July 16, 2011
The U.S. Army Corps of Engineers, Omaha District, will temporarily halt releases from the regulating tunnels at Garrison Dam to perform a routine inspection of the tunnel walls Monday.
The purpose of the inspection is to assess the performance of the tunnel walls after recent, prolonged water releases. The inspection is scheduled for 1 p.m. CT, estimated to take several hours and should be complete by late Monday afternoon.
Engineers will use a remotely operated camera to conduct the inspection.
"We’re aiming to keep the duration of the shutdown to a minimum so we can minimize stage changes on the river below Garrison Dam," said Todd Lindquist, Operations Project Manager at Garrison. "People monitoring the river in the Bismarck-Mandan might see a slight reduction in the river stage in that area."
The anticipated stage reduction is estimated at less than two tenths of a foot, Lindquist said . While the river is expected to continue a slow, steady decline, the public should be mindful that this slight reduction in the river stage at Bismrack-Mandan will be offset by a corresponding stage increase of less than two tenths of a foot. Following completion of the inspection, the Corps will restart releases through the regulating tunnels.
The travel time for water from Garrison Dam to the Bismarck-Mandan area is one day. The temporary, slight fluctuation in the river stage in the Bismarck-Mandan should be seen sometime late Tuesday, said Lindquist.
The temporary shutdown is not an emergency shutdown. Dam inspections are and routine part of the U.S. Army Corps of Engineers’ current surveillance program. Inspections are conducted more frequently during high water events.