OMAHA, Neb. (KCAU) – The flood control zone of the Missouri River Mainstem Reservoir System has the full flood control capacity available for the 2021 runoff season, according to the U.S Army Corps of Engineers (the Corps).
John Remus, the chief of the Corps Missouri River Basin Water Management Division said the flood water that had been stored in 2020, had all been evacuated as of December 21, 2020.
At Gavins Point in Yankton, South Dakota, releases are being maintained at 17,000 cubic feet per second. It will be adjusted as needed in response to ice formation on the Missouri River below Gavins Point Dam.
The December 2020 runoff above Sioux City was 48% more than normal at 1.2 million acre feet (MAF). For the entire year of 2020, runoff was 31.1 MAF, 121% of average. The average annual runoff is 25.8 MAF.
The runoff forecast above Sioux City for 2021 is expected to be 10% less than normal at 23.1 MAF based on significantly drier-than-normal soil moisture conditions, low plains snowpack, and below-average mountain snowpack.
“Runoff forecasts are developed using the best information as it exists today. As mountain snowpack continues to accumulate, our forecasts will be updated to reflect those changes,” Remus said.