Determination of River Drainage Area Threshold for Extraction of Drainage Network by DEM

The algorithm for delineation of a river drainage network proposed by O′callaghan and Mark is widely used. A drainage area threshold is used to produce a continuous network, so that different network is obtained by varying drainage area threshold. A method in which the relation between source density (or drainage density) and the threshold is used to produce an ideal drainage network is proposed. The drainage area threshold with stabilized source density (or drainage density) is wanted. The method is used in Yanduhe watershed and a good result is obtained. The proposed approach removes the subjective decision on the choice of drainage area threshold.