OMAHA, Neb. – The full flood control capacity of the Missouri River mainstem reservoir system is available for the 2016 runoff season. All 2015 stored flood waters have been evacuated from the reservoir system, according to the U.S Army Corps of Engineers (Corps) Missouri River Water Management Division.

“For most of January, Gavins Point releases were set at 24,000 cubic feet per second to complete the evacuation of stored flood water and prepare the reservoirs for the upcoming runoff season. The last remaining 2015 flood water was evacuated by late January when the combined storage in the reservoirs reached 56.1 million acre feet (MAF), the base of the flood control zone,” said Jody Farhat, chief of the Missouri River Basin Water Management Division.

“Releases from Gavins Point were reduced from 24,000 cfs to the normal winter release rate of 17,000 cfs starting in late January,” said Farhat. “The entire flood control capacity of the mainstem reservoir system is ready to capture runoff in the spring, reducing flood risk while providing good support to the other authorized project purposes.” 

As of Feb. 1, the mountain snowpack was 92 percent of average in the reach above Fort Peck and 72 percent of average in the reach from Fort Peck to Garrison. Normally 64% of the total mountain snowpack accumulation has occurred by Feb. 1. Mountain snowpack will continue to accumulate over the next few months and normally peaks in mid-April.

View the mountain snowpack graphic here: http://www.nwd-mr.usace.army.mil/rcc/reports/snow.pdf

January runoff above Sioux City, Iowa, was 114 percent of average. Based on the current soil moisture and mountain and plains snowpack conditions, 2016 runoff in the Missouri River Basin above Sioux City, Iowa, is forecast to be 23.3 MAF, 92 percent of average. Average annual runoff is 25.3 MAF.

During the winter, the Corps will closely monitor conditions throughout the basin and make reservoir regulation adjustments to lessen the impact of river ice formation. “Ice conditions on the Missouri River will be monitored below Garrison, Oahe, and Gavins Point dams, and releases will be adjusted if necessary.”

Flow support for Missouri River navigation will likely be at full service levels for the first half of the 2016 season. The actual service level will be based on the total volume of water stored in the reservoir system on Mar. 15, in accordance with guidelines in the Master Manual. The Missouri River navigation season will begin on Apr. 1 at the mouth. Flow support for the second half of the navigation season, as well as the navigation season length, will be based on the actual July 1 system storage.

The Corps will continue to monitor basin conditions, mountain snow and plains snow accumulation, and fine tune the regulation of the reservoir system based on the most up-to-date information.

Monthly water management conference calls

The Corps will host its second conference call of 2016 on Friday, Feb. 5, at 1:00 pm CST to inform basin stakeholders on current weather and runoff forecasts and the planned operation of the reservoir system in the coming months. Presentation materials will be available via webinar. The call is intended for Congressional delegations; Tribes; state, county and local government officials; and the media. It will be recorded in its entirety and made available on the Defense Video and Imagery Distribution System at www.dvidshub.net/unit/OmahaUSACE.

Reservoir Forecasts

Gavins Point Dam releases averaged 22,400 cfs in January. Releases were reduced from 24,000 cfs to 17,000 cfs beginning on Jan. 28. Releases are expected to average 17,000 cfs through February. The reservoir behind Gavins Point Dam ended January at elevation 1206.0 feet. The reservoir will rise slightly at the beginning of February, before ending the month back near elevation 1206.0 feet.

Fort Randall Dam releases averaged 20,800 cfs in January. Releases will range from 14,000 cfs to 17,000 cfs during February as necessary to maintain the elevation at Gavins Point. The reservoir ended January at elevation 1345.4 feet, up 5.6 feet during the month. The reservoir is expected to rise more than 4 feet during February. The refill of the reservoir is designed to increase winter hydropower generation at Oahe and Big Bend.

Big Bend Dam releases averaged 22,500 cfs during the month of January. Releases are expected to average 19,700 cfs this month. The reservoir will remain near its normal elevation of 1420.0 feet during February.

Oahe Dam releases averaged 24,800 cfs during the month of January. Releases are expected to average 18,600 cfs this month. The reservoir ended January at elevation 1607.5 feet, down 1.7 feet during the month. The reservoir level is expected to remain near its current elevation in February.

Garrison Dam releases were gradually increased from 15,000 cfs to 20,000 cfs during January averaging 17,400 cfs for the month. Releases are expected to average 19,000 cfs in February. Garrison ended January at elevation 1838.8 feet, down 1.2 feet from the end of December. The reservoir level is expected to decline about 1 foot during February.

Fort Peck Dam releases averaged 6,800 cfs in January. Releases were reduced to 6,000 cfs in early February. The reservoir dropped 0.5 foot during January, ending the month at elevation 2233.8 feet. The reservoir level is forecast to rise slightly during February.

The forecast reservoir releases and elevations discussed above are not definitive. Additional precipitation, lack of precipitation, or other circumstances could cause adjustments to the reservoir release rates.

The six mainstem power plants generated 741 million kilowatt hours of electricity in January. Typical energy generation for the month of January is 708 million kWh. The power plants are projected to generate 9.3 billion kWh of electricity this year, compared to the normal of 10 billion kWh.

To view the detailed three-week release forecast for the mainstem dams, go to: http://www.nwd-mr.usace.army.mil/rcc/reports/twregfcast.pdf    

Missouri River Mainstem Reservoir Data

Water releases and energy generation for January

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