Approach and Outcomes
The original model had utilised SRTM digital elevation data. As considerably more accurate LiDAR had become available in the interim period a new XP-RAFTS hydrological model and new TUFLOW hydraulic model were developed. The TUFLOW model utilised a three metre grid resolution and contained eleven 1D structures. A joint calibration was undertaken for the December 2010 and January 2011 flood events. Simulations were then undertaken for 1%, 5% and 20% AEP design events. Maps were created for peak flood depths, peak water levels, peak velocities, peak flood hazard and peak flood risk. The study revision showed a significant reduction in flood extent attributable mostly to the change in terrain data input. This also resulted in significant reductions of peak flood hazard and peak flood risk.