不同坡度下反坡水平阶的蓄水减沙效益

Storage of Water and Sediment Reduction Benefits of Reverse-slope Terrace under the Different Slopes

在昆明松华坝迤者小流域,在自然降雨条件下定点观测不同坡度下径流和泥沙的流失特征,研究反坡水平阶对不同坡度下坡耕地的蓄水减沙效益。结果表明:反坡水平阶总体上对坡耕地为5°和15°的减水效益分别达到75.98%和74.55%,减沙效益总体上分别达到了85.91%和80.52%;坡耕地为25°的减水效益总体上达到了43.48%,减沙效益总体上达到了69.15%。不同坡度下反坡水平阶坡面对照自然坡面得出的用水减沙比表现为坡度越小用水减沙比越大,坡度越大用水减沙比越小。说明坡度越小,反坡水平阶对径流和泥沙的拦截效果越明显,反坡水平阶有直接蓄水减沙的水土保持功效。

The runoff and sediment characteristics were observed and storage of water and sediment reduction benefits were studied on reverse-slope terrace on the different slopes under the natural rainfall conditions in Yizhe Watershed of Songhuaba reservoir in Kunming.The result shows that the rates of runoff reduction have reached to 75.98% and 74.55% on slope land of 5°and 15° in all,the rates of sediment reduction have reached to 85.91% and 80.52% on the reverse-slope terrace,runoff and sediment reduction have reached to 40.48% and 69.15% on the farmland of 25°.In comparison with the water use and sediment reduction under natural slope,it shows that the smaller the degree of slopes,the greater the ratio of the water use to sediment reduction under different slopes of reverse-slope terrace;otherwise,the greater the degree of slopes,the smaller the ratio of the water use to sediment reduction.It shows that reverse-slope terrace has evident effect on runoff and sediment interception when slope is smaller,and that the reverse-slope terrace has a direct effect on soil and water conservation.