Gavins Point releases are currently being stepped down to minimum winter release levels as drought conditions persist throughout the Missouri River basin.

“Gavins Point releases were set at 37,500 cubic feet per second (cfs) near mid-November to meet the navigation flow targets on the Missouri River. After the navigation season ended, releases were stepped down, and they reached 16,000 cfs on December 5,” said Jody Farhat, Chief of the Missouri River Basin Water Management Division. “Releases from Gavins Point will continue to be gradually reduced and will be targeted at the minimum level of 12,000 cfs this winter to conserve water in the reservoir system, as outlined in the Master Manual.” 

Further gradual reductions from 16,000 cfs to 12,000 cfs will be made in close coordination with the intake operators downstream from Gavins Point to the mouth to ensure water supply is served to the extent reasonably possible. Temporary increases above 12,000 cfs may be necessary to keep water intakes along the lower river operational particularly during periods of ice formation.

Runoff into the reservoir system was 87 percent of normal during November. The 2012 calendar runoff forecast increased from 19.2 to 19.7 million acre feet (maf) due to a slight improvement in runoff in the upper portions of Missouri River basin. The annual runoff forecast is 79 percent of normal.

System storage declined 1.3 maf in November. “Our studies indicate that we will likely begin the 2013 runoff season about 8 maf below the base of the annual flood control and multiple use zone,” said Farhat. Fort Peck, Garrison and Oahe are expected to start the runoff season approximately 10 to 11 feet below the desired operating level.

Due to the below normal system storage, it is likely that the Corps’s flow support for Missouri River navigation will be at or near minimum service for the first half of next year’s navigation season as a drought conservation measure. Minimum service flow support is designed to provide an 8 feet deep by 200 feet wide navigation channel rather than the 9 feet by 300 feet supported with full service flows. The actual service level will be set based on the March 15 system storage in accordance with guidelines in the Master Manual. If dry conditions persist through the spring flow support for the second half of the navigation season, as well as the navigation season length, may be reduced based on the July 1 storage check. In addition to minimum winter releases, reductions in navigation flow support and season length are additional drought conservation measures.

As of Dec. 3, the mountain snowpack was 96 percent of normal in the reach above Fort Peck and 89 percent of normal in the reach from Fort Peck to Garrison.

The comment period on the draft 2010-2011 Annual Operating Plan closed Nov. 23. The final plan will be published by the end of December. It will be published in the Reports & Publications section of the Water Management website at: https://www.nwd.usace.army.mil/MRWM.

Conference calls planned for January

As was done in 2012, the Corps will begin monthly informational calls in 2013 as part of efforts to communicate more frequently and broadly with the basin stakeholders. The first call is scheduled for Jan 8. During the calls, the Corps will discuss current basin conditions and the reservoir release plans and forecasts with federal, state, county and local officials, Tribes, emergency management officials, independent experts and the media.

Audio files of the conference calls will be made widely available. The official schedule for the Jan. 8 call will be released later this month.

Reservoir Forecasts

Gavins Point releases averaged 34,200 cfs during the month of November. Releases were gradually reduced from 37,500 cfs starting on Nov. 23 and reached 18,000 cfs on Nov. 29. Releases were held at that rate for 6 days before being reduced to 16,000 cfs on Dec. 5. The reservoir behind Gavins Point dam ended October at elevation 1207.7 feet. It is expected to decrease to elevation 1207.5 by the end of this month.

Fort Randall releases averaged 30,600 cfs during the month of October. Releases were stepped down approximately one day prior to Gavins Point releases and reached 13,500 cfs on Dec. 4. Releases will range from 10,000 cfs to 14,000 cfs for the remainder of December as necessary to maintain the elevation at Gavins Point. The reservoir ended November at elevation 1340.2, down 5.2 feet from the previous month. It is expected to end December near elevation 1339.3 feet. The reservoir is normally drawn down to elevation 1337.5 feet in the fall, and then refilled over the winter to provide increased winter hydropower generation at Oahe and Big Bend.

Big Bend releases averaged 24,300 cfs during the month of November. They are expected to average 10,500 cfs in December. The reservoir will remain near its normal elevation of 1420 feet this month.   

Oahe releases averaged 26,100 cfs during the month of November. Releases are expected to average 10,500 cfs during the month of December. The reservoir ended November at elevation 1593.3 feet, down 1.1 feet during the month. The reservoir is expected to climb nearly two feet during December.

Garrison releases averaged 22,100 cfs in November. Releases were increased from 20,000 to 22,000 cfs in early November. In December, releases will be reduced from 22,000 cfs to 16,000 cfs near mid-month to prepare for possible river freeze-in. Once an ice cover is established, releases will be gradually increased to 22,500 cfs. November releases are expected to average 18,500 cfs.  The reservoir ended the month at elevation 1830.3, down 1.2 feet from the previous month. It is forecast to decline by less than one foot in December ending the month at elevation 1829.7 feet.

Fort Peck releases averaged 10,400 cfs in November. Releases were increased from 10,500 cfs to 11,000 cfs in early December, and will remain at that rate during the month. The reservoir ended the month at elevation 2228.3, down 1.7 feet from the previous month. It is expected to decline by 1.4 feet during December, ending the month near elevation 2227 feet.

The forecast reservoir releases and elevations discussed above should not be assumed to be definitive. Additional precipitation or lack of precipitation in the basin could cause adjustments to the reservoir release rates.

The six mainstem power plants generated 857 million kilowatt hours of electricity in November. Typical power generation for the month of November is 740 million kWh. The power plants are projected to generate a 10.3 billion kWh of electricity this year, which is near the normal amount of 10 billion kWh hours.

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. 

MISSOURI RIVER MAIN STEM RESERVOIR DATA

WATER RELEASES AND ENERGY GENERATION FOR NOVEMBER