Photo By Eileen Williamson | Each month, from January through the end of the runoff season, Missouri River water...... read more read more
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OMAHA, Neb. – While the Missouri River basin has seen improved runoff for two consecutive months, it is not enough to overcome the long-term drought persisting in much of the basin.
July runoff in the Missouri River basin above Sioux City, Iowa was 3.2 million acre-feet, which is 98% of average and 0.7 MAF more than was forecast last month. This has led to an annual runoff forecast of 20.6 MAF, which is 80% of average and 0.6 MAF higher than last month’s forecast.
“As expected, reservoir inflows in July have been declining due to the warmer and drier conditions in the upper Missouri River Basin,” said John Remus, chief of the U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division. “Per the July 1 System storage check, navigation support was increased slightly to 500 cubic feet per second above minimum-service levels. The navigation support season will be 3 days shorter than normal per the guidance in the Master Manual,” added Remus.
USACE will evaluate lower Missouri River flow conditions to set Gavins Point releases to ensure that flows at the four downstream navigation target locations will be at or above the target levels.
“The monthly study indicates that the winter release from Gavins Point, which is based on the September 1 System storage check, will likely be at a minimum rate of 12,000 cfs,” added Remus.
System storage peaked on July 20 at 52.1 MAF. System storage on August 1 was 51.8 MAF, 4.3 MAF below the base of the Annual Flood Control and Multiple Use Zone. “System storage is expected to continue to decline further into the Carryover Multiple Use Zone during the remainder of 2022 as we make releases during the drier summer and fall periods to meet the authorized purposes,” said Remus.
Drought Conditions:
Overall drought conditions across the basin changed little during the month of July. According to the National Drought Mitigation Center, approximately 62% of the Missouri River basin is currently experiencing some form of abnormally dry or drought conditions, with 6% being extreme or exceptional drought. The seasonal drought outlook, which extends through the end of October, shows drought conditions will persist and expand across the lower basin. Drought information can be viewed at: https://droughtmonitor.unl.edu/.
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 was completely melted by the first week of July. 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.
The mountain snowpack graphics can be viewed at: http://go.usa.gov/xARQC.
Monthly Water Management Conference Calls
Water management calls include an update on the Missouri River mainstem reservoir system operations. The next call for 2022 will be held Thursday, August 4. 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
o Average releases past month – 22,600 cfs
o Current release rate – 25,000 cfs
o Forecast release rate –26,300 cfs
o End-of-July reservoir level – 1206.2 feet
o Forecast end-of-August reservoir level – 1206.5 feet
o 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
o Average releases past month – 21,700 cfs
o End-of-July reservoir level – 1354.8 feet
o Forecast end-of-August reservoir level – 1355.1 feet
o 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
o Average releases past month – 20,200 cfs
o Forecast average release rate – 26,300 cfs
o Forecast reservoir level – 1420.6 feet
• Oahe Dam
o Average releases past month – 21,200 cfs
o Forecast average release rate – 26,400 cfs
o End-of-July reservoir level – 1598.4 feet (near July 1 level)
o Forecast end-of-August reservoir level – 1597.1 feet
• Garrison Dam
o Average releases past month – 20,800 cfs
o Current release rate – 21,000 cfs
o Forecast release rate – 21,000 cfs
o End-of-July reservoir level – 1838.0 feet (up 2.2 feet from July 1)
o Forecast end-of-August reservoir level –1836.9 feet
o Notes – Releases will be maintained at 21,000 cfs through mid-September.
• Fort Peck Dam
o Average releases past month – 7,600 cfs
o Current release rate – 8,000 cfs
o Forecast average release rate – 8,000 cfs
o End-of-July reservoir level – 2222.2 feet (near July 1 level)
o Forecast end-of-August reservoir level – 2221.4 feet
o Notes: Releases will be maintained at 8,000 cfs through mid-September.
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 728 million kWh of electricity in July. Typical energy generation for July is 960 million kWh. The power plants are expected to generate 7.1 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
| Date Taken: | 08.03.2022 |
| Date Posted: | 08.03.2022 10:00 |
| Story ID: | 426411 |
| Location: | OMAHA, NEBRASKA, US |
| Web Views: | 291 |
| Downloads: | 0 |
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