Drought conditions, particularly in the Missouri River basin above Sioux City, Iowa, will result in slower winter releases from Gavins Point Dam in an effort to conserve water upstream.
The U.S. Army Corps of Engineers said winter releases from Gavins Point Dam in South Dakota will be 12,000 cubic feet per second, compared to last winter's releases of 17,000 cfs.
"Reservoir inflows in August were much lower than average, and we expect below-average inflows into the system through the rest of 2021," said John Remus, chief of the U.S. Army Corps of Engineers' Missouri River Basin Water Management Division.
Despite localized heavy rainfall events throughout the basin during August, drought conditions expanded across the basin due to the exceptionally dry soils. August runoff in the upper basin was 54 percent of average. The 2021 calendar year forecast for the upper basin, updated Sept. 1, is 14.7 million acre-feet (MAF), 57 percent of average. Average annual runoff for the upper basin is 25.8 MAF.
According to the National Drought Mitigation Center, approximately 83 percent of the Missouri River basin is experiencing some form of abnormally dry conditions or drought as of Sept. 2. The seasonal drought outlook, which extends through the end of November, shows drought conditions persisting across most of the upper basin.
As he did back in June, Remus has sent a letter to intake owners and water users on the lower Missouri River about conditions in the upper river basin and how this will likely affect the operation of the river's reservoir system during the winter. The letter was sent so organizations would have adequate time to make necessary intake modifications and or develop contingency plans to maintain access to the water.
"I understand the importance of the Missouri River in providing water supply to citizens in the lower basin, and I want to remind you that a Gavins Point release of 12,000 cfs is not unprecedented. During the 2000-2007 drought, releases from Gavins Point were as low as 9,000 cfs," Remus wrote.
The water provider for most of Jefferson City is not expecting any issues with providing service.
In 2011, Missouri American Water put a new 12.5 million- gallon-per-day water intake pipeline and pumping station online, which was built on the banks of the river.
Company officials said the new pipeline and station have helped maintain reliable water service to Jefferson City during record-setting drought.
This system is 30 feet deeper and extends 80 feet farther into the river than the system installed in the 1960s.