Check dams are frequently built in mountain streams as sequences of stair-like grade-control structures to stabilise longitudinal profiles and decrease bedload transport rates. However, their effect on sediment connectivity is still not properly understood owing to missing field data about particle mobility through check-dam sequences. In this study, we tracked tagged particles in a reach intensively managed by torrent control works (i.e., a straightened channel stabilised by a sequence of consolidation check dams and bank reinforcements) and in an untreated pool-riffle reach with similar catchment-scale characteristics. Data on water level and particle mobility were collected over two years and five resurveys. In addition, we measured the grain-size characteristics of armour and subarmour bed layers to assess potential armouring processes in relation to the presence of the check dams. The tracking of tagged particles showed clear differences in the longitudinal and channel-unit patterns of particle retention between the studied reaches after two bankfull events. The presence of the torrent control works accelerated the downstream transport of the tagged particles despite lower calculated unit stream powers in comparison with those in the unmanaged reach. We observed a close-to-normal longitudinal distribution of the tagged particles and longer travel distances in the managed reach. In contrast, the pool-riffle reach indicated high retention of recovered particles in fresh bar deposits and a left-skewed distribution of the final travel distances. In addition, the managed reach with check dams indicated strong bed armouring processes that likely made the vertical exchange of particles between sedimentary layers difficult. In contrast to the general perception of check dams as decelerators of downstream sediment fluxes, our field experiment demonstrated a specific case when sequences of consolidation check dams in small and relatively low-gradient managed channels can act as boosters of longitudinal sediment connectivity.

止水坝通常建在山区河流中，形成一系列阶梯状的坡度控制结构，以稳定纵剖面并降低基床运输速度。然而，由于缺少有关通过坝坝序列进行的颗粒迁移的现场数据，人们对它们对沉积物连通性的影响仍未得到正确的理解。在这项研究中，我们跟踪了由洪流控制工作密集管理的河段中的带标记颗粒（即，通过一系列固结止水坝和河岸加固物加固的拉直通道）以及未经处理的具有类似集水规模特征的池pool河段。在两年和五次重新调查中收集了有关水位和颗粒迁移率的数据。此外，我们测量了装甲层和子装甲床层的粒度特征，以评估与止水坝的存在有关的潜在装甲过程。跟踪标记后，在两次堤满事件之后，所研究河段之间的颗粒保留纵向和通道单元模式存在明显差异。洪流控制工作的存在促进了标记颗粒的下游传输，尽管与未管理范围相比，计算出的单位流功率较低。我们观察到标记颗粒的纵向分布接近正常，并且在受控范围内具有更长的行进距离。相比之下，池壁浅滩达到率表明回收的颗粒在新鲜棒状沉积物中的保留率很高，并且最终移动距离呈左偏分布。此外，带止水坝的受控河段表明床层铠装过程坚固，这可能使沉积层之间的垂直颗粒交换变得困难。与通常将止水坝作为下游沉积物通量的减速剂的一般看法相反，我们的现场实验表明，在较小且相对较低坡度的受控河道中，固结止水坝的序列可作为纵向沉积物连通性的助推器。