Enabling Improved Fluvial Process Characterization in Hydrodynamic and Hydrologic Models through Better Representation of River Bathymetry

Abstract:

Accurate bathymetric representation is critical for flood modeling and forecasting as it directly impacts hydrodynamic outputs such as inundation extent and depth which then indirectly impact surface-subsurface interactions. Quantifying and isolating the impact of specific bathymetric characteristics on surface–subsurface interactions can facilitate effective bathymetric incorporation in hydrologic and hydraulic models, especially in data-sparse regions. This study analyzes how bathymetric incorporation impacts fluvial processes such as infiltration, groundwater recharge, and lateral seepage. It also quantifies the level of geomorphological detail required for accurate modeling of flood related physical processes in a large-scale watershed. For creating large-scale topographic datasets with multiple bathymetric configurations, an automated framework called System for Producing RIver Network Geometry (SPRING) is implemented. These configurations are then simulated for multiple flood events using a computationally efficient physically distributed model named Integrated Channel and Pond Routing (ICPR). Comparison of surface and subsurface outputs from different configurations show that the channel volume, bed surface area and thalweg can significantly affect surface-subsurface interactions and these effects vary with river characteristics.