HAMBURG, Iowa (AP) — Crews are trying to beat floodwaters expected to arrive in Hamburg on Tuesday by building up a secondary barrier to protect the small Iowa town after the swollen Missouri River punched a massive hole in the main levee.
The river ruptured two levees in northwest Missouri on Monday, sending torrents of water over rural farmland toward Hamburg, in southwest Iowa, and a Missouri resort community downriver. By Wednesday, water spilling through a nearly 300-foot hole in the levee near Hamburg was expected to top a secondary levee built last week to protect the town.
The U.S. Army Corps of Engineers said crews are working to increase that wall’s height by 3 feet. If it breaks, parts of Hamburg could be under as much as 10 feet of standing water, officials said.
“For right now, we believe we’ll be able to get that elevation raised in the time available as that water flows across in the next 48 hours,” Col. Bob Ruch, the corps’s Omaha District commander, said Monday evening. “We’ve had excellent working conditions.”
Across the border in Missouri, the river broke a 225-foot-wide hole through a levee near Big Lake in Holt County. About 30 residents had stayed in the resort town after the river started rising, but they were told to leave Monday. Big Lake is about 45 miles south of Hamburg.
The corps steadily has increased the amount of water it is releasing from dams along the Missouri River to account for excess water from heavy spring rains in the northern Plains and to clear out space for above-average snowmelt coming down from the Rocky Mountains.
Releases from the river’s five lower dams should reach 150,000 cubic feet of water per second Tuesday — more than twice the previous record releases.
Areas in Montana, North Dakota and South Dakota already have seen some flooding, and officials predict the problems will linger through the summer.
National Weather Service hydrologist Dave Pearson described the breach near Hamburg as “pretty substantial.” He said water was “flowing through quickly” but still must cross several miles of rural land to reach the Hamburg area.
It wasn’t clear how deep the floodwaters approaching Hamburg were or whether they would prove too much for the secondary levee. Local officials posted video of the breach that showed the water spreading over a large area of farmland.
Terry Holliman, who owns an auto parts store in the town of about 1,100 residents, said water was shooting into farmland near one of three spots where the levee previously had leaked.
“It’s impressive,” Mr. Holliman said early Monday. “The force is unbelievable.”
About 300 Hamburg residents left their homes and businesses last week under an evacuation order after partial breaches in the main levee, which is about 5 miles south in rural Atchison County, Mo.
The corps has been building up the secondary levee to protect low-lying areas of Hamburg since the partial breaches. Officials were able to stabilize the initial leaks but predicted the main levee eventually would fail.
Corps projections show that if the secondary levee fails, the volume of water released upstream during a levee break could leave 8 to 10 feet of standing water in southern Hamburg. The area includes manufacturing and agricultural businesses. Water could reach the fire station and City Hall, but it likely wouldn’t reach the northern part of town, where most residents live.