Water conservation measures were enacted for the second half of the navigation flow support season based on the July 1 Missouri River Mainstem Reservoir System storage, per the guidelines outlined in the Master Manual.
Very dry conditions continue to impact the upper Missouri River Basin above Sioux City, IA (upper Basin) despite recent heavy rainfall in the lower Basin. As a result of the low precipitation and widespread drought conditions, June runoff in the upper Basin was 52% of average.
The updated 2021 upper Basin runoff forecast is 15.6 million acre-feet (MAF), 60% of average. If realized, this runoff amount would be the 10th driest year in the upper Basin since 1898. System storage on July 1 was 55.2 MAF, 0.9 MAF below the base of the Annual Flood Control and Multiple Use Zone. System storage is expected to decline further into the Carryover Multiple Use Zone during the remainder of 2021.