Premium ContentMouse over Home then click on Premium Content for information.There is reason to hope that even in a worn-down state, levees along the Missouri River can withstand the one to two months of flooding that remain, officials say.
On Friday, the U.S. Army Corps of Engineers announced its schedule for cutting back releases from the six upstream dams whose unprecedented discharges have burst downstream levees and flooded homes, farms and highways.
Continued high releases threaten levees protecting the homes of 40,000 people and billions of dollars of infrastructure in the greater Omaha area, including Eppley Airfield, Offutt Air Force Base and Fort Calhoun Nuclear Station.
From a high of 160,000 cubic feet per second — the rate water flowed Friday — releases from Gavins Point Dam are scheduled to be cut nearly in half by the end of August and three-fourths by the end of September.
Based on Friday's schedule, the river should be back in its banks at Omaha by mid- to late September, said John Remus, chief of the hydrologic engineering branch for the Omaha corps.
Local officials say conditions should start to improve much sooner.
Council Bluffs Mayor Tom Hanafan said the city calculates the river could drop off the Bluffs' levees within about a month. That's because the river will drop below the bottom of the levee before it drops below flood stage.
The homes of about 30,000 Council Bluffs residents are at risk from a levee breach, and the city has 28 miles of levees to protect.
"We're doing everything humanly possible and financially possible to hold those levees," Hanafan said. "Do I have perfect confidence? I can't say that. I can say this: I feel more confident today than I did when we started."
Communities and businesses have been battling flooding since late May.
Like Hanafan, those managing the flood fight for Omaha, Eppley Airfield, Sarpy County and Offutt Air Force Base say the levees are holding up well.
In Douglas, Sarpy and Pottawattamie Counties, as elsewhere along the river, workers have extended and elevated levees, plugged drainage holes and blanketed mushy areas with heavy layers of sand and gravel. Continuous monitoring allows workers to more quickly identify and repair sand boils and rodent burrows.
Martin Cleveland, construction engineer for the Papio-Missouri River Natural Resources District, said improvements and repairs since late May have kept the floodwaters at bay. The NRD maintains the levees that protect Sarpy County and Offutt Air Force Base.
"We feel pretty secure — there's been two months of this now. We feel that they (Corps of Engineers) have a good handle on how to react to problems that do occur," Cleveland said.
Marty Grate of the Omaha Public Works Department said the city could open some floodgates in about a month if releases occur as scheduled. That would allow for more normal drainage of rainwater and would lessen the likelihood of pooling in eastern Omaha.
"The good news is now we have something to plan against," Grate said. "Being totally in the dark is uncomfortable. . At least now we can plan and we can work toward that end."
Steve Coufal, executive director of the Omaha Airport Authority, said airport consultants and staff will be analyzing the corps' schedule to see how it will affect the levees and groundwater levels. Pressure from groundwater is what would collapse runways — something the airport has been able to avoid by installing 70 wells.
"There's light at the end of the tunnel," Coufal said.
Col. Robert Ruch, commander of the Omaha district of the corps, said the reservoir reductions do not mean the danger has passed.
"Now is the time to really make sure we double-down on our . forces and make sure we're watching levees," he said. "My fear is not seeing something coming."
That's because problems continue to occur, as both Ruch and Hanafan noted.
Hanafan said a problem popped up Thursday night along the Bluffs' levees. Several sand boils were discovered just south of Interstate 80. Crews on Friday were laying a heavy blanket of sand and gravel to suppress the boils and plugging a nearby culvert.
In Omaha, crews are putting the finishing touches on a sand blanket to cover a mushy spot that developed last weekend.
Brig. Gen. John McMahon said concern about levee conditions was the reason the corps decided not to empty any more water from the reservoirs this winter than required to return to a normal flood-storage level before next year's runoff season.
"We're concerned that the longer we keep water on them, the greater the risk of failure," said McMahon, commander of the corps' Northwestern Division, which oversees the Missouri River.
This summer's unprecedented flooding is the result of higher-than-normal snowpack and spring rains. McMahon said the corps calculates runoff reaches that level once every 500 years. That doesn't mean the same thing couldn't happen next year, but the odds are against it, he said.
At the end of August, the corps will pause its release reductions to assess whether the drawdown is damaging either the dams or the levees. The corps is concerned that soggy soil could slough off levees and dams if water levels drop too quickly.
If the dams and levees look good, the corps will continue to lower releases to about 40,000 cubic feet per second by Oct. 1. At that level, the corps believes the valley will be able to fully drain of flooding and the river can return to its banks.
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