The U.S. Army Corps of Engineers says runoff projections along the Missouri River Basin are being impacted by a below average snowpack and dry soil.
Ryan Larsen, reservoir regulation team lead with the Corps, says runoff for the calendar year 2022 is projected to be below average. He made his comments during the Corps’ February Missouri River Basin conference call.
“It’s important to note that we are roughly 60% through the accumulation period with mountain snowpack typically peaking in mid-April,” Larsen said. “In summary, the 2022 calendar year runoff forecast is 21.7 million acre feet or 84% of average.”
National Weather Service hydrologist Kevin Low says mountain snowpack is accumulating at slower-than-normal rates.
“Snowpack conditions in the mountains can generally be categorized as below normal, by this point in the winter, we’ve normally accumulated a little bit over 60% of the seasonal peak snow water equivalent,” Low said. “So we’re just over the halfway mark there in our snow accumulation season, and so things could still change.”
Low adds the main element impacting the Missouri River Basin is widespread drought.
“Those soils in the extreme eastern fringe of the Missouri Basin have recovered somewhat,” Low said. “The drought monitor that Doug (Kluck) showed, and was released today, reflects that over 87% of the basin remains abnormally dry or worse.”
Low reiterated that Water Year 2021 – which runs from October 2020 to September 2021 – was the 17th driest on record. Larsen explains that low plains snowpack is contributing to the lower runoff projections.
“The snow is currently very low to non-existent over much of the basin, with the heaviest plains snow concentrated in central and eastern North Dakota,” Larsen said. “The plains snow pack typically melts from mid-February to April.”
Corps officials say releases from Gavins Point Dam in South Dakota will remain at 12,000 cubic feet per second.