近年来设计和建造岸边排水结构物的实践指出,这些结构物一般均位于堤防外部,而堤身有时则距河中自然水位水边线很远。在这种情况下,若存在着异质土壤时(上层土壤较下层不易透水),除由河中(水库中)向外成水平方向渗水外,在堤与河间的被淹滩地上,还成垂直方向地向下渗水,且有时其量很大。为此,在这种情况下需要定出此种渗水 In recent years, the practice of designing and constructing shore drainage structures has pointed out that these structures are generally located outside the embankments, while the dike is sometimes far from the natural water level in the river. In this case, if there is heterogeneous soil (the upper layer is not permeable to the lower layer), except in the middle of the river (in the reservoir) seepage into the horizontal direction, on the flooded land between the embankment and the river, Water seepage down in the vertical direction, and sometimes in large quantities. For this reason, it is necessary to specify such water seepage in this case