Dinâmica da desembocadura do rio Itanhém, Alcobaça, BA / Morphodynamics at the Itanhaém Inlet, Alcobaça, BA

AUTOR(ES)

Mariana Coppede Cussioli

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

05/10/2010

RESUMO

The morphodynamic processes at inlet systems are related to a variety of forcing conditions that create unique hydrodynamic conditions. The interaction of tidal currents, wave conditions, and river discharge at different levels result in complex dynamic patterns. The present work aims to understand the processes that control the dynamics of the Itanhaém River, Alcobaça (BA). The system dynamics was analyzed through the combined application of LANDSAT5-TM satellite images, field measurements and numerical modelling. A set of satellite images (for 1987, 1990, 1996, 2007, 2008 and 2009) was used to extract the coastline contours which, combined with the bathymetric data, defined the grids for a series of numerical experiments. Three modules of the MIKE 21 FM model have been applied: wave propagation, hydrodynamic and sediment transport, including the feedback between the morphological changes and the hydrodynamics. The description of the processes observed through the satellite images and the results of the numerical experiments show that there is a spit growth driving the inlet southwards between 1987 and 2007. In 2007 the spit reached its maximum extent and a high wave energy event breached the spit leaving the system with two openings to the ocean. The sediment supply to the southern sandbar is controlled by the longshore drift, with its quantities being apparently controlled by the inlet width. The main mechanism of sediment transport in the study area is mainly due to the northeasterly waves, moving sediments southwards. The more energetic southerly waves, which could lead to transport in the opposite direction, are refracted due to the wide shelf and the presence of coral reefs in the region. The new inlet formed by the spit breach became the main flow channel. This flow interrupts part of the littoral drift, retaining sediment updrift and limiting the sediment supply downdrift. The size and width of the new inlet define the amount of sediment being bypassed, controlling the growth of the sandbar.

ASSUNTO(S)

desembocadura inlet modelagem numérica. morfodinâmica morphodynamics numerical modelling pontal arenoso sand spit

Documentos Relacionados

• Diagnóstico Geoambiental de Zonas de Manguezal do Estuário do Rio Itanhém, Município de Alcobaça Região Extremo Sul do Estado da Bahia
• Alimentação e impactos da espécie exótica bagre-africano (Clarias gariepinus Burchell,1822) no estuário do rio Itanhém, Bahia
• Estudo arqueobotânico dos restos alimentares silvestres do sítio arqueológico Alcobaça, |Buíque-PE
• Carbon and Electron Flow in Mud and Sandflat Intertidal Sediments at Delaware Inlet, Nelson, New Zealand
• Dynamics of sandbars and sandspits associated to the caravelas river mouth (BA)