Unraveling Flood Inundation Dynamics in the Backwater: A Case Study of Darby Creek, PA

The majority of the world's population resides within 50 km of a coast, where expanding large coastal population hubs, often located near the mouths of rivers, make fluvial morphodymics in the backwater increasingly challenging. To deepen our understanding of these systems and flood inundation dynamics due to morphological alterations, we have developed an integrative iterative fluvial morphological model. The model uses a combination of International River Interface Cooperative (iRIC) software, a water surface profile model, and a 2D model for shear stresses and morphological alterations, and represents the disparate hydraulics of the backwater, quasi-normal and transitional flows. The integrated models generate a new digital elevation model of the study area, which serves as the starting point for the next iteration of flow, ultimately modeling geomorphic changes through time. This model is applied to Darby Creek in Metro-Philadelphia, PA, one of the most flood-prone urban areas in the US. The model was ran for this study area using a range of discharges and sediment fluxes. The simulations were tested against LiDAR surveys and Landsat images. Unraveling urban backwater dynamics has the potential to contribute to flood planning and mitigation, infrastructure sustainability, and protecting the coastal environment.