Riffle-pool sequences are fundamental, ubiquitous morphological features of alluvial rivers that are thoroughly studied in general and commonly incorporated into river restoration projects. Most previous investigations on the effect of riffle-pool sequences on hyporheic exchanges focused on solely bed undulation, because that is widely thought to be the defining feature of riffle-pool sequences. However, riffle- pool sequences also have significant width undulations that are vital to riffle-pool sequences morphodynamics, yet relatively few studies exist on the effect of such undulations on hyporheic exchanges. Thus, in this study based on laboratory experiments and numerical simulations, we investigate the effect of bed and width undulations on hyporheic zone characteristics for various ratio of width amplitude to bed amplitude. The variation of hyporheic exchange characteristics (i.e. hyporheic exchange flux and residence time) for different riffle-pool designs were also assessed by creating prescribed topography of synthetic river valleys. The results showed that due to pressure variation along width undulations, the upwelling and downwelling patterns can also be observed for only width undulations in rivers, in the absence of bed undulations, and as width undulation amplitude decreases, the normalized hyporheic exchanges (Q*_HZ) increase and normalized median residence time (RT*) decreases. Also, simultaneous channel bed and width undulations result in higher Q*_HZ especially when a pool is located in an expansion (aka “oversized” cross-section) and a riffle in a constriction (“nozzle”). Our results suggest that river restoration project that artificially construct wide pools and constricted riffles will achieve maximum Q*_HZ and RT*, though they will not be geomorphically self-sustainable.

冲水池序列是冲积河流的基本，普遍存在的形态特征，已对其进行了全面研究，并普遍纳入河流修复项目中。以前大多数关于浅滩-池序列对低渗交换的影响的研究仅集中在河床起伏，因为人们普遍认为这是浅滩-池序列的定义特征。然而，浅滩池序列也具有明显的宽度起伏，这对于浅滩池序列的形态动力学至关重要，但是关于这种起伏对水流交换影响的研究相对较少。因此，在这项基于实验室实验和数值模拟的研究中，我们研究了床和宽度波动对流变区宽度和床幅比的变化对流变带特征的影响。通过创建合成河谷的指定地形，还评估了不同浅滩池设计的水交换特性（即水交换流量和停留时间）的变化。结果表明，由于压力沿宽度波动而变化，在没有河床波动的情况下，仅在河流中的宽度波动也可以观察到上升和下降趋势，并且随着宽度波动幅度的减小，归一化的流变交换（Q *_HZ）增加，标准化中位停留时间（RT *）减少。同样，同时出现的河床床底和宽度波动会导致更高的Q * _HZ，尤其是当水池位于扩展区（又称“超大”横截面）和狭窄区的浅滩（“喷嘴”）时。我们的结果表明，人为建造宽水库和狭窄浅滩的河流修复项目将达到最大Q * _HZ和RT *，尽管它们在地貌上不能自立。