Rock Island Engineer District Releases Mississippi River Computer Model

The Rock Island Engineer District announced January 29 the release of a long-awaited computer model of Upper Mississippi River flows. The model covers 320 river miles, from Mississippi River Lock and Dam 19 (Mile 364) to Thebes, Ill., (Mile 44), using the Hydrologic Engineering Center River Analysis System (HEC-RAS) model.

The hydraulic model was a collaborative effort by federal and state agencies, facilitated by the Rock Island and St. Louis districts. Federal agencies involved include the Federal Emergency Management Agency, the U.S. Geologic Survey, and the National Weather Service.

Scott Whitney, district flood risk manager with the Rock Island District, told The Alton Telegraph that the model took almost $500,000 and 17 months to develop, out of a total estimated project cost of $2 million. Work on it began in August 2016. It considers so many variables that it can take hours to run a scenario.

Replaces Multiple Models

The hydraulic model will provide consistent and reliable answers on potential impacts caused by levee or floodplain alterations, the district said. 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.

Sign up for Waterway Journal's weekly newsletter.Our weekly newsletter delivers the latest inland marine news straight to your inbox including breaking news, our exclusive columns and much more.

The district called it “an essential tool to understanding the risks that currently exist to the river communities and … a critical first step for the development of a systemic flood risk management strategy.” It said the hydraulic model will improve flood preparation and response, real-time river forecasting and real-time inundation mapping.

Development of the hydraulic model was supported by five states, local communities, and several 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 [flood risk management] strategy for the region,” the district said.

The UMR hydraulic model will leverage the ongoing Corps Water Management System 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 model is undergoing “rigorous technical review to ensure accuracy and reliability.” It has been released for public use; interested parties can send the Rock Island District a one-terabyte external hard drive onto which the model can be loaded.