“Excess” interstitial fine sediment (<2 mm) is known to cause deleterious impacts on streambed ecosystems. Current methodologies available to assess ingress and its vertical and horizontal components still lack standardization, and the accuracy of commonly used assessments is still debatable. Here, we evaluate three fine sediment trap designs that measure only vertical (V), only horizontal (H), and both vertical and horizontal (HV) ingress mechanisms. Sediment traps were deployed in triplicates to: (i) evaluate measurement variability within traps of the same type; (ii) evaluate the effects of trap design on particle size distributions of infiltrated fine sediment and; (iii) assess methodologies used to calculate vertical and horizontal ingress mechanisms. Ingress rates were recorded for each sediment trap during seven deployment periods (lasting from 2 to 10 days) at a range of flow conditions at four sites. A total of 252 traps were deployed. Results from the triplicate assessment of traps with the same design showed that most measurements presented high variability and that particle size distributions were significantly affected by trap design. Here, different sediment traps were able to estimate directional ingress mechanisms. However, direct comparison between HV with either H or V traps led to an overestimation of horizontal or vertical ingress mechanisms, respectively. Better estimations were found when comparing HV observations to half the accumulation in either H or V, due to the proportional trap volume available for each accumulation mechanism according to trap design.

中文翻译：

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使用可回收沉积物收集器采样器测量砾石河床中的细小沉积物进入的挑战

已知“过量”间质细沉积物（<2 毫米）会对河床生态系统造成有害影响。目前可用于评估侵入及其垂直和水平组件的方法仍然缺乏标准化，并且常用评估的准确性仍然存在争议。在这里，我们评估了三种精细沉积物捕集器设计，它们仅测量垂直 (V)、仅测量水平 (H) 以及垂直和水平 (HV) 进入机制。沉积物捕集器一式三份部署，目的是：（i）评估同一类型捕集器内的测量变异性；(ii) 评估捕集器设计对渗透细沉积物粒度分布的影响；(iii) 评估用于计算垂直和水平侵入机制的方法。记录了四个地点在七个部署期间（持续 2 至 10 天）在一系列流动条件下每个沉积物捕集器的进入率。总共部署了252个陷阱。对具有相同设计的捕集器进行三次重复评估的结果表明，大多数测量结果具有较高的变异性，并且捕集器设计对颗粒尺寸分布有显着影响。在这里，不同的沉积物捕集器能够估计定向进入机制。然而，HV 与 H 或 V 陷阱之间的直接比较分别导致水平或垂直进入机制的高估。当将 HV 观测值与 H 或 V 中的一半积累进行比较时，发现了更好的估计，因为根据捕集器设计，每个积累机制可使用成比例的捕集器体积。