The interaction of sediment supply and hydrographs can affect, on a mesoscale, geomorphic features like pools and riffles, which are fundamental units of many gravel bed rivers. In the past decades, different hypotheses have been developed to characterize the hydrodynamics of pool‐riffle sequences; however, most of the previous studies considered equilibrium or near‐equilibrium sediment transport conditions. Here we investigate the stability of pools and riffles during a sequence of different hydrographs representative of a natural flow regime, without satisfying the equilibrium sediment transport condition. In the current study, the effects of bed geometry, sediment sorting and hydrograph duration, are explained and quantified. The results show that under nonequilibrium conditions, the reversal episodes are not always competent enough for complete self‐maintenance during a single flood. However, width variations and grain sorting effects prevented the pools to be completely filled up with the upstream sediment supply. Hydrograph duration had a significant role in the riffle bed geometry. Even though a single flood (irrespective of the magnitude) was not competent enough to restore the pool‐riffle feature, a sequence of floods progressively improved conditions for self‐maintenance. These findings can bring more insight into flow management strategies, in terms of the importance of multiple sequential floods for restoring rivers with high sediment supply.

中文翻译：

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一次洪水还不够：时变流量和非平衡的多形沉积物输运下的池-肋自养

沉积物供应和水文图的相互作用会在中尺度上影响地貌特征，例如水池和浅滩，这是许多砾石床河流的基本单位。在过去的几十年中，已经开发出了不同的假设来表征池-浅滩序列的流体动力学。但是，以前的大多数研究都考虑了平衡或接近平衡的泥沙输送条件。在这里，我们在不满足平衡泥沙输送条件的情况下，研究了代表自然流态的一系列不同水位图期间水池和浅滩的稳定性。在当前的研究中，解释和量化了河床几何形状，沉积物分选和水文持续时间的影响。结果表明，在非平衡条件下，在一次洪水期间，逆转事件并不总是足以完全自我维护。但是，宽度的变化和谷物的分选效果阻止了上游上游沉积物供应完全填满这些池。水文仪的持续时间在浅滩床几何中起着重要作用。即使一次洪水（大小不一）也不足以恢复池滩特征，但一系列洪水却逐渐改善了自我维护的条件。这些发现可以从多次连续洪水对恢复高含沙量河流的重要性方面为流量管理策略提供更多见识。水文仪的持续时间在浅滩床几何中具有重要作用。即使一次洪水（无论其大小如何）都不足以恢复池滩特征，但一系列洪水却逐渐改善了自我维护的条件。这些发现可以从多次连续洪水对恢复高含沙量河流的重要性方面为流量管理策略提供更多见识。水文仪的持续时间在浅滩床几何中起着重要作用。即使一次洪水（大小不一）也不足以恢复池滩特征，但一系列洪水却逐渐改善了自我维护的条件。这些发现可以从多次连续洪水对恢复高含沙量河流的重要性方面为流量管理策略提供更多见识。