OMAHA, NE – Gavins Point releases were reduced from 31,000 cubic feet per second (cfs) to 26,000 cfs to lessen downstream flooding. Heavy rainfall in the lower Missouri Basin resulted in increased tributary flows below the Missouri River Mainstem Reservoir System (System). Gavins Point releases will be increased back to 31,000 cfs as downstream flows recede. Fort Randall releases were reduced to as low as 19,500 cfs to limit the rise of the Gavins Point reservoir level, which was impacted by high runoff from localized rain and reduced releases.
Fall public meetings will be held in five cities throughout the basin during the third week of October to describe the results of the regulation of the System in 2017 and present the planned operation for the coming year in accordance with the draft 2017-2018 Annual Operating Plan..
The total volume of water stored in the Missouri River mainstem reservoirs is currently 59.2 million acre-feet (MAF), occupying 3.1 MAF of the 16.3 MAF combined flood control storage zones according to the U.S. Army Corps of Engineers (Corps). “System storage peaked on July 9 at 61.8 MAF and is declining, lowering 1.0 MAF in September. 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 Kevin Grode, team leader in the Corps’ Missouri River Basin Water Management office.
Drought conditions persist in the upper Missouri River basin as runoff into Fort Peck and Garrison was below average. “Runoff in the lower reaches, from Oahe to Sioux City, was near or above average due to above normal precipitation in those reaches,” said Grode. September runoff above Sioux City was 1.0 MAF, 91 percent of average. The 2017 runoff forecast in the Missouri River Basin above Sioux City, Iowa, is 28.5 MAF, 112 percent of average.
Garrison releases were reduced from 20,000 cfs to 17,500 cfs on October 6. Releases will be reduced to 15,000 cfs on October 11. Missouri River stages in the Bismarck area will decline about 1.5 feet due to the release reductions 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 Grode. Based on the September 1 System storage check, the Gavins Point winter release rate will be at least 17,000 cfs.
Weekly updates on basin conditions, reservoir levels and other topics of interest can be viewed here: http://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 System based on the most up-to-date information.
Draft Annual Operating Plan and Fall Public Meetings
In mid-September, the Corps posted the draft 2017-2018 AOP for the System on its website at http://www.nwd-mr.usace.army.mil/rcc/aop.html. 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 Fish 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 September. Releases are expected to average near 31,000 cfs during October but will be adjusted as necessary based on downstream river conditions. The Gavins Point reservoir ended September at elevation 1207.5 feet and will be near 1207.5 feet during the fall and winter months.
Fort Randall Dam releases averaged 30,000 cfs in September. Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point. The reservoir ended September at elevation 1353.2 feet and is expected to decline during October ending the month near 1345.0 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 22,600 cfs in September. Releases are expected to average 19,100 cfs this month. The reservoir will remain near its normal elevation of 1420.0 feet during October.
Oahe Dam releases averaged 25,100 cfs during September. Releases are expected to average 19,000 cfs in October. The reservoir ended September at elevation 1610.3 feet, falling 0.4 foot during the month. The reservoir level is expected to decline approximately another 0.5 foot during October.
Garrison Dam releases averaged 23,500 cfs for the month. Releases will be reduced by 3,000 cfs per day beginning on October 4 to the fall release of 15,000 cfs. Garrison reservoir ended September at elevation 1841.5 feet, declining 1.8 feet during the month. The reservoir level is expected to fall about 0.4 foot during October, ending the month near elevation 1841.1 feet.
Fort Peck Dam releases averaged 7,500 cfs during September. Releases were reduced to 6,000 cfs in mid-October and will remain at 6,000 cfs during the fall. The reservoir ended September at elevation 2236.7 feet, declining 0.7 foot during the month. The reservoir is expected to fall approximately 0.5 foot during October ending the month near elevation 2236.2 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 855 million kWh of electricity in September. Typical energy generation for September is 889 million kWh. The power plants are projected to generate 9.5 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 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 1967-2016 Average
|
Change in September
|
|
Fort Peck
|
2236.7
|
-0.7
|
15,377
|
105
|
-152
|
|
Garrison
|
1841.5
|
-1.8
|
19,029
|
104
|
-581
|
|
Oahe
|
1610.3
|
-0.4
|
19,568
|
113
|
-129
|
|
Big Bend
|
1420.5
|
+0.4
|
1,660
|
97
|
+24
|
|
Fort Randall
|
1353.2
|
-3.9
|
3,257
|
97
|
-333
|
|
Gavins Point
|
1207.5
|
+0.6
|
362
|
87
|
+14
|
|
|
|
Total
|
59,253
|
106
|
-1,157
|
WATER RELEASES AND ENERGY GENERATION FOR SEPTEMBER
|
|
Average Release in 1,000 cfs
|
Releases in 1,000 acre-feet
|
Generation in Million kWh
|
|
Fort Peck
|
7.5
|
444
|
72
|
|
Garrison
|
23.5
|
1,401
|
220
|
|
Oahe
|
25.1
|
1,492
|
232
|
|
Big Bend
|
22.6
|
1,344
|
82
|
|
Fort Randall
|
30.0
|
1,786
|
185
|
|
Gavins Point
|
31.0
|
1,845
|
64
|
|
|
|
Total
|
855
|