YANKTON, S.D. - The reservoir at Gavins Point Dam dropped a half-foot in the past 24 hours the dam near Yankton continues to discharghttp://www.siouxcityjournal.com/news/local/article_cbfdf9a0-a023-11e0-812c-001cc4c03286.htmle record releases from the Missouri River.
The U.S. Army Corps of Engineers announced today the elevation of the pool at Gavins Point Dam was 1205.9 feet at midnight today, down .5 feet from midnight Saturday. The pool is currently about four feet shy of the top of the spillway gates, which are at 1210 feet.
The change to Gavins Point's reservoir level was the biggest drop in any of the six dams upstream of Sioux City, according to figures the U.S. Army Corps of Engineers released this morning.
Water levels also declined a tenth of a foot behind Fort Peck Dam in eastern Montana and fourth-tenths of a foot at Big Bend Dam near Fort Thompson, S.D. They increased six-tenths of a foot at Fort Randall Dam west of Wagner, S.D., three-tenths of a foot at Oahe Dam near Pierre, S.D., and a tenth of a foot at Garrison Dam near Riverdale, N.D.
Heavy rains early last week spurred the release of 160,000 cubic feet per second from the dam. Previously, the corps had planned to restrict peak releases to 150,000 cfs.
In the week since the increase, corps officials said although they planned to hold releases at 160,000 cfs, reservoirs behind the six dams are nearly full and have little storage space left. Lack of space meant the system was vulnerable to showers and thunderstorms, which officials said could result additional releases from the dams.
In the week since the increase, corps officials said although they planned to hold releases at 160,000 cfs, reservoirs behind the six dams are nearly full and have little storage space left. Lack of space meant the system was vulnerable to showers and thunderstorms, which officials said could result additional releases from the dams.
The corps modified releases from the dams, increasing flow rates from some while reducing discharge from others, in order to manage what space there is and reduce the pool levels behind some of the dams.
In particular, they reduced outflows from Fort Randall Dam to lower the pool level at Gavins Point. They also restricted flows from the Oahe Dam to because of high flows from the Bad River and increased discharges from Big Bend Dam.
Jody Farhat, chief of the corps Missouri River Water Management, told reporters last week that reservoir levels should begin to decline early this week. More room in the reservoirs would give the corps more flexibility should heavy rains occur, she said.
"Until we gain a couple feet of capacity in these reservoirs, heavy rain will likely result in those increases," Farhat said Thursday.
Jody Farhat, chief of the corps Missouri River Water Management, told reporters last week that reservoir levels should begin to decline early this week. More room in the reservoirs would give the corps more flexibility should heavy rains occur, she said.
"Until we gain a couple feet of capacity in these reservoirs, heavy rain will likely result in those increases," Farhat said Thursday.
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