基于DEM的复杂地形流域特征提取

The extraction of properties in catchment with complex terrain based on DEM

利用流域数字高程模型(DEM)构建数字水系模型并提取流域水系特征是分布式水文过程模拟的重要前提。提出了面向分布式水文过程模拟和流域特征提取的数字水系模型,并针对现有方法对复杂地形DEM中含有的平地、洼地及其嵌套情形的处理不足,提出了栅格水流分类、填洼分类与归并及有效填平处理、河谷平地的出流代价法构建栅格流向和流序等新的处理方法,并在开发的软件系统得到实现。使用该方法创建的黄土岭流域数字水系模型和提取的水系等流域特征结果表明:本文方法可有效应对复杂地形流域的处理,提取的流域水系特征与实际自然水系比较吻合,能够有效地消除现有方法在地形平坦区域容易产生的平行河道、奇异河道、河道变形等不足。

The extraction of drainage network, catchment properties information and the simulation of distributed hydrological process of catchment based on DIEM have been a hot spot over the last ten years, the construction of digital drainage network model of catchment based on DIEM and the extraction of drainage network of catchment are important premises of simulating catchment＇s distributed hydrological processes. The structure of digital drainage network model suitable for extracting catchment properties and simulating hydrological process of catchment is proposed. The methodology and algorithm suitable for the topography of complex catchment are designed to overcome the shortcomings in the efficiency, validity and effects of existing methods, such as classification of raster drainage, classification and amalgamation of depression area, valid fill-up of depression, classification of flat area, the method of out-flow cost of constructing direction and order of raster drainage in flat areas of river valley, which considers ambient terrain and astringency toward potential waterway. These methodologies and algorithms are applied and implemented in the software systems developed, and the systems are successfully used in constructing digital drainage network model and extracting catchment properties information including classified waterway, subbasins raster, the vector polygon borders and properties parameters of subbsins of Huangtuling catchment in Zhejiang province. The result of test shows the proposed methods in the paper can cope with and handle various catchments with complex terrain, the drainage network extracted matches well with the natural drainage network in Huangtuling catchment. The shortcoming of parallel, odd waterways and deformation waterways created in the existing methods can be effectively overcome and solved. The research result can provide a basis for the simulation of the distributed hydrological processes for catchment.