Simulating of Emergent and Self-Organizing Features in Fluvial-Deltaic Dynamic System

Channels formation and evolution in deltaic plains tends to be complicated by both fluvial and marine processes. Understanding the ways in which channel development after avulsion is critical to tackling many geomorphologic and river management problems. In general, models for channel development include physical modeling in laboratory flumes and computer numerical simulation. The former is limited to short-term processes at small scale and costs much. The latter often refers to the Computational Fluid Dynamics (CFD) models which are used to simulate the micro-scale interactions between flow hydraulics and sediment. Their predictions are circumscribed by the accuracy and extent of the initial and boundary conditions, the assumptions made by the modeller and the dependence of the model on parameterizations which may have a weak physical basis. Both are not suitable for modeling channel avulsion and development at larger scale which involve complex non-linear relations and interactions. In the paper, an improved multi-flow routing algorithm was integrated in a cellular modeling framework to explore the dynamics of channel avulsion and subsequent new course formation in fluvial-deltaic system. The algorithm allows for lateral transfer of water at angles of up to approximately 180deg to the downstream direction. Modeling results appear able to reproduce many of the larger-scale emergent and self-organizing features observed in the Yellow River Delta. This study demonstrates the utility of relatively simple algorithms to simulate complex emergence features of channel processes in fluvial-deltaic system.