By DOUG SCHMITZ
Iowa Correspondent OMAHA, Neb. — With current releases at Gavins Point in the Missouri River Basin increasing from 20,000 to 24,000 cubic feet per second (CFS) as of Jan. 8, the U.S. Army Corps of Engineers continues preparing the Missouri River Mainstem System for the 2019 runoff season. “The higher-than-average winter releases from Gavins Point will continue the evacuation of the stored flood waters from the 2018 runoff season,” said John Remus, chief of the Corps’ Missouri River Basin Water Management Division. He said Gavins Point Dam winter releases normally range between 12,000-17,000 cubic feet. “These releases will provide additional hydropower generation during the winter, which is one of the peak power demand periods,” he explained. “In addition, the higher-than-average releases will benefit municipal and industrial water intakes below Gavins Point Dam, which can be impacted by low water levels during periods of ice formation.” According to the Corps, the 2018 calendar year runoff was 41.9 million acre feet (MAF), the third highest runoff in 120 years of recordkeeping from 1898-2017, exceeded only in 1997 and 2011. As of Jan. 6, the total volume of water stored in the system is 56.6 MAF, occupying 0.5 MAF of the 16.3 MAF combined flood control storage zones. Nicole Shorney, Corps hydraulics engineer, said based on current soil moisture conditions, Plains and mountain snowpack and long-term temperature and precipitation outlooks, the 2019 calendar year runoff forecast is 25.7 MAF above Sioux City, Iowa – 101 percent of average. Average annual runoff is 25.3 MAF. The runoff forecast will be updated on a monthly basis, and more often if warranted, throughout 2019. The Corps said current studies indicate that flow support for Missouri River navigation will be at full service levels for the first half of the 2019 season, which begins on April 1 at the mouth. In addition, the actual service level will be based on the total volume of water stored in the system on March 15, in accordance with the guidelines in the Master Manual. Flow support for the second half of the navigation season, as well as navigation season length, will be based on the actual July 1 System storage. River ice conditions below all system projects will be closely monitored throughout the winter season. The Corps will also continue to monitor basin and river conditions, including Plains and mountain snow accumulation, and will adjust system regulation based on the most up-to-date information. The mountain snowpack accumulation period is underway. This is currently below average in both reaches; however, the accumulation period is less than 50 percent complete. Other reservoir forecasts Fort Randall Dam releases averaged 21,400 CFS in December 2018. Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point. The reservoir level was at 1,340.1 feet at the end of December, rising 3.1 feet during the month. The reservoir will gradually be refilled during the winter to increase winter hydropower generation at Oahe and Big Bend. Big Bend Dam releases averaged 19,800 CFS in December. Releases were expected to average 25,400 and the reservoir remained near its normal elevation of 1,420 feet during January. Oahe Dam releases averaged 22,000 CFS in December, and releases were expected to average 24,800 in January. The reservoir ended December at elevation 1,607.2 feet, remaining steady during the month. The reservoir level was expected to decline approximately another 0.3 foot last month. Garrison Dam releases averaged 20,500 CFS in December. Releases are currently at 16,000 and will remain near that rate to prepare for possible river freeze-in at Bismarck, N.D. Once an ice cover is established, releases will be gradually increased to 26,000 CFS. The reservoir level was 1,839.6 feet at the end of December, a reduction of 0.6 foot during the month. The reservoir level was expected to continue declining through January and be near elevation 1,838.7 feet at the end of the month. Fort Peck Dam releases averaged 11,600 CFS during December. Releases remained near 12,500 in January. The reservoir level was 2,237.2 feet at the end of December, declining 1.4 feet during the month. The reservoir level was expected to continue declining through January and be near elevation 2,235.9 feet at the end of the month. The Corps said forecast reservoir releases and elevations are not definitive, and additional precipitation, lack of precipitation or other circumstances could cause adjustments to the reservoir release rates. Moreover, the six mainstem power plants generated 758 million kilowatt hours (kWh) of electricity last December. Typical energy generation for that month of the year is 684 million kWh. The power plants are projected to generate 12.3 billion kWh this year, compared to the long-term average of 9.3 billion. 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 2018-19, which is available to read online at www.nwd.usace.army.mil/MRWM/Public-Meetings |
