CHARACTERIZATION OF BOTTOM SEDIMENTS IN THE RÍO DE LA PLATA ESTUARY

MOREIRA, D.; SIMIONATO, C. G.

Montevideo

Congreso; INTERCOH 2017 International Cohesive Sediment Dynamics Meeting; 2017

IMFIA Universidad de la República del Uruguay

Draining the second largest basin of South America, the Río de la Plata (RdP) is one of the largest and most turbid estuaries of the world (Figure 1). Its fresh water plume impacts the properties of the shelf for more than 500 km. The sediments? load that reach the system mainly come from the Paraná river (in its two main branches, Paraná de las Palmas and Paraná Guazú), and has been estimated in more than 160 million tons per year. From that total, 10% correspond to bedload (sand and silt) and 90% to suspended matter (clay). The deposits go from sand on the upper es-tuary and silts in the intermediate estuary, to clay and silts in its exterior part. In the area of the salt wedge, where the river waters meet the sea waters, the flocculation of suspended sediments occur and, therefore, a zone of maximum turbidity occur. Turbulence over the bottom, due to tidal currents, waves or winds, can be strong enough to mix and homogenize the water column, and re-suspend the sediments.The aim of this work is to characterize the bottom surficial sediments long-term mean distribution and to study their composition including the or-ganic matter and water contents, to obtain a qualitative description of the mean transports.