OMAHA, Neb. -- Flow support for the 2022 Missouri River navigation season ended Nov. 21 as releases were reduced toward winter rates at Gavins Point Dam.
“Releases from Gavins Point Dam are being reduced to the winter release of 12,000 cubic feet per second,” said John Remus, Chief of the Missouri River Basin Water Management Division.
“Releases from Gavins Point are currently 13,000 cfs and we will reduce releases to 12,000 by Dec. 11. We will closely monitor river conditions, and releases will be adjusted this winter to the extent practical to lessen the impacts of river ice formation on stages in the lower river.”
As the colder, winter temperatures enter the basin, the U.S. Army Corps of Engineers will closely monitor Missouri River ice conditions between the System reservoirs and downstream of Gavins Point Dam for potential ice jams that could impact river stages and water intakes.
Runoff in the upper Missouri River Basin above Sioux City, Iowa, was 540,000 acre-feet during November, 51% of average. The 2022 calendar year runoff forecast is 19.0 million acre-feet, 74% of average. Average annual runoff is 25.7 MAF.
The total volume of water stored in the Missouri River mainstem reservoirs is currently 46.0 MAF, which is 10.1 MAF below the base of the System flood control storage zone. System storage is forecast to begin the 2023 runoff season at 45.8 MAF, which is 10.3 MAF below the base of the system flood control zone.
Releases from Fort Peck Dam were stepped up to 6,000 cfs on Dec. 5 and are scheduled to be held at that rate through December. Releases from Garrison Dam were increased to 16,000 cfs on Dec. 2. Releases from Garrison are typically set near 16,000 cfs prior to the river freeze-in to reduce the risk of ice-induced flooding in the Bismarck area. Releases will be gradually increased to 23,500 cfs later in the winter, as conditions permit, following the formation of a stable river ice cover. Releases at Fort Peck and Garrison dams are being adjusted as a storage-balancing measure in the upper reservoirs.
Mountain and Plains Snowpack
Mountain snowpack in the upper Missouri River Basin is accumulating at slightly-above average levels. About 25% of the mountain snowpack typically accumulates by Dec. 1, and normally peaks near April 17. While the mountain snowpack is currently above average, it is too early in the season to make a projection of the final 2023 mountain snowpack. Additionally, plains snowpack in the upper Missouri River Basin is sparse.
2022-2023 Annual Operating Plan
The comment period for the 2022-2023 Annual Operating Plan ended Nov. 24. The final AOP is scheduled for publication by the end of 2022 and will be posted online with other Missouri Basin Water Management Reports.
Monthly Water Management Conference Calls
Monthly water management calls will resume in Jan. 2023.
Reservoir Forecasts
- Gavins Point Dam
- Average releases past month – 26,600 cfs
- Current release rate – 13,000 cfs
- Forecast release rate – 12,000 cfs
- End-of-November reservoir level – 1207.3 feet
- Forecast end-of-December reservoir level – 1207.5 feet
- Notes: Releases were reduced to 14,000 cfs on Dec. 1. The winter release rate will be 12,000 cfs based on the Sept. 1 System storage check and may be adjusted to lessen the impacts of winter ice formation.
- Fort Randall Dam
- Average releases past month – 24,000 cfs
- End-of-November reservoir level – 1337.7 feet
- Forecast end-of-December reservoir level – 1339.3 feet
- Notes: Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point. 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 reservoir will refill to the base of the flood control pool from December to February.
- Big Bend Dam
- Average releases past month – 20,000 cfs
- Forecast average release rate – 12,700 cfs
- Forecast reservoir level – 1420.7 feet
- Oahe Dam
- Average releases past month – 20,200 cfs
- Forecast average release rate – 12,700 cfs
- End-of-November reservoir level – 1589.1 feet
- Forecast end-of-December reservoir level – 1590.2 feet
- Garrison Dam
- Average releases past month – 15,100 cfs
- Current release rate – 16,000 cfs
- Forecast average release rate – 18,500 cfs
- End-of-November reservoir level – 1831.9 feet
- Forecast end-of-December reservoir level – 1829.8 feet
- Notes – Releases were increased to 16,000 cfs on Dec. 2, prior to the river freeze-in at Bismarck, North Dakota. Once an ice cover is established, probably in mid-December, releases will be gradually increased.
- Fort Peck Dam
- Average releases past month – 4,500 cfs
- Current release rate – 6,000 cfs
- Forecast average release rate – 6,000 cfs
- End-of-November reservoir level – 2219.6 feet
- Forecast end-of-December reservoir level – 2218.9 feet
- Notes: Releases were increased to 6,000 cfs on Dec. 5.
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 612 million kWh of electricity in November. Typical energy generation for November is 745 million kWh. The power plants are projected to generate 7.5 billion kWh of electricity this year, compared to the long-term average of 9.4 billion kWh.
To view the detailed three-week release forecast for the mainstem dams, go to http://go.usa.gov/xVgWr.
MISSOURI RIVER MAINSTEM RESERVOIR DATA
|
|
Pool Elevation
(feet above mean sea level)
|
Water in Storage
(1,000 acre-feet)
|
|
On November 30
|
Change in November
|
On November 30
|
% of 1967-2021 Average
|
Change in November
|
Fort Peck
|
2219.6
|
-0.3
|
12,002
|
83
|
-55
|
Garrison
|
1831.9
|
-1.4
|
16,125
|
90
|
-383
|
Oahe
|
1589.1
|
-1.8
|
13,644
|
77
|
-409
|
Big Bend
|
1420.6
|
-0.3
|
1,676
|
98
|
-7
|
Fort Randall
|
1337.7
|
-5.4
|
2,201
|
66
|
-315
|
Gavins Point
|
1207.3
|
-0.7
|
359
|
92
|
-16
|
|
|
Total
|
46,007
|
83
|
-1,185
|
WATER RELEASES AND ENERGY GENERATION FOR NOVEMBER
|
|
Average Release in 1,000 cfs
|
Releases in 1,000 acre-feet
|
Generation in Million kWh
|
Fort Peck
|
4.5
|
266
|
40
|
Garrison
|
15.1
|
901
|
132
|
Oahe
|
20.2
|
1,202
|
166
|
Big Bend
|
20.0
|
1,192
|
68
|
Fort Randall
|
24.0
|
1,429
|
133
|
Gavins Point
|
26.6
|
1,584
|
73
|
|
|
Total
|
612
|