Author(s): Tatiane Souza Rodrigues Pereira; Guilherme Da Cruz Dos Reis; Kamila Almeida Dos Santos; Klebber Teodomiro Martins Formiga
Linked Author(s):
Keywords: HEC-RAS; Flood mapping; LiDAR; Copernicus DEM; Digital elevation models; Urban flooding
Abstract: Digital Elevation Models (DEMs) are important for accurate flood simulations, but how different DEM sources affect small-scale urban flood modelling remains poorly understood. This study compared four DEMs (LiDAR 1m, NASADEM 30m, Topodata 30m, Copernicus DEM 30m) for flood mapping using HEC-RAS 1D/2D modelling in a 1.92 km² urban area in Goiânia, Brazil. River bathymetry was measured with ADCP at 21 cross-sections. Three flood events were modelled, including a 100-year design flood. The Copernicus DEM showed the smallest differences compared to LiDAR (RMSE 0.72-7.50 m) and simulated 0.973 km² of inundation for the design event, close to LiDAR's 1.044 km². NASADEM and Topodata underestimated 18.2% and 23.5%. These results suggest Copernicus DEM may be suitable for design flood forecasting at small scales.
Year: 2026