Gavins Point Dam

Water flows through Gavins Point Dam near Yankton, S.D., in this 2011 file photo. The U.S. Army Corps of Engineers is increasing water releases to 42,000 cubic feet per second on Wednesday and then incrementally increasing releases to 55,000 cfs by Sunday.

OMAHA -- Siouxland residents will notice the Missouri River water levels beginning to recede soon.

The U.S. Army Corps of Engineers on Sunday began incrementally reducing water releases from Gavins Point Dam from 58,000 cubic feet to a winter rate of 20,000 cfs by Dec. 11. On Monday, releases were at 52,000 cfs.

The winter releases from the dam near Yankton, South Dakota, will be higher than the average winter mark of 12,000 cfs-17,000 cfs so the corps can continue to evacuate above-average runoff into the Missouri River's six reservoirs to make room for next spring's runoff. Releases were above average all summer and fall.

Runoff in 2018 upstream of Sioux City is expected to be the third-highest total since record keeping began in 1898. The 2018 runoff forecast is 41.4 million acre feet, 163 percent of average. The record is 61 MAF in 2011.

"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," John Remus, chief of the corps' Missouri River Basin Water Management Division, said in a news release.

As of Friday, storage in the reservoir system was 58 MAF, occupying 1.9 MAF of the 16.3 MAF flood control zone. Storage is projected to drop another 1 MAF by Dec. 1 with the rest of the surplus water 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," Remus said.

Get local news delivered to your inbox!

* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

Copyright 2018 The Sioux City Journal. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.


Load comments