Federal dam managers said Thursday they will increase the flows on the Boise River to 8,800 cubic feet per second measured at Glenwood Bridge by Friday.
The U.S. Army Corps of Engineers and the Bureau of Reclamation, the two agencies that control Boise River flows, will increase the flows from Lucky Peak Dam by 250 cfs by Friday, making river flows the highest since 1983.
More than 2 million acre-feet of water in the form of snow remains in the Boise River watershed and is expected to come into the three Boise River reservoirs by July 1.
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Those reservoirs are at 68 percent of capacity and have about 300,000 acre feet of storage space available to capture the water. State officials said federal managers are 640,000 acre-feet short of the storage space they should have.
But U.S. Army Corps of Engineers Lt. Col. Damon A. Delarosa said Wednesday that federal dam managers were making “a very calculated decision” in keeping flow below 10,000 cfs. Based on history, federal officials believe they have a 10 percent chance of having to raise the river to more than 10,000 cfs before flood season ends, Delarosa said.
Delarosa is commander of the Corps’ Walla Walla District, which has responsibility for Idaho. Idaho Gov. Butch Otter said state and local officials are on “the same page” as the Corps, which makes the final decision on water releases. Delarosa said the agencies may raise the river as weather dictates.
The forecast for the next two weeks is cool and wet, with frequent showers expected in the next several days.
Vulnerable property owners should get prepared and buy flood insurance, because it takes 30 days for new policies to take effect. Ada County is posting information on its websites about how to get ready to evacuate and how to get an alert in case of more flooding.