Modeling the Suspended Sediment Transport in a Very Wide, Shallow, and Microtidal Estuary, the Río de la Plata, Argentina

Abstract

The impact of the diverse processes responsible for the distribution of suspended sediments in the wide, shallow, and microtidal Río de la Plata estuary and the adjacent shelf is studied by means of a set of process‐oriented numerical simulations. Model results show that the large width and the geometry of the estuary play a major role in the sedimentation processes. The widening and deepening of the estuary drives a significant reduction in current speeds at (i) the confluence of the tributaries and (ii) downstream Barra del Indio Shoal. Thus, sediment deposition enhances downstream those areas. Even though tides are of small amplitude in the study area, they have a significant impact on lateral mixing and resuspension of the bottom sediments. Resuspension augments the concentration of fine sediments in the layers close to the bottom, but tidal energy is not enough to lift them to the surface. Winds (which can be quite strong over this area) enhance horizontal mixing, smoothing the pattern produced by tides. Wind waves increase the concentration of sediment by vertical mixing, and their effect is most evident along the southern coast where wind waves lift the sediments resuspended by tides to the surface. The estuarine circulations associated to the bottom salinity front acts retaining sediments upstream the Barra del Indio Shoal, where estuarine currents and flocculation play an important role in sediment deposition.

Nonlinear Interaction Between the Tide and the Storm Surge with the Current due to the River Flow in the Río de la Plata

“…1). The bottom salinity front (Guerrero et al 1997) and the turbidity maximum of the RdP are located downstream the shoal throughout the year (Moreira et al 2013;Dogliotti et al 2016); the shoal, in turn, develops because of the related sediments dynamics (Moreira and Simionato 2019). The surface salinity signal associated with the freshwater plume of the RdP can extend for many (Campos et al 1999;Piola et al 2008;Romero 2008).…”

“…The Río de la Plata (RdP; Fig. 1) is an extensive estuarine system located on the eastern coast of Southern South America, at approximately 35 • S, that drains the waters of the second largest basin of the subcontinent, after the Amazon River (Moreira and Simionato 2019). The RdP has a freshwater zone (Meccia et al 2013;Guerrero et al 1997) highly influenced by tides (Simionato et al 2004b;D'Onofrio et al 2008), hereinafter referred to as FTZ, that extends from the mouths of the main tributary rivers (Paraná and Uruguay; Fig.…”

“…Sailing, and passengers and commodities transportation activities take place daily between Argentina, Uruguay and the countries located at the upper Plata Basin (Paraguay and Brazil), along channels that demand permanent dredging (Re et al 2010;Santoro et al 2011;Re and Menéndez 2011). The RdP is also the main source of drinking water for the millions of inhabitants in the region (Moreira and Simionato 2019). As a consequence of its development, the FTZ is the main focus of aquatic and atmospheric contamination, which also concentrates there (Simionato et al 2004b).…”

Validación De Las Ecuaciones Empíricas De Transporte De Sedimentos Por Arrastre Y Suspensión Empleando Mediciones en Campo

“…Se puede mencionar además que Moreira, D., & Simionato, C. G. (2019) y Horvat, M., & Horvat, Z. (2020), destacan la importancia de realizar una simulación numérica que permitan analizar cuantitativamente el transporte de sedimentos y el caudal líquido, sin embargo, para lograr tal fin se requieren mayor cantidad de datos de medición de un rango mayor al estudiado y en mayor longitud de tramos de estudio como lo indican Yu, B. Y., Wu, P., Sui, J., Ni, J., & Whitcombe, T. (2020) en su investigación realizada al río Huai de China que lo han realizado por más de 58 años, a pesar de ello los resultados obtenidos muestran una buena aceptación en cuanto a la validación de los valores de las ecuaciones empíricas versus las mediciones de campo.…”

Temporal and Spatial Variability Scales of Salinity at a Large Microtidal Estuary

“…These models must include the effect of Coriolis force, due to the wide extent of the Río de la Plata. The fine sediment dynamic has also been studied by coupling the wave effect to a 3D hydrodynamic model [23][24][25][26]. Nevertheless, due to the complexity of the system, only a few 3D hydrodynamic models have been calibrated using salinity data [22,23].…”