Analyses of suspended sediment transport provide valuable insight into the role that sediment supply plays in causing geomorphic change. The sediment supply within a river system evolves depending on the discharge, flood frequency and duration, changes in sediment input, and ecohydraulic conditions that modify sediment transport processes. Changes in supply can be evaluated through analyses of coupled changes in suspended sediment concentration and grain size. The concentration of sand in transport in the Green and Colorado Rivers is most strongly controlled by discharge and the bed sand grain size distribution. Since the 1950s, sand loads have decreased in response to declines in peak discharge in the Green River and coarsening of the bed sand in the Colorado River. However, changes in the bed sand grain size distribution are associated with large changes in suspended sand concentration in both rivers; concentration varies by a factor of ~3 in the Green River and a factor of ~8 in the Colorado River, depending on the bed sand grain size distribution. Analyses of hysteresis in suspended sediment measurements show that sediment depletion during annual floods is most strongly controlled by flood duration, with peak discharge being nearly equally important in the Green River. Despite channel narrowing in both rivers, periods of bed sand coarsening and sediment depletion during annual floods indicate that these rivers are not necessarily in sediment surplus. Channel narrowing appears to be strongly controlled by short‐term declines in flood magnitude and the ecohydraulic effects of vegetation and may not be indicative of the long‐term sediment budget.

中文翻译：

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洪泛区增长导致的河道变窄是否必然表明沉积物过剩？犹他州峡谷地的格林河和科罗拉多河中泥沙运移分析的经验教训

悬浮泥沙运移的分析提供了宝贵的见解，以了解泥沙供应在引起地貌变化中的作用。河流系统中的泥沙供应量会根据流量，洪水频率和持续时间，泥沙输入量的变化以及改变泥沙输送过程的生态水力条件而变化。可以通过分析悬浮沉积物浓度和粒度的耦合变化来评估供应量的变化。格林河和科罗拉多河中运输过程中的沙尘浓度受流量和河床沙粒尺寸分布的强烈控制。自1950年代以来，由于绿河（Green River）的峰值流量下降和科罗拉多河（Colorado River）的地层砂变粗，沙的负荷有所减少。然而，两条河流中河床沙粒尺寸分布的变化与悬浮砂浓度的大变化有关；取决于河床沙粒的大小分布，绿河中的浓度变化约3倍，科罗拉多河中的变化约8倍。悬浮泥沙测量中的滞后分析表明，年度洪水期间泥沙的消耗受洪水持续时间的影响最大，在绿河中，洪峰流量几乎同样重要。尽管两条河流的河道都变窄，但在每年的洪水中，河床的沙子变粗和沉积物枯竭的时期表明，这些河流并不一定处于沉积物过剩状态。