基于DEM的湟水流域河网阈值分析

River Network Threshold Analysis of Huangshui Basin Based on DEM

基于ArcMap10.2,提取了湟水流域在不同集水面积阈值下的河网,采用河网密度法和水系分维法分别确定阈值,提取河网与实际河网作叠加分析,对比得出最佳阈值,判断流域地貌侵蚀发育所处的阶段。结果表明,阈值越大,河网越稀疏;集水面积阈值与河网密度之间存在幂函数关系,采用河网密度二阶导数法、水系分维法计算出的阈值分别为13 000、14 000,河网密度法提取出的河网与实际吻合度更高,两种方法对比验证提高了流域阈值选定的准确度,最后得到湟水流域最佳集水面积阈值为13 000;盒维数计算结果为1.065 5,说明流域地貌正处于侵蚀发育的初始阶段。

Based on the ArcMap10.2 hydrological analysis module, the river network under different catchment area thresholds in the Huangshui Basin was extracted. The optimal threshold of water catchment area was determined by two methods of the density method of river network and the fractal dimension method of river system. The most suitable threshold was obtained after superposition analysis. Box dimension calculation results determine the stage of watershed landform erosion development. The results show that the larger the threshold is, the sparser the river network is. There is a power function relationship between the threshold and density. The calculation result of the former is 13 000, while the latter is 14 000. The river network extracted by the density method is more consistent with the actual situation. In addition, the comparison of the two methods improved the accuracy of the experimental results. Finally, the optimal catchment area threshold of Huangshui watershed is 13 000. The box dimension calculation result is 1.065 5, indicating that the watershed landform is in the early stage of erosion development.