AHP-GIS analysis for flood hazard assessment of the communities nearby the world heritage site on Ayutthaya Island, Thailand

Abstract

Thailand faced the worst flooding in half a century in 2011. A previous flood had harshly affected the UNESCO World Heritage Site (WHS) and the surrounding communities. The aims of this study were to assess the spatial distribution of flood hazards and analyze how past experience contributed to community flood readiness. Both GIS analysis and household surveys (n = 405) were systematically performed. According to the Analytic Hierarchy Process (AHP) technique, approximately half of the whole community area (52.63%) and the WHS (44.8%) were at high risk of flooding. Pratuchai, the most populated subdistrict, was at the highest flood hazard level. Runoff and road density were the main contributors to flooding in a community. Regression analysis found that there was a negative correlation between past flood experience and residents’ flood readiness. According to the cluster analysis, there were two groups of respondents: i) those who had more experience with both flood hazards and the inaccessibility of urban services during a flood and were less likely to prepare themselves for future floods (n = 313) and ii) those who had less experience with floods and the inaccessibility of urban services and were more likely to prepare for future floods (n = 92). This implies, in short, that the local populace had not learned much from past experiences of a flood disasters. Advance urban flood management, multi-hazard zoning, and effective flood risk communication are urgently needed to improve flood resilience in the WHS communities.