Seminar 13th June, Amphi D, IUEM – Recent work in the Río de la Plata in Uruguay: Nearbed cohesive sediment dynamics and remote sensing in turbid waters by Francisco Pedocchi

Presentation Summary

The presentation will cover two different efforts that I have led in recent years to understand the cohesive sediment dynamics in the Rio de la Plata. The Rio de la Plata is a very wide estuary in South America with an average water discharge of 670×10⁹ m³/yr and an average sediment discharge of 160×10⁹ kg/yr, mostly composed of silt and clay.

First, I will present near-bed suspended sediment measurements performed during storms using multifrequency acoustics. These measurements allowed us to observe, for the first time in the Rio de la Plata, the formation of a hyper-concentrated layer of sediment near the bed that lasted for several hours due to the stirring effect of waves and self-stratification. This work was part of the PhD thesis of Rodrigo Mosquera.

Next, I will show some recent work on remote sensing. This work focused on estimating low levels of chlorophyll a (below 10 µg/L) in the very turbid waters of the Rio de la Plata. The work also showed that the inherent optical properties (IOPs) of the suspended sediment had a seasonal pattern. We related this variation to the seasonal arrival of “fresh” sediments from the upper Rio de la Plata basin. This work was part of the PhD thesis of Fernanda Maciel.

Short Bio of Francisco Pedocchi

I was born in 1976 in Montevideo, Uruguay. In 2001 I graduated as a Civil Engineer with specialization in Hydraulics and Environmental Engineering from the School of Engineering of Universidad de la Republica, Uruguay, under the supervision of Prof. Ismael Piedra Cueva. In 2005 I obtained a Master of Science degree and in 2009 a Doctor of Philosophy degree in Civil Engineering from the University of Illinois at Urbana Champaign, USA, under the supervision of Prof. Marcelo H. Garcia.

Since 2009 I have been working in the Instituto de Mecanica de los Fluidos e Ingenieria Ambiental (IMFIA) at the School of Engineering of Universidad de la Republica, Uruguay, currently as Full Professor.

My research and outreach work relates to the Rio de la Plata estuary dynamics, including cohesive sediments and their interaction with waves and currents, flow and sediment measurement in the field and in the laboratory using both acoustic and optical instrumentation, and more recently remote sensing.

My work takes place in close collaboration with other members of IMFIA River and Coastal Hydraulics Division and I maintain permanent interaction with researchers from computing science, applied mathematics, and biology.

I am using this sabbatical year in 2024 to strengthen IMFIA’s international connections.

You can contact Francisco Pedocchi by mail here.