To study the characteristics of the distribution of the preferential paths and the affecting factors in the Three Gorges area, four soil profiles were dug to observe the distribution of preferential paths in the Quxi watershed in the Yangtze River basin. The Morisita exponential test method was used to examine the distribution type of preferential paths. The physical properties and infiltration characteristics of the soil were also measured to evaluate their relationship to preferential paths. The results showed that in this area, preferential paths clustered and mainly distributed in the 80-100 cm soil layer, and along the interface between the weathered layer and semi-weathered layer. There were more non-capillary pores in the 83-110 cm layer than in the other layers. It can be derived that most non-capillary pores in this layer were preferential paths caused by geological processes and rotten plant roots. The percentage of coarse soil particles increased with the depth of the soil layer. In the deeper soil layer, the coarse soil particles helped the formation of preferential paths. The fastest steady infiltration rate was observed in the of 83-110 cm layer, which is inferred to be due to the greater number of preferential paths.

为研究长江三峡花岗岩地区优先流对渗流和地表径流的影响，以长江三峡地区曲溪小流域作为试验用地，选择适当的土壤剖面作为观测剖面。采用自记流量计测量了优先流、渗流和降雨过程。在小流域出口处设置90°薄壁三角堰和水位计记录了地表径流过程，分析了优先流和渗流、地表径流之间的关系。结果表明，在同等降雨条件下，优先流晚于渗流出现，早于渗流停止。优先流流量在剖面渗流总量中的比例可达2.40%～48.72%。优先流水分通量最大可达剖面渗流水分通量的17200倍，会在很大程度上增加土壤水分运动通量。在同场降雨中，优先流的介入使得渗流流量峰值出现时间提前。优先流的出现导致地表径流峰值出现时间延迟，洪水历时过程延长。前期影响雨量及产流次雨量较小时，优先流与地表径流之间相互影响较大。

为了研究三峡地区花岗岩林地优先流影响因子，在长江三峡地区曲溪小流域内选定的实验坡面下部，垂直开挖了一个长度为2.9m、深度为2.60m的土壤剖面。在降雨过程中观察优先流过程，分析降雨对优先流的影响。同时对该地区的土壤物理性质和土壤渗透特性进行了测定，分析其对优先流的影响。分析结果表明，影响长江三峡花岗岩区优先流产流的降雨量在26mm(24h降雨量)以上。长江三峡库区的降雨可分为递减降雨型、均匀降雨型、突发降雨型及峰值降雨型4种类型，不同降雨类型对应的优先流过程都表现出相应的降雨过程特征。不同降雨类型的优先流出现时间也各有差异，峰值降雨型降雨产生的优先流出现时间最早，其次是突发降雨型、递减降雨型、均匀降雨型。当一场降雨中的最大降雨强度>0.075mm/min时，就有可能产生优先流。非毛管孔隙比例较大的土壤中容易形成优先流。研究区林下土壤中粗颗粒含量呈现出由上层至下层逐渐增多的趋势。对于较深层次土壤来说，它们含有的较粗颗粒有利于优先流的形成。优先流的存在使距地表83～110cm土层中土壤稳渗速率较其他土层得以大幅度提高，土层内快速运动的水流又加速了优先流的形成与发展。

为模拟长江三峡库区优先流运动，以Macro模型为基础模型，依据长江三峡花岗岩区试验地特征及观测数据，对模型驱动变量、土壤物理特性参数进行了适当修正，得到了试验地区优先流运动模型。应用EF统计方法对实测结果和模拟结果进行了检验，检验结果表明不同层次土壤中优先流流量的EF统计值均大于0.89，说明所建立的优先流模拟模型能够较好地模拟优先流过程。

较为系统地总结了部分前人关于林下枯落物和苔藓对水土保持、环境保护等方面作用的研究成果，林下枯落物和苔藓均具有较强的吸持降水、涵养地表径流、增加地表糙率、改良土壤特性等作用。部分学者的研究成果还表明，苔藓对环境变化具有指示和监测作用。