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Posted 1/29/2018

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Rock Island District
Corporate Communications Office 
(309) 794-5729

Upper Mississippi River System including Illinois Waterway

The development of an updated hydraulic model for the Upper Mississippi River (UMR) is an essential tool to understanding the risks that currently exist to the river communities and is a critical first step for the development of a systemic flood risk management (FRM) strategy. The model is a tool to more accurately evaluate and communicate impacts of existing or proposed modifications to levees or floodplains. This new model will lead to better and more consistent flood risk management. The hydraulic model will improve flood preparation and response, real time river forecasting and real time inundation mapping. The hydraulic model is strongly supported by the five states, local communities, and NGO’s. In fact, this is one thing a largely divided stakeholder group has collectively agreed upon in more than a decade and could serve as an important catalyst to development of a more collaborative and holistic FRM strategy for the region.

The development of the UMR hydraulic model has been a collaborative effort by federal and state agencies, facilitated by USACE Rock Island and St. Louis Districts covering 320 river miles from Mississippi River Lock and Dam 19 (River Mile 364) to Thebes, Illinois (River Mile 44) using the Hydrologic Engineering Center River Analysis System (HEC-RAS) model. The UMR hydraulic model will leverage the ongoing Corps Water Management System (CWMS) water control focused modeling effort. The UMR hydraulic model is intended to address flood risk management purposes and will incorporate detailed features such as additional cross sections, will model the entire floodplain bluff to bluff, and focus on large magnitude flood events.

The UMR hydraulic model has been collaboratively developed with other Federal agencies (USGS, NWS and FEMA), states of Iowa, Illinois, and Missouri to ensure transparency, buy-in and understanding of the model capabilities and limitations. Nongovernmental Organizations (NGOs) have also had several opportunities to be briefed and comment on the scope, methodology and progress during the development process. It is envisioned that many of these stakeholders will utilize this model for their own applications and analyses. The model is undergoing rigorous technical review to ensure accuracy and reliability.

The UMR hydraulic model will provide consistent and reliable answers on potential impacts caused by levee or floodplain alterations. It will replace multiple models currently in use, leading to better and more consistent flood risk management. The HEC-RAS model will run unsteady flow hydrographs and will provide a tool to efficiently evaluate proposed changes to the system.


flood risk FRM Hydraulic Model Rock Island District Upper Mississippi River USACE