter releases into the Souris River from Rafferty and Alameda Reservoirs in Saskatchewan, and from Lake Darling near Minot, are currently under way. The flow of water is not expected to surpass 65 cubic feet per second, but it is anticipated to be a sufficient amount to allow all three reservoirs to reach their prescribed target elevations by Feb. 1, 2013.
A news release from the Upper Souris National Wildlife Refuge stated: "Unlike most winters when the gates are closed on Lake Darling and no water is being released, this winter's releases are necessary to match outflows with inflows coming from Canada, ensuring Lake Darling does not creep above the elevation of 1,596.0. This is the target elevation that Lake Darling needs to be at by February 1st of each year as set by the International Agreement."
Lake Darling was at 1,595.88 feet Wednesday morning with a discharge rate of 20 cfs. According to the NWS, releases will be increased to 65 cfs by the end of November and are expected to remain at that level until mid-January. The NWS cautions that winter flows "will certainly lead to thinner ice conditions than are typical when flow is lower or absent in the river."
In its November report on hydrological conditions in Canada, the recently formed Water Security Agency noted that minimal winter releases were likely to slightly lower both Rafferty and Alameda Reservoirs to meet their required flood storage levels as of Feb. 1, 2013. Both reservoirs are currently within approximately two feet of their target level.
According to the Water Security Agency, "Long range precipitation forecasts from Environment Canada for southern and central Saskatchewan show that below or near normal precipitation is most likely for the winter of 2012/13, with only a low probability of above normal precipitation."
Given the current moisture conditions over the Souris River drainage in Saskatchewan and the long-range outlook, it is anticipated that prairie runoff in the spring of 2013 "may be below normal given typical snowmelt rates."
Forecasts are subject to change over the next several months as is the anticipated amount of spring runoff. The amount of winter snowfall, location and duration of spring rains and temperatures during the melt are all key factors that can greatly influence the actual amount of water that will reach the Souris River Basin.