Flood Risk Assessment and Mitigation Measures in Nakhon Si Thammarat City -

Abstract

        Nakhon Si Thammarat City regularly faces with floods, particularly during November to January each year. The most recent floods causing severe impacts were in 2017. Two floods affected 208,387 households in 23 districts, and killed 12 people. The total value of such damages was approximately 466,292,917 Baht. Therefore, the objective of this study was 1) analyze flood risk areas in Nakhon Si Thammarat City, 2) analyze policy gap related to the flood mitigation measures in Nakhon Si Thammarat City, and 3) propose some recommendations on flood mitigation in Nakhon Si Thammarat City. This study employed GIS as the main tool for analyzing, processing, and illustrating flood variables. Then, risk analysis and content analysis were conducted to consider policy gaps and point out some guidelines to cope with floods in the future.
           The findings showed that high risky flooding areas were the north and the central part of the city, comprising Pak Phun Subdistrict, Tha Sak Subdistrict, Tha Wang Subdistrict, Klang Subdistrict, Nai Mueang Subdistrict, Nakian SubDistrict and Pho Sadet Subdistrict. Such areas cover 23.430 square kilometers (14,643.37 rai), or 16.96 percent of the total area. Both structural and non-structural measures should be implemented for flood mitigation, for instances, the construction of a drainage canal or a new water diversion canal, the construction of retention area (monkey cheek), and zoning legislation for the municipality to allow some areas to be flooded. This is to prevent and reduce the impacts in the risky areas.