Overbank Flow and Runoff Simulation Using Two-Dimensional Diffusion-Wave Method
As the hydrokinetic wave algorithm is based on the unidirectional flow assumption,it is not applicable to deal with the non-unidirectional flow generated by riverbank overflow.In order to accurately simulate the true physical overbank flow sce-nario,a two-dimensional diffusion wave method was applied in modeling the Qijiang flood disaster event that occurred in Chongq-ing on June 22,2020.The GSSHA(Gridded Surface Subsurface Hydrologic Analysis)model was used in this investigation.The simulated flood peak percentage error is 0.34%with parameter optimization,and the NSE coefficient is 0.84.Overall,there is good agreement between the measured and generated hydrographs.The research shows that compared with the dynamic wave model,the two-dimensional diffused wave model could improve the simulation accuracy and effectively solve the problem of flood peak time lag and peak height drop that caused by river overflow,which provids a theoretical basis and method support for flood prediction in the basin under complex hydrodynamic conditions.