MAYAR MOHD ASSEM
Kariyata River Basin 2011 flood event simulation using hydrologic and hydraulic models
Minjiao LU
Flood is one of the most serious natural hazards in Japan. Kariyata river basin is one of the vulnerable regions which faced two extreme flood events in 2004 and 2011 due to heavy rainfall. Precipitation in the recent event exceeded the recorded value in 2004.
In this study the recent flood event is simulated for floodplain classification and 1D - 2D models domain identification purpose. For achieving this goal; first, runoff hydrographs are obtained using GSSHA distributed hydrological model simulation. Next, hydrologic data are routed using HEC-RAS (1D) and TUFLOW (2D) hydraulic models. Floodplains are delineated and calibrated with measured floodplain in Arc-GIS. Results show that 1D model has good agreement in positive lateral slope regions while negative lateral slope region is well represented by 2D model. Based on spatial analyses and calibration of delineated floodplain, it was found that floodplain extension and classification is function of lateral slope. Hence, the smallest lateral slope value of the region which is well represented by 1D model (0.007) is used as limit between 1D and 2D model domains. Based on this criterion Shiotani sub-basin was divided into two domains for 1D and 2D models. A nested 1D-2D model using 1D-2D TUFLOW was set up. Simulations results are recalibrated with measured inundated area. Calibration shows that, domains identification based on lateral slope criterion, improved floodplain accuracy and significantly reduces the computation time. In summary, this study gives user the opportunity to apply 1D and 2D models on required regions, lead user to a better result and reduce computational time.
Please use "previous botton" to return the previous page