Method and Study of Impacting Factors for Extracting River Channel Network from SRTM DEM Data

River network and related watershed information directly derived from DEM is the basis of development and application of distributed hydrological models.The Pearl River Delta area is one of the most developed economy area of China,and one of the largest net-river areas with complex structure in the world.The studies of distributed river network and watershed are very important to the watershed plan and water resource optimization and utilization.Firstly discussed the basic method of extracting river channel network of watershed based on grid DEM data,then introduced the detailed procedures of river channel network extraction by using a GIS software Arc/Info and presented a case study in Pearl River Delta area for rapid extracting river channel characteristic information in large-scale areas.Finally,the characteristics of river channel network at sub-watersheds of Pearl River Delta area were compared.