(Omaha) -- U.S. Army Corps of Engineers officials are warning of the risk of more flooding along the Missouri River.
Officials with the corps and the National Weather Service held a conference call to brief area stakeholders on the flooding potential late Monday morning. Kevin Low of the weather service's Missouri Basin River Forecast Center says the risk is due to an "active hydrologic start" in the basin during September.
"There has been rain somewhere in the Missouri River basin every day so far in September," said Low. "There are broad areas of eastern Montana, North Dakota, South Dakota and northern Nebraska that have received in excess of 400% of the normal precipitation usually received in the first two weeks of September. Accumulated rainfall estimates over the past 16 days exceeds five inches over broad areas of northwest Montana, western North Dakota, eastern South Dakota and northwest Nebraska."
Excessive runoff causing record flooding is reported along the James, Vermillion and Big Sioux rivers in South Dakota. John Remus, chief of the corps Missouri River Water Management Division, says the corps took steps to address the flow of moisture from South Dakota by reducing releases from the Gavins Point Dam from 70,000 to 60,000 cubic feet per second over the weekend.
"This was an attempt to reduce the peak stage between Sioux City and Omaha," said Remus. "Our models indicate this may prevent the flood from overtopping Interstate 29 north of Omaha. The plan is hold the release to 60,000 cubic feet per second for no more than three days."
Remus says the corps will then gradually raise the releases to 80,000 cfs in order to increase flood control storage.
"We presently have more than half the flood control storage with just over 11 weeks left until we will have to reduce to our winter release rates," he said. "Based on present forecasted conditions, we will be holding the 80,000 cubic feet per second release from the next several weeks. I want to stress the temporary reduction we did over the weekend did not precipitate the need to increase system releases. The increased system releases were going to be necessary to evacuate the flood control storage."
Kevin Grode, civil engineer with the corps' Missouri River Water Management Division team says additional runoff in the basin's northern portion the last three months of the year will dictate any additional changes in Gavins Point outflows.
"If we continue to see above average--and sometimes much above average runoff--in October, November, December," said Grode, "then, that's going to play into how long we stay at 80,000, or even if we have to increase, or possibly even decrease. But, we simply don't know what kind of runoff we're going to be receiving--especially in October, November and December.
"Mother Nature has been very fickle these last few months," he added.
This latest flood threat comes as preliminary repairs have been completed to 12 damaged levees along the river in the corps' Omaha division, with 21 remaining. Colonel John Hudson, commander of the corps' Omaha district, says areas behind the levees will see the greatest flooding risk from the latest runoff.
"Some of the outlet breaches in the system with the high water may see some flow into them," said Hudson. "So, areas such as 601--that outlet breach at the tieback levee--may see some elevated water levels, as water flows from the riverside into land. You might also see some of that on the southern end of the L-575 levee system southwest of Hamburg. Those outlet breaches might see some increased flow as the river goes up."
However, corps officials say additional damage to communities and properties impacted by the first two rounds of flooding is not anticipated. However, residents need to pay attention to the latest weather service information, and act accordingly. Corps surveillance teams have been sent out to monitor the latest conditions.