Thursday, May 26, 2011

Latest Press Release: 110,000 cfs by end of June

The Corps of Engineers Omaha District has just released the latest projection that releases from Gavin's Point Dam will increase to 110,000 cfs by the end of June.

Here's the link to the press release on their facebook page:
http://www.facebook.com/notes/us-army-corps-of-engineers-omaha-district/dam-releases-to-reach-historic-levels/226335560712480

Here's the link to Omaha District Press Releases:
http://www.nwo.usace.army.mil/html/pa/pahm/newsreleases2011.htm

Here's the press release. Predictions for all mainstem Corps dams are included:


Dam Releases to Reach Historic Levels
May 26, 2011
Omaha, Neb. – Releases from the Missouri River reservoirs will reach historic levels in the coming weeks, the result of above-normal snow in the mountains and extraordinary rain over the last several weeks.  Significant flooding in cities, towns and agricultural land is expected in North and South Dakota with many areas from Sioux City, Iowa, to the Mississippi rising above flood stage.



Flows from five of the six dams are expected to reach a record 110,000 cubic feet per second (cfs).  The previous high releases were 70,000 cfs in the fall of 1997.  “Public safety is our number one concern,” said Brig. Gen. John McMahon, commander of the Northwestern Division of the Army Corps of Engineers.  “We are working closely with state and local emergency management teams to identify potential flood areas, provide residents with the most current information and help protect vital public infrastructure.

“People along the river are encouraged to make evacuation plans to protect their possessions and property. Maps for potential flood areas will be available at www.nwo.usace.army.mil <http://USACEARMY.pr-optout.com/Url.aspx?520028x528846x467124>  and from local emergency management offices,” he added.

Flooded areas are expected to be inundated for several months.

“Moving water out of the reservoirs is essential to prevent the spillways from being overtopped which would make flooding much worse,” said General McMahon. “Our release plan is based on the rain we’ve already received and the forecasted snow melt.  More heavy rain storms could cause major revisions.”  At these levels, additional releases do not significantly change the foot print of the flooding, only the depth.

In the last month, the upper basin has received a year’s worth of rain.  “The amount of rain has nearly filled the reservoirs, doing away with most of the flexibility we had built into our operations for this year,” said Jody Farhat, Chief of the Water Management Division here.  “With the arrival of the 140 percent-of-normal snowpack runoff, all the reservoirs will reach their maximum levels.”

Releases Fort Peck, Mont., are expected to reach 40,000 cfs in early June and peak at 50,000 cfs in early July.  The reservoir is forecast to reach within a foot of the top of the spillway gates.

Garrison releases will increase from the current 75,000 cfs to 85,000 cfs on Monday, May 30 and reach 105,000 cfs about mid-June. The peak reservoir level will likely reach the top of the spillway gates at 1853.9 feet.  Many areas along the river in the Bismarck-Mandan area will be flooded with 3 to 6 feet of water.

Oahe releases will follow a pattern similar to Garrison, reaching 85,000 cfs on Saturday, May 28 and as high as 100,000 cfs by June 6 and 110,000 cfs by late in the month.  The reservoir will peak within a foot of the top of the spillway gates at 1619 feet. Many areas along the river in Pierre will be flooded with 2 to 6 feet of water.

Big Bend releases will mirror those from Oahe, with its reservoir level remaining at 1420 feet.

Releases from Fort Randall will gradually increase from the current 61,000 cfs to 110,000 cfs by late-June.  River stages in the reach below the dam should rise 2 to 6 feet.

Releases from Gavins Point will gradually increase from the current 63,000 to 110,000 cfs by the end of June.  River stages 3-6 feet above flood stage are expected from just below Sioux City to the mouth north of St. Louis.

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