High flows thrust Missouri Basin into uncharted territory
Omaha, Neb. -- Updated forecasts from the National Weather Service are suggesting record flows and heavier volume runoff than earlier models predicted, Corps river managers announced today.
"There's no good news," said Jody Farhat, Chief of the Corps' Missouri River Basin Water Management Division in Omaha. "Water releases are forecast to reach 85,000 cubic feet per second (cfs) out of Garrison and Oahe dams because of steady rain and an above-normal mountain snowpack."
Farhat said that the Corps is approaching the top of the gages at all three upper basin dams - Fort Peck, Garrison and Oahe. "Basically, there is little or no storage left in our reservoirs," she said.
For the Bismarck area, Garrison releases of 85,000 cfs will mean reaching a stage of 17.5 to 18 feet, a situation not encountered since Garrison Dam was built in the 1950’s. "It moves us into uncharted territory," said Farhat. The previous record release from Garrison Dam was 65,200 cfs in 1975.
The Pierre area below Oahe Dam will fare a little better because of a buyout program for low-lying properties and repair of drainage problems during the past five years. Still, Pierre will see stages not seen since the dam was constructed. The record release from Oahe Dam prior to this event was 59,300 cfs in 1997.
At Gavins Point farther south, Farhat expects flows to reach 75,000 cfs by June 1 – 5,000 cfs above the record set in 1997 – and additional increases to the 80,000 to 85,000 cfs range are likely by early June.
The Corps' latest water releases are based on the newest river forecasts for the Yellowstone River provided by the National Weather Service’s Missouri Basin River Forecast Center.
"This is the situation where we are today," said Farhat, "But it's not the worst case scenario because snowmelt and additional heavy rainfall may mean even higher releases."
Snowpack in the reach above Fort Peck hit 141 percent of normal peak, with current conditions at about 108 percent of the normal peak accumulation. The snowpack above Garrison Dam reached 136 percent of normal peak, but is slow to melt, with 132 percent of the normal peak accumulation remaining and actually gaining snow in some of the higher elevations.
For more information, go to:
• The Missouri River Basin forecast center. (Clicking on the dots will send you to Advance Hydrologic Prediction Service maps for different parts of the basin.) http://www.crh.noaa.gov/mbrfc/
• The Advanced Hydrologic Prediction Service Maps are found also at http://water.weather.gov/ (arrows in the upper left half of the window will help you navigate to other areas).
• This link is for the western half of North Dakota: http://water.weather.gov/ahps2/index.php?wfo=bis&view=1%2C1%2C1%2C1%2C1%2C1%2C1%2C1&toggles=10%2C7%2C8%2C2%2C9%2C15%2C6.
• This link shows the western half of South Dakota: http://water.weather.gov/ahps2/index.php?wfo=unr&view=1%2C1%2C1%2C1%2C1%2C1%2C1%2C1&toggles=10%2C7%2C8%2C2%2C9%2C15%2C6.
• This is the Missouri River Basin Water Management Page: http://www.nwd-mr.usace.army.mil/rcc/current.html.
• Another site to check out is: http://www2.mvr.usace.army.mil/WaterControl/new/layout.cfm.
