A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science in Urban Environmental Management

Thesis (M. Sc.) - Asian Institute of Technology, 2020

The water-related hazards, such as river floods, flash floods, and droughts, cause serious harm to human activities and their assets. Hence, the multiple hazard assessment reduction focusing on changing climate and urbanization is necessary. The main objective of this study is to determine key factors influencing multiple waterrelated hazard assessment and reduction in different temporal and spatial scales in a selected sub-region of the Yom River Basin, Thailand. The concept of multiple water-related hazard assessment applied a combination of the MCDA approach, spatial analysis and simulation modeling to evaluate the multiple hazard in the area. The dataset is obtained from various governmental agencies related to hydrological hazards both primary and secondary data covering local decisionmakers{u2019} interviews as primary data and historical and projected data as secondary data including relevant key variables to simulate the MHA. The major factors influencing the multiple hazards are rainfall, discharge, natural green surface area and natural/ built wetlands. The multiple hazards generally occurred in the upper and western sub-region in the wet and dry season. Typically, river flood hazard arisen in the middle and lower part of the region in the wet season as well as and flash flood occurred in the hilly area, but drought hazard regularly covered the sub-region in dry season. In the local areas, the river flood and drought hazard hit all the focused local areas in wet and dry season whereas flash flood hazard attacked some local area located in hilly areas. Finally, the possible options for hazard reduction based on NBS integrated with the natural green surface area and natural/ built wetlands as key factors that help to minimize the hazard severity and its areas by increasing the green areas at 7 percent and constructing the natural/ built wetlands integrating with planning for water management to cope the hazard in the area.