Levels on the Missouri River will surge even higher in the next few days as the U.S. Army Corps of Engineers tries to ease pressure from flooding by ramping up releases from Gavins Point Dam.
Thursday evening, releases from the dam were to increase to 90,000 cubic feet per second, said Kevin Grode, who manages releases for the Corps of Engineers. That’s more than a quadrupling of what the discharges had been just a week ago.
While it’s not immediately clear how much the releases will raise river levels, what appears clear is the Missouri River is expected to reach record levels in some stretches, notably around Brownville.
As a result, the rising Missouri River in the next day or so is likely to overtop federal levees on the Missouri and Iowa sides and inundate Interstate 29 near Brownville in the process. Water levels may also require the shutdown of the Cooper Nuclear Station.
The good news: The river is projected to start dropping next week.
Extraordinary flooding along the Niobrara River is the reason behind the increased releases from Gavins Point, Grode said. Once the Niobrara starts dropping, the Corps will be able to reduce releases from Gavins Point, he said.
The goal will be to get releases back down to 20,000 cfs, he said.
In 2011, the flood of record on the Missouri River, releases from Gavins Point reached 160,000 cfs. But those were different circumstances, and the Missouri River downstream wasn’t also absorbing floodwaters.
One of the remarkable differences between 2011 and this flooding in 2019 is how much water has accumulated in the reservoir behind Gavins Point dam, he said.
In 2011, the reservoir level itself didn’t rise above its normal operating range. Instead, it simply passed through floodwaters from the five much larger upstream reservoirs.
This year the reservoir is filled to its limit, Grode said.
Grode said the Corps will do an engineering analysis after the flooding has subsided to determine how much releases from Gavins Point contributed to the river’s level.