As an active ecotone between the surface stream and groundwater, hyporheic zone (HZ) plays a crucial role in hydrological and ecological processes. Previous numerical simulation and experimental studies have shown that hyporheic exchange can be affected not only by current but also by geometric characteristics of the streambed. However, the geometric characteristics that affect hyporheic exchange remain unclear. In this study, a one-way sequential coupling method was established to connect the river water flow and pore-water flow in the streambed. The change of flux at the interface, mass flux, depth, and area of hyporheic zone were investigated by altering the bed geometric characteristics, i.e. the depth, crest position, and shapes of bedforms. The results clearly demonstrate the following conclusions: (a) the hyporheic exchange flux, depth and area with wave-like bedform is greater than the triangular bedform. (b) The increase of the bed height accelerates the hyporheic exchange processes at the sediment–water interface. (c) A good linear relationship was found between the depth and area of the hyporheic zone. These results provide necessary theoretical understandings of hyporheic exchange, broadening the knowledge of mechanism of stream-streambed exchange processes.

作为地表河流和地下水之间的活跃交错带，次流带（HZ）在水文和生态过程中起着至关重要的作用。以前的数值模拟和实验研究表明，水流交换不仅会受到电流的影响，还会受到河床几何特征的影响。然而，影响低流交换的几何特征仍不清楚。在这项研究中，建立了一种单向顺序耦合方法来连接河床中的河流水流和孔隙水流。通过改变床层的几何特征，即床层的深度、波峰位置和形状，研究了潜流带界面通量、质量通量、深度和面积的变化。结果清楚地证明了以下结论：（a）低流交换通量，波浪状床型的深度和面积大于三角形床型。(b) 床层高度的增加加速了沉积物-水界面的潜流交换过程。(c) 潜流带的深度和面积之间存在良好的线性关系。这些结果为水流交换提供了必要的理论认识，拓宽了对流-河床交换过程机理的认识。