In recent years, climate change has caused extreme climate conditions. This intensifies and increases the amount of rainfall that caused floods in many regions of the world. The recent floods in Queensland, Australia provide evidence of the effects of increased climate change to the state and its population. The flash flood that occurred on the 10th of January 2011 in the West Creek catchment in the City of Toowoomba was a sudden and unexpected event making it difficult to implement flood mitigating/preventive measures. To reduce the impact of flood damage, this study aimed to develop an improved flood inundation model in the part of West Creek catchment using Geographic information systems (GIS) and the HEC-RAS hydraulic model. A digital elevation model (DEM) derived from LiDAR data was the primary data source for flood modelling. The geometric data (e.g. stream centreline, banks, flow path centreline and cross-sections, etc.) were extracted from the DEM and used in the analysis. A high resolution satellite image was used to classify land cover. Roughness coefficients were assigned according to different land cover types. Field measurements were also conducted to support the modelling process. These include measuring culverts, stream cross-sections, etc. The result was flood inundation map that clearly shows the spatial extent of the flooded area along part of West Creek and lower elevation areas within the catchment
