Morphological features in the macrotidal estuary of Rio Gallegos, Argentina

GINSBERG, S SUSANA; MELO, WALTER D; PERILLO, GERARDO ME; PERILLO, GERARDO M. E.

Bahía Blanca

Congreso; Open Science Meeting; 1999

LOICZ

Río Gallegos Estuary is localized in the south of Santa Cruz province,Argentina. Gallegos River at the West and Chico River at the Southwest, are theirtributaries. It is 47km length and its width is 5 km at the mouth, between Punta Loyolaand Punta Bustamante. This width continues along 30 km until the Killik Aike Surfarm. After that, it begins abruptly close to the Güer Aike place. Río Gallegos is amacrotidal estuary, and its tidal ranges mean is between 12 and 14 meters. This tidal isconsidered one of the biggest in the world.Extensive tidal flats, within estuarine zones, are often associated with majorriver discharges of sediments. However, in Río Gallegos estuary, the tidal flats are welldeveloped although the input of sediment, associated with rivers is negligible. Atpresent the tidal flat sediment comes from the cliffs erosion that skirts the north coast.The estuary is formed by a series of intertidal banks with widely varying dimensionsthat is conforming a complex pattern. Results show a highly variable morphology wherethe tidal flats and banks are being reworked inducing continual changes in the estuary.Field studies were undertaken to define the morphology and physical conditionsthat characterize Río Gallegos Estuary. Although considerable studies have bee donealong the estuary, virtually not information exists on the general characteristics aboutsubtidal zone. Therefore, this paper deals with one aspect that has not previouslystudied, as the processes affecting the dynamics and banks behaviour.