Author(s): Bohua Zhao; Shanghong Zhang; Eerdun Ding
Linked Author(s):
Keywords: Flat region; DEM; Extracting river network; Improved Burning method; Beiyun river watershed
Abstract: To the issue that the extracted river network based on DEM is important to the distributed hydrological model, but in flat region there are some problems, like the uncertain flow direction, the depressions and the inverse slope. A variety of methods have been proposed to solve these problems, like AGREE method and Stream Burning method, all these methods could get the right river network, the main disadvantage of the above method is the big change for the DEM, as a result, it will have great influence to the further hydrological analysis. In this paper, based on analysis the above methods, we proposed a burning improved method to deal with the flat region. Search for each outlet points along with the river channel to its start points, then lower the start points and outlet points a critical depth, connect each start points and outlet points to make the river channel a convergence gradient, then use the D8 algorithm to make the flow concentrate orderly. That is to say, by changing the elevation of the river channel and enabling it to have the elevation gradient, ensure the extracted network can sink flow in direction of the actual river network. Contrasted with other modified methods, the improved burning method is more rational to the modified DEM and can solve the problem of depressions in flat region. Applied the improved method to Beiyun river watershed, we found it could meet the requirement of the accuracy and have less influence for the subsequent analysis.
Year: 2013