The U.S. Army Corps of Engineers did "an extraordinary job under a lot of duress" in managing record flooding along the Missouri River this summer, although changes in management could help prevent a repeat, an independent panel has concluded.
The corps was not negligent in its management of the flooding, the report found, although it said changes in evaluating flood storage allocations should be considered.
The findings were included in a 99-page analysis released Tuesday that was prepared by a four-member panel appointed by the corps.
The panel said the corps did not accurately predict what turned out to be record runoff, but neither did other forecasting agencies.
Bill Lawrence, a member of the panel and a meteorologist with the National Weather Service in Tulsa, Okla., said a large area of Montana - roughly 250,000 square miles - was hit with 300 percent of normal precipitation in May.
"It wasn't just one or two areas," Lawrence said. "It was an area about the size of Georgia."
The report shows the infrastructure of the dams performed as designed with no deficiencies, said Neil Grigg, a member of the panel and professor at Colorado State University.
Grigg said the corps' management of the river is bound by the master manual in which seven of eight of its authorized purposes call for releases through dams to support recreation, navigation or other uses.
He said there is no "fixed formula" to operate the six dams on the Missouri and said the corps acted "appropriately and in line" with its decision-making based on the master manual.
The study said the inaccuracy of forecasting runoff prevented the corps from increasing releases and providing more flood storage.
Grigg said modeling and communication can be improved, and a review of flood storage allocations should include floods like 2011 or larger.
Brig. Gen. John McMahon of the corps said, as of last week, the goal is to have 16.8 million acre-feet of flood storage available by the end of March.
McMahon said levees along the river suffered $630,000 in damage and estimates are still being compiled on damage to dams and channels.
If more space is dedicated to flood protection, the end result is less water available for other uses, he said.
Sen. Kent Conrad, D-N.D., said in a statement that the good news was the dams and other flood protection structures worked as designed.
But, he added, the corps must improve its communication with the public and forecasting.
"Nonetheless, we are still awaiting the results from the federal review that I requested looking at the corps' actions leading up to the devastating floods this spring," Conrad said. "There are lessons that need to be learned here for future flood preparation."
McMahon said a review of the flood storage allocation should be completed by the end of March.
Sen. John Hoeven, R-N.D., will be in Bismarck today talking to leaders about sand build-ups along the Missouri River, particularly near the mouth of the Heart River.
Hoeven said the flooding this summer illustrated the lack of communication between the corps and North Dakota, going back to a time when the state was experiencing a drought.
"You can't manage the river the same every year," Hoeven said. He said the report made it "pretty darn clear" any management plan must account for dry cycles as well as wet cycles.
"In the dry years we were saying, ‘Hey, we have to conserve water.'"
This fall, Hoeven said he, along with state officials, were telling the corps that water levels were too high.
Hoeven said a good start in creating more flood storage capacity would be improving how observations and forecasts are made on the ground.
Gov. Jack Dalrymple was contacted for comment on the report, but a spokesman said his schedule had not allowed him to review it Tuesday.
Any changes in the master manual could include new legislation on the federal level. The last time the master manual was updated, it took 14 years and cost $33 million, Grigg said.
The Garrison Dam was operated 1.3 feet higher than its maximum capacity at the height of the flood, while Oahe Dam was ½-foot lower than its maximum, he said.
There were fears below Oahe that if water was released through the spillway - which has never happened - the water would flow through an unlined channel causing major erosion and damage along its banks, he said.
McMahon, who is the corps' northwest division commander, said any changes would take time. He said officials are reviewing the report to determine if any recommendations will be incorporated into the 2012 annual operating plan scheduled for release in January.
"We have a lot to chew on," McMahon said.
When asked if the report "vindicated" the corps' response to the flood, Grigg said, "We didn't use that word. This was a technical report."
He said flood control should be the dominant purpose of all authorized uses of the system, especially during extreme events.
Reach reporter Brian Gehring 250-8254 or firstname.lastname@example.org.