Hydrodynamic and suspended sediment transport controls on river mouth morphology

F. Falcini , A. Piliouras , R. Garra , A. Guerin (1) , D. J. Jerolmack , J. Rowland , C. Paola

1 IPGP - Institut de Physique du Globe de Paris

mouths building into standing bodies of water have strikingly varied growth habits. This presents a compelling pattern formation problem that is also of great practical relevance for subsurface prediction and managing coastal wetlands. Here we present a generalized 2.5-dimensional potential vorticity (PV) theory that explains sedimentation patterns of a sediment-laden stationary jet by coupling an understanding of vorticity with suspended sediment concentration fields. We explore the physical meaning of this new sediment-PV definition, and its impact on outflow depositional patterns, by analyzing data from a shallow wall-bounded plane jet experiment and by discussing new theoretical insights. A key result is that lateral advection and diffusion of suspended sediment are directly proportional to jet vorticity, a feature that reveals the mechanistic process that forms elongated channels by focused levee deposition. The new PV theory constitutes a more generalized mathematical framework that expands the Rouse theory for the equilibrium of suspended sediment.

Keywords: river mouth; suspended sediment; potential vorticity

Domains: Sciences of the Universe [physics]

F. Falcini, A. Piliouras, R. Garra, A. Guerin, D. J. Jerolmack, et al.. Hydrodynamic and suspended sediment transport controls on river mouth morphology. Journal of Geophysical Research: Earth Surface, 2014, 119, pp.1-11. ⟨10.1002/2013JF002831⟩. ⟨insu-03581155⟩