CHAPTER 7 .0 Hydrography and Sediment Transport Characteristics of the Rio de la Plata
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events. When the air masses reach Brazil their movement is reduced and the air is
warmed. Later, warm air masses return to the South originating northerly winds, which
may carry new maritime or continental tropical warm air masses. Northern winds stop
when a new polar air mass begins to advance from the Patagonian region to the North.
The most frequent storms affecting the Rio de la Plata are called "Sudestadas". They
are produce by the interaction between frontal systems (with SW-NE trajectories) and
the littoral low pressure system, generating strong SE winds. Usually the storms affect the area for several days. The "Sudestada" is responsible for disastrous flooding
events along the Argentinean Rio de la Plata coastal area.
The coastal area is also affected by southwesterlies winds ("Pampero"). They originate from the passage of polar air masses arriving from the south of the Andean Mountain Range. The Pampero is a strong, dry and cold wind. They originate as dry air moves
fast along the Patagonian and Pampa regions arriving at the Rio de la Plata from the
SW. The "Pampero" present velocities between 50-60 km h- 1 , and occasionally 'up to
90 kmh- 1 •
7.3
Hydrographic Characteristics
7.3.1
Morphology
Morphological studies conducted during the "Estudio para la Evaluacion de la Contaminacion en el Rio de la Plata" (Cavallotto 1987; Parker and Lopez Laborde 1988; 1989),
based on the 1964-1969 comprehensive survey allowed to recognise areas with particular features, characterized as "morphological units" (Fig. 7.3):
Playa Honda: The subaqueous prolongation of the Parana River Delta, limited approximately by the 6 m isobath, representing a widespread shallow area crossed by channels.
Sistema Fluvial Norte: This area includes all the channels that extend from the Rio de
la Plata watersheds to Colonia, characterized by a series of erosive furrows, developed
by the erosive action of the Uruguay and Parana Bravo Rivers. It includes channels,
longitudinal benches and subaqueous asymmetrical sandy dunes.
Banco Grande de Ortiz: This unit develops over a large portion of the Rio de la Plata
between Canal Norte, over the Uruguayan coast, and Gran Hoya del Canal Intermedio.
It appears as a large plateau with steep southern slope which flattens to the North and
SE, limited by the 6 m isobath.
Gran Hoya del Canal Intermedio: A widespread depression to the South of Banco
Grande de Ortiz, formed by three morphological elements known as "Rada Exterior",
"Canal Intermedio" and "Sistema de Bancos Chico and Magdalena".
Canal Norte: It extends between the Uruguayan coast and Banco Grande de Ortiz, with
a depth around 5 m. It forms a gentle depression related to the Sistema Fluvial Norte
channels.
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events. When the air masses reach Brazil their movement is reduced and the air is
warmed. Later, warm air masses return to the South originating northerly winds, which
may carry new maritime or continental tropical warm air masses. Northern winds stop
when a new polar air mass begins to advance from the Patagonian region to the North.
The most frequent storms affecting the Rio de la Plata are called "Sudestadas". They
are produce by the interaction between frontal systems (with SW-NE trajectories) and
the littoral low pressure system, generating strong SE winds. Usually the storms affect the area for several days. The "Sudestada" is responsible for disastrous flooding
events along the Argentinean Rio de la Plata coastal area.
The coastal area is also affected by southwesterlies winds ("Pampero"). They originate from the passage of polar air masses arriving from the south of the Andean Mountain Range. The Pampero is a strong, dry and cold wind. They originate as dry air moves
fast along the Patagonian and Pampa regions arriving at the Rio de la Plata from the
SW. The "Pampero" present velocities between 50-60 km h- 1 , and occasionally 'up to
90 kmh- 1 •
7.3
Hydrographic Characteristics
7.3.1
Morphology
Morphological studies conducted during the "Estudio para la Evaluacion de la Contaminacion en el Rio de la Plata" (Cavallotto 1987; Parker and Lopez Laborde 1988; 1989),
based on the 1964-1969 comprehensive survey allowed to recognise areas with particular features, characterized as "morphological units" (Fig. 7.3):
Playa Honda: The subaqueous prolongation of the Parana River Delta, limited approximately by the 6 m isobath, representing a widespread shallow area crossed by channels.
Sistema Fluvial Norte: This area includes all the channels that extend from the Rio de
la Plata watersheds to Colonia, characterized by a series of erosive furrows, developed
by the erosive action of the Uruguay and Parana Bravo Rivers. It includes channels,
longitudinal benches and subaqueous asymmetrical sandy dunes.
Banco Grande de Ortiz: This unit develops over a large portion of the Rio de la Plata
between Canal Norte, over the Uruguayan coast, and Gran Hoya del Canal Intermedio.
It appears as a large plateau with steep southern slope which flattens to the North and
SE, limited by the 6 m isobath.
Gran Hoya del Canal Intermedio: A widespread depression to the South of Banco
Grande de Ortiz, formed by three morphological elements known as "Rada Exterior",
"Canal Intermedio" and "Sistema de Bancos Chico and Magdalena".
Canal Norte: It extends between the Uruguayan coast and Banco Grande de Ortiz, with
a depth around 5 m. It forms a gentle depression related to the Sistema Fluvial Norte
channels.