Officials continue to fully assess the scope of this spring’s flooding, officials with the U.S. Army Corps of Engineers (USACE) said Thursday.
During a USACE Northwestern Division, Missouri River Water Management Division conference call Thursday, an update was provided on recovery efforts.
John Leighow, chief of Readiness and Contingency with the Northwestern Division of the USACE, said much of the river below Gavins Point Dam remains above flood stage.
"Despite the relief from the immense rains in May and June, the waters of the Missouri, Kansas and Osage river basins remain largely above flood stage — substantially higher than the average for this time of year," Leighow said. "The river is expected to remain at flood stage for some time. While our assessment teams and contractors are moving forward with repairs where feasible, our field engineers have yet to get boots on the ground to accurately assess the scope of damages to approximately 150 miles of damaged levees."
Still, he said conditions have given officials more clarity as to the extent of this spring’s flooding.
"Drier weather is permitting gauge readings to drop along the Missouri River, enabling us to gain more granularity on the extent and cost of damages in the region," he said. "You have likely heard us refer to what we call phase I of our recovery efforts. This consists of initial and temporary repairs to over 150 breaches prior to the next flood season in March 2020. The total cost of these efforts is currently $120 million and we expect that number to rise as repairs continue."
Kevin Low with the National Weather Service Missouri Basin Forecast Center said flooding is ongoing along the James and Big Sioux rivers in South Dakota, with each expected to crest late next week.
John Remus, chief of the Missouri River Basin Water Management Division, said a big runoff year is still expected.
"The July 1 forecast for runoff above Sioux City, Iowa, is 49.9 million acre feet (maf)," Remus said. "This is slightly lower than our June 1 forecast of 50 million acre feet, yet realize this runoff will be the second largest runoff in the 120-year record."
He said that reservoir storage is currently 68.4 maf, or just above the base of the system’s exclusive flood control zone, and that 12.3 maf of the 16.3 maf of flood control storage is occupied.
"System storage is expected to peak in a week or so as the reservoirs continue to capture the last of the runoff from the melting mountain snow pack," he said.
Remus said that Gavins Point Dam releases are expected to remain at 70,000 cubic feet per second through the end of July.
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