OMAHA, Neb. -- Despite improved runoff in June, water conservation measures will continue for the second half of the navigation flow support season based on the July 1 Missouri River Mainstem Reservoir System storage.
June runoff in the Missouri River basin above Sioux City, Iowa was 5.2 million acre-feet, 94%of average. The updated 2022 runoff forecast is 20.0 MAF, 78% of average and 1.7 MAF higher than last month’s annual runoff forecast. June runoff into Garrison was 110%of average.
“Heavy rain in mid-June on the upper Yellowstone River, coincided with mountain snowmelt increasing inflows into Garrison reservoir,” said John Remus, chief of the U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division.
The only other reach above average was Gavins Point to Sioux City, which was 136% of average.
“While soil moisture has improved in some areas over the last month, drought conditions persist across much of the Missouri River basin, and mainstem reservoir levels remain below normal,” said Remus.
“Based on the July 1 System storage the navigation flow support service level will be increased slightly, and, per the guidelines in the Master Manual, the navigation flow support season will be 3 days shorter.”
Due to the ongoing drought and the amount of water stored in the reservoir system, water conservation measures will likely continue through the remainder of 2022 and into 2023. The monthly study indicates that the winter release rate from Gavins Point, which is based on the September 1 storage check, will likely be at a minimum rate of 12,000 cfs.
Navigation:
Gavins Point Dam releases will be set to provide navigation flow support at a level 500 cfs above minimum-service at all four target locations (Sioux City, Omaha, Nebraska City, and Kansas City). Flow targets may be missed to conserve water if there is no commercial navigation in a given reach. The navigation flow support season will be 3 days less than the normal 8-month season.
Mountain Snowpack:
Mountain snowpack in the upper Missouri River Basin has melted. The mountain snowpack peaked above Fort Peck on April 29 at 85% of average, while the mountain snowpack in the Fort Peck to Garrison reach peaked on May 3 at 92% of average. Mountain snowpack normally peaks near April 17.
“Now that the snow has melted, we expect to see System storage decline as we make releases during the drier summer and fall periods to meet the authorized purposes,” said Remus.
The mountain snowpack graphics can be viewed at: http://go.usa.gov/xARQC.
Monthly Water Management Conference Calls
Water management calls include an update from the National Weather Service’s Missouri Basin River Forecast Center, and an update on the Missouri River Mainstem Reservoir System operations. The next call will be held Thursday, July 7. All calls are recorded in their entirety and are available to the public on our website at https://go.usa.gov/xARQv.
Reservoir Forecasts:
- Gavins Point Dam
- Average releases past month – 19,700 cfs
- Current release rate – 22,500 cfs
- Forecast release rate – 24,000 cfs
- End-of-June reservoir level – 1206.0 feet
- Forecast end-of-July reservoir level – 1206.0 feet
- Notes: The Gavins Point release will be adjusted to provide navigation flow support 500 cfs above minimum service on the lower Missouri River.
- Fort Randall Dam
- Average releases past month – 17,100 cfs
- End-of-June reservoir level – 1355.5 feet
- Forecast end-of-July reservoir level – 1354.9 feet
- Notes: Releases will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point and to back up Gavins Point releases.
- Big Bend Dam
- Average releases past month – 16,300 cfs
- Forecast average release rate – 23,700 cfs
- Forecast reservoir level – 1421.0 feet
- Oahe Dam
- Average releases past month – 15,500 cfs
- Forecast average release rate – 24,700 cfs
- End-of-June reservoir level – 1598.2 feet (up 1.5 feet from May 31)
- Forecast end-of-July reservoir level – 1597.5 feet
- Garrison Dam
- Average releases past month – 19,800 cfs
- Current release rate – 21,000 cfs
- Forecast release rate – 21,000 cfs
- End-of-June reservoir level – 1835.8 feet (up 6.3 feet from May 31)
- Forecast end-of-July reservoir level – 1837.1 feet
- Notes – Releases will be maintained at 21,000 cfs through August.
- Fort Peck Dam
- Average releases past month – 8,200 cfs
- Current release rate – 8,000 cfs
- Forecast average release rate – 8,000 cfs
- End-of-June reservoir level – 2222.2 feet (up 0.1 feet from May 31)
- Forecast end-of-July reservoir level – 2221.6 feet
- Notes: Releases will be maintained at 8,000 cfs through August.
The forecast reservoir releases and elevations discussed above are not definitive. Additional precipitation, lack of precipitation or other circumstances could cause adjustments to the reservoir release rates.
Hydropower:
The six mainstem power plants generated 595 million kWh of electricity in June. Typical energy generation for June is 850 million kWh. The power plants are expected to generate 7.2 billion kWh this year, compared to the long-term average of 9.4 billion kWh.
To view the detailed three-week release forecast for the mainstem dams, go to https://go.usa.gov/xARQB.
The Missouri Basin Web App provides links to these reports and others that are updated more frequently. http://go.usa.gov/xE6fC
Special Note:
Friday, July 8 is considered by some to be "National Video Game Day", although it has a cousin, "National Video Games Day" that will be recognized on Sept. 12.
Regardless, National Video Game Day provides an opportunity to bring attention to the Missouri Basin Balancer web-based video game that was re-launched earlier this year. The game allows players take control of two dams along an interior river system. The river begins in the mountains where snowfall and snowmelt can be affected by warm or cool spring temperatures. If temperatures are warm, early spring rainfall can accelerate snowmelt and if temperatures are cool, snowmelt may be delayed or if snow accumulates into early summer, runoff could be delayed and extend later into the summer.
Learn more about the game's development.