A Spatially Explicit Multi-Criteria Analysis Method on Solving Spatial Heterogeneity Problems for Flood Hazard Assessment

Flood hazard assessment and mapping of flood prone area are of great importance for flood management, as well as the reduction of potential losses of life and property caused by flooding. In this study, a spatially explicit multi-criteria analysis approach which emphasizes on spatial heterogeneity in decision-making process is developed for flood hazard assessment, and it has been applied to the area including Hanyang, Caidian and Hannan of Wuhan, China, where flood events occur frequently. Factors associated with flood mechanism and characteristics of the watershed itself were selected, and primary analysis was implemented to make the factors concise and essential. This paper emphasized the spatial heterogeneity problem in flood hazard assessment by incorporating spatial ordered weighted averaging (OWA) method into windows-based local spatial multi-criteria analysis (MCA). On one hand, the local normalization was applied to normalize the criteria, and entropy-based local criteria weights were calculated to adjust the criteria weight at local level. On the other hand, spatial OWA method with spatially variable risk preference was applied to assign different order weights at different locations. The results indicate that the proposed approach focused on the flood hazard at local level, and the flood hazard map presented more dispersive distribution of the high and very high hazard area than that derived by global MCA. Furthermore, flood hazard in important and unimportant area was distinguished by paying more attention to the former one. And the distribution of high hazard area tends to be mainly located in populated and developed areas.