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- Erosion of rocky shores- protection promoted by sandy beaches and shore platformsPublication . Moura, Delminda; Gabriel, Selma; Jacob, J.; Fortes, Conceição; Silva, Paulo A.; Horta, João; Abreu, TiagoO sector costeiro do Algarve central entre as praias da Galé e Olhos de Água deve a sua fisiografia crenulada a um sistema cársico bem desenvolvido em rochas carbonatadas. As arribas possuem no sopé uma plataforma litoral rochosa ou uma praia arenosa. Os principais objectivos do projecto de investigação EROS são: (i) a quantificação da dissipação da energia das ondas ao longo de plataformas litorais e de praias arenosas com diferentes declives e exposição às ondas; (ii) a caracterização da refracção e difracção das ondas e da modificação das correntes forçadas pelo controle morfológico. A metodologia base centra-se na aquisição de dados de ondas e correntes utilizando transdutores de pressão e correntómetros colocados em transeptos normais à linha de costa, de modo a obter o espectro completo de ondas e correntes, desde a água profunda até aproximadamente à base das arribas, quer nas plataformas quer nas praias.
- Wave transformation on shore platform and adjacent sandy beach - Southern PortugalPublication . Gabriel, Selma; Moura, Delminda; Horta, João; Oliveira, SóniaThe knowledge on coastal processes is not only of basic and practical importance (for instance in engineering applications) but also of socio-economic relevance. Crenulated coasts are complex geomorphic environments where both erosive (into headlands) and depositional processes (in embayed beaches) occur simultaneously. Waves represent an important morphogenic factor and the most important source of energy to coastal zones. However, field data reporting the interaction between waves and rocky coastal features is still scarce, leading to a poor understanding on rates and drivers of surf attenuation at rocky shores. Waves abrasion and erosion on shore platforms depend on the platform properties, morphology of the adjacent continental shelf, and water depth upon the platform surface, which is controlled by tides, available sediment and wave climate (e.g.,Stephenson and Kirk, 2000; Marshall and Stephenson, 2011). Shore platforms extending in the intertidal zone at the rocky cliffs’ toe are natural morphological barriers to wave propagation and energy attenuation (Ogawa et al., 2011). Over short time scales the beaches in a crenulated coast are modified mainly by waves causing setup and set down in the surf zone leading to a very complex pattern and circulation modified by the interaction between the currents induced by waves and the incident waves. The mechanisms involved in morphological modifications in those environments are still not well understood (Silva et al., 2010). This work aims to compare the waves behavior both on a shore platform and adjacent pocket beach in response to exactly the same offshore wave conditions.