Authors: Reza Saleh Alipour – The University of Alabama
Title: A Multi-Scale Comparison of Hydrodynamic and Terrain-Based Models for Operational Flood Inundation Mapping
Presentation Type: Poster Presentation
Abstract: Accurate flood inundation mapping is essential for reliable forecasting and effective emergency response, yet it remains challenging in data-constrained and heterogeneous environments. Physically-based hydrodynamic models such as HEC-RAS 2D and TRITON can represent flood processes with high physical fidelity, but their extensive input requirements and computational demands can limit feasibility for near-real-time operations and large-domain deployment.
In contrast, terrain-based approaches such as HAND-FIM and FLDPLN offer faster and more accessible alternatives, but the performance of terrain-based methods relative to hydrodynamic models across complex terrain and urban settings remains insufficiently established. This study presents a structured, cross-model evaluation of HEC-RAS 2D, TRITON, HAND-FIM, and FLDPLN using consistent spatial inputs to compare accuracy in flood extent and depth, computational efficiency, and operational suitability across multiple spatial scales and study areas.
Model performance is assessed using standard metrics for inundation extent and depth, including CSI, F1 score, recall, RMSE, etc. The resulting comparisons provide practical guidance on when simplified terrain-based workflows can deliver sufficiently reliable flood maps for operational use, and under what spatial, hydrologic, and decision-making constraints, hydrodynamic modeling remains necessary. Overall, the study clarifies model strengths and limitations and supports evidence-based selection of flood inundation mapping approaches for scalable, near-real-time forecasting across diverse geographic contexts.