Missouri River basin flooding updates

commentary by Steve Schnarr

Unprecedented releases of water from upper river dams are due to massive snowpack melting combined with heavy rains. That water is combining with recent heavy rains in the lower river to cause flooding throughout the basin. Looking into the future, things don't look good. This year, snowpack accumulation above Garrison Dam in North Dakota was 141 percent of "normal" this year. Of that snowpack, 132 percent remains unmelted. With a long, cool spring, the danger of flooding remains for months to come.

Releases at Garrison Dam, the current hotspot along the mainstem, will be ramped up to 85,000 cubic feet per second (cfs) by Monday. This is 20,000 more than the previous record and is expected to remain at this level throughout the summer. This level will cause major flooding in Bismark/Mandan. According to a KX TV story linked below, the maximum release from the dam is 140,000 cfs. The emergency spillway can be opened releasing a total of an amazing 660,000 cfs (There's NO reason to believe, at this point, that either of these levels would be reached).



What this means for communities downstream of the most downstream dam, Gavin's Point, is unclear at this point. Projections of dam releases change daily, but the latest announcement suggests releases up to 85,000 cfs by June 3. We look forward to some honest assessment from the Corps of Engineers. However, an article below suggests that Omaha, for example, will probably remain at flood stage (29 feet) until summer, and this does not account for heavy rains.

The lower river communities below the Platte River, from Plattsmouth, NE, to Atchison, KS, are in the most danger due to heavy flows from tributaries like the Platte and Nishnabotna. Below Kansas City, major flooding will be more dependent on tributaries like the Grand, Osage and Gasconade. But with baseline flows from the dams so much higher, there's little flexibility for heavy rains - meaning residents and cities will be on pins and needles all summer long.

Here's a link where you can see the hydrological predictions for gages you select in the Missouri River basin. Click here. Check the gage you want to see on the left and the information you want on the right then click "Make My River Page" You can bookmark your selected page for reference as the flood season progresses.

There are links to other great river stage products and flooding maps on the Missouri River Relief "River Links" page: www.riverrelief.org/links/

Here's a string of stories related to flooding across the basin, for a taste of how different communities are being affected.Click the article title to read it.So much is happening right now, you can really get a feel for it by checking out the home page of each news source for updates in that local area.

Montana
See previous posts for more, but here is a dramatic video of kayak surfers below the Black Eagle Dam at Great Falls (posted at Great Falls Tribune): http://www.greatfallstribune.com/videonetwork/957972865001/Kayakers-on-the-flooded-Missouri-River


North Dakota
Reuters - May 25, 2011 - "Army Corps warns of record rise on Missouri River"
This story makes it clear that the Corps of Engineers at this point has no idea how high the flooding will go and explains some of the variables in place. 
KX TV - Bismark/Mandan - May 25, 2011 - "Corps on Unknowns"
More details on the uncertain situation - includes link to video. 
Bismark Tribune - May 26, 2011 -"Sandbagging aimed at 100 year flood"
Bismark Tribune - May 25, 2011 - "'100 years would be too soon for another round ...'"


South Dakota
Yankton Press-Dakotan - May 26, 2011 - "A River On The Rise - Corps Officials Warn Of Increased Water Flows"
The first mention I've seen of 85,000 cfs out of Gavin's Point Dam by June 3. 
KSFY TV (Pierre) - May 25, 2011 - "Flood Watch 2011 video"   (is that Paul Lepisto filling bags?)

Sioux Falls Argus Leader - May 25, 2011 - "Oahe Reservoir rises to record levels"


Nebraska
"Omaha World Herald - May 25, 2011 - "River Cities brace for high water"
Explains the precarious situation Omaha/Council Bluffs will be in for the summer.