April 2, 2009

Garrison Dam Shuts off the Missouri River

The U.S. Corps of Engineers made history March 24 when they made the decision to close the Garrison Dam and allow no water to be released into the Missouri River.

The recent risk of flooding in the Bismarck-Mandan area drove the Corps to make their decision. The water in the Missouri had risen near Bismarck to an estimated 15.5 feet, less than half a foot from the 16-foot flood stage.

The Corps had been carefully watching the river flow, ice dams and other factors that contributed to the area’s flooding. Paul Johnston, spokesman for the Corps, said that on March 21, the Garrison Dam, which usually releases 19,000 cubic feet per second, was taken down to a 6,000 cfs release, a near record for the dam.

On March 24 the Corps matched their lowest point ever, when the dam was taken down to a 4,000 cfs output, and they made history several hours later when the dam was closed completely, with zero release.

Corps officials note that from time to time throughout the year, releases from power generating units are reduced to zero, but only for short periods of time. The reasons vary, including maintenance and load schedules, but this was the first time that no water was released for this extent of time.

Johnston said that taking the release down to zero was not an extensive or strenuous process.

"It’s a matter of a few key strokes on the computer. It’s not fun like you would imagine with a big valve that has to be turned," Johnston said.


The Weather Network