Lake Sakakawea runoff outlook
Current conditions indicate near normal snowmelt runoff can be expected in the Missouri River Basin this spring.
While the outlook issued by the U.S. Army Corps of Engineers is notable, it is subject to change in the coming weeks as the winter season still has the potential to add to the snowpack.
Historically, only about 45 percent of peak mountain snowpack is reached by this time of year.
The Corps is continuing to prepare the Missouri River Mainstem Reservoir System, including Lake Sakakawea, for the upcoming runoff season. According to the Corps, the volume of water currently stored in the system is 56.3 million acre feet which occupies only 0.2 MAF of what is considered “flood control storage.”
This spring’s runoff, says the Corps, is estimated to be 26.6 MAF above Sioux City, Iowa. The long-term average is 25.3 MAF, making the current projection about 105 percent of normal.
The Jan. 1 projections for water levels in Lake Sakakawea show a peak elevation of 1,845 feet in July. That compares with a peak of 1,846.6 feet in July 2017.
Runoff projections are based on soil moisture conditions and plains and mountain snowpack. The Corps updates its runoff outlooks each month. Last week mountain snowpack water content above Fort Peck Reservoir in Montana was rated at 109 percent of average. The Fort Peck to Sakakawea reach, which includes the Yellowstone River, is currently about 125 percent of average.