Abstract:
Galoya River basin affected by flash flood during the north-east monsoon period. The Department of Irrigation, Metrological Department and Disaster Management Center to predict flash flood events. However, these programmes have a number of scarcities for several forecast areas in nation. Developing a GIS based model that integrates basin physiographic characteristics will allow the hydrologist to better predict flood events. In this study, I have developed geospatial model to establish the flooding potential for the upper Gal Oya river basin. The dynamic GIS parameters used to model development are slope and flow accumulation, land cover and vegetation, soil hydrologic, drainage classes and precipitation. All these layers were converted to raster datasets, using the basic attribute field responsible for flooding potential analysis each model parameter was assigned weights at the time of reclassifying, a rank of least flood potential (1) to most flood potential (9). Finally, each layers were overlayed with a weighted overlay analysis. For the weighted overlay analysis, each layer was given certain weights evaluated by their influence in flooding potential. The final flooding potential map was obtained as colored map with scale 1 to 9. This model can be easily simulated in any other basin in the nation by changing the input parameters. Study area under different flooding potential scale. More than 70% of the area is under the low to medium vulnerability with respect to flooding potential. Rest of is under high to very high flooding potential area.
