T. D. C. Pushpakumara, T. V. A. Isuru, (doi: 10.23953/cloud.ijarsg.366)

GIS (Geographic Information Systems) are used to store and process terrain data. Using GIS for could be very effective in flood modelling as it becomes very accurate with the use of the Digital Elevation Models. These DEMs could be analyzed with various tools in GIS software and by processing these terrain models, data necessary for the development of flow and flood models can be extracted with a minimum effort in the field. In this research Attanagalu Oya river basin was selected due to its constant exposure to floods and the model for Attanagalu Oya would be processed and the data extracted would be exported in to Hec-Hms and Hec-Ras software to model the flow and create a flood simulation to determine the extent of the flood. By using future rainfall forecasts in the flood simulation developed in this research future floods can be forecasted with great accuracy. As this model could be used to forecast the future floods and their extent it makes this model a warning system for future floods and could be used to mitigate the property loss and the damage incurred. Keywords