FLOOD RISK AREA ANALYSIS USING GEOGRAPHIC INFORMATION SYSTEMS AND THE ANALYTIC HIERARCHY PROCESS (AHP): A CASE STUDY OF THE SONGKHRAM RIVER BASIN

Abstract

The Songkhram River basin has been persistently affected by recurrent flooding, primarily due to its geomorphological characteristics as a low-lying basin with gentle slopes. This condition is further intensified by the backwater effect from the Mekong River during the flood season, which significantly constrains the drainage capacity of the river system. When there is a large amount of water during the rainy season, it causes the water to overflow the banks and flood the community and agricultural areas, causing damage. The purpose of this study was to assess the flood hazard of the Songkhram River basin using the Analytical Hierarchy Process (AHP) combined with the Geographic Information System (GIS) to analyze six factors: elevation, slope, runoff, average rainfall, land use and Distance from stream. The results of the study will be a flood-risk map. It is divided into 5 risk levels: very low flood risk area of 101.93 sq. km. (0.78%), low flood risk area of 193.43 sq. km. (1.47%), medium flood risk area of 304.11 sq. km. (2.31%), high flood risk area of 298.05 sq. km. (2.27%), and very high flood risk area of 155.42 sq. km. (1.18%), respectively. The analysis results show that flood risk areas in 17districts (Si-Songkhram District, Nakhon Phanom Province District) have the highest flood risk areas, most of which are community and agricultural. The results of the analysis be used to plan water management in the region to cope with flood problems.

Keywords: The Songkhram River Basin, Analytical Hierarchy Process, Flood Hazard