Fort Peck Reservoir Water Levels 17 Feet Lower Then 2021 Levels

For the 2022 calendar year, Missouri River basin runoff above Sioux City, Iowa, totaled 19.3 million acre-feet, 75 percent of average. This was the 30th lowest annual runoff for the Missouri River Basin in 125 years of record-keeping.

The ongoing drought shows little relief in sight and the U.S. Army Corps of Engineers predicts runoff into the mainstem reservoir system will remain below normal. For 2023, runoff in the Missouri River basin above Sioux City, Iowa, is forecast to be 20.8 MAF, 81 percent of average.

This is based on current runoff trends, drier than normal soil conditions, and nearly average plains and mountain snowpack. At the start of the 2023 runoff season, which typically begins around March 1, the total volume of water stored in the mainstem reservoir system is expected to be 45.7 MAF, 10.4 MAF below the top of the carryover multiple use zone. The Mainstem Missouri River reservoir system is designed to use the water contained within the carryover multiple use zone to provide service to the eight Congressionally authorized purposes during extended droughts. Those purposes are flood control, navigation, water supply, irrigation, hydropower, recreation, water quality control, and fish and wildlife.

Service to the authorized purposes will continue to be reduced to conserve water in the reservoir system should drought conditions persist. Primary drought conservation measures outlined in the Master Manual include reducing winter releases and flow support for navigation. Flow support to navigation was provided at or near the minimum service level throughout the 2022 season. A significant portion of the water stored in the multiple use zone was used in 2021 and 2022 to serve the authorized purposes and resulted in implementation of water conservation measures.

To further conserve water in the Missouri River Mainstem reservoir system, minimum releases from Gavins Point Dam are scheduled this winter while still serving the needs of the municipal, industrial and powerplant water intakes along the lower river.

Mountain snowpack in the upper Missouri River Basin is accumulating at slightly above-average rates. The Jan. 1, mountain snowpack in the Fort Peck reach was 111 percent of average, while the mountain snowpack in the Fort Peck to Garrison reach was 103 percent of average. More than half the mountain snowfall typically occurs from Jan. 1 to mid-April, and normally peaks near April 17. The mountain snowpack graphics can be viewed at: http://go.usa.gov/xARQC.

The plains snowpack, which typically melts from mid-February into April, is currently above normal. Over 2 inches of snow water equivalent (SWE) covers much of the plains, with up to 6 inches in the central Dakotas and in the upper James River basin in North Dakota.

The six mainstem power plants generated 475 million kWh of electricity in December. Typical energy generation for December is 682 million kWh. Total energy generation for 2022 was 7.5 billion kWh of electricity, compared to the long-term average of 9.4 billion kWh. Forecast generation for 2023 is 7.7 billion kWh.

Fort Peck Reservoir dropped to an elevation of 2,218.8 feet at the end of December and is expected to fall almost another half foot by the end of January. The lake’s elevation is about 7 feet lower than at the same time last year and 17 feet lower than at the end of December in 2020.

Releases from the reservoir are scheduled to be 6,500 cubic feet per second for the next two months.