延河流域沟壑密度统计学特征及影响因素分析

丁琳 刘辉

摘 要：为研究延河流域沟壑密度统计学特征，该文基于延河流域DEM数据及ArcGIS软件，运用水文分析法及均值变点法提取最佳沟谷网络，并在Excel中进行沟壑密度统计分析。结果表明：研究区总沟壑密度为1.16km/km2，各分区沟壑密度趋势为D1区>D2区>D3区>D4区；不同分区，不同等级沟谷的平均长度及沟壑密度均存在较大差异；同一等级的沟谷在不同分区中的空间分布不同，沟壑密度也存在空间分异性；这些沟壑密度特征是地貌因素及土壤性质等耦合作用的结果。本研究将有助于揭示土壤侵蚀的空间差异性，深入理解沟壑密度的影响因素，从而为有针对性地提出水土保持综合防治措施提供理论依据。

关键词：沟壑密度；沟壑特征；影响因素；延河流域

中图分类号 P931.6 文献标识码 A 文章编号 1007-7731（2016）14-0108-04

Abstract：In order to study the statistical characteristics of gully density in the Yanhe river basin，this paper based on DEM of Yanhe river basin and ArcGIS software，using hydrological analysis method and mean value change-point method to extract the best gully system，and analyzed gully density in Excel software.The results show that：the total gully density in study area is 1.16km/km2，and the trend of gully density in partition areas is D1area>D2area>D3area>D4area；in different partitions，the average lengths of gullies and gully density with different classes have great differences；the gullies with same classes in different partition areas have different space distribution，and spatial heterogeneity of gully density also exists；these gully density characteristics are the results of landform factors and soil properties and so on.The study will help to reveal the spatial differences of soil erosion，and understand deeply the influence factors of gully density，then provide theoretical basis for coming up with integrated control measures of soil and water conservation pertinently.

Key words：Gully density；Gully characteristics；Influence factors；Yanhe river basin

土壤侵蚀使土地资源遭到破坏，土壤肥力和质量下降，已成为全球性的重大环境问题之一[1]。定量评价区域的土壤侵蚀量、土壤侵蚀强度及其空间分布特征，对于采取相应措施减少水土流失、保护和合理利用土地资源具有重要意义[2]。土壤侵蚀强度除了可用土壤侵蚀模数和土壤侵蚀厚度评价外，还可以采用沟壑密度来定量描述。沟壑密度可用于描述地面切割破碎程度，以单位面积上的沟谷总长度来度量[3]。沟壑密度越大，地面越破碎，土壤侵蚀程度越大[4]。目前，关于沟壑密度的提取方法，主要有外业调查法、遥感图像处理法、数字高程模型（DEM）法、地形图量算法等[5-6]。随着数字高程模……