MORPHOLOGICAL FEATURES AT THE ALGARVE ROCKY COAST: FIRST ORDER FACTORS ON THEIR GENESIS AND EVOLUTION. MORFEA

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Publications

Relationship between wave energy and coastal morphology in the central Algarve rocky coast (Galé to Olhos de Água)

Publication . Bezerra, Maria Margarida Tarrio Agreiro; Moura, Delminda; Ferreira, Óscar; Taborda, Rui

The coastal zones’ geomorphological evolution is the result of subaereal weathering and marine abrasion. To quantify the role of the waves’ action as a geomorphic process particularly on shore platforms sculpture is the main goal of the current work. For that purpose, a numerical modeling for wave propagation (STWAVE) was used to determine differences on breaking wave characteristics along the study area. This program was used inside an operational toolbox (SMS 9.2) that allows data pre-processing from a GIS software (ArcGIS 9.2). The MATLAB R2007a software was used to obtain significant wave heights and wave energy at the breaking position along the study area, for each tested condition. The different coastal morphologies and mass movements were identified on the field and compared with the described evolution in literature (Marques, 1997). Since the study area presents strong longshore variation in exposition to the waves and different wave energies, several sections were defined. It was then possible to analyze the frequency of occurrence of a given coastal morphology and the frequency of mass movements for each section and compare with longshore variations on wave energy for both average and storm conditions.

2008Conference object

Open access

Role of shore platforms on coastal cliffs protection in Algarve (South Portugal): first approach

Publication . Gabriel, Selma; Moura, Delminda; Ferreira, Óscar; Pacheco, André; Matias, Ana; Veiga-Pires, C.

The complex interaction between morphogenetic processes acting on rocky coasts and substrate characteristics difficult the assessment of its evolution at different time scales. In opposition to other coastal environments such as beaches, where variations on substrate’s attributes are constrained to a few possibilities, rocky coasts expose substrates having large amount of variables, among them, lithology, mechanical and chemical strength, density and orientation of faults and joints and, rocks’ texture and structure (e.g., Trenhaile, 2003).

2010Other

Open access

O futuro das costas rochosas no Algarve: influência da herança geomorfológica

Publication . Gabriel, Selma; Moura, Delminda; Viegas, José; Veiga-Pires, C.

As costas rochosas evoluem sob a acção conjugada de processos marinhos e aéreos, sendo a sua magnitude e rapidez, dependente de factores intrínsecos às propriedades de massa das rochas. Na costa rochosa meridional do Algarve, a herança morfológica do Último Máximo Interglacial(UMI), a variabilidade litológica e a intensidade da fracturação, a par com a subida do nível médio do mar (NMM), são os principais factores que determinam o presente comportamento das arribas litorais e a sua evolução futura a curto prazo. A taxa de erosão foi no passado superior à presente, sendo expectável que venha a aumentar rapidamente num futuro próximo, devido a um processo de auto-regulação.

2009Conference object

Open access

Coastal morphology along the Central Algarve rocky coast: driver mechanisms

Publication . Moura, Delminda; Gabriel, Selma; Jacob, J.

The boundary between the mainland and the sea – the littoral fringe - crosses several sub-environments, among them, the rocky coasts whose evolution depends on marine and sub-aerial processes as well as on the rocks’ mass properties. The study area - in central Algarve (South Portugal) - is framed in a rocky coast exposing carbonate rocks. This work identifies the main drivers to the coastal morphology in that region. Several morphological features such as beaches, cliffs, and shore platforms were surveyed, mapped, and correlated with the most common wave conditions in the area. Shore platforms show a strong correlation with the most vigorous wave climate conditions. In opposition, zeta bays occur in the more sheltered sector to the dominant waves and in a relatively straight coastline. Symmetrical small bays are mainly related with the sedimentary influx from rivers reaching the coast. The cliff heights and profiles are lithologically and structurally controlled.

2011Journal article

Open access