Morphodynamic evolution and sedimentology of a microtidal meander bend of the Venice Lagoon (Italy)

Meandering channel networks exert a fundamental control on hydrodynamic and morphodynamic processes within tidal landscapes. The planform of tidal meanders develops through erosional and depositional processes, which occur along the outer and inner bank of the bend, respectively. The present study describes the internal architecture and morphodynamic evolution of a tidal meander bend in the Venice Lagoon (Italy), by integrating aerial photographs, bathymetric field surveys, three-dimensional high-resolution geophysical investigations, sedimentary cores and numerical modeling. We find that the evolution of tidal channels is punctuated by abrupt changes in channel dynamics, which are triggered here by changes in tidal asymmetry and increase in water and sediment discharge from lateral tributaries. Our results suggest that dynamics at a specific meander can be dependent on events that happen elsewhere in the system, and meandering patterns in the tidal landscape can retain the signatures of processes acting at larger spatial scales.