岷江源头区水土流失模拟计算与动态分析

通过对卫星遥感图片的解译以及ArcGIS软件的应用,借助已有水文数据和通用水土流失方程(USLE)模拟计算了岷江源头区1974年、1994年以及2002年的年水土流失总量。同时,按照国家水利部公布的水土流失强度标准,将该区域分为无流失区、轻度流失区、中度流失区和强度流失区四个水土流失等级。结果表明:(1)该区域年水土流失总量从1974年到2002年呈下降趋势,1994年~2002年减少的速度远远大于前20年。(2)研究区域的水土流失强度有从流失严重的等级向流失轻微的等级转化的趋势,从转化面积来看,主要是由轻度流失区向无流失区转化以及中度流失区向轻度流失区转化。从转化比例来看,强度流失区减少得最多,大多转化为中度流失区。

Simulating Calculation and Dynamic Analysis of Soil Erosion in Headwater Region of Minjiang River

By means of hydrological data and USLE model,this study calculates the annual soil loss of headwater region of Minjiang River in 1974,1994 and 2002. During those computing process,remote sensing and GIS techniques are applied. Then,the whole region are classified into four types according to the standards of erosion strength from the Ministry of Water Resources. The results are presented as following: (1) The annual soil loss in this region kept a decreasing trend from 1974 to 1994. Soil erosion decreased more rapidly in latter 8 years than in former 20 years. (2) There was a trend that soil erosion strength transferred from severe erosion classes to slight ones. As for area,the main transference happened from slight erosion region to no erosion one and from moderate erosion region to slight one. As for transferring rate,strong erosion region abate most. Main of them changed into moderate erosion region.