Abstract:

Crop loss assessment is critical for decision making in flooding management. From the perspective of disaster chain, flooding damage is a complex interaction of hazard factors (e.g., extreme precipitation), local topographic attributes and vulnerability of affected bodies, and thus characterized by large temporal and spatial variations. Developing a physically based modelling chain that can capture the dynamic evolution and spatial heterogeneity of the disaster process is critical for timely and efficient emergency response to flooding prevention. This study presented a modelling framework for estimating crop loss due to flooding, by coupling the flooding vulnerability curves with the Rainfall−Runoff−Inundation (RRI) model developed by the International Center for Water Hazard and Risk Management. The flooding vulnerability curve was shown as a function of inundation depth, duration and crop stage. A quantitative assessment of crop loss at gridded scale was established by integrating the inundation maps, crop distribution, and flooding vulnerability curves. The framework was applied to two representative flooding events on the Jianghan plain to demonstrate its capability to estimate crop losses due to rainstorm−induced flooding. The results showed that the RRI model could reasonably simulate the formation and retreat of the flooding peak as well as the surface inundation dynamics in accordance with the rainstorm, with the simulation error ranging from −14.8% to 11.5% for the runoff, the simulation accuracy exceeding 80% for the inundation area, the matching rate ranging from 84.2% to 87.1% for the inundation depth, and the estimated deviation of crop loss rate were −33.8% to 6.4%, −10.8% to −9.5%, and −6.0% to 1.8% for areas covered, areas affected and areas of total crop failure, respectively. The method proposed in this study provides a fundamental support for the rapid assessment and risk early warning for flooding mitigation and post−disaster reconstruction.

Key words: Rainstorm and flooding, Loss assessment, Hydrodynamic model, Jianghan plain, Crops