基于HEC-HMS模型的时间步长对次洪模拟的影响分析

Effects of Time Step Length on Simulation Results of the HEC-HMS

运用HEC-HMS水文模型,初步建立了适用于晋江西溪流域的暴雨洪水模型。在此基础上,采用15 min和60 min两个模拟时间步长,研究模拟时间步长的变化对模拟结果的影响,进而寻求最佳的时间步长和模拟结果。结果表明:时间步长对模拟结果存在一定的影响,当改变时间步长时,需要通过参数的调整,才可得到相似的模拟结果,在其他参数不变的情况下,模拟时间步长减小,蓄量常数(K)呈逐渐增大的趋势。同时,当采用较短的模拟时间步长时,模型的模拟效率得到提高。

In this study,a spatially distributed hydrologic model,HEC-HMS,was examined for its applicability in the Xixi watershed,a 1 259 km2 drainage basin in Fujian,southeast China.To study the effect of time step length on the model results,simulations were performed for time step lengths ranging from 60 min to 15 min at the basin scale.The results indicated： For different time step length,the simulation results will be similar with changing the model parameters.For example,the travel time of the flood wave through routing reach（K） will increase with time step length decreases.A choice for a certain time step length should be made before calibration of the model,and a smaller time step length should,in principle,give a more reliable result.