Evidence of water being released from Lake Darling can be seen at various locations along the Souris River in Minot. Water that has been pooling behind a series of coffer dams within the city has risen to the point where it is flowing over multiple control structures.
The result is an opening of river ice near dams and bridges. A general deterioration of ice thickness can be expected elsewhere in the Souris.
Lake Darling releases of 20 cubic feet per second began at mid-month. As of Tuesday the release rate had been increased to 40 cfs. According to an earlier release from the Upper Souris National Wildlife Refuge, the releases can be expected to be increased to 65 cfs by the end of this week and likely remain at that level throughout the winter.
Movement of water sufficient to keep a section of river from freezing could be seen at Minot’s Water Treatment Plant Tuesday. Flows in the Souris are expected to continue throughout the winter due to releases from Lake Darling.
The releases from Lake Darling are in response to water being released into the Souris from Rafferty and Alameda Reservoirs in Saskatchewan, Canada. The releases are considered both minimal and necessary to prevent key Souris River impoundments from inching above preferred winter storage levels.
Lake Darling's normal operating level during the winter months is 1,596 feet. It stood at 1,595.86 feet Tuesday morning. Lake Darling's elevation on the same date in 2010, preceding the flood of 2011, was 1,595.37 feet.
The amount of water being released from the two Canadian reservoirs is approximately 20 cfs each, an amount which reached the Souris River's Sherwood crossing earlier this week and has begun entering Lake Darling. The goal is for Rafferty to be lowered to 1,802.9 feet and Alameda to 1,840.6 feet by Feb. 1 operating levels stipulated by international agreement. In terms of elevation, that means Rafferty needs to drop .4 feet and Alameda 1.5 feet. Lake Darling's releases are being made to coincide with the additional inflow from Canada and to prevent Minot's nearest upstream reservoir from surpassing the 1,596 mark.
As is the case in Minot and other points along the Souris, Saskatchewan's Water Security Agency is urging that anyone considering venturing onto Souris River ice this winter do so with extreme caution. The WSA calls flow under the ice "an extremely serious hazard."
The operating plan for the Souris River remains unchanged from what it was during the historic flood of 2011. A goal contained in Saskatchewan's longterm plan for management of the Souris River Basin includes reaching an agreement with the International Souris River Board and International Joint Commission for a new Souris River operating plan to be implemented in 2015.