Published February 02 2011
Lake Traverse drawdown to start early
Meanwhile, a corps official said flows on the Otter Tail River are too high for an early drawdown at Orwell Reservoir near Fergus Falls, Minn.
Both storage areas have impacts on Red River flooding. Water from Lake Traverse near Wheaton, Minn., flows into the Bois de Sioux River, which merges with the Otter Tail River to form the Red River at Wahpeton, N.D.
Lake Traverse is currently at an elevation of 976.5 feet, a few inches below the level during summer months.
The corps plans to draw down the lake to as low as 974 feet, which will free up a total of about 75,000 acre-feet of water storage, said Ferris Chamberlin, chief of water management and hydrology for the corps’ St. Paul District.
“We hope like heck to have it down to 974.5 (feet) or lower before runoff begins, but runoff seems to keep coming earlier and earlier,” he said.
Typically, drawdown occurs from March 1 to March 31, but the corps will start two weeks earlier this year as it did last year, Chamberlin said.
Last year at this time the corps was releasing about 100 cfs from Lake Traverse, but the current discharge rate is closer to 200 cfs because of heavy rains last summer and fall, he said.
Starting Feb. 14, the outflow will increase to 400 cfs. On March 1, it will jump again to a channel capacity of 1,100 cfs.
As the discharge increases, Bois de Sioux ice conditions will deteriorate and become unsafe as far downstream as Wahpeton-Breckenridge, the corps said, advising anglers and snowmobilers to use caution.
Chamberlin said flows into Orwell Reservoir are too high to start drawing it down early. Channel capacity is 1,200 cfs, and the corps hopes flows will drop to 1,100 cfs by March 1 so it can start drawing down the reservoir, he said.
The reservoir currently stands at 1,062 feet, or 2 feet below the normal summer level. The corps plans to start drawing it down on March 1 to as low as 1,050 feet, which would provide 12,800 acre-feet of storage.
“You try to be as aggressive as you can opening gates, passing flow, but you can only pass so much water through the structures,” Chamberlin said.
Some homeowners along the Otter Tail River near Fergus Falls have battled flooding this winter because of ice jams. It hasn’t been a big problem since around Christmas, but water levels in lakes and rivers remain high and some township roads are still underwater, Otter Tail County Sheriff Brian Schlueter said.
Officials count on Orwell to provide valuable water storage, Schlueter said.
“If that’s going to be at a super high level going into spring, that’s of course a concern,” he said.
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