Spillway opens as tunnels close
By Daniel Arens
Water came gushing out from the Garrison Dam spillway this Monday as the United States Corps of Engineers opened nine of the 28 gates to send water out from Lake Sakakawea.
The decision to open the spillway is not due to an emergency situation, nor will there be an increase in the output of water entering the Missouri River and flowing downstream. At the same time the Corps opened the spillway, they closed the three release tunnels west of the power plant.
In total, 9,000 cubic feet per second (cfs) of water was released from the lake with the spillway opening, which is the same level previously released through the tunnels. The spillway simply offers another means for the Corps to siphon water in response to high lake levels.