KANSAS CITY, Mo (Reuters) – Residents in Hamburg, Iowa, were dry on Tuesday morning and waiting for the Missouri River to reach a secondary flood wall following a widely expected and widening levee breach miles south of the city.
Contractors have been raising the secondary levee by several feet near Hamburg, while a secondary levee has limited flooding from another levee breach 45 miles to the south in Big Lake, Missouri, the U.S. Army Corps of Engineers said.
"Right now, we are still dry," Hamburg Fire Chief Dan Sturm said in a telephone interview on Tuesday. "But the water will encroach on the town within 24 hours."
With heavy rain expected up and down the Missouri River basin over the next two weeks, the challenge flood fighters face could grow.
The Missouri River basin forms the northwest portion of the Mississippi River basin that stretches from Montana to western New York and funnels water south into the Gulf of Mexico.
Heavy winter snowmelt feeding the river's headwaters in the Rocky Mountains and heavy spring rains have forced the Corps to release water from six dams from Montana through South Dakota to relieve swollen reservoirs.
The Corps warned that Hamburg's secondary levee needed to be three feet higher based on new river projections. Iowa expects to raise the levee protection using about 3 miles of new barriers to be placed by the National Guard and filled by the Corps by 3 p.m. on Wednesday.
About 300 of Hamburg's 1,200 residents, those living on the south side of town, were under mandatory evacuation orders.
Parts of the Big Lake, Missouri, area that includes a village and resort were flooded Tuesday after the breach of a nearby levee Monday not controlled by the federal government, said Diana McCoy, a Kansas City District Corps spokeswoman.
A recently built secondary levee in Holt County, Missouri, near Big Lake has limited flooding, McCoy said.
PARK, ROADS CLOSED
Water is covering farmland and most people have evacuated the area, said Linda Burnsides, an employee at Big Lake State Park, closed because of potential flooding.
Flooding or possible flooding has closed some secondary roads in Holt County, said Jessica Wilson, a volunteer in the Holt County sheriff's office.
Several Interstate 29 segments in Iowa were closed due to flooding, including 20 miles north from Council Bluffs. The Corps expects the Hamburg levee breach to inundate a stretch of I-29 within two days. Other area roads were also closed.
Multiple sandboils found Tuesday afternoon on a levee in Mills County, Iowa, across the river from Offutt Air Force Base, prompted a sandbagging operation and request for direct Corps assistance, Mills County spokeswoman Sheri Bowen said.
The levee southeast of Omaha protects a mainly agricultural area in the Northwest corner of Mills County that has a handful of homes, and no evacuations have been called for, Bowen said.
Upstream from the breaches in the Missouri levees, federal officials reached a planned maximum water release rate at the Gavins Point Dam above Yankton, South Dakota, on Tuesday. The rate reached 150,000 cubic feet per second.
The river runs freely from Gavins Point for more than 800 miles to the Mississippi River near St. Louis, making the flows from that dam the focus for residents downriver.
Ultimately, the Corps plans water releases to peak at the 150,000 cubic feet per second rate from the five reservoirs in the Dakotas, more than twice the previous record pace, and hold that pace at least through mid-August.
The Missouri River is expected to reach up to seven feet above flood stage at Sioux City, Omaha and Kansas City when the flows from the maximum release rates reach those areas.
The Missouri River flooding has displaced thousands of South Dakota and North Dakota residents. Authorities warned on Tuesday that residents in some small communities near Bismarck, North Dakota, should leave before road access is cut off.
The National Weather Service issued a flash flood warning Tuesday for parts of western North Dakota as a slow moving thunderstorm dropped up to 2 inches of rain per hour.
The NWS sees a threat for "above normal precipitation for the upper Missouri basin, the northern plains area for the next 6 to 14 days," according to Michael Eckert, a forecaster with the service's Hydrometeorological Prediction Center.
He said the periodic thunderstorms that have plagued the region recently were not unusual for this time of year, but this year's rainfall is "unfortunately right along the Missouri River and down into the mid-Mississippi River."
(Additional reporting by Michael Avok, David Bailey and James B. Kelleher; Editing by Jerry Norton)