基于RUSLE的黄土洼小流域土壤侵蚀与水土保持研究

Study on soil erosion and soil and water conservation of Huangtuwa watershed based on RUSLE

采用修订的通用水土流失方程(RUSLE)、调查还原法和淹没分析等方法,对天然淤地坝多年平均拦截泥沙量和天然淤地坝所在黄土洼小流域侵蚀空间分布进行研究。结果表明:2000—2011年坝淤地及上游丘陵沟壑区平均土壤侵蚀模数为8 116.14t/(km2·a);RUSLE模拟的淤地坝及上游丘陵沟壑侵蚀区土壤侵蚀模数为7 714.73t/(km2·a),通过与实测值对比,模拟精度为95%。模拟的黄土洼小流域强烈侵蚀、极强烈侵蚀和剧烈侵蚀区域占流域面积的53.18%,研究区土壤侵蚀严重;黄土洼天然坝地的泥沙主要来源于坡度大于15°的粱峁耕种区、沟间地和坝地边缘。黄土洼小流域进行人工水土保持措施后侵蚀模数降低26.15%;天然淤地坝将周围控制区域的泥沙全部拦截,对黄土洼小流域泥沙拦截贡献率高达77%,水土保持效益明显。黄土洼天然淤地坝在没有人为干扰的情况下,还可淤积泥沙体积约为2.303×106 m3。

Using methods such as RUSLE,investigation reduction and submergence analysis,the quantity of average annual intercepted silt and the spatial distribution of soil erosion in Huangtuwa watershed are analyzed.The results show that the average soil erosion modulus of the silt arrester and upstream hilly and gully erosion region is 8 116.14 t/（km^2 ·a）during the period of 2000—2010,which is 7714.73 t/（km^2 ·a）simulated by RUSLE,and the simulation accuracy is 95% by comparing the calculated and measured values.In the watershed,erosion areas with strong,very strong and violent eroded,account for 53.18% of the watershed area, which indicate watershed erosion modulus is relatively high.Loess sediments lying within the natural dam come mainly from beam hilly farming area,inter-gully and dam edge whose slope is greater than 15°.The erosion modulus is decreased by 26.15% under the artificial water and soil conservation condition.Natural check dam can interception all sediments in the control area,and the contribution rate to the sediment interception in Huangtuwa watershed could be up to 77%, and the effects of the soil and water conservation are apparent.The sedimentation volume of Huangtuwa natural check dam is about 2.303×10^6 m^3 .