流域洪水模拟的分布式时变汇流方法及应用

在考虑流域降雨时空变化和流域地形对流域产、汇流影响的基础上,提出了一种流域洪水模拟的新方法——分布式时变汇流方法。该方法在分布式产、汇流模拟过程中,增加了时变因子,克服了传统方法中忽略降雨在时间上变化的影响。此外,该方法还充分利用了GIS和遥感技术,使得模型中的大多数参数均可从DEM、土壤类型图或遥感影像中获取,只需要率定少数敏感参数。尽管模型结构简单,却能反映降雨径流过程的物理机制。因此,它可用于无资料地区的水文预报,便于应用与推广。将该方法用于浙江省皎口水库流域的洪水模拟,结果显示该模型效率高,模拟的流量曲线与实测曲线吻合较好,并且模拟结果不受降雨强度大小的限制。对双峰型或多峰型洪水,该方法不仅能很好地模拟出各峰的形状,而且主次洪峰分明。

A Method for Spatially Distributed Time-variable Routing of Simulated Watershed Flood

Through considering the effects of spatiotemporal transformations as well as watershed topography on runoff routing,this paper reports the development and implementation of the new method named spatially dis- tributed time-variable routing method.The method incorporates time-variable factors into distributed yielding and routing simulations.In this way,it can overcome the shortcomings of ignoring the changes of excess rainfall over time in the traditional methods.Inaddition,with the support of the geographical information system (GIS) and remote sensing(RS),most of the parameters in the model can be obtained by means of DEM,soil maps and/or satellite images.Among the others,only some sensitive parameters need to be determined through calibration.Al- though the model seems to be simple,it can reflect the physical mechanism of rainfall- runoff process.In conse- quence,the method can predict the runoff hydrograph in the ungauged watersheds,so that it can be extended to other areas in the future.In the combination of this method with GIS technique,stream responses to runoff events in the Jiaokou Reservoir Watershed in Zhejiang Province were predicted.Results showed that the model efficiency was high,and the simulations were approximately consistent with the observations for the shapes of runoff hydro- graphs when the factor for the changes of excess rainfall over time was considered in the model.Most importantly, the floods can be identified by the shapes of each peak including the major and minor ones of all floods,especially of the double-peaks or multi-peaks flood,regardless of the rainfall intensity.