Chapter 9
Geomorphological and Physical Characteristics
of the Bahia Blanca Estuary, Argentina
Gerardo M.E. Perillo . M. Cintia Piccolo
9.1
Introduction
Located at the southwest of the Buenos Aires Province, Argentina, the Bahia Blanca
Estuary (Fig. 9.1) is considered the second largest estuary in the country after the Rio
de la Plata. However, its geomorphologic and physical characteristics vary significantly
from all other estuaries in Argentina and South America. Actually The Wash, located
in the United Kingdom, is probably the only estuary in the world that have general
characteristics quite similar to Bahia Blanca.
Besides its scientific interest, the estuary is economically very important since the
largest deepwater harbour system of Argentina, which manages most of the country's
exports of agricultural products, is located along its northern coast. Associated with
the Ingeniero White port, a series of subsidiary harbours are related to petrochemical industries, fisheries and the largest naval base of the country.
Although research studies in this estuary date back to 1967, most of them were related to specific biologic and chemical projects. Little information about the geomorphology and physical parameters was available prior to the intense studies that started
in 1983 and continues today. About 90% of all the studies made in the estuary were
concentrated on its Principal Channel.
Furthermore, during 1990 the navigation route included in the Principal Channel
was dredged from 9.5 m (33 ft) to 13.5 m (45 ft) nominal depths. Over 35 million m 3 of
sediment were extracted from the channel and harbour areas and disposed on the tidal
flats and offshore locations. This dredging has introduced major changes in the circulation pattern of the estuary and the amount of sediment transport that have not
been estimated yet.
Even though the now available large data base, only the general characteristics of
this very complex environment have been uncovered. The objective of this review is
to provide the present status of the knowledge about the geomorphological and physical characteristics of the estuary and to define the main directions that future research
should follow to obtain a better picture of its dynamics.
9.2
Geological Setting
The Bahia Blanca Estuary occupies the northern border of the Cretaceous-Tertiary
Colorado Sedimentary Basin (Zambrano 1972). Sediments associated to the estuary
proper are from Pliocene (Chasico Fm) and Pleistocene (Pampa Fm) ages plus recent
material. Both formations are related to fluvial estuarine sediments (Aliotta et al. 1996).
Geomorphological and Physical Characteristics
of the Bahia Blanca Estuary, Argentina
Gerardo M.E. Perillo . M. Cintia Piccolo
9.1
Introduction
Located at the southwest of the Buenos Aires Province, Argentina, the Bahia Blanca
Estuary (Fig. 9.1) is considered the second largest estuary in the country after the Rio
de la Plata. However, its geomorphologic and physical characteristics vary significantly
from all other estuaries in Argentina and South America. Actually The Wash, located
in the United Kingdom, is probably the only estuary in the world that have general
characteristics quite similar to Bahia Blanca.
Besides its scientific interest, the estuary is economically very important since the
largest deepwater harbour system of Argentina, which manages most of the country's
exports of agricultural products, is located along its northern coast. Associated with
the Ingeniero White port, a series of subsidiary harbours are related to petrochemical industries, fisheries and the largest naval base of the country.
Although research studies in this estuary date back to 1967, most of them were related to specific biologic and chemical projects. Little information about the geomorphology and physical parameters was available prior to the intense studies that started
in 1983 and continues today. About 90% of all the studies made in the estuary were
concentrated on its Principal Channel.
Furthermore, during 1990 the navigation route included in the Principal Channel
was dredged from 9.5 m (33 ft) to 13.5 m (45 ft) nominal depths. Over 35 million m 3 of
sediment were extracted from the channel and harbour areas and disposed on the tidal
flats and offshore locations. This dredging has introduced major changes in the circulation pattern of the estuary and the amount of sediment transport that have not
been estimated yet.
Even though the now available large data base, only the general characteristics of
this very complex environment have been uncovered. The objective of this review is
to provide the present status of the knowledge about the geomorphological and physical characteristics of the estuary and to define the main directions that future research
should follow to obtain a better picture of its dynamics.
9.2
Geological Setting
The Bahia Blanca Estuary occupies the northern border of the Cretaceous-Tertiary
Colorado Sedimentary Basin (Zambrano 1972). Sediments associated to the estuary
proper are from Pliocene (Chasico Fm) and Pleistocene (Pampa Fm) ages plus recent
material. Both formations are related to fluvial estuarine sediments (Aliotta et al. 1996).