YANKTON, S.D. (KCAU) – April runoff of the upper basin of the Missouri River to Sioux City was the third highest recorded, according to the U.S. Corps of Engineers. They said that through the 121 years of recording, average runoff is 2.9 million acre feet (MAF), but April 2019 was 7.8 MAF.
In addition, runoff from Gavins Point Dam in Yankton, South Dakota to Sioux City, Iowa reached 2.3 MAF, making it the second highest on the record.
With the near-record runoff of the upper basin, the Corps forecasts the runoff for 2019 at 42.3 MAF, which makes it the third highest. The current top three years of record runoffs are 61 MAF in 2011, 49 MAF in 1997, and 42.1 MAF in 2018.
With the high runoffs, releases along the Missouri River will be above average for summer. The above average release could continue into November, according to the Corps.
John Remus, the chief of the Corps Missouri River Basin Water Management Division, said that releases at Gavins Point are at 55,000 cubic feet per second (cfs). This is about 25,0000 cfs more than normal.
“We will maintain Gavins Point releases at this rate to continue evacuating water from Oahe and Fort Randall, which are using much of their respective flood storage,” said Remus. “We want to reduce the pool levels in Oahe and Fort Randall a few feet to provide flexibility should we need to reduce Gavins Point releases for short periods over the remainder of the spring and summer.”
Gavins Point releases have been above full service levels to help reduce flood storage at Oahe and Fort Randall.
Mountain snowpacks reached their peak mid-April. Snowpack at Fort Peck reached 105 percent, and Fort Peck to Garrison was 4 percent more than normal.
“Fort Peck and Garrison reservoirs have adequate flood control space to capture and manage the mountain snowmelt runoff,” Remus said.
For the month of April, the power plants generated 794 million kWh of electricity. This is 101 million kWh more than normal for the month. A projection of the year estimated that the plants will generate 12.3 billion kWh of electricity.