Research Of Lushan River Capture Based On DEM

River capture is an important way of the river streams and basin’s evolution. Meanwhile, it is a classical content in the researches of geomorphology and plays a significant role in the formation of Lushan river and basin geomorphology. This paper put forward a research on river capture’s phenomenon in Lushan based on DEM, which not only providing a scientific basis for Lushan river and basin geomorphology and promoting for deepening the understanding of Lushan geomorphological features, but also providing a new approach to the research of the river capture’s phenomenon and becoming an example in the researches of digital geomorphology.This paper takes three typical river captures, JinXiugu river capture, Da Jiaochang river capture (including Han Kouxia river capture and Lu Linhu river capture), as the research object. It uses DEM data of Lushan as the foundation and applies the spatial analysis method of GIS to Lushan river capture. The main research conclusions and results including the following aspects:(1) The1:10000scale5m resolution DEM data and the1:50000scale25m resolution DEM data are used in the basin extraction of Lushan river capture. After comparing the river streams data and the basin data, different DEM resolution and accumulated confluence’s influence on this research, this paper confirm to use the1:10000scale5m resolution DEM data and cumulative amount for3000in the research. On the basis of all above, the research divides the basin of the area into hair and extracts pirate river basin and captured river basin. At the same time, it also extracts the divide line in the experimental area.(2) Based on the extracted basin boundary line and the divide line, according to the known capture sites, this paper extracts disconnected divide line caused by river capture and connects the divide line on both sides of capture sites. The paper designs an algorithm to reset elevation values to the DEM grids related to the connection lines. Based on all above, it divides the basin again, and gets the river capture and basin before the river capture.(3) From the two aspects of the geological structure and the landform, this paper discusses the rock lithology, geological structure, valley form, slope, river bed gradient and river and the surfaceincision’s relationship with the river capture, and analyzes the evolution mechanism of the Lushan river capture. (4) On the basis of the existing water and basin data, combining the recovered river and basin data before river capture, according to the river valley and the terrain expressed by the existing DEM data, this paper performs the dynamic course of the river capture’s evolution in the research area.