OMAHA, NE – Runoff in the Missouri River Basin above Sioux City, Iowa, was 2.4 million acre feet (MAF) during February, 219 percent of average. “Warm temperatures melted much of the plains snowpack that had accumulated throughout the winter in the upper Missouri River basin resulting in above average runoff during February,” said Jody Farhat, chief of the Corps of Engineers’ (Corps) Missouri River Basin Water Management Division. Only small areas in central North Dakota have significant plains snowpack remaining. Areas of eastern Montana and central Wyoming have less than an inch of liquid content in their remaining snowpack, and little or no snow remains elsewhere in the Dakotas. “Runoff from plains snowmelt that would normally occur in March and April started early this year and some has already entered the reservoir system,” said Farhat. “Additionally, warm temperatures released water that had been locked up in river ice, contributing to higher than average February runoff.”
The total volume of water stored in the Missouri River Mainstem Reservoir System is currently 57.2 MAF, occupying 1.1 MAF of the 16.3 MAF flood control zone. “The 2017 runoff season started in early February with all system flood control storage available,” said Farhat. “Over 93 percent of the flood storage is currently available to capture runoff from the remaining plains snowpack, spring rainfall and runoff from the mountain snowmelt.” Weekly updates on plains and mountain snowpack 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 2017 runoff forecast in the Missouri River Basin above Sioux City, Iowa, is 29.1 MAF, 115 percent of normal. The updated forecast is approximately 2.9 MAF more than last month due to the continued accumulation of mountain snowpack. As of March 6, the mountain snowpack was 98 percent of average in the reach above Fort Peck and 131 percent of average in the reach from Fort Peck to Garrison. Normally the mountain snowpack peaks in mid-April. View the mountain snowpack graphic here: http://www.nwd-mr.usace.army.mil/rcc/reports/snow.pdf.
Beginning in mid-March, releases from Gavins Point Dam will be adjusted to provide flow support for navigation. Flow support for Missouri River navigation be at full service levels for the first half of the 2017 season. Full service navigation flow support is generally sufficient to provide a 9-feet-deep by 300-feet-wide channel. Flow support for the second half of the navigation season and the season length will be determined based on the July 1 system storage check in accordance with guidelines in the Master Manual. The navigation season opening dates are as follows:
- Sioux City, IA : March 23
- Omaha, NE : March 25
- Nebraska City, NE : March 26
- Kansas City, MO : March 28
- Mouth near St. Louis, MO : April 1
The Corps will continue to monitor basin conditions including plains snowmelt, mountain snow accumulation, and spring rainfall and will adjust reservoir operations accordingly. If changed conditions result in a significant increase in flood risk, the Corps will appreciably increase its communication and outreach efforts to convey that information to basin stakeholders.
Monthly Water Management Conference Calls.
The Corps will host its third monthly conference call of 2017 on Tuesday, March 7, to inform basin stakeholders on current weather and runoff forecasts and the planned operation of the reservoir system in the coming months. Presentation materials will be available via webinar. The call is intended for Congressional delegations; Tribes; state, county and local government officials; and the media. These calls are recorded and placed on the Defense Video and Imagery Distribution System at www.dvidshub.net/unit/usace-nwd and on iTunes search “Missouri River Basin”.
Spring Public Meetings
Five public meetings will be conducted throughout the basin April 11-13. The purpose of these meetings is to update the region on current hydrologic conditions and the planned operation of the mainstem reservoir system during the coming months. Meeting times and locations are listed below.
- Tuesday, April 11 – Smithville, MO
- Start time: 11 a.m. (CDT)
- Jerry Litton Visitor Center
- 16311 DD Hwy
- Tuesday, April 11 – Council Bluffs, IA
- Start time: 5 p.m. (CDT)
- Western Historic Trails Center
- 3434 Richard Downing Ave.
