5 May 2023

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.

4 May 2023

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.

13 Apr 2023

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.

7 Apr 2023

Upper basin runoff forecast improves with spring precipitation

The latest 2023 calendar year runoff forecast for the Missouri River Basin above Sioux City, Iowa is showing improvement. The 2023 calendar year runoff forecast above Sioux City is 26.4 million acre-feet (MAF), 103% of average. The runoff forecast is based on current soil moisture conditions, plains snowpack, mountain snowpack, and long-term precipitation and temperature outlooks. March runoff in the Missouri River Basin above Sioux City was 1.7 MAF, 57% of average.    

7 Mar 2023

Upper basin runoff forecast below average; Gavins Point releases to increase for navigation flow support; April public meetings

The updated 2023 calendar year runoff forecast for the Missouri River Basin above Sioux City, Iowa, continues to be below average. The 2023 calendar year runoff forecast above Sioux City is 21.5 million acre feet, 84% of average. The runoff forecast is based on current soil moisture conditions, plains snowpack, mountain snowpack, and long-term precipitation and temperature outlooks. February runoff in the Missouri River Basin above Sioux City was 1.0 MAF, 86% of average.

7 Feb 2023

Below average runoff continues for the upper Missouri River Basin in 2023

The updated 2023 calendar year runoff forecast for the Missouri River Basin above Sioux City, Iowa, continues to be below average. January runoff in the Missouri River Basin above Sioux City was 1.1 million acre-feet, 134% of average. Runoff was above average due to warmer-than-normal temperatures in the upper basin resulting in some snowmelt runoff.

6 Jan 2023

Dry Conditions expected to persist for the Missouri River Basin

For the 2022 calendar year, Missouri River basin runoff above Sioux City, Iowa totaled 19.3 million acre-feet, 75% 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% of average.

6 Dec 2022

Releases from Gavins Point Dam reduced to winter rates

Flow support for the 2022 Missouri River navigation season ended Nov. 21 as releases were reduced toward winter rates at Gavins Point Dam. “Releases from Gavins Point Dam are being reduced to the winter release of 12,000 cubic feet per second,” said John Remus, Chief of the Missouri River Basin Water Management Division.

30 Nov 2022

Automation of Gridded HEC-HMS Model Development Using Python: Initial Condition Testing and Calibration Applications

Abstract: The US Army Corps of Engineers’s (USACE) Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) rainfall-runoff model is widely used within the research community to develop both event-based and continuous rainfall-runoff models. The soil moisture accounting (SMA) algorithm is commonly used for long-term simulations. Depending on the final model setup, 12 to 18 parameters are needed to characterize the modeled watershed’s canopy, surface, soil, and routing processes, all of which are potential calibration parameters. HEC-HMS includes optimization tools to facilitate model calibration, but only initial conditions (ICs) can be calibrated when using the gridded SMA algorithm. Calibrating a continuous SMA HEC-HMS model is an iterative process that can require hundreds of simulations, a time intensive process requiring automation. HEC-HMS is written in Java and is predominantly run through a graphical user interface (GUI). As such, conducting a long-term gridded SMA calibration is infeasible using the GUI. USACE Construction Engineering Research Laboratory (CERL) has written a workflow that utilizes the existing Jython application programming interface (API) to batch run HEC-HMS simulations with Python. The workflow allows for gridded SMA HEC-HMS model sensitivity and calibration analyses to be conducted in a timely manner.

4 Nov 2022

Gavins Point Dam releases to be reduced to winter release rate in late November

Six public meetings were held during the week of Oct. 24 to present current hydrologic conditions and the planned operation of the Missouri River mainstem reservoir system for the remainder of 2022. The public meetings were held in six locations in the Missouri River basin and a virtual public meeting was held Nov. 3. The meetings included draft plans for regulating the system in 2023. “We will continue to make releases from Gavins Point Dam to provide flow support at a level 500 cubic feet per second above minimum service, through the end of the navigation flow support season,” said John Remus, chief of the USACE, Missouri River Basin Water Management Division. “The flow support season will end three days early, on Nov. 28, at the mouth of the Missouri River.”