The water runoff forecast for the upper Missouri River basin has been lowered for the year.
The runoff in the upper basin can be a factor in the flood risk for the Leavenworth area. But despite the reduction, the runoff forecast remains above average. And there still is a potential for flooding from the Missouri River, according to the U.S. Army Corps of Engineers.
Rainfall in the upper basin, the area of the river north of Sioux City, Iowa, has been well below normal since January, according to a news release from the Corps of Engineers’ Missouri River Basin Water Management Division.
Some areas of the Dakotas received less than half of their normal precipitation during the first four months of the year.
The water runoff forecast for the upper basin is updated at least once a month. The Corps of Engineers announced Thursday that the latest runoff forecast reduces the total for 2020 by 3.3 million acre-feet to 32.2 million acre-feet.
The average annual runoff for the upper basin is 25.8 million acre-feet.
The adjusted forecast for 2020 is still in the top 25% of the 122 years of runoff records.
“This is still an above average runoff forecast,” John Remus, chief of the Corps of Engineers’ Missouri River Basin Water Management Division, said in a news release. “The upper basin runoff for the remainder of 2020 depends on mountain snowmelt and rain events.”
Last year, the Leavenworth area saw its second and fourth worst floods on record.
On March 23, 2019, the Missouri River crested at 31.3 feet in Leavenworth, making it the second worst recorded flood in the city’s history, according to the National Weather Service.
The Missouri River reaches its minor flood stage in the Leavenworth area at 20 feet. The river reaches its moderate flood stage at 24 feet and major flood stage at 30 feet.
The river crested again June 1, 2019, at 28.66 feet, marking the fourth worst flood in the city’s history.
The worst flood in the city’s recorded history occurred in 1993.
The Missouri River crested July 28, 1993, in Leavenworth at 35.34 feet, according to NWS.
Repair work has started for at least some of the levees in Leavenworth County that were damaged by last year’s flooding.
As of 2 p.m. Friday, the Missouri River was at a depth of 9.51 feet in the Leavenworth area, which is well below flood stage, according to the NWS.