More Missouri River floodwater is heading this way.
Releases from Gavins Point Dam in northeast Nebraska will increase to 160,000 cubic feet per second by Thursday as a result of continued rain in South Dakota — where as much as 6 inches fell recently — and northern Nebraska.
The corps is currently releasing a record 150,000 cfs from the dam, causing widespread flooding along the river in eastern Nebraska and western Iowa and further downstream.
The higher flows are not expected to cause the river to rise significantly at Omaha, said Monique Farmer, a corps spokeswoman. The river was 5.5 feet above flood stage Tuesday at Omaha.
The impact of an additional discharges will result in the river rising 8.4 to 12 inches at Sioux City, Iowa, and 3.6 inches to 4.8 inches from Omaha to Rulo, Neb.
Farmer said river levees that have been hardened or heightened to defend against flows based on the 150,000 cfs releases should operate fine under the increased flows.
Corps officials have been ramping up releases since late May to flush historic and unprecedented floodwater out of six reservoirs in the northern plains.
Officials planned to hold Gavins Point releases at 150,000 cfs for an extended period of time, said Brig. Gen. John McMahon, commander of the Northwestern Division.
“Unfortunately, recent rains have reduced our flexibility, and we must evacuate these floodwaters to manage the remaining flood control storage in the reservoir system,'' he said Tuesday. “As we've stated all along, heavy rain storms could result in major revisions.”
The corps is working with state and local emergency management teams to identify potential flood areas, provide residents with current information and help protect vital infrastructure.
“This continues to be a very dynamic situation and dangerous at the same time,” McMahon said. “People along the river are encouraged to make evacuation plans to protect their possessions and property.''
Flooded areas are expected to be inundated for several months.
Jody Farhat, the corps water management chief in Omaha, said rainfall is once again erasing most of the flexibility designed into dam operations this year.
She said the corps continues to evaluate the amount of water entering the system and will revise plans as needed.
Gavins Point will increase releases by 5,000 cfs over two days. The 160,000 cfs level will be attained by Thursday and remain at that level through August.
Updated inundation maps from Gavins Point to Rulo will be available online no later than Wednesday night at the Omaha District website.
Inundation maps for south of Rulo will be available by the weekend on the Kansas City District website.
Contact the writer:
402-444-1127, david.hendee@owh.com
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