As a result of the low precipitation and widespread drought conditions, June runoff in the upper Missouri River Basin was 52% of average.
John Remus is the chief of the US Army Corps of Engineers’ Missouri River Basin Water Management Division. He says the Corps’ updated 2021 upper Basin runoff forecast is 15.6 million acre-feet– which is 60% of average. If realized, this runoff amount would be the 10th driest year in the upper Basin since 1898.
Average releases from the Oahe Dam at Pierre/Fort Pierre in June were 27,800 cfs. At the end of June, the reservoir level was at 1604.9 feet– down one foot from the end of May. The July forecast average releases at Oahe are expected to be 30,900 cfs with the reservoir level ending the month at 1603.1 feet. If realized, the reservoir level will have dropped 2.8 feet in two months.
According to the National Drought Mitigation Center, approximately 74% of the Missouri River basin is currently experiencing some form of abnormally dry or drought conditions, an increase of 9% since the end of May. The seasonal drought outlook, which extends through the end of September, shows drought conditions will persist or expand across the upper basin.
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 during the remainder of 2021.
Remus says an intermediate service level will be maintained through the end of the navigation flow support season, which ends December 1. He says the water conservation measure is necessary to ensure authorized purposes will be served in the short and long term.
Infographic credit US Army Corps of Engineers.
Comments