基于栅格的分布式降雨径流模拟系统及应用

A Grid-based Distributed Rainfall-runoff Simulation System and Its Application

研制了一套基于栅格的分布式降雨径流模拟系统,利用流域地形、土壤、土地利用等空间数据和水文气象数据,可以进行流域特征提取、空间数据内插、降雨径流模拟及计算结果的三维动态显示和统计。通过在黄土岭流域的应用,说明该系统具有较好的模拟降雨径流过程的能力,而且使用方便。

A grid-based distributed rainfall-runoff simulation system has been developed in this paper. The system can split the catchment into a number of square or rectangular grid elements using DEM, extract topographic attributes of elements such as slope, upslope flow contributing area, and classify the grid elements into hillslope el- ements and channel ones. Each hillslope grid element has model components for interception, infiltration, overland flow and lateral soil water flow, and each channel element has model component of channel flow. The infil- tration and excess rainfall on each hillslope element are calculated using the Green-Ampt infiltration equation, soil lateral flows are based on Darcy＇s law and continuity equation, overland and channel flows are described by one dimensional kinematic wave approximation to the St Venant equations. Implicit finite differential scheme is used to solve these equations. The hydrological parameters are determined from digital soil and land use data. The system also has the ability of spatial data interpolation, visualization and statistics of the results. The interpolation approaches include Thiessen, Kriging, inverse distance weighted averaging, and trend surface methods. The visual components of system include the 1-D and 3-D visualization of rainfall, infiltration, surface runoff, and subsurface flows for one or all elements, and synchronized 3-D visualization for any two processes of the catchment. The system was applied to the simulation of two flood events happened in Hangtuling watershed, Zhejiang Province, China. The data input for the simulation were： rainfall and runoff time series of two events, the DEM, land use map, and soil map of the watershed. By sensitivity analysis of parameters, Manning＇s roughness of surface and soil saturated hydraulic conductivity were determined to be calibrated. The first event was used to calibrate the model, and the second for testing. The results show that the system is capable of simulating rainfallrunoff processes with least data requirements and easy operation.