Cellular braided river model

High resolution RC river model.

Reduced complexity modelling of river evolution

Reduced-complexity (RC) models are based on simple abstractions of the physics governing flow and sediment transport and have the potential to provide insight into emergent phenomena, while also benefiting from greater computational efficiency than conventional modelling approaches.

Past work in this area has been funded by the Royal Society and by a NERC studentship undertaken by Rhian Thomas (now at Glasgow) on the development of a cellular model of braided river evolution over historic timescales (see upper right).

Andrew’s more recent research has involved development of higher resolution RC river models (see lower right), and their intercomparison with hydrodynamic models that have a stronger physical basis, in order to evaluate the assumptions that underpin RC approaches.

This has also motivated a focus on the ability of RC approaches to capture fundamental aspects of river morphodynamics, such as the initiation, growth and migration of free bars. For example, the image below shows simulated alternate bars generated by a small initial bed pertubation imposed at the inlet to a laboratory flume channel (plot shows bar and pool topography; white is high, black is low).

Current work in this area involves the development and application of RC models to investigate flow, bar formation and sedimentology in large sand bed rivers.

Back to Andrew Nicholas research projects