Development, Validation, and Application of a Large-Scale 2D Hydrodynamic Model for the Lower Mississippi River

A comprehensive two-dimensional hydrodynamic model has been developed for the Lower Mississippi River (LMR) using Adaptive Hydraulics (AdH). Spanning nearly 1000 miles from the confluence of the Ohio River at Cairo, Illinois, to the Gulf of Mexico, this model integrates the river’s main channel, floodplain, and significant tributaries. The model covers over 22,000 square miles and is composed of approximately 1.3 million nodes, providing high resolution across a vast area. Bathymetric data for the model comes from 2023 multi-beam and single-beam surveys conducted by the US Army Corps of Engineers' Memphis, Vicksburg, and New Orleans districts. The model is validated using data from several gage locations distributed throughout the LMR, as well as continuous water surface profiles. By incorporating a system-wide approach, this model enables large-scale analysis of hydrodynamic behavior, moving beyond the more common reach-by-reach assessments. It provides a more comprehensive understanding of river flow dynamics. This model is set to support a variety of future applications, including the evaluation of batture roughness effects on flowlines and flood attenuation throughout the river. Additionally, it will serve as a foundation for the development of an operational low water model, which will enhance predictions of navigational depths across the LMR. Such capabilities are essential for improving navigation during low water events and for optimizing flood risk management strategies. This model represents a critical tool for advancing hydrodynamic modeling and river system analysis at a large, operational scale.