泥石流是特殊的流域侵蚀作用，用其他流域过程一样，密切联系着流域的形态特征。一般说来，泥石流都发生在小流域（10~2km~2以下），而经典的流域形态研究所涉及的流域范围却达到了10~7km~2的尺度。我们想知道泥石流小流域是否具有特殊的数量特征。通过流域特征量的统计，我们看到，与一般流域相比，泥石流小流域的特征参数之间的关系形式上相同，而在数值上不同，这从一个方面肯定了流域演化存在着普遍规律（如自组织临界性），同时也证明泥石流是流域演化历史的特殊一幕。这样，泥石流的区域演化问题就真正同一般的流域系统演化问题联系起来了：流域系统演化的一系列方法将有助于我们进一步建立泥石流的系统动力学。

Abstract:Morphology of small drainage basin is in principle the same as general basins , di sregarding its scale .Data concerning characteristics of basins of debris flow , from The DataBase of Debris Flow in China , are used in this paper to examine their properties in small scale.In fact , di stributions of characteristic factors , including area , length, elevation, gradient , and degree of incision , of drainage basins of debris flow , are subject to distributions in the unique form of the generalized Gamma distribution , i .e., in special cases , the Weibull distribution , Gamma distribution and others alike, only distinctive in the value of parameters.The unification of distributions for various factors indi cates some invariance of scale in the drainage system ,with power laws hidden behind .Some power relations have been actually revealed ,i .e., that between length and area, length and gradient ,gradient and area, etc..All the power exponents diff er f rom those supposed theoreti cally for drainage evolution at some stable states , enhancing our belief in the periodicallity of debris f low that occurs only in some special phase in the evolution history .On the other hand , debris -f low surges of the Jiangjia Gully reveal another power relation between discharge and f low depth , which corresponds to that between discharge and area for usuall flood process , and therefore prove it s validity for debris f low as well.The consi stency in all respects ensures that appearances of debri s f lows in regions are also representative for debri s flow in individual basins .Then, debris flow in a certain basin finds its origination from the drainage pattern .