News Releases

Below average Missouri basin runoff continues; Draft Annual Operating Plan available for comment

Published Oct. 11, 2016
The Missouri River Water Management office releases a report at the beginning of each month to the public documenting the monthly river forecast and release schedule. The Missouri River Water Management Division is part of the Northwestern Division of the U.S. Army Corps of Engineers and is located in Omaha, Nebraska.

The Missouri River Water Management office releases a report at the beginning of each month to the public documenting the monthly river forecast and release schedule. The Missouri River Water Management Division is part of the Northwestern Division of the U.S. Army Corps of Engineers and is located in Omaha, Nebraska.

OMAHA, NE – September runoff in the Missouri River Basin above Sioux City, Iowa, was 1.0 million acre feet (MAF), 91 percent of average, according to the U.S. Army Corps of Engineers (Corps). This marks the fourth consecutive month with below average runoff in the upper basin. The 2016 calendar year runoff forecast is 22.7 MAF, which is 90 percent of the historic average.

The total volume of water stored in the Mainstem Reservoir System on October 1 was 57.4 MAF, occupying 1.3 MAF of the 16.3 MAF combined flood control storage zones. “System storage declined 0.7 MAF during September. Water that was captured in the reservoirs during the spring and summer is being released during the drier months to serve navigation, irrigation and other authorized purposes. During the fall and winter, we will evacuate all water stored in the flood zones of the reservoirs and start next year’s runoff season with all flood control storage available,” said Jody Farhat, chief of the Corps’ Missouri River Basin Water Management Division.

Based on the July 1 system storage, the Corps is providing a full 8-month navigation season with full service flow support. Full service flow support is generally sufficient to provide a navigation channel that is 9 feet deep and 300 feet wide. The ending dates for flow support for the 2016 navigation season by location are indicated below: 

 

2016 Navigation Season – End of Navigation Flow Support  
Location  End Date
Sioux City, Iowa November 22
Omaha, Nebraska November 24
Nebraska City, Nebraska
November 25
Kansas City, Missouri
November 27
Mouth near St. Louis, Missouri
December 1

Based on the September 1 system storage, Gavins Point Dam winter release will be at least 17,000 cubic feet per second (cfs). This release rate is generally sufficient to meet the needs of downstream water intakes during the winter, but may be increased slightly during periods of ice formation on the lower river. Winter releases normally range between 12,000 and 17,000 cfs.

“Full service navigation support and the System winter releases of 17,000 cfs should be sufficient to evacuate all water stored in the flood zones of the reservoirs prior to the start of next year’s runoff season,” said Farhat. ”However, releases will be adjusted as needed in response to changing basin conditions throughout the fall and winter.”

Draft Annual Operating Plan Public Comment Period

The Corps held its draft Annual Operating Plan (AOP) meetings Oct 5-7 in five cities throughout the basin to present the plan for operating the system for the remainder of 2016 and in 2017. The PowerPoint presentation given at each meeting can be viewed here: http://www.nwd-mr.usace.army.mil/rcc/reports/pdfs/Fall2016AOPPresentation.pdf. Comments on the plan will be accepted through November 11. Comments can be emailed to: Missouri.Water.Management@nwd02.usace.army.mil or mailed to: 

 Missouri River Basin Water Management
1616 Capitol Avenue, Suite 365
Omaha, NE 68102-4909 

Reservoir Forecasts 

Gavins Point releases averaged 22,200 cubic feet per second (cfs) during September and will be adjusted throughout the fall to meet navigation targets in reaches with commercial barge traffic. The Gavins Point reservoir ended September at elevation 1207.2 feet and will remain near elevation 1207.5 feet during October. 

Fort Randall Dam releases averaged 20,800 cfs in September. Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point Dam, but no significant changes in releases are expected at this time. The reservoir ended September at elevation 1353.4 feet, falling 1.7 feet during the month. 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. The reservoir is expected to end October near elevation 1345.0 feet. 

Big Bend Dam releases averaged 17,300 cfs in September. Releases are expected to average 11,300 cfs this month. The reservoir will remain near its normal elevation of 1420.0 feet during October. 

Oahe Dam releases averaged 18,800 cfs during September. Releases are expected to average 11,300 cfs in October. The reservoir ended September at elevation 1609.9 feet, falling 0.6 feet during the month. The reservoir level is expected to rise slightly during October. 

Garrison Dam releases averaged 16,900 cfs during the month. Releases were reduced to the fall rate of 13,000 cfs starting September 15 and will remain near 13,000 cfs during October. Garrison reservoir ended September at elevation 1838.5 feet, falling 0.8 feet during the month. The reservoir level is expected to fall less than 1 foot during October, ending the month near elevation 1837.8 feet. 

Fort Peck Dam releases averaged 6,300 cfs during September. Releases were reduced from 8,000 cfs to 4,500 cfs starting September 13 and will remain near 4,500 cfs during October. The reservoir ended September at elevation 2233.4 feet, down 0.5 feet during the month. The reservoir level rose more than 1 foot in early October due to heavy rainfall. It is expected to remain near its current elevation of 2234.6 feet during the remainder of the month. 

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 641 million kWh of electricity in September. Typical energy generation for September is 895 million kWh. The power plants are projected to generate 7.5 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


 

Pool Elevation

(feet above mean sea level)

Water in Storage

(1,000 acre-feet)

 

On September 30

Change in September

On September 30

% of 1967-2015 Average

Change in September

Fort Peck

2233.4

-0.5

14,659

100

-101

Garrison

1838.5

-0.8

18,040

99

-273

Oahe

1609.9

-0.6

19,428

112

-197

Big Bend

1420.3

+0.0

1,650

97

+3

Fort Randall

1353.4

-1.7

3,276

98

-145

Gavins Point

1207.2

+0.6

355

85

+14

 

 

Total

57,408

103

-699

WATER RELEASES AND ENERGY GENERATION FOR SEPTEMBER

 

Average Release

(1,000 cfs)

Releases

(1,000 acre-feet)

Generation

(Million kWh)

Fort Peck

6.3

374

62

Garrison

16.9

1,008

155

Oahe

18.8

1,118

170

Big Bend

17.3

1,027

61

Fort Randall

20.8

1,236

133

Gavins Point

22.2

1,320

59

 

 

Total

641



Contact
Amy Gaskill
503-808-3710
amy.j.gaskill@usace.army.mil

Release no. 20161011-001