Based on the current soil moisture and snowpack conditions, runoff in the Missouri River Basin above Sioux City, Iowa, is forecast to be 26.1 million acre feet (MAF) in 2014, up slightly from the 25.1 MAF recorded in 2013. Normal runoff is 25.2 MAF.

“Although drought conditions in the Missouri River Basin improved significantly in 2013, the Missouri River mainstem reservoir levels remain below normal due to the lingering effects of the 2012 drought,” said Jody Farhat, Chief of the Water Management Division. “Improved runoff into the reservoir system in 2013, in combination with the drought conservation measures that were implemented, increased the total volume of water stored in the reservoirs by 2 million acre-feet since last year at this time. However, the upper three reservoirs, Fort Peck in eastern Montana, Garrison in North Dakota, and Oahe in South Dakota, remain 5 to 11 feet below the desired operating levels.” 

The near-normal runoff in 2013 was the product of below normal plains and mountain snowmelt runoff offset by above normal summer and fall precipitation in the Dakotas and eastern Montana. “Wet soil conditions in the Dakotas will likely contribute to spring runoff in 2014,” said Farhat. “However, because the reservoirs levels are below normal, the reservoir system is in excellent condition to capture high runoff this spring should that occur.”

In addition to the normal flood control capacity of 16.3 MAF, the latest reservoir forecast indicates that an additional 6 MAF of storage capacity will be available in the carryover multiple-use zone on March 1, near the start of the runoff season. That effectively increases the total flood control capacity available by more than 35 percent. The carryover multiple-use zone, which is often referred to as the reservoir system’s “bank account for drought,” contains 38.5 MAF of water when full. It’s designed to serve the eight Congressionally authorized purposes, though at reduced levels, through a 12-year drought like that of the 1930s and early 1940s. Those purposes are flood control, navigation, water supply, irrigation, hydropower, recreation, water quality control, and fish and wildlife.

To conserve water in the mainstem reservoir system, winter releases from Gavins Point are scheduled at the lowest level possible while still serving the needs of the municipal, industrial, and powerplant water intakes along the lower river. “Gavins Point releases have ranged from 13,000 cubic feet per second (cfs) to 18,000 cfs so far this winter to ensure intakes remain operational as cold temperatures moved through the region building ice on the river,” said Farhat. Releases have been above the target rate of 12,000 cfs to offset water lost to ice formation. “We will continue to monitor river ice conditions and adjust releases as necessary to ensure water supply is served to the extent reasonably possible.”

Due to the below normal system storage, it is likely that the Corps’ flow support for Missouri River navigation will be between minimum and full service for the first half of next year’s navigation season as a drought conservation measure. Minimum service flow support is designed to provide an 8-feet-deep by 200-feet-wide navigation channel rather than the 9 feet by 300 feet supported with full-service flows. The actual service level will be set based on the total volume of water stored in the reservoir system on March 15 in accordance with guidelines in the Master Manual. Flow support for the second half of the navigation season, as well as the navigation season length, will be set based on the actual July 1 system storage.

As of Jan. 1, the mountain snowpack was 110 percent of normal in the reach above Fort Peck and 113 percent of normal in the reach from Fort Peck to Garrison. Light-to-moderate plains snowpack has accumulated over much eastern Montana, North Dakota, and eastern South Dakota.

“The Corps will continue to monitor the plains and mountain snowpack through the winter and into spring, as well as basin soil conditions to fine tune the regulation of the reservoir system based on the most up-to-date information,” said Farhat.

View mountain snowpack graphic here: https://www.nwd-mr.usace.army.mil/rcc/reports/snow.pdf

Final 2013–2014 Annual Operating Plan released

After reviewing comments received on the draft, the Missouri River Basin Water Management Division developed and released the Final Annual Operating Plan for the Missouri River Basin for 2013–2014. The plan is posted at https://www.nwd-mr.usace.army.mil/rcc/aop.html

Monthly water management conference calls begin for 2014

The Corps will host its first conference call of 2014 on Thursday, Jan. 9, to inform basin stakeholders on current weather and runoff forecasts and the planned operation of the reservoir system in the coming months. The call is intended for Congressional delegations, Tribes, and state, county and local government officials, and the press. It will be recorded in its entirety and made available to the public as a free podcast in iTunes. Subscribe at https://itunes.apple.com/podcast/missouri-river-basin-water/id508457675. Or, simply run a search for Missouri River Basin Water Management in iTunes. The audio file will also be posted to the Omaha District’s facebook page and other social media outlets following each call.

Discontinuation of hardcopy news releases

The Corps has announced that this edition of the Missouri River news release will be the last in hardcopy format. “We encourage interested parties to read the news releases on our website, or they can sign up to have the news release emailed to them,” said Farhat. News releases are published under the information section of the Water Management website at:  https://www.nwd-mr.usace.army.mil/rcc. Interested parties also can sign up for the email version at the website by clicking on “Add Me To Your Email List” at the bottom of the home page.

Reservoir forecasts

Gavins Point releases averaged 15,000 cfs during December. Releases will gradually be reduced to 12,000 cfs as conditions permit. The reservoir behind Gavins Point Dam ended December at elevation 1207.5 feet. It is expected to remain near that level this month.

Fort Randall releases averaged 13,900 cfs during December. Releases are expected to average 12,700 this month and will be adjusted as necessary to maintain the elevation at Gavins Point. The reservoir ended December at elevation 1337.8 feet. It is forecast to rise 7 feet by the end of the month. The refill of the reservoir is designed to increase winter hydropower generation at Oahe and Big Bend.

Big Bend releases averaged 12,100 cfs during December. They are expected to average 19,600 cfs this month. The reservoir will remain near its normal elevation of 1420 feet.

Oahe releases averaged 13,100 cfs during December. Releases are expected to average 19,100 cfs this month. The reservoir ended December at elevation 1601.3 feet, up 0.3 foot during the month. The reservoir is expected to fall 0.3 foot during the month of January.

Garrison releases averaged 15,800 cfs in December. Releases were set at 16,000 cfs in December to prepare for the river freeze-in. Releases were gradually increased to the winter release rate of 18,000 cfs in early January. The reservoir ended the month at 1833.0 feet, down 1.0 foot from the previous month and is expected to decline 1.4 feet in January.

Fort Peck releases averaged 6,300 cfs in December. Releases were increased to 7,000 cfs in early January. The reservoir ended the month at elevation 2223.0 feet, down 0.5 foot from the previous month and is forecast to fall 0.5 foot this month.

The forecast reservoir releases and elevations discussed above are not definitive. Additional precipitation, lack of precipitation or other unknown circumstances could cause adjustments to the reservoir release rates.

The six mainstem power plants generated 491 million kilowatt hours of electricity in December. Average power generation in December is 689 million kWh. The 2013 total power generation was 7.6 billion kWh. The power plants are projected to generate 8.4 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: https://www.nwd-mr.usace.army.mil/rcc/reports/twregfcast.pdf 

MISSOURI RIVER MAINSTEM RESERVOIR DATA

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WATER RELEASES AND ENERGY GENERATION FOR DECEMBER