Seasonal Spatial Analysis in Determination of Flash Flood and Drought Hazard Areas Using AHP and GIS:A Case Study of Kampong Speu Province in Cambodia

Abstract

Climate change increases the incidence and magnitude of extreme events, especially, hydro-meteorological events including floods and droughts. Cambodia faces serious floods and droughts almost every year. Hazard mapping is significant for mitigation and prevention approaches. The integration of the Analytical Hierarchy Process (AHP) with Geographic Information System (GIS) and Remote Sensing data expressed the appreciated inquiry method in the current study. The purpose of this study is to map the seasonal spatial distribution of flash flood and drought hazard with the support of the AHP method and GIS techniques of Kampong Speu Province in Cambodia. The hazard maps are separated into two seasons, rainy season and dry season. Ten parameters are used to assess flash flood hazards including rainfall, elevation, slope, soil types, geology, flow direction, stream order, landuse, distance from drainage, and drainage density. Besides, eight parameters such as rainfall, relative humidity, average temperature, maximum temperature, slope, soil types, landuse, and drainage density are used to identify the drought hazard. With the help of AHP and GIS, the flash flood and drought hazards were further used to develop a bi-hazard map over Kampong Speu Province. The results reveal that Aoral, Thpong, Phnum Srouch, and Samraong Tong Districts are located in very high hazard to the rainy seasonal flash flood with 9.29%, 0.61%, 0.28%, and 0.01% of the total areas, respectively. For the dry seasonal flash flood, the above-mentioned districts are located in very high hazard spatial distribution with 12.68%, 1.48%, 1.10%, and 0.04% of the total areas, respectively. Furthermore, Basedth, Kong Pisei, Odongk, and Samraong Tong Districts are located in very high hazard to rainy seasonal drought with 4.30%, 4.28%, 4.08%, and 2.62% of the total areas, individually. About 4.26%, 4.21%, 2.72%, 1.76%, and 0.7% of the total areas located in Odongk, Kong Pisei, Samraong Tong, Basedth, and Thpong Districts respectively are found in the very high hazard to dry seasonal drought. Bi-hazard areas are identified as very low (12% of the total areas), low (31% of the total areas), moderate (24% of the total areas), high (30% of the total areas), and very high (3% of the total areas). All districts are identified as located in the very high bi-hazard. Thpong District has the largest areas prone to very high bi-hazard with 64.59 km2 (0.93% of the total areas). The obtained maps create the various dataset and serve as information for comprehensive hazard assessment. It is also reflected as essential information for planners and decision-makers for the future operational flash flood and drought mitigation measures, planning, management, and sustainable development.

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