The dimensions and organization of deltaic islands and channels dictate delta morphology. This study presents experimental results modelling deposition at a river mouth and flow bifurcation around delta islands. Mouth bar formation and channel bifurcation is achieved in a laboratory setting by alternating input of suspended load transport and bedload transport. These two modes of transport produce two characteristic deposits with different advection lengths. Suspended load transport creates a steep deposit far from the inlet, while bedload creates a low angle, levéed deposit near the inlet. This study found that flow bifurcations occur where the proximal and distal deposits encroach on one another; and determined that there is a relationship between the frequency of suspended load transport and the length to channel bifurcation. Frequent flooding causes shorter length to bifurcations, whereas infrequent flooding causes greater length to bifurcations. This work overturns the hitherto understood mechanism of bifurcation location as a function of only high‐transport conditions. Instead, the interactions between the sediment transport and deposition from normal flow and large‐scale flooding events dictate delta island morphology.

中文翻译：

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洪水间歇性对河流三角洲系统分叉的影响：实验和理论

三角洲岛屿和河道的尺寸和组织决定了三角洲的形态。这项研究提供了模拟三角洲岛屿河口沉积物和分流的实验结果。在实验室设置中，通过交替输入悬挂载荷运输和床载荷运输，可以实现口栏的形成和通道的分叉。这两种运输方式产生了具有不同对流长度的两个特征性沉积物。悬吊的载荷传输在远离入口处形成陡峭的沉积物，而基床载荷在入口附近形成低角度的倾斜沉积物。这项研究发现，流动分叉发生在近端和远端沉积物相互侵入的位置。并确定悬挂的载荷传输的频率与通道分叉的长度之间存在关系。频繁的泛洪导致分支的长度较短，而很少的泛滥导致分支的长度较大。这项工作推翻了迄今仅作为高运输条件的函数的分叉定位机制。取而代之的是，正常流量和大规模洪水事件造成的泥沙输运与沉积之间的相互作用决定了三角洲的岛屿形态。