Water releases from Gavins Point Dam will be reduced Sunday, Nov. 25, from 58,000 cubic feet per second to 55,000 cfs, the U.S. Army Corps of Engineers announced today.
Releases will be incrementally reduced over the next few weeks to winter release rates ahead of the river’s icing-in in the upper portions of the basin.
Releases from Gavins Point Dam are forecast to be 20,000 cfs by Dec. 11. System releases from Gavins Point Dam are forecast to be higher than average, in the 20,000 cfs range, through the winter.
Projected river stages for the Missouri River downstream from Gavins Point Dam are available from the National Weather Service, Advanced Hydrologic Prediction Service, Missouri Basin River Forecast Center.
The 2018 runoff year for the Missouri River Basin upstream from Sioux City is on track to be the third highest since recordkeeping began in 1898. The 2018 runoff forecast is 41.4 million acre feet. Runoff in 1997 was 49 MAF and in 2011 a record 61 MAF.
“Although higher than average river levels have presented a challenge to those along the river, on a few occasions, we were able to reduce releases when it would lessen flooding impacts from downstream rain events,” said John Remus, chief of the Corps’ Missouri River Basin Water Management Division.
Current system storage is 58 million acre feet with 1.9 million acre feet of stored runoff that still needs to be released before the 2019 runoff begins. System storage is projected to decline an additional 1 million acre feet by Dec. 1 with the remainder being released gradually through the winter.
“We have to clear most of the stored runoff before the river up north freezes over in December. The higher than average winter releases are necessary to evacuate the remainder of the 2018 runoff before the 2019 runoff begins. ” said Remus.
The six system reservoirs are operated as a hydraulically and electrically integrated system to meet the congressionally authorized purposes of flood control, navigation, irrigation, water supply, water quality control, hydropower generation, recreation and fish and wildlife, including threatened and endangered species.