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基于径流泥沙的运移过程,构建了沿汇流路径,结合不同土地覆被对泥沙拦截能力系数模拟每个像元截留泥沙使其不进入水库量的模型.结合单位体积淤泥的清淤费用、水库使用年限及贴现率进行构建价值量模型,并在二滩水库的集水区进行了模型的运用.结果表明:2000～2005年,土地覆被格局的变化主要体现在雅砻江中上游草地向林地的转化和下游亲水区林地向农田和草地的转化.由此影响到2000和2005年土壤侵蚀总量变化不大,但2005年集水区向水库输沙总量有较大增加,农田也成为二滩水库最为主要的产沙源.多数被侵蚀的土壤在向二滩水库的运移过程中被各类生态系统截留,截留泥沙量的高值集中分布于二滩库区周边.林地平均截留泥沙绝对量较低,截留泥沙的能力未能得到有效发挥.集水区对于减轻进入二滩水库泥沙服务的总经济价值在2000和2005年分别达到442.2和785.8亿元.
Based on the transport process of runoff sediment, a model was built to simulate the interception of sediment along each channel by the confluence of different land cover and sediment interception ability, so as to prevent sediment from entering the reservoir. Combined with the silt dredging Cost, age of reservoir and discount rate, and used the model in the catchment area of Ertan Reservoir.The results showed that the change of land cover pattern mainly reflected in the middle and upper reaches of Yalong River from 2000 to 2005 The conversion of grassland to forest land and the conversion of forestland to the farmland and grassland in the downstream hydrophilic area, thus affecting little change in the total amount of soil erosion in 2000 and 2005. However, the total amount of sediment transport to the reservoir in the catchment area increased greatly in 2005 , And farmland also became the most important source of sediment production in Ertan Reservoir.Most of the eroded soil was intercepted by all kinds of ecosystems during the migration to Ertan Reservoir and the high values of sediment concentration were concentrated in Ertan reservoir area The average absolute amount of sediment trapped in the forest land is relatively low, and the ability to catch sediment can not be effectively utilized. The total economic value of the catchment area for mitigating sediment supply to the Ertan Reservoir reached 442.2 and 7 respectively in 2000 and 2005 8.58 billion yuan.