The 2018 runoff forecast in the Missouri River Basin above Sioux City, Iowa, is 29.0 million acre feet (MAF), 115 percent of normal according to the U.S. Army Corps of Engineers (Corps) Missouri River Water Management Division. “The updated forecast increased from last month due to the continued accumulation of mountain and plains snowpack in the upper basin,” said John Remus, Chief of the Missouri River Basin Water Management Division. “Based on the current plains and mountain snowpack, runoff into the Fort Peck and Garrison reservoirs is expected to be above average from March through July,” said Remus. 

As of March 1, the mountain snowpack was 129 percent of average in the reach above Fort Peck and 134 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: https://www.nwd-mr.usace.army.mil/rcc/reports/snow.pdf.

Plains snowpack is currently heaviest in central and eastern Montana. The snowpack’s liquid content, or snow water equivalency (SWE), ranges from 2 to 8 inches. As of March 1, the rest of the upper basin has much less plains snowpack, ranging up to 2 inches of SWE. The Corps is cooperating with other agencies to acquire plains snow measurements in the upper basin.

All 2017 stored flood waters were evacuated from the Missouri River mainstem reservoir system (System) as of January 15, when the total volume stored in the System reached 56.1 MAF. System storage is currently 56.4 MAF, occupying 0.3 MAF of the 16.3 MAF flood control zone. “Nearly all of the System’s flood storage is currently available to capture runoff from the remaining plains snowpack, spring rainfall and runoff from the mountain snowmelt,” said Remus.” 

Winter releases from Gavins Point were increased from 18,000 cubic feet per second (cfs) to 20,000 cfs in early March. Gavins Point releases will be adjusted, if needed, in response to basin conditions. 

Beginning in mid-March, releases from Gavins Point Dam will be adjusted to provide flow support for Missouri River navigation. Flow support for Missouri River navigation will be at full service levels for the first half of the 2018 season. 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, as well as the navigation season length, will be based on the actual July 1 System storage. 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

Weekly updates on basin conditions, reservoir levels and other topics of interest can be viewed here: https://www.nwd-mr.usace.army.mil/rcc/reports/pdfs/weeklyupdate.pdf.

The Corps will continue to monitor basin conditions, river ice conditions, and plains and mountain snow accumulation, and will adjust the regulation of the System based on the most up-to-date information.

Monthly Water Management Conference Calls

The Corps will host its third monthly conference call of 2018 on Tuesday, March 6, to inform basin stakeholders on current weather and runoff forecasts and the planned operation of the System. Presentation materials will be posted on the MRBWM website at: https://www.nwd-mr.usace.army.mil/rcc/. The call is intended for Congressional delegations; Tribes; state, county and local government officials; and the media. It will be recorded in its entirety and made available to the public on the Defense Video and Imagery Distribution System at www.dvidshub.net/unit/usace-nwd.

Spring Public Meetings

Five public meetings will be conducted throughout the basin April 17-19. 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 17 – Smithville, MO
Start time: 10 a.m. (CDT)
Jerry Litton Visitor Center
16311 DD Hwy

Tuesday, April 17 – Omaha, NE
Start time: 4 p.m. (CDT)
Nebraska Regulatory Office
8901 South 154th St.

Wednesday, April 18 – Pierre, SD
Start time: 10 a.m. (CDT)
Ramkota Hotel
920 W Sioux Ave.

Wednesday, April 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, April 19 – Fort Peck, MT
Start time: 10 a.m. (MDT)
Fort Peck State Fish Hatchery
277 Montana Highway 117

Reservoir Forecasts

Gavins Point Dam releases averaged 18,000 cfs during February. Releases were increased to 20,000 cfs on March 4. 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 26,000 to 28,000 cfs. The Gavins Point reservoir ended February at elevation 1206.8 feet and will remain near 1206.0 feet during March.

Fort Randall Dam releases averaged 15,700 cfs in February. Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point. The reservoir ended February at elevation 1349.5 feet, rising 1.7 feet during the month. The reservoir will continue to gradually rise to near 1355.2 feet during March to provide increased winter hydropower generation at Oahe and Big Bend.

Big Bend Dam releases averaged 15,700 cfs in February. Releases are expected to average 23,100 cfs this month. The reservoir will remain near its normal elevation of 1420.0 feet during March.

Oahe Dam releases averaged 17,600 cfs during February. Releases are expected to average 22,600 cfs in March. The reservoir ended February at elevation 1607.8 feet, rising 1.5 feet during the month. The reservoir level is expected to rise 0.9 foot during March.

Garrison Dam releases averaged 25,200 cfs during February. Releases are gradually being reduced to 22,000 cfs at the beginning of March. Garrison reservoir ended January at elevation 1837.8 feet, declining 1.3 feet during the month. The reservoir level is expected to rise 1.7 feet during March, ending the month near elevation 1838.9 feet.

Fort Peck Dam releases averaged 10,400 cfs during February. Releases were reduced to 8,000 cfs on March 5 and will remain at that rate during March. The reservoir ended February at elevation 2233.9 feet, declining 1.0 foot during the month. The reservoir is expected to rise 1.1 feet during March ending the month near elevation 2235.6 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 636 million kWh of electricity in February. Typical energy generation for February is 617 million kWh. The power plants are projected to generate 11.2 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 https://www.dvidshub.net/unit/usace-nwd.

MISSOURI RIVER MAINSTEM RESERVOIR DATA

WATER RELEASES AND ENERGY GENERATION FOR FEBRUARY