Extraction And Analysis On Distributed Erosion Slope Length In Watershed Scale

Extraction and Analysis on Distributed Erosion Slope Length in Watershed ScaleThe slope length is one of the important terrain parameters in soil erosion research area. Itis very important for quantitative evaluation of the erosion processes in the reaction of theconcept of slope length on soil erosion. In this study, on the basis of the previous work of theextraction of the slope length, the author does a further study in slope length extraction limitscondition for analysis, design, and extraction. The results of accuracy and uncertainty analysisare also being analysised.The main findings are as follows:(1) Distributed erosion slope length (including erosion, transport, and deposition)compatible with the soil erosion process, to reflect the erosion with the terrain changes, anypoint erosion slope length at watershed scale. Distributed slope of the theoretical formula, thecombination of truncated by the DEM, the slope length factor, by the flow of algorithmdesign and design processes and methods;(2) The artifical DEM was used to prove the correctness of the D8, MS, FMFD,DEMON, Dinf five kinds of algorithm design, studies have shown that the Demon can becompared to theoretical results similar slope length values.(3) Based on the actual DEM (Xiannangou catchment), the comparison of the relief mapwith extraction result of channel networks and shoulder line, verify the correctness of thechannel networks and shoulder line extraction method; the DEMON, D8algorithm forchannel extraction effect better;the threshold determines the channel level, a differentthreshold to decide the maximum slope, but different regions have different geomorphologicalfeatures, so so the experts who is more familiar with the study area to set the threshold;(4) Different resolutions, different undulating terrain conditions affect the accuracy ofthe extracted slope length ideal DEM contrast DEMON method performed better in precisionerror, suitable for the extraction of slope flow algorithm; but alsofound in the complex slopeconditions, compared with the theoretical value of GIS-based approach overestimated theslope length.(5) Discussion the cutoff condition in different resolution in Xiannangou catchment.The study found that the lower resolution, the grid size increases, the impact of the channelincreases, high-resolution DEM ditchchannel threshold low resolution channel threshold, andgives the corresponding threshold under different resolutions; (6) Slope length scale transformation exploration and study, based on histogrammatching method can achieve better slope length scale transformation;(7) Design the software combined with empirical models (RUSLE, CLSE) and model.The software can be a reasonable conversion of the relevant data, analyze, calculate, completesoil erosion on the watershed scale estimates.