A Study On Building Topography Of Stream Networks Based On HC-DEM

The process that runoff and sediment material collect into the channel and migrate through the channel network is important in simulating the hydrological and erosion areas. And river confluence relations in the basin is the base of hydrological and erosion models. However, current methods which used to establish the digital hydrological networks and confluence relationship can hardly be called by digital hydrological model. So it cannot be effective for the hydrological and erosion simulation. Therefore, the establishment of the hydrological network and river confluence relations has a high practical and scientific value.In this paper, after collect datum at home and abroad and analyze various studies about how to build a digital hydrological network and obtain topological relation of the various hydrological elements, we choose the method which use the digital elevation model (DEM) to extract the spatial data of hydrological elements and establish of hydrological network that based on vector topological data structure, then calculus river confluence relations.This method combines the advantages of existing methods to establish hydrological network .one is based on graph theory ,use depth-first traversal and the visual programming techniques; the other is based on the DEM to generate watershed and river network data, then artificial establishment of correspondence between the river and valley. This method is sophisticated, easy and efficient.In this study, the method based on digital elevation model (DEM) extract of watershed hydrology feature. Then obtain hydrology hydrological landscape elements spatial data, such as node, river and sub-basin. Next, the design vector hydrological network model, then use the vector data overlay analysis and programming to build hydrology network and river confluence relationship.In this study, we select Xian-Nangou Watershed in Loess Plateau to do experiment. Applying above methods and processes, we extract the spatial data of hydrological landscape elements, and establish hydrological network and river confluence relations. The results show that the hydrological network and their topology (River confluence relationship) which was extracted meet the actual reality, It can descript the hydrology of Xian-Nangou. This article proposed the method that establishment of hydrological networks and river confluence relationship is a meaningful attempt.