HYDRO‐GEOMORPHOLOGICAL AND SEDIMENTOLOGICAL PROCESSES ALONG THE MAJOR FLUVIAL‐LACUSTRINE DELTA OF THE PARANÁ RIVER (ARGENTINA). THEIR ROLE IN FLOODPLAIN CONSTRUCTION

DOMINGUEZRUBEN, L. G.; SZUPIANY, R. N.; RAMONELL, C.; RU, M.; GARCIA, M.

EARTH SURFACE PROCESSES AND LANDFORMS

JOHN WILEY & SONS LTD

Año: 2023

0197-9337

River-dominated sea deltas have been thoroughly studied by differentauthors. In these environments the interrelationship of the hydrosedimentologicalvariables between river, tides, and waves, amongothers, are the main factors controlling the delta formation. However, fewstudies have focused on the deltaic processes in river-lagoonenvironments and even fewer in large river floodplains (defined here as aFluvial-Lacustrine Delta, FLD) and their role in floodplain construction.This study provides a comprehensive and novel approach analysiscombining satellite imagery treatment and aerial photographs with adetailed field measurements of sediment samplers, cores, and acoustictechniques applied to quantify flow and discharge distribution along main,secondary, floodplain channels and lagoons systems under differenthydro-sedimentological conditions. All data allow a full description ofdeltaic processes and the main variables that control the evolution of themajor FLD located along Paraná River floodplain (Argentina). Theseresults show: i) pre-existing local geology elements affect the deltaicprocesses; ii) hydro-sedimentological behavior of the main channel and its connection with the floodplain channels and independent basinsystems affect the delta evolution; iii) the dynamics (temporally andspatially) of sediment transport input and the interaction with lagoonsproduce different delta front bars planform and composition, iv) periods ofmean and high water levels play a key role in the delta evolution, and v)the rapid vegetation growth above the formed bars favors thesedimentation of fine material, producing permanent changes and leadingto floodplain construction. Particularly, our findings suggest a complexinterrelationship between the different factors in this particularenvironment, such as hydrology, local geology, main/secondary andfloodplain channels, sediment supply, sediment transport modes,vegetation, and free surface slopes. All these factors act together in acomplex manner, providing unique features to the system that could helpus better understand the floodplains construction in large river systemsworldwide.