Multi-hazard Risk Assessment Using GIS and RS Applications: A Case Study of Pak Phanang Basin

Abstract

Droughts and floods are natural phenomena where risks of occurrence are likely to continue to grow in Pak Phanang Basin. In the southern east coast of Thailand, Pak Phanang Basin covers a total area of 308,000 hectares with a total population of approximately 600,000. In this paper, the risk of drought and flood using GIS and RS is assessed and effective risk assessment process for the studied area is identified. The findings reveal that approximately 75,815 hectares, or 25 % of the total land area, exhibited a high multi-hazard risk. However, approximately 120,737 and 82,710 hectares, equivalent to 39 % and 27 % of the total land area respectively, were estimated to be experiencing medium and low multi-hazard risk. Further analysis revealed that residential areas and shrimp farms, especially in Nakhon Si Thammarat, Huasai, and Pak Phanang Municipality, are under high multi-hazard risk, while agricultural land scattering over the basin is consistent with medium multi-hazard risk. Finally, the swamp, located in the southernmost zone of the basin in Cha-uat District, faces low multi-hazard risk. Moreover, this paper concludes with risk management strategies and public participation integrated with risk assessment.

Keywords

• Drought and flood hazards
• geographic information system
• risk assessment
• remote sensing