ChapterS
Physical Characteristics and Processes of the
Rio de la Plata Estuary
Mariana B. Framinan . Maria P. Etala . Eduardo M. Acha . Raul A. Guerrero
Carlos A. Lasta . Otis B. Brown
8.1
Introduction
The Rio de la Plata Estuary, located at 35°00'S on the Atlantic coast, drains the se~ond
largest basin in South America. The drainage area covers over 3.1 x 10 6 km 2 and includes parts of Argentina, Bolivia, Brazil, Paraguay and Uruguay. It is the most developed basin in South America: the population of the hinterland is estimated to be 30 million inhabitants. Two of the major ports in the region, the cities of Buenos Aires, Argentina, and Montevideo, Uruguay, lie along its shores. The Rio de la Plata also provides access to ports upstream along the Parana, Paraguay, and Uruguay Rivers. Biologically, the estuary is also very important (Cousseau 1985; Boschi 1988). The outer
region, where the fresh waters rich in nutrients interact with the coastal waters, is the
spawning and nursery area of many coastal species. Because of its regional importance, the Rio de la Plata Estuary has been the subject of many research programs
which try to understand different aspects of the environment and ecosystem.
The aim of this chapter is to review the physical characteristics of the estuary, especially those of the outer estuary. Discussion will focus mainly on the analysis of
results from recent studies presented by the authors. These studies are based on in situ
information, satellite imagery and modelling. They are part of ongoing research programs carried out as a joint effort by institutions from Argentina and USA.
In the following section, a brief description is presented of the Rio de la Plata environment, its physiographic setting, climatology, and hydrology. Section 8.3 analyses
the tidal regime in the estuary. In Section 8.4 results of the study of the salinity field
are presented; the stratification, the effects of river and wind forcing, and the implications of the salinity distributions on circulation, are discussed. The temperature field
and its variability are analysed in Section 8.5, based on in situ and remote sensing
information. The last section presents a study of the turbidity front, a characteristic
feature of the Rio de la Plata Estuary.
8.2
Rio de la Plata Environment
8.2.1
Physiographic Setting
The Rio de la Plata is located on the east coast of South America, between 34°00'S and
36°20'S, and 55°00'W and 58°30'W. It is a shallow, large-scale, coastal plain estuary that
covers an approximate area of 35 000 km 2 (Fig. 8.1). It is 320 km long, and its width
Physical Characteristics and Processes of the
Rio de la Plata Estuary
Mariana B. Framinan . Maria P. Etala . Eduardo M. Acha . Raul A. Guerrero
Carlos A. Lasta . Otis B. Brown
8.1
Introduction
The Rio de la Plata Estuary, located at 35°00'S on the Atlantic coast, drains the se~ond
largest basin in South America. The drainage area covers over 3.1 x 10 6 km 2 and includes parts of Argentina, Bolivia, Brazil, Paraguay and Uruguay. It is the most developed basin in South America: the population of the hinterland is estimated to be 30 million inhabitants. Two of the major ports in the region, the cities of Buenos Aires, Argentina, and Montevideo, Uruguay, lie along its shores. The Rio de la Plata also provides access to ports upstream along the Parana, Paraguay, and Uruguay Rivers. Biologically, the estuary is also very important (Cousseau 1985; Boschi 1988). The outer
region, where the fresh waters rich in nutrients interact with the coastal waters, is the
spawning and nursery area of many coastal species. Because of its regional importance, the Rio de la Plata Estuary has been the subject of many research programs
which try to understand different aspects of the environment and ecosystem.
The aim of this chapter is to review the physical characteristics of the estuary, especially those of the outer estuary. Discussion will focus mainly on the analysis of
results from recent studies presented by the authors. These studies are based on in situ
information, satellite imagery and modelling. They are part of ongoing research programs carried out as a joint effort by institutions from Argentina and USA.
In the following section, a brief description is presented of the Rio de la Plata environment, its physiographic setting, climatology, and hydrology. Section 8.3 analyses
the tidal regime in the estuary. In Section 8.4 results of the study of the salinity field
are presented; the stratification, the effects of river and wind forcing, and the implications of the salinity distributions on circulation, are discussed. The temperature field
and its variability are analysed in Section 8.5, based on in situ and remote sensing
information. The last section presents a study of the turbidity front, a characteristic
feature of the Rio de la Plata Estuary.
8.2
Rio de la Plata Environment
8.2.1
Physiographic Setting
The Rio de la Plata is located on the east coast of South America, between 34°00'S and
36°20'S, and 55°00'W and 58°30'W. It is a shallow, large-scale, coastal plain estuary that
covers an approximate area of 35 000 km 2 (Fig. 8.1). It is 320 km long, and its width