Above-Average Releases To Continue On Missouri River

In its monthly report of Missouri River reservoir conditions, the Corps of Engineers said August 7 that higher-than-average releases are planned from all Missouri River projects through November.

“Due to the water currently being stored in the reservoirs and the higher-than-average runoff being forecast in the Missouri River Basin above Sioux City, Iowa, Gavins Point releases will remain near 58,000 cubic feet per second (cfs.) for the remainder of the navigation season to ensure evacuation of all stored flood waters prior to next year’s runoff season,” said John Remus, chief of the Missouri River Basin Water Management Division.

The Corps’ current 2018 runoff forecast in the Missouri River Basin above Sioux City, is 39.8 million acre feet (maf.), 157 percent of average. July runoff was 5.1 maf., 155 percent of normal.

Total water storage in the mainstem reservoir system was 64.7 maf. as of August 1, occupying 11.3 maf. of the 16.3 maf. flood-control zone.

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“System storage peaked on July 8 at 68.4 maf. and is gradually declining,” Remus said. “Approximately 30 percent of the system’s flood storage remains available to capture runoff from late summer rainfall events. The current amount of vacant flood control storage provides flexibility to lessen downstream flooding should suddenly-developing large rainfall events occur anywhere in the basin.”

When necessary, the releases will be reduced from the system projects and utilize the available flood control space in the reservoirs, in order to lessen flooding downstream of all the projects.

The six mainstem power plants generated 1,336 million kilowatt hours (kwh.) of electricity in July. Typical energy generation for July is 943 million kwh. The power plants are projected to generate 13.3 billion kwh of electricity this year, compared to the long-term average of 9.3 billion kwh.