News Releases

Above average Missouri Basin runoff in October, reduction to winter release rates to occur in late November

Published Nov. 4, 2016
OMAHA, Neb. – Runoff in the Missouri River Basin above Sioux City, Iowa, was 1.9 million acre feet (MAF) during October, 155 percent of average, according to the U.S. Army Corps of Engineers (Corps). The 2016 calendar year runoff forecast is 24.1 MAF, 95 percent of average. Average annual runoff is 25.3 MAF.

The total volume of water stored in the Mainstem Reservoir System on November 1 was 57.2 MAF, occupying 1.1 MAF of the 16.3 MAF combined flood control storage zones. “System storage declined less than anticipated during October, only 0.2 MAF, as a result of heavy rainfall over north central Montana and northwestern Wyoming. During the remainder of fall and winter, we will complete the evacuation of the flood zones of the reservoirs to ensure we start next year’s runoff season with the full flood control capacity of the system 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. Flow support for the 2016 Missouri River navigation season will end on the dates indicated below:
2016 Navigation Season – End of Navigation Flow Support

Location  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 releases will be at least 17,000 cubic feet per second (cfs). “Releases from Gavins Point will be stepped down approximately 3,000 cfs each day beginning in late November until they reach the winter release rate,” said Farhat. “Higher than expected inflow during October may allow us to provide slightly higher winter releases this year. Higher releases would provide additional hydropower generation during the winter, one of the peak power demand periods. It would also benefit municipal and industrial water intakes below Gavins Point dam, which can be impacted by low water levels during periods of ice formation.” Gavins Point winter releases normally range between 12,000 and 17,000 cfs. Basin conditions will continue to be monitored and releases adjusted accordingly.

Draft Annual Operating Plan Public Comment Period Closes November 11

The draft 2016-2017 Annual Operating Plan was released in mid-September and public meetings were held throughout the basin in early October. 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 22,000 cfs during October and will be increased to 25,000 cfs in early November. They are expected to remain near that level until they are stepped down to the winter release rate in late November. The Gavins Point reservoir ended October at elevation 1208.4 feet and will be lowered to near elevation 1207.5 feet during November.
Fort Randall Dam releases averaged 20,500 cfs in October. Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point Dam. The reservoir ended October at elevation 1344.7 feet, falling 8.7 feet during the month.

The reservoir is expected to end November near 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 11,000 cfs in October. Releases are expected to average 14,400 cfs this month. The reservoir will remain near its normal elevation of 1420.0 feet during November.

Oahe Dam releases averaged 12,700 cfs during October. Releases are expected to average 13,900 cfs in November. The reservoir ended October at elevation 1609.6 feet, falling 0.3 feet during the month. The reservoir level is expected to be near elevation 1609.2 by the end of November.

Garrison Dam releases averaged 13,000 cfs during the month. Releases will remain near 13,000 cfs during November. Garrison reservoir ended October at elevation 1839.0 feet, rising 0.5 feet during the month. The reservoir level is expected to rise slightly during November, ending the month near elevation 1839.6 feet.

Fort Peck Dam releases averaged 4,600 cfs during October and will remain near 4,500 cfs during November. The reservoir ended October at elevation 2234.8 feet, up 1.4 feet during the month. The reservoir is expected to rise slightly during November, ending the month near elevation 2235.5 feet.

The forecasted 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 518 million kWh of electricity in October. Typical energy generation for October is 811 million kWh. The power plants are projected to generate 7.6 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

 

Average Release

(1,000 cfs)

Releases

(1,000 acre-feet)

Generation

(Million kWh)

Fort Peck

4.6

286

47

Garrison

13.0

799

123

Oahe

12.7

779

115

Big Bend

11.0

677

42

Fort Randall

20.5

1,258

129

Gavins Point

22.0

1,355

63

 

 

Total

518

 

 

 

Pool Elevation

(feet above mean sea level)

Water in Storage

(1,000 acre-feet)

 

On October 31

Change in September

On October 31

% of 1967-2015 Average

Change in October

Fort Peck

2234.8

+1.4

14,954

103

+295

Garrison

1839.0

+0.5

18,217

100

+177

Oahe

1609.6

-0.3

19,323

114

-105

Big Bend

1420.8

+0.5

1,680

98

+30

Fort Randall

1344.7

-8.7

2,621

95

-655

Gavins Point

1208.4

+1.2

385

91

+30

 

 

Total

57,180

105

-288


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

Release no. 20161104-001