北方土石山区典型坡面优先流特征研究

以太行山区崇陵流域的典型坡面为研究对象,通过亮蓝(Blue-FCF)与KI染色示踪试验,利用图像处理软件技术,计算优先流形态特征参数,分析5个不同坡位的优先流形态特征变化规律。结果表明:(1)随着坡位升高,坡面土壤厚度、容重逐渐减小,而总孔隙度、渗透系数、饱和含水量逐渐增大,凋萎系数与田间持水量则呈现波动变化趋势;(2)随着坡位的升高,染色剂运移深度不断增加,基质流区域占比减小而优先流区域占比增大;各坡位染色面积比随深度缓慢下降,在40cm以下深度范围高坡位点的土壤水分与周围土体交互作用较低坡位点较弱;染色剂入渗体积随坡位升高而逐渐增大;(3)随着坡位的升高,优先流对实际水分运移的贡献增大,高坡位坡面水分以优先流为主要方式向下入渗;(4)土壤质地与容重是影响土石山区坡面不同坡位优先流差异的主要因素。

Characteristics of Preferential Flow on Typical Slope in Northern Rocky Mountain Area

Taking the typical slope of the Chongling Basin in the Taihang Mountain area as the research object, the dye tracer experiments with Blue-FCF and KI were performed. The image processing software was used to explore the changes of preferential flow morphological characteristics at the five different slope positions. The results showed that:(1) With the increase of altitude, the soil thickness and bulk density of each slope position gradually decreased, and the total porosity, permeability coefficient and saturated moisture content gradually increased, while the wilting coefficient and field water holding capacity tended to fluctuate. (2) With the rise of slope position, the depth of dye migration increased, the matrix area decreased and the preferential flow area gradually increased; the stained area rate of dye infiltrate decreased with the increase of the depth. The interaction between soil moisture and surrounding soil in the depth below 40cm was weaker than that in the lower slope; the volume of dye infiltration increased gradually as the rise of slope position; (3)As the slope position increased, the contribution of the preferential flow to the actual water transport increased and the water flow infiltrated with preferential flow as the main method on higher slope; (4) Soil texture and bulk density were the driving forces for the difference of preferential flow at different slope positions in earth-rock mountainous area.