This paper uses flume experiments to investigate the influence of lateral width confinement on channel morphology, sediment sorting, and bedload transport. Three runs of about 60 hr were carried out under constant feeding rate equal to 0.6 l/s and 8 g/s, with a bimodal mixture of natural sediments, a fixed flume slope of 3%, and width imposed by lateral walls from 0.12 to 0.50 m in order to model three different flow confinement configurations. Despite the three runs transporting at the same rate on average, they presented different gravel‐bed river morphologies and different degrees of bed complexity. The three runs also presented differences in bedload transport rate fluctuations associated with different magnitude and mechanisms of bed storage and release of sediments. The intermediate width configuration (Run 2) was found to have a minimum storage and release of sediments compared with both the wider configuration (Run 1) and the narrower configuration (Run 3). Runs 1 and 3 were characterized by a significant storage and release of sediments resulting in a highly fluctuating bedload transport rate; however, while Run 1 (braiding morphology) stored and released sediments through lateral deposits and bed variations with planimetric sorting, Run 3 (single‐thread channel) stored and released sediments through variations in bed elevation accompanied by vertical sorting. We extrapolated this concept to the full set of gravel‐bed river morphologies, thus speculating about the channel morphology for optimal sediment transfer.

中文翻译：

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响应横向约束的形态，床荷和分选过程变异性：砾石河道物理模型的结果

本文通过水槽实验研究了横向宽度限制对河道形态，沉积物分选和基床输运的影响。在等于0.6 l / s和8 g / s的恒定进料速率下，进行了三轮运行，运行时间约为60小时，采用自然沉淀物的双峰混合物，固定的水槽坡度为3％，并且侧壁的宽度为0.12到0.5mm。 0.50 m，以便模拟三种不同的流量限制配置。尽管三轮平均以相同的速度运输，但它们呈现出不同的砾石河床形态和不同程度的河床复杂性。这三个运行还显示了与不同量级和床层存储和沉积物释放机制相关的床载输水速率波动的差异。与较宽的配置（运行1）和较窄的配置（运行3）相比，中间宽度的配置（运行2）被发现具有最小的沉积物存储和释放。试验1和试验3的特征是大量沉积物的沉积和释放，导致床载运移速度波动很大。然而，虽然运行1（编织形态）通过侧向沉积和通过平面分选的床层变化来存储和释放沉积物，但是运行3（单线程通道）是通过床高的变化以及垂直分类来存储和释放沉积物。我们将此概念外推到整个砾石河道形态，从而推测出最佳沉积物输送的河道形态。