Chapter 6
The Argentina Estuaries: A Review
M. Cintia Piccolo . Gerardo M.E. Perillo
6.1
Introduction
Despite of its long and extended coastline (5700 km), the number of Argentine estuaries is relative small compared with other countries of comparable size. Mainly, the
difference strives in the climate and the hydrological regime that characterize the
country. Whereas the climate in the NE of Argentina is hot and humid with mean annual precipitation of 1950 mm and maximum of 2437 mm; the NW is relatively dry
and hot. In the center of the country the climate is mild with average precipitation on
the order of 1 000 mm, and in the South is dry and cold with annual precipitation of
300 mm or less.
Based on the pluvial regime, Riggi (1944) defined a series of geohydrographic basins. According to him the rivers that flow into the Atlantic ocean can be classified as:
a Parana-Uruguay River system,
b rivers that flows along the South of Buenos Aires plains,
c steppe basin of the Colorado River, and
d the Andean-steppe rivers that flow across Patagonia.
Each of these geohydrographic basins has its own physical characteristics but, when
they are combined with the geomorphology and typical dynamics of the coast different types of estuaries are generated.
The regions with more precipitation are concentrated in the same river basin:
Parana and Uruguay Rivers basins that discharge into the RIO de la Plata. Other examples are the rivers that belong to the Salado basin that discharge in Samborombon
Bay (Fig. 6.1). These rivers flow in a region oflow slope and mature relief; thus resulting in a meandering pattern. River discharge is significant and prevents the penetration of the saline water from the coastal ocean because it is opposed to a microtidal
regime. Samborombon Bay is a shallow environment being greatly affected by the high
sediment output from RIO de la Plata (Lopez Laborde and Nagy, this book; Framifian
et al. 1998).
Buenos Aires province has the largest number of rivers and small streams that discharge into the Atlantic ocean. Most of those located to the south of the Salado basin
originate in the Tandilia and Ventania hill systems. In general, they are short streams
that cross an extended region of dunes (2-8 km wide) before flowing into the coastal
ocean. Dunes affect in two ways the fluvial discharge: on one side, they produce significant modifications in the stream flow as they force the streams to circulate on low
relief areas increasing river length and generating sometimes shallow lagoons. Sec-
The Argentina Estuaries: A Review
M. Cintia Piccolo . Gerardo M.E. Perillo
6.1
Introduction
Despite of its long and extended coastline (5700 km), the number of Argentine estuaries is relative small compared with other countries of comparable size. Mainly, the
difference strives in the climate and the hydrological regime that characterize the
country. Whereas the climate in the NE of Argentina is hot and humid with mean annual precipitation of 1950 mm and maximum of 2437 mm; the NW is relatively dry
and hot. In the center of the country the climate is mild with average precipitation on
the order of 1 000 mm, and in the South is dry and cold with annual precipitation of
300 mm or less.
Based on the pluvial regime, Riggi (1944) defined a series of geohydrographic basins. According to him the rivers that flow into the Atlantic ocean can be classified as:
a Parana-Uruguay River system,
b rivers that flows along the South of Buenos Aires plains,
c steppe basin of the Colorado River, and
d the Andean-steppe rivers that flow across Patagonia.
Each of these geohydrographic basins has its own physical characteristics but, when
they are combined with the geomorphology and typical dynamics of the coast different types of estuaries are generated.
The regions with more precipitation are concentrated in the same river basin:
Parana and Uruguay Rivers basins that discharge into the RIO de la Plata. Other examples are the rivers that belong to the Salado basin that discharge in Samborombon
Bay (Fig. 6.1). These rivers flow in a region oflow slope and mature relief; thus resulting in a meandering pattern. River discharge is significant and prevents the penetration of the saline water from the coastal ocean because it is opposed to a microtidal
regime. Samborombon Bay is a shallow environment being greatly affected by the high
sediment output from RIO de la Plata (Lopez Laborde and Nagy, this book; Framifian
et al. 1998).
Buenos Aires province has the largest number of rivers and small streams that discharge into the Atlantic ocean. Most of those located to the south of the Salado basin
originate in the Tandilia and Ventania hill systems. In general, they are short streams
that cross an extended region of dunes (2-8 km wide) before flowing into the coastal
ocean. Dunes affect in two ways the fluvial discharge: on one side, they produce significant modifications in the stream flow as they force the streams to circulate on low
relief areas increasing river length and generating sometimes shallow lagoons. Sec-