PROPAGATION OF UNCERTAINTY FROM FLOOD INUNDATION MODELING TO DAMAGE ESTIMATIONS: TRADE-OFFS IN USING CHANNEL BATHYMETRY DERIVED FROM TOPOGRAPHIC LIDAR

This study evaluates the impact of terrain model resolution on flood inundation and damage assessments for a test river reach in Northern Italy. High-resolution topographic LiDAR (TL) data were compared against a benchmark incorporating bathymetric surveys. Using 2D hydraulic simulations and flood damage models, the study analyzed residential and agricultural damage sensitivity to inundation depth variations. The results indicate that, although inundation depth differences with coarser DTMs remained within 1 m, they cause loss estimation discrepancies of up to ±20% for the residential sector and 8-10% for crops. Variations are especially significant near activation thresholds for the damage mechanisms assumed in the models, as observed in cereal crops and residential areas with shallow flooding. Findings highlight the importance of considering the propagation of uncertainties in flood hazard modeling, with implications for risk assessment accuracy and cost-effectiveness in data acquisition strategies.