基于RUSLE的北洛河上游流域侵蚀产沙模拟研究

以RS、GIS和RUSLE模型结合SEDD模型,分析了退耕还林前后北洛河上游流域1990年、2000年和2010年土壤侵蚀强度和产沙量的时空变化特征。结果表明:3个时期年平均土壤侵蚀模数分别为18189.72,7 408.93,2 857.76t/(km~2·a),年均输沙模数分别为14 093.31,5 997.65,2 394.37t/(km~2·a),均呈减小趋势。3个时期的土壤侵蚀量在地形上的分布表现出趋同性,即高程上均在1 475~1 575m内平均侵蚀模数和侵蚀量表现出最大值。随着坡度增加,平均侵蚀模数增加,流域内75%以上的侵蚀量均来自于坡度15°区域。3个时期平均侵蚀模数均遵循阳坡半阳坡半阴坡阴坡的规律。研究为该区域生态环境建设效益评价及水土资源合理利用提供有益信息。

Soil Erosion and Sediment Yield Assessment Based on RUSLE in Beiluo River on the Loess Plateau, China

Under the background of the "Grain for Green" program to control severe soil loss from human activities,the soil erosion and sediment yield were estimated based on the sediment delivery distributed model (SEDD) and the revised universal soil loss equation (RUSLE) in the upper reaches of the Beiluo River on China's Loess Plateau.The model was used to simulated the spatial vatiations of soil erosion intensity and sediment yield in 1990,2000 and 2010.The results show that the average soil erosion modulus were 18 189.72 t/ (km2 · a),7 408.93 t/(km2 · a) and 2 857.76 t/(km2 · a),respectively,and the average annual sediment yield were 14 093.31 t/(km2 · a),5 997.65 t/(km2 · a) and 2 394.37 t/(km2 · a),respectively in 1990,2000 and 2010.Besides,the average soil erosion modulus gradually decreased with the increasing vegetation coverage.The results also showed that both the soil erosion modulus and sediment yield were the highest in the altitude of 1 475～1 575 m.The average soil erosion modulus gradually increased with the increasing slope gradient,and with 75％ of soil erosion was ascribed to the region with slope ＞15°.Moreover,the ranking of the average soil erosion modulus from high to low was:sunny slope＞half-sunny slope＞half-shady slope＞shady slope.This results provide an useful reference for the rational utilization of water and soil resources and offer a technical basis for using RUSLE to estimate the soil erosion on the Loess Plateau of China.