基于GIS的小流域土壤侵蚀与产沙的简化模拟

A Simple GIS-Based Modeling of Soil Erosion and Yield in Small Basin

将泥沙输移能力公式与USLE公式相结合,建立了一个简化的分布式小流域产沙模型,并将其应用于川中丘陵区小流域的土壤侵蚀与泥沙输移的空间分布模拟。得到的主要结论:1.该模型适用于川中丘陵区小流域产沙的模拟;2.魏城河流域1980—1987年8 a平均土壤侵蚀量为16.8×104t,侵蚀模数为675.8 t/(km2.a),模拟得到的输沙模数为238.6 t/(km2.a),泥沙输移比为0.35;3.魏城河流域主要以微度侵蚀为主,占到全流域总面积的68%,强度侵蚀占流域面积的1%,主要分布在坡度较陡的流域边缘地带;4.相对其他因子,降雨与坡度对该流域侵蚀产沙的影响更为突出。

This paper proposed a simple distributed sediment prediction model by combing the USLE and transport capacity equations, and applied it in hilly area of Sichuan province to model the spatial distribution of soil erosion and transport. The main results are as follows： 1. the model established in this paper is applicable for sediment modeling in hilly area of Sichuan province ;2. with the sediment delivery ratio of O. 35 ,the average annual potential soil erosion is 16.8 thousands t,the erosion modulus is 675.8 t/（km2 ~ a） in Weichenghe basin,and the modeled soil yield modulus is 238.6 tY（ km2 ~ a） ;3. the Weichenghe basin is dominated by mild erosion which accounts for 68% of whole basin area, and the extremely intensive erosion accounts for less than 1%, and the intensive erosion mainly occurs at the edge of the basin where the slope is very steep ; 4. the rainfall and slope effect the soil erosion more than other factors in this study area.