The morphodynamic evolution of river deltas is intimately tied to flow and sediment partitioning at bifurcations. In this work, the long-term equilibrium configuration of a simple delta network is investigated by means of an analytical model, which accounts for the effect of small tidal oscillations. Differently from individual bifurcations where tidal action is always a stabilizing factor, in the case of a tree-like delta with multiple bifurcations a dual response emerges. Specifically, depending on the values of four reference parameters functions of tidal amplitude, upstream flow conditions, and channels geometry, tides can either promote or discourage an unbalanced discharge distribution. This behavior primarily concerns the apex bifurcation, which is affected by the variations of the relative tidal amplitude at the internal nodes. In turn these variations depend on how flow and sediment are diverted upstream. The stability of steady-state solutions is found to be governed by the sign and magnitude of the slope asymmetry between channels. This work provides a basic modeling framework for the interpretation of the autogenic response of multiple coupled micro-tidal bifurcations, which can potentially be extended to include in a unified scheme erosional and depositional processes typical of fluvio-deltaic systems.

河流三角洲的形态动力学演化与分叉处的水流和沉积物划分密切相关。在这项工作中，通过分析模型研究了简单三角网络的长期平衡配置，该模型解释了小潮汐振荡的影响。与潮汐作用始终是稳定因素的单个分叉不同，在具有多个分叉的树状三角洲的情况下，会出现双重响应。具体来说，根据潮汐幅度、上游流动条件和渠道几何形状的四个参考参数函数的值，潮汐可以促进或阻止不平衡的流量分布。这种行为主要涉及顶点分叉，它受到内部节点处相对潮汐幅度变化的影响。反过来，这些变化取决于流量和沉积物如何向上游转移。发现稳态解的稳定性受通道之间斜率不对称的符号和大小控制。这项工作为解释多个耦合微潮分叉的自生响应提供了一个基本的建模框架，该框架可以潜在地扩展到包括统一方案中典型的河流三角洲系统的侵蚀和沉积过程。