Based on the September 1 System storage check, the U.S. Army Corps of Engineers announced that the Gavins Point winter release rate will be at least 17,000 cfs.

While drought conditions persist in the upper Missouri River basin, August runoff above Sioux City was 1.8 million acre-feet (MAF), 129 percent of average. “With the exception of the Fort Peck reach, August runoff into the Missouri River mainstem reservoirs was above average due to above average precipitation across the Dakotas.” said John Remus, chief of the Corps’ Missouri River Basin Water Management Division. The 2017 runoff forecast in the Missouri River Basin above Sioux City, Iowa, is 28.7 MAF, 113 percent of average. 

The total volume of water stored in the Mainstem Reservoir System is currently 60.2 MAF, occupying 4.1 MAF of the 16.3 MAF combined flood control storage zones. “System storage peaked on July 9 at 61.8 MAF and is gradually declining. The water currently stored in the annual flood control zone will be released during the remainder of the year to serve navigation, water supply and other downstream purposes and will be completely evacuated prior to the start of next year’s runoff season,” said Remus.
Garrison releases will be reduced from the current release rate of 30,000 cubic feet per second (cfs) to the fall rate of 20,000 cfs beginning September 10. Missouri River stages in the Bismarck area will decline about 3.0 feet due to the release reduction from Garrison.

As previously announced, the Corps will be providing flows to support full-service navigation as well as a full, eight-month navigation season. Full-service flow support is generally sufficient to provide a navigation channel that is 9 feet deep and 300 feet wide. “Gavins Point releases will be adjusted as necessary to meet full-service navigation targets in reaches with commercial navigation,” added Remus. 

Weekly updates on basin conditions, reservoir levels and other topics of interest can be viewed here: https://www.nwd-mr.usace.army.mil/rcc/reports/pdfs/weeklyupdate.pdf.

The Corps will continue to monitor basin conditions and will adjust the regulation of the reservoir system based on the most up-to-date information.

Draft Annual Operating Plan and Fall Public Meetings

In mid-September, the Corps will post the 2017-2018 Draft Annual Operating Plan (AOP) for the Missouri River Mainstem Reservoir System on its website at https://www.nwd.usace.army.mil/MRWM/Public-Meetings/. Fall public meetings will be held in five cities throughout the basin during the third week of October to discuss the draft report and take comments on the proposed AOP. The comment period on the draft AOP will close on November 17. The public meetings will include a presentation from the Corps regarding 2017 operations and plans for regulating the reservoir system in 2018, followed by a question and answer session. 

The public meetings will be conducted at the times and locations listed below.

Tuesday, Oct. 17 – Smithville, MO

• Start time: 11 a.m. (CDT)
• Jerry Litton Visitor Center
• 16311 DD Hwy

Tuesday, Oct. 17 – Nebraska City, NE

• Start time: 4 p.m. (CDT)
• Lewis and Clark Interpretive Center
• 100 Valmont Drive

Wednesday, Oct. 18 – Fort Peck, MT

• Start time: 11 a.m. (MDT)
• Fort Peck State Hatchery
• 277 Montana Highway 117

Wednesday, Oct. 18 – Bismarck, ND

• Start time: 6 p.m. (CDT)
• Bismarck State College, National Energy Center of Excellence (NECE), Bldg. 15, Rm 335
• 1200 Schafer Street

Thursday, Oct. 19 – Pierre, SD

• Start time: 10 a.m. (CDT)
• Ramkota Hotel, Lake Rm
• 920 W Sioux Avenue

Reservoir Forecasts

Gavins Point Dam releases averaged 31,000 cfs during August. Releases are expected to be increased to 32,000 cfs in mid-September and will be adjusted as necessary based on downstream river conditions. The Gavins Point reservoir ended August at elevation 1206.9 feet and will continue to increase through September, ending the month near 1207.5 feet.

Fort Randall Dam releases averaged 29,400 cfs in August. Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point. The reservoir ended August at elevation 1357.1 feet and is expected to decline during September ending the month near 1353.5 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. The annual drawdown will continue in October and November.

Big Bend Dam releases averaged 27,700 cfs in August. Releases are expected to average 24,400 cfs this month. The reservoir will remain near its normal elevation of 1420.0 feet during September.

Oahe Dam releases averaged 29,700 cfs during August. Releases are expected to average 24,700 cfs in September. The reservoir ended August at elevation 1610.7 feet, rising 0.6 feet during the month. The reservoir level is expected to remain nearly steady during September.

Garrison Dam releases averaged 33,000 cfs for the month. Releases were reduced to 30,000 cfs in early September and will be reduced to 20,000 cfs beginning on September 10. Garrison reservoir ended August at elevation 1843.3 feet, declining 2.8 feet during the month. The reservoir level is expected to fall about 1.3 feet during September, ending the month near elevation 1842.0 feet.

Fort Peck Dam releases averaged 10,100 cfs during August. Releases were reduced to 9,000 cfs in early September and will be decreased to 6,000 cfs on September 16. The reservoir ended August at elevation 2237.4 feet, declining 1.6 feet during the month. The reservoir is expected to fall approximately 1 foot during September ending the month near elevation 2236.5 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.

The six mainstem power plants generated 1,061 million kWh of electricity in August. Typical energy generation for August is 994 million kWh. The power plants are projected to generate 9.7 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 https://www.nwd-mr.usace.army.mil/rcc/reports/twregfcast.pdf.

WATER RELEASES AND ENERGY GENERATION FOR AUGUST

MISSOURI RIVER MAINSTEM RESERVOIR DATA