May runoff in the Upper Missouri River Basin was about 130% of average.
According to the US Army Corps of Engineers, the 2020 calendar year upper basin runoff forecast is 32.3 million acre feet or 125% of average.
Chief of the US Army Corps of Engineers’ Missouri River Basin Water Management Division John Remus says the upper basin runoff for the remainder of the year will depend on mountain snowmelt– which will enter the Fort Peck and Garrison reservoirs early this month– and summer rain events. He says nearly 80% of the system’s flood control storage is currently available. As of June 1, the mountain snowpack was 84% of average in the reach above Fort Peck and 83% of average in the reach from Fort Peck to Garrison.
Average releases from the Oahe Dam reservoir last month were 26,800 cubic feet per second. They’re projected to be slightly lower this month, averaging 25,300 cfs. The estimated end-of-June reservoir level is 1612.8 feet.
Average releases from the Big Bend reservoir last month were 27,000 cfs. Forecast average release rate for June is 25,200 cfs with a reservoir level of 1420.7 feet.
Additional precipitation, lack of precipitation or other circumstances could cause adjustments to the reservoir release rates.
Weekly updates on basin conditions, reservoir levels and other topics of interest can be viewed here: https://go.usa.gov/xE6wa.
To view the detailed three-week release forecast for the mainstem dams, go to http://go.usa.gov/xVgWr.
