Upper Mississippi River System Hydraulic Model Update

Rock Island District
Published Oct. 1, 2021
Upper Mississippi River Hydraulic Model Graphic

Upper Mississippi River Hydraulic Model Graphic


Upper Mississippi River System, including Illinois Waterway


The development of a standardized and seamless flood risk management 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 systemic flood risk management (FRM) strategy. The model is a tool to more accurately evaluate and communicate impacts of floodplain modifications that have occurred or may be proposed in the future. This new model will lead to better predictability and more consistent flood risk management. The hydraulic model has been strongly supported by the five states, federal agencies, local communities and non-governmental organizations. 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. A Hydrologic Engineering Center River Analysis System (HEC-RAS) hydraulic model is proposed. This model would incorporate software improvements, navigation dams and the availability of period-of-record inflow data files for various model users. The updated UMR Hydraulic HEC-RAS model would allow for wider use for floodplain management on the UMR system in support of flood risk management and 408 Levee Modification studies. The HEC-RAS model would run unsteady flow hydrographs and provide a base condition to efficiently evaluate proposed changes to the system and subsequent transference of risk. It would replace multiple models currently in use, leading to better and more consistent flood risk management. State, county and the local community officials would have access to enhanced flood risk information to assist with community communication and decision making processes regarding land-use and future development in high risk flood areas. Flood planning tools are critical to proactively reduce hazard risks and invest in hazard response and recovery capacity. The community based flood planning would mitigate risk to health, safety and property posed by floods in order to protect life, property, the economy and lower the demand for emergency response activities.


Approximately $500,000 of FY16 funding was reprogramed to collaboratively develop, test and review this new hydraulic model for Reach 1 (320 river miles) from Lock and Dam 19 at Keokuk, Iowa (River Mile 364), to Thebes, Illinois (River Mile 44). This increment of the model was completed and widely released for partner and stakeholder use in January 2018. It is important to understand that this was a model development effort, not a traditional USACE study authority which compare alternatives or consequences of courses of action. Since this tool is likely to be used for future studies or evaluations, it was developed in a highly collaborative and transparent manner coupled with external expert reviews to ensure the greatest degree of trust, credibility and confidence from our partners, stakeholders and public. Broader application and testing of the model by expanded stakeholder groups may identify further refinements or enhancements. This new tool will serve to accurately and realistically predict changes in water movement and depth profiles in response to a variety of “what if” land-use variables. Such information is integral to the risk-informed planning, evaluation and decision-making processes.

The first reach of model development was well received by communities and stakeholder groups in the UMR. Three additional reaches of the UMR still need to be developed to fulfill the intent to have a standardized hydraulic model platform for the entire UMR.

$575,000 of FY19 funding was reprioritized and received to expand the model development to incorporate priority Reach 2 (219 river miles) ($350,000), extending upstream from Lock and Dam 19 at Keokuk, Iowa (River Mile 364), to Lock and Dam 11 at Dubuque, Iowa (River Mile 583), and Reach 4 Dubuque, Iowa, to Minneapolis, Minnesota ($225,000). Reaches 2 and 4 were completed in September of 2020 and was widely released for partners and stakeholders in October of 2020.

$485,000 out of an estimated $615,000 was provided in FY21 to start the final phase, or Reach III, of the model. This reach of the model incorporates the Illinois Waterway, 291 River Miles from Grafton, Illinois (River Mile 000) to Lockport, Illinois (River Mile 291). The entire Reach III is scheduled to be completed in January of 2022. 

Additional Information


SI - Special Interest

Summarized Project Costs

Estimated Federal Cost

$ 1,690,000

Estimated Non-Federal Cost

$ 0

Estimated Total Project Cost

$ 1,690,000

Allocations Prior to FY 2022

$ 1,560,000

FY 2021 Allocation


FY 2022 Allocation


FY 2022 President's Budget


FY 2022 Total Capability



Major Work Item Prior Fiscal Year

FY 2021:  Expanded the model development to incorporate the final Reach 3 along the Illinois Waterway (291 river miles), extending from Grafton, Illinois (River Mile 000) to Lockport, Illinois (River Mile 291). Conducted a Federal and State partner review of the draft model and report.

Major Work Item Current Year

FY 2022:  If funded, work will proceed with completion of Phase III of the hydraulic model, and mark completion of hydraulic model for the entire Mainstem Upper Mississippi River and Illinois River Hydraulic model.