Integrated flood risk assessment and zonation method: a case study in Huaihe River basin, China

Flood risk assessment and risk level zonation is very important for preventing the watershed flood disaster and making disaster mitigation plans. We establish a flood disaster risk assessment model based on GIS and natural disaster risk assessment theory. We build up a risk assessment index system based on hazard of natural environment and vulnerability of economic society. Furthermore, we propose two indices, reservoir storage modulus and flood detention basin modulus, and use them to characterize human intervention capability on flood in the hazard index set. To reduce the occurrence of the inconsistency problems when using analytic hierarchy process (AHP) method in multi-indices comparison, we use the coupled AHP and expert scoring method to determine the weights of indices. We apply the methodology to the Huaihe River basin. The results show that the multi-year average risk zonation map from 1960 to 2010 is consistent with the historical flood disaster distribution, which verifies the applicability of this method in flood disaster risk assessment.