INVESTIGATING SEDIMENT DEPOSITION VARIATIONS IN FLOODPLAINS OF THE LOWER MISSISSIPPI RIVER- A SEDIMENTOLOGICAL, GEOCHEMICAL, AND GEOSPATIAL APPROACH

Mississippi River floods are some of the costliest climate-related disasters in the world. Compound flooding is a type of flooding that happens when multiple events occur simultaneously that exacerbate the duration or longevity of flooding in an area. For example, River levees that are designed to prevent significantly high river stages could be breached if excessive localized rainfall caused an increase in discharge from tributaries while simultaneously receiving a surge in discharge from excessive rainfall that happened upstream.

There has been extensive research in creating hydraulic and hydrological models to predict compound flooding, but considerations of the sedimentation process have not been extensively researched. This study evaluates sediment deposition changes of two Lower Mississippi River floodplains that have shown an increased rate of floods over the last decades using stream gauge data. Sediment cores were analyzed using multiple techniques: grainsize analysis, XRF, and Radiocarbon dating of any organics found. Additionally, historical and present geospatial data was used to show differences in elevation of the study locations. Understanding changes in sedimentation could assist in better modeling and the mitigation and management of compound flooding.