Title:

Léo Szewczyk - From flume to field: channel plug formation and architecture

Event:

No Related Event

Keywords:

RBD | IAHR | Léo Szewczyk

Video Introduction:

While the general processes involved in abandoned channel infilling are well documented, the deposition processes and architecture of the coarse-grained part of the channel fill (i.e., the channel plug) are less studied. This impacts floodplain evolution as well as fluvial reservoir modelling, as the coarse-grained deposits are rarely included in the models, although they can form preferential erosion areas and connectivity bridges in the abandoned channels. The channel plug is often described as formed by a single wedge-shaped sedimentary body whose length is controlled by the bifurcation angle and the channels respective lengths. However, these assumed geometrical controls on channel plugs were never formally identified on the field and the exact processes of channel plug formation remain mostly unobserved. This work focused on (1) observing the deposition processes of bedload sediments in disconnecting channels and determining their controls and (2) identifying the hydraulic and geometric factors controlling the channel plug architecture. For this, a flume model designed specifically to induce channel disconnection and monitor abandoned channel infilling was designed. Later, field surveys in currently disconnecting or recently abandoned channels were used to compare the experimental results with bedload deposition in natural cases.