- Wednesday, April 12 – Fort Peck, MT
- Start time: 11 a.m. (MDT)
- Fort Peck State Fish Hatchery
- 277 Montana Highway 117
- Wednesday, April 12 – Bismarck, ND
- Start time: 6 p.m. (CDT)
- Bismarck State College, National Energy Center of Excellence (NECE), Bldg. 15, Rm 431
- 1200 Schafer Street
- Thursday, April 13 – Pierre, SD
- Start time: 10 a.m. (CDT)
- Ramkota Hotel
- 920 W Sioux Ave.
Reservoir Forecasts
Gavins Point Dam releases averaged 17,000 cubic feet per second (cfs) during February and will remain near that level through mid- March. Releases will be increased 3,000 cfs per day beginning on or about March 19 until they reach navigation support levels, which are estimated at 25,000 to 28,000 cfs this spring. The Gavins Point reservoir ended February at elevation 1206.5 feet and will remain near 1206.0 feet during March.
Fort Randall Dam releases averaged 11,600 cfs in February. Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point Dam. The reservoir ended February at elevation 1353.4 feet, rising 7.4 feet during the month. The reservoir will continue to gradually rise, ending March near 1355.2 feet. The reservoir is normally refilled during the winter to provide extra winter hydropower generation at Oahe and Big Bend Dams.
Big Bend Dam releases averaged 16,400 cfs in February. Releases are expected to average 15,400 cfs this month. The reservoir will remain near its normal elevation of 1420.0 feet during March.
Oahe Dam releases averaged 16,500 cfs during February. Releases are expected to average 14,700 cfs in March. The reservoir ended February at elevation 1608.0 feet, rising 0.1 feet during the month. The reservoir level is expected to continue rising during March due to the melt of the remainder of the plains snowpack and spring rains, ending the month near elevation 1609.6 feet.
Garrison Dam releases averaged 13,200 cfs during the month of February. Releases were increased from 13,000 cfs to 14,000 cfs on March 5. Releases will remain at that rate through March. Garrison reservoir ended February at elevation 1838.3 feet, rising 0.8 feet during the month. The reservoir level is expected to rise during March, ending the month near elevation 1839.5 feet also due to plains snowmelt and spring rains.
Fort Peck Dam releases averaged 5,000 cfs during February. Releases are forecasted to average 4,500 cfs during March. The reservoir ended February at elevation 2234.9 feet, rising 1.0 feet during the month. The reservoir is expected to rise during March as a result of plains snowmelt and spring rains and is forecast to end the month near elevation 2236.3 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 461 million kWh of electricity in February. Typical energy generation for February is 621 million kWh. The power plants are projected to generate 10.1 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
|
Average Release
(1,000 cfs)
|
Releases
(1,000 acre-feet)
|
Generation
(Million kWh)
|
Fort Peck
|
5.0
|
276
|
43
|
Garrison
|
13.2
|
732
|
112
|
Oahe
|
16.5
|
914
|
138
|
Big Bend
|
16.4
|
911
|
56
|
Fort Randall
|
11.6
|
646
|
68
|
Gavins Point
|
17.0
|
945
|
44
|
|
|
Total
|
461
|
WATER RELEASES AND ENERGY GENERATION FOR FEBRUARY
|
Pool Elevation
(feet above mean sea level)
|
Water in Storage
(1,000 acre-feet)
|
|
On February 28
|
Change in February
|
On February 28
|
% of 1967-2016 Average
|
Change in February
|
Fort Peck
|
2234.9
|
+1.0
|
14,983
|
108
|
+219
|
Garrison
|
1838.3
|
+0.8
|
17,997
|
109
|
+237
|
Oahe
|
1608.0
|
+0.1
|
18,816
|
110
|
+16
|
Big Bend
|
1420.7
|
-0.1
|
1,675
|
98
|
-2
|
Fort Randall
|
1353.4
|
+7.4
|
3,272
|
97
|
+564
|
Gavins Point
|
1206.5
|
-1.3
|
338
|
91
|
-32
|
|
|
Total
|
57,081
|
108
|
+1,002
|