Perpustakaan Digital ITB

Floods have become an increasingly frequent disaster worldwide due to urbanization and climate change. Sophisticated flood risk mitigation must be implemented to ensure adequate disaster resilience. HEC-RAS 2D and TELEMAC-2D are examples of two-dimensional hydraulic modelling tools to simulate and mitigate flood risk. Because they utilized different numerical schemes and discretization, a comparative analysis is necessary to evaluate the implications of those differences on their results. This thesis simulated a building integrated historical flood event and a 25-year flood scenario generated from a calibrated HEC-HMS model. Differences in setup remained to evaluate if they could generate similar results. TELEMAC utilized finer mesh between buildings which were integrated into the mesh by creating holes. HEC-RAS 2D integrated building with modelling terrain and utilized coarser mesh. The resulting 25-year flood inundation was used to generate flood hazards and risk maps to evaluate their applied implications. Both models generated remarkably similar inundations, though TELEMAC simulated slightly larger inundations caused by its mesh who could not capture terrain and bathymetry information as fine as HEC-RAS with its subgrid bathymetry feature. This was also influenced by its wetting-drying algorithm who could not do partial wetting like HEC-RAS’ volume-based computation. HEC-RAS ability to process subgrid bathymetry with coarser mesh contributed to faster computation times. Despite the unrealistic velocity simulation, it could accurately distribute flood extent around buildings. The resulting risk map reflected the discrepancy observed in model results. TELEMAC was able to simulate higher hazards between buildings due to its finer mesh, providing useful information for designing evacuation routes. Overall, both models have demonstrated their remarkable capabilities. If computation time is not a limiting factor, TELEMAC could be used, especially for flash floods prone area. Conversely, HEC-RAS could be used for large-scale modelling, whose depths are the main parameter of concern.