延河流域水土保持措施减蚀效应分析

 利用延河流域35个雨量站50多年的日降雨、数字高程模型、土壤类型图、土地利用图和植被覆盖图、水土保持措施调查数据,结合黄土高原的区域特征,运用CSLE,在ArcGIS的支持下分别计算研究区1986、1997和2006年土壤侵蚀量,以1986年的水土保持措施实施情况作为基期水平,模拟1997、2006年在水土保持基期水平情景下的土壤侵蚀量,对比分析水土保持措施变化对土壤侵蚀量的影响。结果表明:以1986年作为基期,新增水土保持措施在1997年减少土壤侵蚀量96万t,在2006年减少土壤侵蚀量628万t;考虑2006年降雨特征不同于研究区多年降雨特征,按照2006年降雨特征计算,则新增水土保持措施在2006年减少土壤侵蚀量140万t。研究结果可为延河流域水土保持效益评价、水土流失治理和生态建设提供参考。

Quantitative assessment of impacts on decreasing erosion by soil and water conservation measures in Yanhe River Basin

This study collected the daily precipitation data from 35 gauges in the period of 1953 to 2006,soil type map,a digital elevation model（DEM）,data of soil and water conservation measures,land use maps interpreted from Landsat TM images acquired in 1986,1997 and 2006 and NDVI maps calculated from the images of the same period.Then we used the CSLE model to calculate soil loss amount of every grid unit with the soil erosion factors map layers,simulated soil erosion of 1997 and 2006 based on the state of soil and water conservation measures in 1986,and analyzed the impacts on soil erosion by soil and water conservation measures.Change of soil and water conservation measures from 1986 to 1997 and to 2006 decreased soil erosion amount by 960 000 t and 6 280 000 t in 1997 and 2006 respectively.Considering special rainfall character in 2006 different from the ordinary rainfall character in a long period,the decreased soil loess amount in 2006 by soil and water conservation is 1 400 000 t.This result would provide some references for benefit assessment of soil and water conservation.