OMAHA, NE --
Releases from Gavins Point Dam will increase by 5,000 cubic feet per second Saturday, June 1 to 75,000 cfs.
Releases were increased to 70,000 cfs on Wednesday.
“Runoff into the upper Missouri River above Sioux City has remained high, and unfortunately, the rain continues to fall in the places we don’t need it,” said John Remus, Chief of the Missouri River Basin Water Management Division.
In the past five days, the National Weather Service, Missouri Basin River Forecast Center is showing 1 to 4 inches of rainfall in South Dakota and Nebraska.
“The rainfall runoff continues to flow into the Oahe, Big Bend, Fort Randall, and Gavins Point reservoirs at significantly higher than average rates,” said Remus
Runoff for the month to date upstream of Sioux City, Iowa is more than 7.5 million acre feet (maf) compared to the long-term average of 3.3 maf.
“We have reduced flows from Garrison Dam to 15,000 cfs to offset some of the high flows entering the system from Garrison to Gavins Point. This will provide additional relief in the Oahe and Fort Randall pools,” said Remus.
Oahe: (Storing in Exclusive Flood Control Zone)
- Total Flood Control Storage: 4.315 MAF
- Current Flood Control Storage: 3.68 MAF (85.3% filled)
- Pool level: 1618.29 ft (Top of flood control – 1620 ft)
- Inflows: 65,000 cfs
- Releases: 30,000 cfs (June 1 37,000 cfs; June 2 40,000 cfs; June 3 48,000 cfs)
Big Bend: (Big Bend is a re-regulation project and has very limited flood control storage)
- Total Flood Control Storage: 0.179 MAF
- Current Flood Control Storage: 0.665 MAF (37.2% filled)
- Pool level: 1421.16 ft (Top of flood control – 1423 ft)
- Inflows: 50,000 cfs
- Releases: 47,000 cfs (June 3 50,000 cfs)
Fort Randall: (Storing in Exclusive Flood Control Zone)
- Total Flood Control Storage: 2.292 MAF
- Current Flood Control Storage: 1.733 MAF (75.6% filled)
- Pool level: 1369.41 ft (Top of flood control – 1375 ft)
- Inflows: 79,000 cfs
- Releases: 60,000 cfs (May 31 65,000 cfs; June 1 68,000 cfs)
Gavins Point: (Gavins Point is a re-regulation project and has very limited flood control storage)
- Total Flood Control Storage: 0.133 MAF
- Current Flood Control Storage: 0.042 MAF (31.4% filled)
- Pool level: 1206.47 ft (Top of flood control – 1210 ft)
- Inflows: 68,000 cfs
- Releases: 70,000 cfs (Going to 75,000 cfs Saturday, June 1 at 8 a.m.)
“Our Missouri Basin Update is being updated daily to ensure we keep the public informed of our operations and our operational decisions,” said Remus.
The effects from releases on the lower Missouri River diminishes at locations further downstream due to the large uncontrolled drainage area and the travel time from Gavins Point Dam. Travel times for releases from Gavins Point take two to three days to reach Omaha, three to four days to reach Nebraska City, and four to five days to reach Kansas City, Missouri.
“We will continue to monitor conditions along the length of the Missouri River and make adjustments as necessary,” said Remus.
Releases will remain higher than average into the fall because the reservoirs have to be at the base of the annual flood control pool by the beginning of the 2020 runoff season.
The National Weather Service issues official stage forecasts for the Missouri River and the public should monitor their nearest upstream gage as fluctuations to river stages will occur with regional precipitation along the rivers and creeks that join the Missouri River downstream from Gavins Point Dam. More information about releases and river stages downstream from Gavins Point Dam is available here http://www.nwd-mr.usace.army.mil/rcc/reports/pdfs/GRFT.pdf and from the National Weather Service, Missouri Basin River Forecast Center https://www.weather.gov/mbrfc/.