Establishing flood damage functions for agricultural crops using estimated inundation depth and flood disaster statistics in data-scarce regions

: Flood damage functions form the core of flood risk assess ment. This study proposes a method for establishing flood damage functions for agricultural crops in data-scarce regions. The method assumes that the flood damage ratio is a function of inundation depth only and utilizes inundation depth estimated from flood extent information and hydro­ dynamic simulations. The parameters of the damage functions are calibrated through the SCE­UA method (Shuffled Complex Evolution method developed at The University of Arizona) so that the calculated flood damages match obser vations compiled in flood disaster statistics. The established three functions show good agreement with actual agricultural damages caused by a rainfall event in 2010 and are validated against another rainfall event in 2009. The results indicate that the established damage functions are capable of estimating flood damage at the district scale, while damage estimations at finer spatial resolution differ between the functions, suggesting that detailed statistical data need to be incorporated to reduce the estimation uncertainty at fine scales.