Researchers use sediment hysteresis in watershed sedimentation studies, however underlying processes controlling sediment hysteresis observations remain an open topic of investigation. We investigate the hypothesis that baseflow water and sediment can control sediment hysteresis in some cases by: (i) modelling water–sediment mixing permutations that considers baseflow and runoff with their own sediment concentration distributions; (ii) analyzing sediment hysteresis for a karst basin with high baseflow contributions in Kentucky, USA by decoupling baseflow and runoff hysteresis via sensor data, a mixing model, and sediment transport modelling; and (iii) analyzing the alternative hypothesis of sediment origin controlling hysteresis for this system using modelling and tracing of sediment origin with stable isotopes. Results from mixing model permutations show that changes to the timing and magnitude of baseflow water and its sediment concentration can shift hysteresis looping from clockwise (HI > 0.1) to counterclockwise (HI < -0.1). Varying the baseflow contribution can reproduce most of the sediment hysteresis results reported in the literature, such as single loops, double loops, figure eights and complex loops. Results from the Kentucky basin where baseflow contributions are high show the dominance of a new taxonomy of sediment hysteresis loops called a ‘J-loop’. 71 % of the loops observed were J-loops while the remaining 29 % were complex loops. The J-loop occurs when baseflow dominates over runoff for a hydrologic event and the baseflow to runoff volume ratio falls between 1.5 and 3. Analyses of the alternative hypothesis show that looping patterns do not depend on sediment origin for the events studied. Sediment origin varied by dominance of the distal sediment source (26 % of events), proximal source (55 %), and nearly equal mixture of the two sources (18 %). J-loops and complex loop occurrence was not consistent with any sediment origin dominance. We analyzed 43 sediment hysteresis studies reported in hydrology journals and found many studies show hysteresis that resembles J-loops. These occur during events with low antecedent moisture, low-intensity rain, and low amounts of runoff—all of which point towards baseflow dominance. The results herein suggest the importance of the J-loops in systems with high baseflow contributions as well as the overall influence of baseflow to impact loop interpretations. This result is relevant because recent findings show that the majority of hydrologic events in many regions are dominated by baseflow. In such systems, the baseflow contribution and it’s control on sediment hysteresis looping challenges the common interpretation that hysteresis loops reflect proximal and distal sediment sources.

中文翻译：

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水文途径和基流贡献，而不是沉积物源的接近程度，决定了沉积物滞后曲线的形状：美国肯塔基州喀斯特盆地的理论发展和应用


研究人员在流域沉积研究中使用沉积物滞后，但控制沉积物滞后观测的潜在过程仍然是一个开放的研究话题。我们通过以下方式研究了基流水和沉积物在某些情况下可以控制沉积物滞后的假设：（i） 对水-沉积物混合排列进行建模，该排列考虑了基流和径流及其自身的沉积物浓度分布;（ii） 通过传感器数据、混合模型和沉积物输运模型解耦基流和径流滞后，分析美国肯塔基州一个高基流贡献的喀斯特盆地的沉积物滞后;（iii） 使用稳定同位素的沉积物起源建模和追踪来分析该系统的沉积物起源控制滞后的替代假设。混合模型排列的结果表明，基流水的时间和大小及其沉积物浓度的变化可以将滞后循环从顺时针 （HI > 0.1） 转变为逆时针 （HI < -0.1）。改变基流贡献可以重现文献中报道的大多数沉积物滞后结果，例如单环、双环、图 8 和复环。来自基流贡献较高的肯塔基盆地的结果表明，一种称为“J 形环”的沉积物磁滞回线的新分类法占据主导地位。观察到的 71% 的循环是 J 形循环，而其余 29% 是复杂循环。当水文事件的基流主导径流并且基流与径流体积比介于 1.5 和 3 之间时，就会出现 J 形环。对替代假设的分析表明，循环模式不依赖于所研究事件的沉积物来源。 沉积物来源因远端沉积物来源（占事件的 26%）、近端来源 （55%） 和两个来源几乎相等的混合 （18%） 的优势而异。J 环和复杂环的出现与任何沉积物起源优势不一致。我们分析了水文学期刊上报道的 43 项沉积物滞后研究，发现许多研究表明滞后类似于 J 形环。这些发生在前期低湿度、低强度降雨和低径流量的事件中，所有这些都指向基流占主导地位。本文的结果表明 J 环在具有高碱流贡献的系统中的重要性，以及碱流对影响环解释的整体影响。这一结果具有相关性，因为最近的研究结果表明，许多地区的大多数水文事件都由基流主导。在此类系统中，基流贡献及其对沉积物磁滞回流的控制挑战了磁滞回流反映近端和远端沉积物源的常见解释。