Few problems despite fast melt
Due to the lateness of the season, a lingering snowpack and a very warm forecast, the National Weather Service warned of a rapid snowmelt in the Minot region. What occurred may have been one of the fastest runoffs in area history.
Snow-covered-ground along the Des Lacs and Souris River drainages quickly transformed to water that flowed into numerous tributaries, road ditches and furrows destined for river basins. In some areas the water came so fast that culverts passing under roadways were unable to handle the rush. Some overland flooding was reported too but, despite the rapid melt, nothing comparable to what occurred in the devasting flood year of 2011.
Many of the problems encountered by rising water over the weekend, even into the early hours of Monday morning, were in areas where spring runoff is often a concern. The Project Road in Burlington was closed for time where rising water from the Des Lacs inched over the roadway and where runoff from a drainage ditch came too fast and high to travel through a culvert.
While high water remained above the Old Settler’s Bridge in Burlington Monday afternoon, it was not an unusual awaking for the Des Lacs where the river has been known to cause havoc for homeowners. According to the NWS, the Des Lacs peaked at 19.39 feet Sunday afternoon. By Monday afternoon the narrow river was receding as rapidly as it rose.
Farther upstream some snow could be seen in coulees leading to the river, but it was readily apparent that the snowpack had changed dramatically. The weekend rush of water would not be repeated, a situation that has occurred on the Des Lacs during previous melts. Nevertheless, the 19.39-foot crest surpassed the 19.16 crest of 1996 to move into fifth place on the river’s list of recorded historical crests.
The flow of the Des Lacs combined with other runoff, most notably Gasman Coulee, to push the Souris River at Minot’s Broadway Bridge to 1,546.63 feet where flood stage is listed at 1,549 feet. By Monday the Souris was slowly declining at Broadway.
The gauge on the Souris at the Boy Scout Bridge west of the city peaked at 14.72 feet late Sunday, just over minor flood stage of 14 feet. The NWS was forecasting a slight rise to 15.1 feet for the Boy Scout Bridge but river gauges indicated otherwise.
Although some areas experienced overland flooding, the good news was that the majority of the rapid runoff remained within the banks of the Souris and Des Lacs. That may not have been possible had the release gates at Lake Darling Dam not been closed while the runoff was under way. Lake Darling’s gates were closed last Friday.
According to the latest information received by the U.S. Army Corps of Engineers, the Lake Darling gates will open to 1,000 cubic feet per second today and to 2,000 cfs Wednesday. The releases represent what may be considered part two of the 2013 runoff season. Still to come is the snowmelt in southern Saskatchewan that will impact the amount of water entering the Souris.
Although some melt has already occurred in Saskatchewan, the bulk of the spring runoff is expected to occur later this week when daytime temperatures reach 50 degrees Thursday and continue to climb into the 70s by Sunday. According to the Saskatchewan Water Security Agency Monday, the snowmelt thus far has been performing as expected.
Water from Boundary Reservoir near Estevan, the smallest of three impoundments in southern Saskatchewan, was being diverted to Rafferty Reservoir at the rate of 1,766 cfs Monday. The release gates at Rafferty were releasing a scant 18 cfs into the Souris Monday. A similar amount was being released at Alameda Reservoir at Oxbow, Sask. Alameda backs up flows from Moose Mountain Creek just above its confluence with the Souris. According to the WSA, all inflows from Rafferty and Alameda reservoirs will be held until peak flows from runoff below the dams subsides.
According to the Corps, those releases will push the level of Lake Darling to approximately 1,598 in early May. Releases from Lake Darling will eventually lower that reservoir to its summer operating level of 1,597 feet, a mark that is expected to be achieved about mid-May provided rainfall does not alter current projections.
Downstream from Minot the Souris is still forecast to raise to historical levels. The latest outlook for the Souris at Towner has the river exceeding 56 feet. The all-time high for the Souris at Towner is 58.73 feet set in 2011. According to the NWS, the Souris is likely to produce a top-five event at Westhope where the Souris enters Manitoba.