Applicability Analysis of Four Flow Accumulation Threshold Determination Methods in Loess Eroded Area

In this paper,a method based on the theory of geomorphic development and drainage fractal dimension is proposed for testing the rationality of four threshold determination methods for catchment area:drainage density method,channel branching method,minimum error in river source distance method,trial and error method.The results show that drainage density method and channel branch method have a good applicability in the watershed of the loess hilly landform and can reflect the accurate information of gully channel.River source minimum error method is controlled by the topography of the river source,which is only applicable to small watershed with little change of topography.Trial and error method is controlled by artificial vision and scale,so it is not suitable for the area with large changes of topography or the complex river network.