Missouri River nears flood stage in Omaha as upstream areas approach ‘wettest year on record’

September 27, 2018

The Missouri River this year has reached its highest levels in Omaha since the historic flooding of 2011.

On Wednesday, the river crested near 28.7 feet, just a few inches below its peak in late June, which itself was a hair below flood stage of 29 feet.

In 2011, the river rose about 7.5 feet higher than levels reached this year.

Lowland flooding this week has closed parks and trails along the river but hasn’t posed a serious threat to urban infrastructure. In June, when high river levels were paired with locally heavy rains, parts of western Council Bluffs flooded because there was nowhere for the water to go.

The river has been running high for several months because of a combination of heavy rains and larger-than-average releases from the massive upstream dams. The increased releases, which started in April, have been necessary for the U.S. Army Corps of Engineers to lower reservoirs to accommodate next year’s runoff, said Eileen Williamson, a spokeswoman for the corps, which manages river levels. Runoff from heavy snowpack and spring rains in the upper part of the watershed has pushed the corps to make the bigger releases.

This week’s high river levels in Omaha are the result of heavy rains in the Sioux City area, not reservoir releases, Williamson said.

Five to 8 inches of rain fell in southeast South Dakota and northwest Iowa last week, said Kyle Weisser, a meteorologist with the National Weather Service in Sioux Falls. “That was on top of what has already been a wet year,” he said. “Some areas are approaching their wettest year on record.”

On Friday, the corps cut back releases from Gavins Point Dam so the river could absorb the runoff without rising even higher, Williamson said. It was at least the third time this year that the corps has cut back releases to accommodate rain runoff, she said.

Runoff from the rain accounted for about a 5.5-foot rise in the river at Omaha, according to numbers provided by Williamson.

Once the rain runoff has washed south and the river is clearly dropping, the corps will resume higher discharges from the dams to continue lowering reservoir levels. Those higher discharge levels are forecast to continue into early December.

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