中文摘要：

华北平原地下水浅埋区水循环主要以垂直方向上的入渗、蒸发和蒸腾的方式存在，同位素可以作为一种有效“示踪剂”揭示降水入渗补给地下水的过程。选择华北平原中、东部地下水浅埋区的衡水和沧州为典型实验点，研究不同降水特征、土壤质地和植被条件下入渗过程的差异性。结果表明，土壤非均质条件下（沧州），降水入渗补给过程中伴随着蒸发、植被蒸腾作用以及与土壤前期水分的强烈混合作用，活塞流入渗的同时土壤100cm深度可能还存在大孔隙优先流；土壤均质条件下（衡水），降水向下均匀入渗，入渗速度较快，土壤水运动以新水基本代替老水的活塞流为主要形式，并经过强烈的蒸发浓缩作用补给地下水。

英文摘要：

In the shallow groundwater areas of North China Plain water cycle mostly occurs as infiltration, evaporation and evapotranspiration in the vertical direction, in which the unsaturated zone plays an important role in precipitation and groundwater. Isotope can be used to trace the process when the precipitation infiltrates and recharges groundwater. In this paper Cangzhou and Hengshui sites are selected as the typical shallow groundwater areas to research the difference of the infiltration process under the different precipitation features, soil textures and vegetation conditions. The results show that at the site with the heterogeneous soil texture the precipitation infiltrates and moves in soil as the piston mode and the mixture effect, and the evapotranspiration effect during the infiltration process is significant in the distribution of soil water. Some evidence is provided for the existence of the preferable flow at 100 m depth. The groundwater is mainly recharged by precipitation. However, at the homogeneous site the infiltration process is uniform and the soil water moves as piston mode, too. Both deep soil water and groundwater are totally recharged by precipitation. After precipitation the recharged groundwater experiences strong evaporation effect.