The Application of Hydraulic Model with Geographic Information System to Flood Risk Mapping Creation in Mae Klong River

要旨

The objectives of this research are to integrate hydraulic model and Geographic Information System (GIS) for studying Mae Klong River runoff and to create the flood risk map based on hydrology and hydraulic approach. The process involved runoff frequency analysis for designing runoff return period, developing GIS data for generating Digital Terrain Modeling (DTM), integration of Hydrologic Engineering Centers River Analysis System (HEC-RAS) model with the DTM to develop regional model for flood plain determination, and designing flood return periods as a model for simulation of the prevention, warning, forecasting and estimating flood risk area. The result from the simulation model of flood in 1996 was presented together with GIS and DTM data. Accuracy of the model, comparing to the flooded data interpreted by the Royal Irrigation Department, was 60.52%. The result from 100 year return period flood simulation found that area with low risk was 99.67sq.km. Moderate risk was 321.18 sq.km., and high risk was 77.57 sq.km.. Further studies should be done on larger basin such as Mae Klong basin by dividing into sub-basins. The network link method to integrate sub-basins should be introduced to have an overview of the basin. The runoff flow in flood plain, river channel, man-made structures and GIS database were important input factors to study runoff flow behavior and predict flood area. Further studies are recommended to include rainfall-runoff model in upstream, roughness values, delicate GIS data and database management.