Submitted Art The drought monitor for July 30 shows 59% of the Missouri River Basin as abnormally dry or worse. Soils are drier than normal in the western portion of the basin and wetter than normal in the eastern portion of the basin. The drought outlook extending through the end of October shows drought conditions persisting or worsening for the western half of the basin.

OMAHA, Neb. – July runoff in the Missouri River basin above Sioux City, Iowa, was 2.8 million acre-feet, 85% of average. Runoff was below average in the upper three reaches and above average in the lower three reaches. The annual runoff forecast above Sioux City, Iowa, is 23.9 MAF, 93% of average.

“July brought warmer and drier weather to the Missouri River Basin,” said John Remus, chief of the U.S. Army Corps of Engineers’ Missouri River Basin Water Management Division. “While every state experienced storms that produced small pockets of above average rainfall, overall precipitation was below normal for the basin.”

The drought monitor for July 30 shows 59% of the basin in an abnormally dry or worse category. Soils are drier than normal in the western portion of the basin and wetter than normal in the eastern portion of the basin. The drought outlook extending through the end of October shows drought conditions persisting or worsening for the western half of the basin.

“Reservoir inflows in July declined due to warmer and drier conditions in the upper Missouri River basin. After peaking in mid-July, System storage is expected to continue declining into the Carryover Multiple Use Zone during the remainder of 2024 as we make releases during the summer and fall periods to support the authorized purposes,” Remus said.

Basin and river conditions continue to be monitored and system regulation will be adjusted based on the most up-to-date information.

Navigation

Per the July 1 system storage check, navigation flow support was increased to 500 cubic feet per second below the full-service level. The flow support season length will be a full eight-month season, ending Dec. 1 at the mouth of the Missouri River.

Gavins Point Dam releases are currently 27,500 cfs. Releases will be set to provide flow support at the intermediate-service level at all four target locations – Sioux City, Omaha, Nebraska City, and Kansas City. Navigation flow targets may be missed in reaches with no commercial barge traffic.

Fort Peck flow test

Test releases from Fort Peck to assess the potential benefits of alternative management scenarios for the pallid sturgeon began on April 26 and were terminated early due to lack of evidence of spawning. The test included two higher flow periods, in late April and June, with target flows at Wolf Point, Montana.

The first peak in releases was completed in early May with peak flows of 18,000 cfs at Wolf Point. Releases were reduced to 10,000 cfs by May 10. The second peak began on June 19 and reached a peak flow of about 20,000 cfs on June 26. Flows were then decreased to an average daily flow of 8,000 cfs around July 7. Releases were increased to 9,000 cfs on July 25 after Fort Peck resumed normal operations.

A female pallid sturgeon was recaptured on July 31, and it was determined via ultrasound that it had spawned. The spawning is the second ever confirmed spawning event on the Missouri River between Fort Peck and Garrison Dams. The United States Geological Survey is reviewing telemetry data to narrow down the location and timing of the spawning.

Reservoir forecasts

Garrison Dam Reservoir Forecast:

– Average releases past month, 22,000 cfs

– Current release rate, 22,000 cfs

– Forecast release rate, 22,000 cfs

– End-of-July reservoir level, 1842.0 feet (down 0.2 feet from June 30)

– Forecast end-of-August reservoir level, 1840.3 feet

Releases will be maintained at 22,000 cfs through mid-September.

The forecast reservoir releases and elevations discussed 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 631 million kWh of electricity in July. Typical energy generation for July is 954 million kWh. The power plants are expected to generate 8 billion kWh this year, compared to the long-term average of 9.4 billion kWh.