Upper Mississippi River System Hydraulic Model Update Complete 

The Rock Island Engineer District, St. Paul Engineer District and St. Louis Engineer District recently completed a seven-year effort to develop an updated, standardized hydraulic model for the Upper Mississippi River System, including the Illinois Waterway. The model can be used to evaluate and communicate the effects of floodplain modifications to provide better predictability and more consistent flood risk management for the Upper Mississippi River System.

The model, which was developed using the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) software, is available for use by federal, state and local agencies as well as non-governmental organizations involved in flood planning and future land-use and development activities. The updated model will allow communities within the Upper Mississippi River System to evaluate flood risks and explore mitigation strategies to more effectively provide protection for those living and working in these areas.

“The new hydraulic model is an essential tool for understanding the current risks that exist within river communities and is a critical first step to support development of a systemic flood risk management strategy,” said Paul St. Louis, Rock Island District senior project manager.

Development of the model took place in four stages, known as reaches. Reaches one, two and four cover the Mississippi River from Thebes, Ill., north to Minneapolis. Reach one was completed in January 2018, and reaches two and four were finished in October 2020.

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 The final stage of the model, reach three, covers the Illinois Waterway from its confluence with the Mississippi River at Grafton to Lockport, Ill., where it joins the Chicago Area Waterway System. 

The model was completed in March 2022 and is now available for public use.

The federally funded project covers more than 1,100 river miles. The total cost was $1.69 million.

For more information on the hydraulic model update or to request a copy of the HEC-RAS model files, visit: or contact the Rock Island District at 309-794-5729.