Missouri Basin runoff below average in October

OMAHA, Neb. – Runoff in the Missouri River Basin above Sioux City, Iowa, for the month of October was 0.9 million acre feet, 78 percent of average. The 2015 runoff forecast is 25.0 MAF, 99 percent of average. Average annual runoff is 25.3 MAF.

The U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division is providing an 8-month navigation season with full service flow support generally sufficient to provide a navigation channel 9 feet deep and 300 feet wide. The ending dates for flow support for the 2015 navigation season by location are:

“Releases from Gavins Point Dam are scheduled to begin decreasing about Nov. 21. Releases will be stepped down approximately 3,000 cubic feet per second each day until they reach the winter release rate,” said Jody Farhat, chief of Missouri River Basin Water Management Division. “Based on the Sept. 1 reservoir system storage, the Gavins Point winter release rate will be at least 17,000 cfs.” Normal Gavins Point winter release rates range from 12,000 to 17,000 cfs.

The total volume of water currently stored in the Mainstem Reservoir System is 58.0 MAF. 1.9 MAF still to be evacuated to bring the system’s reservoirs to their usual minimum flood control elevations.

“System storage declined 1.0 MAF during October,” said Farhat. Our plan is to evacuate all water remaining in the flood control storage zones of the reservoirs prior to the start of next year’s runoff season, which typically begins around March 1.”

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.

Draft Annual Operating Plan public comment period closes Nov. 20

The Corps held its draft Annual Operating Plan meetings in five cities throughout the basin the week of Oct. 26, to present its plan for operating the system for the remainder of 2015 and 2016. The meeting presentation can be viewed at http://www.nwd-mr.usace.army.mil/rcc/reports/pdfs/Fall2015AOPPresentation.pdf.

Public comments on the plan will be accepted through Nov. 20. Comments can be emailed to: Missouri.Water.Management@nwd02.usace.army.mil.

They can also be mailed to:

Missouri River Basin Water Management

U.S. Army Corps of Engineers, Northwestern Division

1616 Capitol Ave., Suite 365

Omaha, NE 68102-4909

Reservoir Forecasts

Gavins Point Dam releases averaged 28,500 cfs in October. Releases will be maintained near 28,500 cfs during the first part of November. The reservoir behind Gavins Point Dam ended October at elevation 1207.8 feet. It will remain near its normal seasonal pool elevation of 1207.5 feet in November.

Fort Randall Dam releases averaged 27,500 cfs in October, and are expected to remain near that rate during the first part of November. Releases will be stepped down near the end of November approximately one day prior to the Gavins Point reductions as necessary to maintain the elevation at Gavins Point. The reservoir ended October at elevation 1344.7 feet, down 9.8 feet during the month.  The reservoir is expected to end November near elevation 1337.5 feet. The reservoir is normally drawn down to that elevation in the fall to provide space for winter hydropower generation at Oahe and Big Bend.

Big Bend Dam releases averaged 15,600 cfs during the month of October. Releases are expected to average 17,400 cfs this month. The reservoir will remain near its normal elevation of 1420 feet during November.

Oahe Dam releases averaged 17,200 cfs during the month of October. Releases are expected to average 16,900 cfs this month. The reservoir ended October at elevation 1610.1 feet, down 1.1 feet during the month. The reservoir is expected to drop less than 1 foot during the month of November.

Garrison Dam releases averaged 13,400 cfs in October. Releases will remain near 13,000 cfs in November. Garrison ended October at elevation 1841.2 feet, down 0.5 feet from the end of September. The reservoir is expected to drop less than 1 foot during November.

Fort Peck Dam releases averaged 4,700 cfs in October. Releases will remain near 4,500 cfs through November. The reservoir remained nearly steady during October, ending the month at elevation 2234.8 feet. The reservoir is forecast to drop less than a foot 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.

The six mainstem power plants generated 651 million kilowatt hours of electricity in October.  Typical energy generation for the month of October is 814 million kWh. The power plants are projected to generate 8.6 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 October