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Sensitivity analysis of 2-D flood inundation model LISFLOOD-FP with respect to spatial resolution and roughness parameter

Kıyıcı, Ezgi
One of the most common disasters in the world is flooding and it’s well known that it causes environmental, social and economic damages. Since these damages could be severe and destructive due to drivers such as climate change and humane factors, the necessity of flood management studies is revealed. Europe has recognized the need for creating flood risk maps and flood hazard maps. 1-D and 2-D hydraulic models have been used to obtain these maps. This study is focused on the sensitivity of a 2-D hydraulic model, LISFLOOD-FP which uses simplified shallow water equations assuming convective acceleration term as negligible. The study area Terme City, which is located in the Middle Black Sea Region of Turkey was exposed to a storm event on July 2012 and the river water level reached the top of the levees. With the help of the available data, the effect of neglected convective acceleration term in hydraulic model is investigated in a benchmarking study where MIKE21 and LISFLOOD-FP hydraulic models are used. The results show that LISFLOOD-FP (Acceleration and Subgrid Channel Solver) is affected by spatial resolution in terms of the representation of flood propagation and computation time. In addition, roughness coefficient can be used to calibrate the model to obtain better results. It's obtained that Subgrid Channel Solver gives better results compared to Acceleration Solver even for coarse resolutions since it allows the use of fine resolutions to define the channel, so that eliminates the negative effects of resampling, to a coarse resolution.