GIS环境下基于GDEM的丹江口库区流域自动提取方法的研究

Automated extraction of drainages in Danjiangkou Reservoir based on GDEM in GIS environment

小流域是一个相对完整的生态过程单元,以小流域为研究单元,可以从中观尺度认识库区的地理规律,从而推动库区的生态环境治理和生态环境建设.研究区域选择丹江口库区,以30m分辨率的DEM为数据源,采用ESRI公司开发的ArcGIS软件,研究流域的自动提取的方法.先对DEM数据进行填洼和削峰的预处理;再经过水流方向的确定,汇流能力分析,流域网络的提取,子流域提取等步骤,最后输出了流域提取的栅格数据.从提取的流域结果来看,通过生成的子流域图层与DEM叠加显示,在山地丘陵地区,流域界线与分水岭非常吻合.但是平坦区域由于等高线稀疏,提取的水系有一定的误差.基于DEM快速提取流域,节省了人力和物力.对南水北调工程长期高效的发挥作用有重要的意义.

Watershed is a relative integrated ecological process unit. We can acknowledge the Geographical law in the reservoir on the medium scale. Taking Danjiankou reservoir as the experimental study object, this paper chooses the DEM of 30m resolution as the data source to introduce the method of extracting river network based on the software of ArcGIS developed by ESRI. Firstly, we fill sinks and remove peaks of the DEM data, then identify the flow direction, analysis the flow accumulation, identified the flow net work, finally, find out the sub-drainages. The result of the study shows： the watershed boundary line is almost identical to the ridge line in the mountain and hill knap area, but in the flat area, the result may exist certain errors because of the sparse contour lines. The fast extraction of watersheds based on DEM greatly saves manpower and material resources. Through this way, we may promote the protection and the construction of the eeo-environment. It is also significant for the South-to-North Water Transfer Project to work efficiently for great lengths of time.