Heavy Rains Temporarily Impact Corps’ Missouri River Release Plans

The Corps of Engineers temporarily reduced reservoir releases into the Missouri River in response to heavy rains and runoff in Kansas and Missouri, the Missouri River Basin Water Management Division announced October 7.

Releases from Gavins Point Dam were reduced from 58,000 cubic feet per second (cfs.) to 46,000 cfs. over a two-day period, beginning at noon on October 7.

The reduction came just two days after the Corps had issued its normal monthly update on reservoir operations, in which it said that it planned to keep Gavins Point releases at 58,000 cfs. through the fall.

“Due to this year’s high runoff and the water currently being stored in the reservoirs, Gavins Point releases will remain near 58,000 cfs. for the remainder of the navigation season to ensure evacuation of all stored flood waters prior to the 2019 runoff season, with much of that occurring before the river freezes over in the northern reaches,” said John Remus, Chief of the U.S. Army Corps of Engineers Missouri River Basin Water Management Division, in the earlier announcement.

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The 2018 runoff forecast for the Missouri River Basin above Sioux City, Iowa, is 40.6 million acre feet (maf.), which is 160 percent of average.

The total runoff above Sioux City in September was 1.7 maf., which is 151 percent of average.

About half of that September runoff—0.8 maf.—occurred in the unregulated reach between Sioux City and Gavins Point Dam. That’s about eight times the average September runoff in that reach, and the highest in September in 120 years of record-keeping, the Corps said.

Total mainstem reservoir storage was 62.2 maf. as of October 1, occupying 6.1 maf. of the designated 16.3 maf. flood control storage.

“System storage declined 2.5 maf. in September and will continue to gradually decline in October,” Remus said.

System storage peaked on July 8 at 68.4 maf., occupying 12.3 maf. of the flood control zone. “Reservoir releases will be adjusted as necessary to provide downstream flood risk reduction and continue evacuation of stored flood water,” he said.

The Corps had previously announced that the navigation season will be extended by 10 days, which will allow for more evacuation of water from the reservoirs. Navigation flow support will end on December 11 at the mouth of the Missouri River, near St. Louis, Mo.

Public Meetings

The 2018–2019 draft Annual Operating Plan for the Missouri River Mainstem System was posted in September at

Public meetings will be held in six cities throughout the basin in early November. These meetings will include a presentation regarding 2018 operations and plans for regulating the reservoir system in 2019, followed by a question and answer session. The public meetings will be conducted at the following locations (all times local):

Fort Peck, Mont.—November 6, 11 a.m.; Fort Peck Interpretive Center, Lower Yellowstone Road.

Bismarck, N.D.—November 6, 6 p.m.; Bismarck State College, Room 304 NECE Building, 1200 Schafer St.

Pierre, S.D.—November 7, 10 a.m.; Casey Tibbs Conference Center, 201 Verendrye Drive.

Sioux City, Iowa—November 7, 4 p.m.; Stoney Creek Hotel & Conference Center, 300 3rd St.

Smithville, Mo.—November 8, 11 a.m.; Paradise Point Golf Course, 18212 Golf Course Road

Nebraska City, Neb.—November 8, 4 p.m.; Lewis and Clark Interpretive enter, 100 Valmont Drive.