Gavins Point Dam releases to be reduced in late November

Press release

Public meetings were held in seven locations along the Missouri River during the week of Oct. 25, including one at Steinhart Lodge in Nebraska City.

The U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division held these meetings to present current hydrologic conditions and planned operation of the Missouri River mainstem reservoir system for the remainder of 2021.

Public meetings are held each fall and spring to update the region on current conditions and planned operations. The meetings included draft plans for operating the system during 2022.

“We will continue to make releases from Gavins Point Dam to provide flow support at an intermediate service level, 1,500 cubic feet per second (cfs) less than full service, through the end of the navigation flow support season,” said John Remus, chief of the USACE, Missouri River Water Management Division.

Gavins Point releases are currently 28,000 cfs. Release reductions to the winter rate of 12,000 cfs are scheduled to begin around Nov. 22. Releases will be gradually reduced by 3,000 cfs each day until reaching a rate of 14,000 cfs.

Releases will then be paused before stepping down 1,000 cfs every five days to the winter release. The navigation flow support season normally ends on Dec. 1 at the mouth of the Missouri River.

Fort Randall releases will be stepped down in a similar manner, approximately one day prior to the Gavins Point reductions.

 Updated reservoir studies indicate that the service level for navigation support for the first half of the 2022 navigation season will likely be at minimum service levels.

Despite several significant rainfall events during October in various parts of the upper Basin, runoff was below normal. Approximately 82 percent of the Missouri River basin is experiencing some form of abnormally dry conditions or drought according to the National Drought Mitigation Center.

The seasonal drought outlook, which extends through the end of January, shows drought conditions persisting across most of the upper Basin.

The 2021 calendar year runoff forecast for the upper Basin, updated on Nov. 1, is 15.0 million acre-feet (MAF), 58 percent of average. If realized, this runoff would be the 10th lowest runoff in 123 years of record-keeping.

Reservoir studies indicate System storage will be well below normal at the start of the 2022 runoff season. System storage is forecast to be about 48 MAF, more than 8 MAF into the System’s conservation zone. This means that the Fort Peck, Garrison, and Oahe reservoirs are expected to be 10 to 12 feet below the bases of their respective flood control zones on March 1.

Navigation

As previously announced, the July 1 System storage check indicated a full-length flow support season but at an intermediate flow support level, 1,500 cfs below full-service, for the second half of the 2021 navigation season.

Full-service flow support is designed to work in tandem with the Missouri River Bank Stabilization and Navigation Project to provide a 9-foot deep by 300-foot wide navigation channel from Sioux City, Iowa to the mouth of the river near St. Louis, Missouri. Flow support is expected to end on the dates indicated below:

    Location                                             End Date

    Sioux City, Iowa                                  Nov. 22

    Omaha                                               Nov. 24

    Nebraska City                                     Nov. 25

    Kansas City, Mo.                                 Nov. 27

    Mouth near St. Louis, Mo.                   Dec. 1

Fall Public Meetings

A recording of the Bismarck, North Dakota meeting held on Oct. 25 is available online at the following address:

https://www.nwd.usace.army.mil/MRWM/Public-Meetings/

        Average releases past month – 30,900 cfs

        Current release rate – 28,000 cfs (as of Nov. 1)

        Forecast release rate – 23,900 cfs (November)

        End-of-October reservoir level – 1208.1 feet

        Forecast end-of-November reservoir level – 1207.5 feet

        Notes: Releases will be adjusted as necessary to meet all downstream navigation targets until the end of the navigation flow support season. The Gavins Point release will be reduced to 14,000 cfs beginning around Nov. 22 at a rate of 3,000 cfs per day, then at a rate of 1,000 cfs every 5 days to the winter release rate of 12,000 cfs.

    Fort Randall Dam

        Average releases past month – 29,100 cfs

        End-of-October reservoir level – 1346.2 feet

        Forecast end-of-November reservoir level – 1337.1 feet

        Notes: Releases will be stepped down near the end of November, approximately one day prior to the Gavins Point reductions as necessary to maintain the desired reservoir elevation at Gavins Point. The Fort Randall pool is normally drawn down to 1337.5 feet in the fall to provide space for winter hydropower generation at Oahe and Big Bend. The annual drawdown will continue in November.

   Big Bend Dam

        Average releases past month – 21,500 cfs

        Forecast average release rate – 14,800 cfs

        Forecast reservoir level – 1420.7 feet

    Oahe Dam

        Average releases past month – 22,000 cfs

        Forecast average release rate – 14,700 cfs

        End-of-October reservoir level – 1596.9 feet

        Forecast end-of-November reservoir level – 1596.4 feet

    Garrison Dam

        Average releases past month – 13,500 cfs

        Current release rate – 13,500 cfs

        Forecast average release rate – 13,000 cfs

        End-of-October reservoir level – 1830.4 feet

        Forecast end-of-November reservoir level – 1829.6 feet

    Fort Peck Dam

        Average releases past month – 5,400 cfs

        Current release rate – 5,000 cfs

        Forecast average release rate – 5,000 cfs

        End-of-October reservoir level – 2227.1 feet

        Forecast end-of-November reservoir level – 2226.4 feet

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.

Hydropower

The six mainstem power plants generated 708 million kWh of electricity in October. Typical energy generation for October is 819 million kWh. The power plants are projected to generate 8.6 billion kWh of electricity this year, compared to the long-term average of 9.5 billion kWh.

To view the detailed three-week release forecast for the mainstem dams, go to http://go.usa.gov/xVgWr.

The Army Corps of Engineers hosted a series of fall public meetings along the Missouri River in late October, including one in Nebraska City at Steinhart Lodge.