Less Missouri River Flood Risk Forecast

After Multiple Years of Higher Flood Risk, Missouri River Basin in Drought Conditions

Chris Clayton
By  Chris Clayton , DTN Ag Policy Editor
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The U.S. Drought Monitor update for March 4 shows most of the Plains states in drought conditions. The lower snowpack in the Plains and drier soil conditions are lowering the risk of widespread flooding along the Missouri River this spring. (Graphic from the National Drought Mitigation Center)

OMAHA (DTN) -- Flood risk along the Missouri River basin is lower than normal heading into spring due to dry soil conditions, the lack of overall snow in the Plains, and lower-than-average mountain snowpack, a hydrologist with the Missouri River Basin Forecast Center said Thursday.

Looking at the moisture, weather conditions and current flow on the Missouri River, officials from the U.S. Army Corps of Engineers and the National Oceanic and Atmospheric Administration concurred on a monthly forecast outlook. The Missouri River basin is drier overall going into spring, though officials cautioned that extreme weather conditions can quickly change the state of play across the basin.

The Corps is still working on levee repairs from 2019's flooding on the Missouri River, which struck in mid-March that year with a "bomb cyclone" that hit Nebraska and South Dakota, causing dozens of levee breaches on the Missouri River south of the dam at Gavins Point, South Dakota. Flooding in the lower part of the basin lasted most of 2019 and caused billions of dollars in damage in towns and farms in the river flood plain.

Roughly 75% of levee repairs in the Kansas City, Missouri, Corps of Engineers District are completed. There remain six levees still under repair or awaiting contract awards. Some breach closures will be completed this spring before planting season, but other breaches will take throughout the summer to complete, a Corps official said on the call. While the risk of flooding will be lower overall, those counties still facing levee repairs remain at greater risk.

"Those folks are going to have to be diligent and paying attention to what's going around them," said Jud Kneuvean, who oversees emergency management for the Corps out of Kansas City. He added, "So we're in contact with all of those sponsors and partners, and they are at risk.

Kneuvean noted farmers in those river bottoms who do not have a fully repaired levee will likely see their crop-insurance rates affected.

"The Corps works closely with the Risk Management Agency in helping them determine whether the levees will afford any type of protection and what that protection level is," Kneuvean said.

While the last three months has seen a strip of increased rainfall in a few states, precipitation overall remains below normal in the northwestern portions of the Missouri River basin, said Doug Kluck, a regional climate director for NOAA, as he highlighted maps spotlighting recent precipitation.

"They are very consistent areas, basically northern South Dakota and eastern Montana, being very dry," Kluck said. Some parts of the basin show increased moisture, "but the big picture is dryness."

The Missouri River basin is largely in drought status. The U.S. Drought Monitor updated Thursday shows most of the upper basin in a D2 severe drought status. Drought conditions intensify in central Wyoming, most of Colorado, as well as southwestern Nebraska and western Kansas, which have hit D3 extreme drought status.

Levin Low, a hydrologist with the Missouri River Basin Forecast Center in the National Weather Service, said mountain snowpack conditions are near normal in the north, but lower in the south. There is little snowpack in the Plains right now. Collectively, the factors for flooding are lower.

"Flood risk for the Missouri River basin is lower than normal, given the dry soil conditions, lack of Plains snow and average-to-lower mountain snowpack," Low said.

Low said there is still a likelihood of minor to moderate flooding in some tributaries to the Missouri River, such as the Little Sioux River in Iowa, and flooding in lower portions of the basin in southeast Nebraska, eastern Kansas and in Missouri.

John Remus, chief of the Missouri River Basin Water Management for the Army Corps of Engineers, stressed the Corps "remains fully committed to the flood-risk reduction mission, protecting stakeholders when we have significant runoff events that pose a threat to human health and safety."

Remus cautioned that widespread thunderstorms do happen in the lower part of the basin as well. Flooding from those large storms "cannot always be mitigated by the operation of the mainstream reservoir."

Currently, though, Remus said the reservoir system in North and South Dakota is in good shape. Remus added that Corps water releases could even be dialed back if dry conditions persist.

As of now, the Corps expects for 2021 that reservoir releases and runoff above Sioux City, Iowa, will reach 21.7 million acre feet for the year, which is 84% of the average of historic water releases on the river -- about 25.8 million acre feet. During the last decade, the Corps has typically forecast above-average runoff.

Chris Clayton can be reached at Chris.Clayton@dtn.com

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Chris Clayton