The U.S. Army Corps of Engineers (Corps) Missouri River Basin Water Management Division is reducing releases from the four lower Missouri River dams because drier conditions in October have reduced runoff into the reservoir system, resulting in faster evacuation of stored flood water. Releases were increased earlier this fall following heavy rains in the upper Missouri River Basin. The 2014 calendar year runoff forecast is 34.7 million acre feet (MAF), 138 percent of normal, which is down 0.8 MAF from one month ago. Average annual runoff is 25.2 MAF. 

Daily releases from Fort Randall and Gavins Point dams will be reduced about 3,000 cubic feet per second (cfs) in a stair-step manner during a four-day period from Nov. 6–9. The total release reduction will be approximately 10,000 cfs and will lower the Missouri River by 2-3 feet. 

“Despite recent reductions, the releases are still above normal and will continue to evacuate flood water stored in the Mainstem Reservoir System, thus reducing our future flood risk,” says Jody Farhat, chief of the Missouri River Basin Water Management Division. “Our reservoir release plans during the fall and winter will ensure we have the entire flood control capacity available next year.”  

The excess water stored in the reservoir system has made it possible for the Corps to extend the navigation season by providing higher winter releases. Navigation service at the mouth of the Missouri River will now end on Dec. 10.  This operation also will benefit hydropower generation and reduce risks to water intakes during ice formation. Gavins Point Dam winter releases, which are normally near 17,000 cfs, will be scheduled at 19,000 cfs from December through February.

The total volume of water stored in the reservoir system at the end of October was 58.1 MAF, down 1.9 MAF for the month. Currently, 2.0 MAF of the 16.3 MAF combined flood control storage is occupied. The Corps will continue to monitor basin conditions and fine tune the regulation of the reservoir system based on the most up-to-date information. 

Reservoir Forecasts 

Gavins Point Dam releases averaged 45,500 cfs for the month of October and are currently at this level.  Flows will be reduced to 36,000 cfs between Nov. 7 and 9 and will continue to be made through the powerhouse and spillway. The reservoir behind Gavins Point Dam ended October at elevation 1206.7 feet and will gradually rise to its normal seasonal pool elevation of 1207.5 feet later this month. 

Fort Randall Dam releases averaged 45,600 cfs in October. Releases through the powerhouse and outlet tunnels will be stepped down to 36,000 cfs starting on Nov. 6. Fort Randall releases will be adjusted as necessary during the remainder of the month to maintain the desired elevation at Gavins Point. The reservoir ended October at elevation 1345.0 feet, down 6.4 feet, and is expected to end November near 1337.5 feet. The reservoir is normally drawn down to 1337.5 feet in the fall to provide space for winter hydropower generation at Oahe and Big Bend dams. 

Big Bend Dam releases averaged 36,000 cfs during the month of October and are expected to reduce to 30,200 cfs this month with all releases made through the powerhouse. The reservoir will remain near its normal elevation of 1420 feet during November. 

Oahe Dam releases averaged 39,000 cfs during October and are expected to reduce to 30,400 cfs this month through the powerhouse. The reservoir ended October at elevation 1609.7 feet, down 3.3 feet, and is projected to drop nearly 2 feet in November. 

Garrison Dam releases were reduced from 24,000 to 20,000 cfs in early October before increasing mid-month to 22,000 cfs and averaging 20,900 cfs for the month. Assuming the flood water evacuation remains on schedule, releases will be reduced from 22,000 to 19,000 cfs in mid-November.  The reservoir behind Garrison ended October at elevation 1842.9 feet, down 1.2 feet, and is expected to drop about 1 foot during November. 

Fort Peck Dam releases averaged 5,100 cfs for the month of October and will remain near 5,000 cfs in November. The reservoir ended October at elevation 2233.0 feet, up 0.4 feet from the previous month, but still one foot below the base of the annual flood control zone. The reservoir is forecast to maintain a nearly steady pool during November. 

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

The six mainstem power plants generated 1,046 million kilowatt hours (kWh) of electricity in October. Typical energy generation for the month of October is 809 million kWh. The power plants are projected to generate 9.7 billion kWh of electricity this year, compared to the normal of 10 billion kWh. 

Draft Annual Operation Plan public comment period closes Nov. 21 

The Corps held its draft Annual Operating Plan (AOP) meetings in five cities throughout the basin, Oct. 27–29, to explain to proposed operation of the system for the remainder of 2014 and in 2015. If you were unable to attend the meetings, the presentation, handouts and draft AOP are available on the Water Management Division’s website at https://www.nwd-mr.usace.army.mil/rcc/. Public comments on the AOP will be accepted through Nov. 21 and can be emailed to the following: Missouri.Water.Management@nwd02.usace.army.mil, or mailed to Missouri River Water Management, U.S. Army Corps of Engineers, Northwestern Division, 1616 Capitol Ave., Suite 365, Omaha, NE 68102-4909. 

MISSOURI RIVER MAINSTEM RESERVOIR DATA   

WATER RELEASES AND ENERGY GENERATION FOR OCTOBER