陕北黄土高原沟道小流域形态特征分析

A PRELIMINARY STUDY ON GEOMORPHIC FEATURES OF SMALL DRAINAGE BASINS ON THE LOESS PLATEAU IN NORTHERN SHANXI

本文就黄土高原不同地貌类型区的小流域进行了形态量计分析。并以河网密度为地表切割程度指标,建立了河网密度与流域形态要素的复相关方程式。

Using the data measured from the topographic map of Northern Shanxi Province with a scale of 1:10000, a relationship between four small drainage basins in different geomorphic units of the Loess Plateau and the second order watershed morphic factors has been obtained. We can see that the law of total stream length with stream order is not available elsewhere at all. As the watershed system is in a developing stage, in Yuan regions, the damage made by channel erosion is more serious than that in hilly regions. There exists a semi-logarithmic relationship between the average intersectional angle (0) and the stream (S) order.Among geomorphic factors of drainage basin, a closer correlation exists.If the drainage density is regarded as the downcutting index of the earth surface, then, the larger the drainage basin area, the smaller the downcutting degree per unit area is. In a small-current drainage basin, the drainage density increases with height difference between the head and mouth of the drainage basin.A multi-correlation is among the drainage area (A) , height difference between the head and mouth (H) of the drainage basin, the length of the main channel (T) and the drainage density (Dd) . It may be described by the regression equation, as follows. Dd = K (T)m (A)-1 (H)t where K is coffi-cient and m,n,t are powers, n<o, m and t>