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  • September runoff near average; Drought conditions continue in Missouri River Basin

    The month of September brought mixed results for precipitation across the Missouri River Basin. Portions of Montana, North and South Dakota, and Nebraska received above average rainfall, while the remainder of the upper basin and lower basin were below average. Overall, September runoff in the Missouri River Basin above Sioux City, Iowa was 1.3 million acre-feet, 109% of the long-term average. The annual runoff forecast for the upper Missouri River Basin above Sioux City, IA is 29.1 MAF, 113% of average and the same as last month’s forecast.

  • Now Available: Draft Missouri River Operating Plan; Possible Fort Peck test flow; Fall public meeting schedule

    Ahead of fall public meetings, the Draft Missouri River Mainstem Reservoir System Annual Operating Plan for the 2023-2024 runoff season is now available for public comment. The public comment period on the draft plan will close Nov. 30. 

  • Gavins Point winter release slightly above minimum rate

    Rainfall in the Missouri River Basin above Sioux City, Iowa, was above normal for the month of August, resulting in above average runoff. However, due to drier-than-normal conditions in previous years, the total storage in the Missouri River mainstem reservoir system remains lower than normal. Based on the Sept. 1 system storage, winter releases from Gavins Point Dam will be 13,000 cubic feet per second, per the criteria in the Master Manual. This release rate is slightly above the minimum rate of 12,000 cfs.

  • Missouri River Basin drought conditions persist

    July runoff in the Missouri River basin above Sioux City, Iowa was 3.3 million acre-feet (MAF), 99% of average. Runoff was near or above average in all reaches except the Fort Peck reach, which was 68% of average. The annual runoff forecast above Sioux City, IA is 28.5 MAF, 111% of average.

  • Gavins Point releases increased after System storage check

    Above average rainfall and fast-melting snow led to above average runoff in the upper Missouri River Basin in June. Runoff above Sioux City, Iowa was 6.7 million acre-feet, which is 122% of average. The annual runoff forecast above Sioux City, Iowa is 29.2 MAF, 114% of average, and about 2.4 MAF higher than last month’s forecast.

  • Rapid mountain snowmelt; above-average May runoff

    Warm temperatures in the mountainous region of the upper Missouri River Basin has led to a quick melt of the mountain snowpack. The rapid melting combined with precipitation in the western half of the Basin resulted in above-average inflow into the reservoir system. May runoff for the Basin above Sioux City, IA was 4.9 million acre-feet, 144% of average.

  • Mississippi River Climate Model–Based Hydrograph Projections at the Tarbert Landing Location

    Abstract: To better understand and prepare for the possible effects associated with potential climate changes on the lower Mississippi River, the State of Louisiana Coastal Protection and Restoration Authority sought information on the historical, current, and projected future hydrodynamics of the Mississippi River. To this end, flow duration curves (FDC) for the Tarbert Landing location were generated, based on climate models derived from two of the four scenarios of the Coupled Model Intercomparison Project, Phase 5 (CMIP5), multimodel ensemble representative concentration pathways (RCPs). The global CMIP5 datasets were used by the variable infiltration capacity land surface model to produce a runoff dataset, using a bias-correction spatial disaggregation approach. The runoff datasets were then applied to simulate streamflow using the Routing Application for Parallel computatIon of Discharge (RAPID) river routing model. Based on the streamflow, FDCs were calculated for 16 CMIP5 as well as observed historical data at the Tarbert Landing location. Key observations from the results are that the 90th percentile exceedance of the simulated versus the observed flows is more frequent for the RCP 8.5 scenario than for the RCP 4.5 scenario and that the maximum annual flows for the RCP 8.5 scenario are generally smaller than for the RCP 4.5 scenario.

  • Fort Peck releases to decline during maintenance

    Releases from Fort Peck Dam will be reduced from 9,000 cubic feet per second to 6,000 cfs on May 22. Releases will be increased back to 9,000 cfs on June 2. If the maintenance work is completed early, releases will return to 9,000 cfs as soon as possible.

  • Spring precipitation improves Missouri River Basin runoff forecast

    Late season plains snowpack accumulation and subsequent melting led to increased runoff throughout the upper Missouri River Basin during April. For the month, runoff was 4.7 million acre-feet, 159% of average, for the basin above Sioux City, IA. The annual runoff forecast for the upper Missouri River Basin above Sioux City, IA is 26.9 MAF, 105% of average, and 0.5 MAF higher than last month’s forecast. However, soil moisture remains slightly below normal in eastern Montana and the western Dakotas, and well below normal in Nebraska. Even with the plains snowmelt, soils dried out in late April over a large portion of the upper basin.

  • Missouri River Spring Virtual Public Meeting - Make Up - April 20

    A virtual make up meeting has been scheduled for April 20 at 1 p.m. after two in-person meetings were canceled due to weather on April 4. The virtual meeting can be accessed at the QR code and the url in the graphic.