“The higher-than-average winter releases from the Missouri River Mainstem System (System) projects, including Gavins Point, will continue the evacuation of the stored flood waters from the 2018 runoff season,” said John Remus, Chief of the Corps’ Missouri River Basin Water Management Division. “The higher-than-average winter releases will provide additional hydropower generation during the winter, which is one of the peak power demand periods. In addition, they will benefit municipal and industrial water intakes below Gavins Point Dam, which can be impacted by low water levels during periods of ice formation”, added Remus.
The November runoff above Sioux City was 1.2 MAF, 118 percent of average. The 2018 runoff forecast in the Missouri River Basin above Sioux City, Iowa is 41.3 million acre feet (MAF), 163 percent of average. If this forecast is realized, the 41.3 MAF of runoff will be third highest runoff in 120 years of record-keeping (1898-2017), exceeded only in 1997 and 2011.
The Missouri River Mainstem reservoir system storage was 57.1 MAF as of December 1, occupying 1.0 MAF of the 16.3 MAF flood control zone. The remaining stored flood waters will be evacuated over the winter and all flood control storage will be available by the start of the 2019 runoff season. System storage peaked on July 8 at 68.4 MAF, occupying 12.3 MAF of the designated 16.3 MAF of flood control storage.
Flows to support navigation will end on December 11 at the mouth of the Missouri River. The navigation season was extended 10 days this year to provide additional time to evacuate stored flood waters.
River ice conditions below all System projects will be closely monitored throughout the winter season. The Corps will also continue to monitor basin and river conditions, including plains and mountain snow accumulation, and will adjust System regulation based on the most up-to-date information. The mountain snowpack accumulation period is underway. The mountain snowpack normally peaks near April 15. The mountain snowpack graphics can be viewed here: http://www.nwd-mr.usace.army.mil/rcc/reports/snow.pdf.
The comment period for the 2018-2019 Annual Operating Plan (AOP) ended November 23. The final AOP, which is to be completed in late December, will be posted on the Water Management website: https://www.nwd.usace.army.mil/MRWM/Public-Meetings/.
Weekly updates on basin conditions, reservoir levels and other topics of interest can be viewed here: http://www.nwd-mr.usace.army.mil/rcc/reports/pdfs/weeklyupdate.pdf.
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 1,108 million kWh of electricity in November. Typical energy generation for November is 738 million kWh. The power plants are projected to generate 12.4 billion kWh of electricity this year, compared to the long-term average of 9.3 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.