Spring Runoff Update – April 19, 2016
April 19, 2016 - Snowmelt runoff is complete or near completion over most of the agricultural portion of the province aside from east central areas. As shown on the attached satellite image from April 18, significant snow covers remain in the Upper Assiniboine, Swan, and Red Deer River Basins.
Snow Cover Satellite Image April, 18, 2016
Buffalo Pound Lake is being maintained near 509.47 m, which is the top of its summer operating range. The Water Security Agency (WSA) is continuing to move water from Lake Diefenbaker down the Qu’Appelle River to bring Pasqua and Echo Lakes up to near the top of their desirable summer operating range (478.84 to 479.15 m) in time for recreation season. These lakes are expected to see an increase of about 0.3 to 0.4 m over the next five weeks.
Last Mountain Lake is at 490.22 m and appears to be nearing a peak, near the top of its desirable summer operating range (489.66 to 490.27 m). Mission and Katepwa Lakes have been holding steady at about 478.26 m, lower than typical summer operating levels but well within their desirable summer operating range of 478.08 to 478.38 m.
Crooked Lake is within the April operating range at 451.74 m and is dropping slowly to within the desirable summer operating range (451.41 to 451.71 m). Round Lake is at a record low level for this time of year and may remain at or near record low levels through 2016 if conditions remain dry. The WSA is unable to operate the Round lake Control Structure as land control agreements are not in place with the federal government and First Nations in the area.
The Quill Lakes are at 520.69 m and nearing a peak as tributary inflows are nearing completion. The lakes are expected to peak near 520.7 m later this week, about 0.05 m above the record peak observed in 2015.
Assiniboine River Basin
Snowmelt in the Whitesand River Basin is nearing completion and the Whitesand River near Canora is nearing a peak. However, snow still remains in the Good Spirit Lake and Assiniboine River Basins and flows are still climbing on many tributary streams and on the main stem of the river.
Peak flows are expected to be near 1:10 year levels, similar to those observed in the springs of 2013 and 2014, but well below peaks observed in the spring of 2011 and summer of 2014. While some out of bank flows are likely, flooding related issues are expected to be limited and short term other than at closed basin systems already high from recent high runoff years.
Fishing Lake is at 530.39 m and appears to be nearing its peak elevation from snowmelt runoff. A peak of 530.4 m is expected later this week. The outlet channel will be opened when the Province of Manitoba stages down outflows from Shellmouth Dam, as permitted under the terms of the 2011 Fishing Lake Channel Operating Agreement
Good Spirit Lake
The current elevation for Good Spirit Lake is suspect with reliable data not expected to be reestablished until later this week. A peak elevation of 485.2 m is expected based on observed and forecasted flows on Spirit Creek and the pre-runoff elevation of the lake. This would be similar to the peak levels observed in May of 2011 and May of 2014 and 0.4 m lower than the July 2014 peak.
Swan and Red Deer River Basin
Flows are generally still increasing in the Swan and Red Deer River Basin as much of the snowpack remains, and are expected to reach at least 1:5 and perhaps as high as 1:10 year levels. Flooding related issues are expected to be quite localized and similar to those described above for the Assiniboine River Basin.
Daytime highs are forecasted to be well above seasonal and near historical records on Tuesday and Wednesday over east central Saskatchewan. Consequently, a rapid melt of the remaining snowpack is expected. Weather forecasts show a chance of some precipitation over east central Saskatchewan on Friday which would add to runoff volumes but is not expected to impact peak flows at this time.
The Water Security Agency will post the next update on April 26, 2016 or before if conditions warrant it.