六盘山香水河小流域地形与植被类型对降雨径流系数的影响

Effect of topographic form and vegetation type on the runoff coefficient in the Xiangshuihe Watershed of Liupan Mountains

基于GIS和SPSS支持下的数据分析，结合宁夏六盘山区香水河小流域2004—2005年6—10月的降雨、径流观测资料，对流域的坡向、海拔和植被对降雨径流的影响进行研究，结果表明：就不同植被类型来看，径流系数以人工林的最大，灌丛的次之，亚高山草甸的最小；就海拔而言，径流系数大小依次为低海拔（2060-2350 m）〉中海拔（2350-2640 m）〉高海拔（2640-2930 m），随着海拔从低到高的变化，天然林的径流系数表现为从高到低再升高的变化趋势，而人工林和灌丛则表现为先增加后减小的变化趋势，亚高山草甸从中海拔至高海拔区呈增大趋势；从不同坡向来看，径流系数大小依次为南坡〉西坡〉北坡〉东坡。

According to the observations of precipitation and runoff in Xiangshuihe Watershed of Liupan Mountains on Jun. - Oct., 2004 and 2005, the effect of slope aspect, altitude and vegetations type on runoff is studied by GIS technique and SPSS software. The results of runoff coefficient for different vegetation types show such an descending order as plantation forest, shrub forest, natural forest, and sub-alpine meadow. The descending order of runoff coefficient for different altitude ranges is lower altitude area （2 060 - 2 350 m）, middle altitude area （2 350 - 2 640 m）, higher altitude area （2 640 - 2 930 m）. With the increasing＇ of altitude, the runoff coefficient in the natural forests decreases at the beginning and then increases, while the runoff coefficients for plantation and shrub forests have the trend of increasing at the beginning and then decreasing. However, the runoff coefficient for subalpine meadow keeps an increasing trend from middle to higher altitude. According to the slope aspects, the runoff coefficient for southern slope is the highest and that for eastern slope is the lowest.