基于DEM的西藏鲁朗河流域数字河网提取时集水面积阈值的确定

Determination of Drainage Area Threshold for Extraction of DEM-based Digital Drainage Networks in the Lulang River of Tibet

以30m分辨率的栅格DEM为数据源,基于Arcgis10.0软件的水文工具箱,结合建模工具建立数字化河网提取模型,提取不同阈值下的鲁朗河流域数字化河网图。在此基础上,运用Arcgis10.0的统计和分析功能,分别计算出各阈值下的河源密度和河网密度。根据河网密度和河源密度与集水面积阈值的关系确定合理的集水面积阈值,结果表明,鲁朗河流域合理的集水面积阈值应为3km2,该集水面积阈值下,共有四级河道,河道总数134条,总河长为286.09km,河网密度为0.162 1km/km2,总河源数69个,河源密度为0.083 5/km2。

With the DEM of 30 m resolution raster as the data source ,based on the hydrological toolbox of Arcgis10 .0 software , combining modeling tools to extract model of digital river networks ,digital river network diagram of Lulang River Basin is extracted under different thresholds .On this basis ,statistics and analysis capabilities of Arcgis10 .0 ,are used to calculate Heyuan density and drainage density of each threshold .According to the relationship between drainage density and Heyuan density and the catchment ar-ea to determine the reasonable catchment area .The results show that ,the reasonable catchment area threshold of the Lulang River Basin should be 3 km2 ,under the threshold ,there are 4 channels ,a total of 134 channels ,the total length is 286 .09 km ,river drain-age density is 0 .162 1 km/km2 ,the total number of Heyuan is 69 ,Heyuan density is 0 .083 5 /km2 .