INVESTIGADORES
ISLA Federico Ignacio
artículos
Título:
Morphodynamics of a gravel-dominated macrotidal estuary...
Autor/es:
FEDERICO IGNACIO ISLA; BUJALESKY, GG
Revista:
RAGA
Editorial:
RAGA
Referencias:
Lugar: Buenos Aires; Año: 2004 p. 220 - 228
ISSN:
0004-4822
Resumen:
Rio Grande city (Tierra del Fuego) is located on two attached beach systems, one of Upper Pleistocene (Sangamonian)
and the other of Holocene age. Both gravel spits grew from north to south modifying the inlet of the Rio Grande estuary. The
present estuary is constrained by the modern and recurved spit Popper Spit. The main characteristic of this macrotidal estuary is
that both margins and the bottom are mainly composed of rounded gravel. Expansion of the city is limited by oceanic and estuarine
coasts, and is taking place towards salt marshes taking up more than 30 hectares in the last 20 years. The alteration of the tidal
prism induced by marsh reclamation and the construction of a bridge may be affecting the inlet dynamics. The area of salt marsh
and gravel banks were calculated by means of supervised classifications derived from a Landsat TM image. The inlet morphology
changes in response to cycles dominated by longshore drift, wave refraction and ebb-tidal delta configuration. Oceanic beaches are
characterised by large disc-shape boulders at the storm berm, spherical pebbles and sand runs at the foreshore, and fine sand on the
low-tide terrace. Although tidal effects are very significant in the dynamics of the estuary, wind can prevail during some days or
during slack water.