The Missouri River’s levels are rising, triggered by recent heavy rainfall in states upriver from Iowa and greater releases from flood control dams. Officials in one southwest Iowa county are advising people to consider evacuating, while others continue to watch the river.
Water is beginning to come back in through a levee breach in the southwest part of Mills County and is migrating north, said Mills County spokeswoman Sheri Bowen. The county still has a lot of standing water between Interstate 29 and the river.
“That standing water is only going to deepen,” Bowen said. “It’s not moving with any significant force right now. But it is moving and increasing a little bit.”
In a news release, the county advised people who live west of I-29 and south of Lambert Ave. to stay alert and think about evacuating. Bowen said that area includes about 40 properties at most, but many of those properties have been vacant since the historic flooding this past spring.
Pottawattamie County Emergency Management Specialist Scott Manz said his county is monitoring the river and the roads, and is concerned about the northwest corner of the county. Like Bowen, he’s also concerned about water that remains from previous flooding and how much the area can hold.
“With that water still sitting there, as the river comes up, those low lying areas will only hold so much before we could have impacts to the roads,” Manz said.
Pottawattamie County has not advised an evacuation yet.
The Missouri River near Omaha, Nebraska and close to Pottawattmie County is expected to crest about a foot and a half above minor flood stage later this week. Near Plattsmouth, Nebraska and close to Mills County, the crest is expected to happen more than 3 feet above minor flood stage.
It’s been a wet year in the Missouri River Basin. The U.S. Army Corps of Engineers had been keeping releases from Gavins Point Dam in Yankton, South Dakota around 70,000 cubic feet per second to help get stored floodwaters out of the system before the 2020 runoff season.
The National Weather Service said precipitation in the first couple of weeks of September has been as high as 600 percent above normal for the basin.
The Corps reduced releases from Gavins Point to 60,000 cubic feet per second over the weekend, hoping to lower the chances of floodwaters reaching I-29.
John Remus with the Corps of Engineers said the Corps will increase releases 5,000 cubic feet each day to bring them up to 80,000 this week, which will make room available in system flood control storage before the 2020 runoff season begins.
“We presently have more than half the flood control storage to evacuate with just over 11 weeks left before we will have to reduce to our winter release rates,” Remus said.
The Corps forecasts runoff for the Upper Missouri River Basin above Sioux City could reach 58.8 million acre-feet this year, more than twice the average amount of runoff in a year. This would be the second highest year on record, behind 2011, which saw runoff reach 61 million acre-feet.
