黄土高原向阳沟流域水土保持措施效益分析

Effect of Soil and Water Conservation Measurements in the Xiangyanggou Watershed

在ArcGIS软件的辅助下,根据不同坡度的土地利用对土壤侵蚀的影响,将向阳沟流域划分了5个坡度等级单元,利用通用土壤流失方程(USLE)对流域现有水土保持措施下不同坡度等级单元侵蚀量进行了估算,并与治理前土壤侵蚀量进行对比分析。结果表明,实施水土保持措施后,水土流失有了极大的改善,水保效益较为可观,但区域仍属中度侵蚀,25°～35°坡度等级单元对流域土壤侵蚀量的贡献最大,其次为15°～25°和＞35°等级单元。根据不同坡度等级单元的水土流失侵蚀模数估算结果分析,结合现有水土保持措施,提出了今后进一步治理的的几点建议。

In terms of the impact of different land uses on soil erosion, the Xiangyanggou watershed was divided into five slope grade units with the aid of ArcGIS. Soil erosion in the units under the conditions of existed soil and water conservation measures was estimated using the universal soil loss equation, and was then contrasted to the case before adopting the measures. Results show that soil and water loss has been greatly controlled, and soil and water conservation measures have evidently plaid a relatively great role. However, the watershed is still suffering from medium erosion, and the 25° - 35° slope grade unit contributes most of soil loss, followed by the 15° - 25° and 〉35° slope grade units. Based on the analysis of estimated modulus for different slope grade units, suggestions for further soil erosion control are presented in combination with existed soil and water conservation measures.