Precipitation in the upper Missouri River Basin (above Sioux City, IA) has been below normal since Jan. 1, 2020, but the runoff forecast remains above normal.
US Army Corps of Engineers data shows September precipitation was 69% of average, well-below normal. The National Weather Service’s Climate Prediction Center is forecasting below-normal precipitation will continue this month.
Corps information also shows the 2020 calendar year runoff forecast for the upper Basin (updated Oct. 1, 2020) is 30.2 million acre-feet, 117% of average. Average annual runoff for the upper Basin is 25.8 MAF. Lower basin runoff has also been below average.
John Remus, chief of the Corps’ Missouri River Basin Water Management Division, says as of yesterday (Oct. 5, 2020) the total volume of stored water (58.6 MAF) occupied 2.5 MAF of the System’s 16.3-MAF flood control zone. He says system storage peaked at 61.8 MAF on July 16 and will decline during the fall. Remus expects all (16.3 MAF) flood control storage space– and possibly slightly more (.8 MAF) will be available before the start of the 2021 runoff season.
The Oahe Dam will undergo a full powerplant outage during the day Tuesday, Oct. 13, 2020, for scheduled maintenance. The US Army Corps of Engineers says zero releases will be scheduled during the daylight hours so the work crew can complete maintenance in the tailrace area.
Oahe Dam:
- Average releases past month – 28,900 cfs
- Forecast average release rate – 20,300 cfs
- End-of-September reservoir level – 1610.4 feet
- Forecast end-of-October reservoir level – 1608.5 feet
Big Bend Dam:
- Average releases past month – 28,500 cfs
- Forecast average release rate – 20,200 cfs
- Forecast reservoir level – 1420.7 feet
The US Army Corps of Engineers will hold two public meetings webinar Nov. 2. The meetings provide an opportunity to update the region on current hydrologic conditions and the planned operation of the mainstem reservoir system during the remaining fall months. It also allows Corps officials to present the draft plans for operating the System next year. Meeting times and webinar information will be at the following link when it becomes available: https://www.nwd.usace.army.mil/MRWM/Public-Meetings/.
Comments