Drought conditions in the Missouri River basin above Sioux City, Iowa continued through August. According to the Master Manual and System Storage Audit of September 1, winter discharge from Gavins Point Dam will be 12,000 cubic feet per second (cfs), as part of overall water conservation measures.
While July brought much-needed moisture to the Missouri River basin, August showed a return to the hot, dry conditions seen in the basin for the past two seasons. August runoff was 0.9 MAF, 62% of average above Sioux City, and 0.6 MAF or 49% of average above Gavins Point Dam. The part of the basin that drains into Oahe Reservoir was particularly dry, seeing only 10% of its average August runoff. The 2022 calendar year forecast for the upper basin, updated September 1, is 20.2 million acre-feet (MAF), or 78% of the average. The average annual runoff for the upper basin is 25.8 MAF.
“Reservoir supplies in August were well below average. We expect below-average inflows to the system through the remainder of 2022,” said John Remus, head of the Army Corps of Engineers’ Missouri River Basin Water Management Division. American. “Based on storage in the system during the September 1 storage audit, Gavins Point winter releases will be 12,000 cfs for the second year in a row,” Remus added.
As of September 2, the total volume of water stored in the system was 50.2 MAF, which is 5.9 MAF below the base of the system’s flood control zone. System storage should continue to shrink throughout the fall. Updated reservoir studies indicate that system storage is expected to be greater than 8.4 MAF below flood control base at the start of the 2022 runoff season.
According to the National Drought Mitigation Center, drought conditions in the basin have worsened over the past month. Seventy-four percent of the basin is experiencing abnormally dry or drought conditions, including 7% extreme or exceptional drought. Northern Montana and southwestern Nebraska have exceptionally dry soil conditions. The September and seasonal drought outlook shows that the existing drought persists and extends into the basin through the end of November.
The Gavins Point Dam releases will be configured to provide navigational stream support at a level of 500 cfs above minimum service to the four target locations (Sioux City, Omaha, Nebraska City and Kansas City). Flow targets may be missed to conserve water if there is no commercial shipping in a given reach. The season support will end on November 28 at the mouth of the Missouri River.
Winter Release Rate
In accordance with the criteria of the main manual, the winter discharge rate is determined based on the storage of the system on September 1. According to system storage as of September 1, winter releases from Gavins Point Dam will be at the minimum rate of 12,000 cfs. In anticipation of low winter discharges, a letter will be sent in early September to all water users downstream of the Gavins Point Dam informing them of the expected discharges and encouraging them to assess the risks to their facilities.
Monthly Water Management Conference Calls
The calls for water stewardship include an update on operations of the main Missouri River reservoir system. The next call for 2022 will be Thursday, September 8. All calls are recorded in their entirety and are publicly available on our website at https://go.usa.gov/xARQv.
Fall Public Meetings
The Northwest Division will host a series of town hall meetings the week of October 24-28. The dates and locations of the meetings are listed below.
- October 24, Fort Peck, MT @ 11:30 a.m. MT – Fort Peck Interpretive Center
- Oct. 24, Bismarck, ND at 5:00 p.m. CT – Bismarck State College
- October 25, Ft Pierre, Sd @ 10:00 a.m. CT – Casey Tibbs Conference Center
- October 25, Sioux City, IA @ 4:00 PM CT – Betty Strong Dating Center
- October 26, Smithville, MO @ 11:00 a.m. CT – Jerry Litton Visitor Center
- October 26, Nebraska City, NE @ 6:00 PM CT – Steinhart Lodge
- Oct. 27, St. Louis, MO @ 10:30 a.m. CT – VIEW17
- Gavins Point Dam
- Average releases last month – 28,900 cfs
- Current circulation rate – 30,000 cfs (as of September 1)
- Expected rejection rate – 30,000 cfs (month of September)
- Reservoir level at the end of August – 1206.8 feet
- Expected reservoir level at the end of September – 1207.5 feet
- Notes: Discharges will be adjusted as needed to meet all downstream navigation targets.
- Fort Randall Dam
- Average releases last month – 28,100 cfs
- Reservoir level at the end of August – 1354.9 feet
- Expected reservoir level at the end of September – 1353.7 feet
- Notes: Discharges will be adjusted as necessary to maintain the desired reservoir elevation at Gavins Point.
- Big Bend Dam
- Average releases last month – 28,800 cfs
- Expected Average Reject Rate – 27,000 cfs
- Expected tank level – 1420.4 feet
- Oahe Dam
- Average releases last month – 29,600 cfs
- Expected Average Reject Rate – 27,000 cfs
- Reservoir level at the end of August – 1596.0 feet
- Expected reservoir level at the end of September – 1593.6 feet
- garrison barrage
- Average releases last month – 21,100 cfs
- Current release rate – 21,000 cfs
- Expected average rejection rate – reduce to 14,000 cfs by mid-September
- Reservoir level at the end of August – 1835.6 feet
- Expected reservoir level at the end of September – 1834.2 feet
- Fort Peck Dam
- Average releases last month – 7,800 cfs
- Current release rate – 7,800 cfs
- Expected average rejection rate – reduce to 4,000 cfs by mid-September
- Reservoir level at the end of August – 2221.0 feet
- Expected reservoir level at the end of September – 2220.4 feet
The projected reservoir flows and elevations discussed above are not definitive. Additional precipitation, lack of precipitation, or other circumstances could cause adjustments to reservoir release rates.
The six main power stations produced 886 million kWh of electricity in August. Typical energy production for the month of August is 1,011 million kWh. Power plants are expected to produce 7.3 billion kWh of electricity this year, compared to a long-term average of 9.4 billion kWh.
To view detailed three-week release forecasts for major dams, go to http://go.usa.gov/xVgWr.
MISSOURI RIVER MAIN RESERVOIR DATA
Pool elevation (feet above mean sea level) Stored water (1,000 acre-feet)
As of August 31 Variation in August As of August 31 % of the 1967-2020 average Variation in August
- Fort Peck 2221.1 -1.1 12,249 84 -222
- Garrison 1835.6 -2.4 17,175 96 -724
- Ahoy 1596.0 -2.2 15 371 87 -651
- Large bend 1420.7 -0.2 1673 98 -12
- Fort Randall 1354.9 0.0 3,401,102 +8
- Pointe Gavins 1206.8 +0.6 345 88 +12
Total 50,214 90 -1,589
WATER LAUNCHES AND ENERGY PRODUCTION FOR THE MONTH OF AUGUST
Average release in 1,000 cfs Release in 1,000 acre-feet Production in millions of kWh
- Fort Peck 7.8 479 74
- Garrison 21.1 1,296,197
- Ahoy 29.6 1,821,262
- Big bend 28.8 1,773 97
- Fort Randall 28.1 1,727,181
- Pointe Gavins 28.9 1,778 73