基于DEM的密云水库上游流域特征提取与分析

以北京市密云水库上游流域的等高线为基础数据,利用软件ArcGIS生成DEM,提取研究区的坡度、坡向和河网水系等,并进行河网分级和子流域划分,对子流域特征进行系统的统计分析。结果表明:研究区高程范围为130～1 695 m,500～1 000 m的高程区间占总面积的55.93%;有68.53%的区域坡度在25°以上,存在潜在强烈侵蚀风险;流域阴向坡与阳向坡比例接近1∶1;流域河网可分为9级,流域可划分为16个子流域。在河网密度、形状系数、河道弯曲系数、河道比降等流域特征参数分析的基础上,获得各子流域的土壤侵蚀强度和汇流调蓄能力。研究结果可为小流域规划和水文模型建立提供参考。

Extraction and analysis of the watershed features based on the Digital Elevation Model of the Miyun Reservoir

The contours map of upstream in Miyun Reservoir in Beijing was the basic data for DEM generation supported by ArcGIS software.Drainage network and basin were graded by slope,aspect and drainage network extracted from DEM.Detailed statistical analysis were used to analyze the characteristic of divided drainage basin.The results showed that areas which heights ranged from 130 to 1 695 m and from 500 to 1 000 m occupied 55.03% of total area.Slope gradient more than 25 degrees took up 68.53% of studied area,where the potential strong erosion risks may exist.The ratio of shady slope to sunny slopes was almost 1∶1.The drainage network was divided into 9 levels,and totally 16 sub-basins.The soil erosion intensity and river confluence and storage capacity of each sub-basin were obtained from the analysis of the river density,the shape coefficient,the coefficient of river bend,the stream gradient and so on.The results could provide references of watershed management planning and hydrological model establishment.