| Summary: | 碩士 === 國立成功大學 === 水利及海洋工程學系碩博士班 === 101 === This study aims to integrate HEC-RAS and FLO-2D models for inundation simulation and assess their performances. The study area focuses on the regional drainage of Dianbao River in Kaohsiung whose low-relief catchment is easily affected by tide level and is hard to drain overland flow properly. In the event that large mountain runoff or storm surge resulting from intense rainfall happens, the catchment often suffers from serious inundation due to the rise of external floodwater and the blocked drainage of internal floodwater. Thus, by analyzing the inundation depth and extent of downstream flat region, a reliable inundation model can act as an early warning system and future reference for the lowland responsing to typhoon events.
This study integrated Triangular Unit Hydrograph, hydraulic model and inundation model to analyze the flood conditions in the inundation areas. To solve the exchange problem between channel and overland flow, this study compared different water levels simulated by HEC-RAS and FLO-2D to obtain the water level hydrograph. By introducing water level hydrograph into FLO-2D, we calculated the inundation extent and depth. Various spatial resolutions were investigated in this study to assess the effect on inundation simulations. In consideration of simulation time and its accuracy, our result indicated that 60m × 60m grid resolution has the best optimal simulation result. The result of the comparison of two simulated inundation maps between FLO-2D model and physiographic inundation-drainage model is that the integration of HEC-RAS and FLO-2D has reasonable inundation extent and simulation results Typhoon Kalmaegi in 2008, Morakot in 2010 and Fanapi in 2011 are further chosen as validation events. According to the comparison between the simulated inundation map and the field survey, we could find out that the integration of HEC-RAS and FLO-2D can reasonably simulate the inundation extent and depth in this area.
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