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- Coastline evolution of the Portuguese south eastern coast: a high-resolution approach in a 65 years’ time-windowPublication . Nave, Silvia; Rebêlo, LuísAbstract. The coast, as the interface between land and sea, is a highly dynamic area, endangered by erosion and flooding, particularly at times of sea-level rise. At the present context of climate change, the use of scientific knowledge to understand coastal dynamics and coastal evolution assessment through time is essential to find a suitable management response for a successful adaptive coastal governance. It is proposed that the obtained high-resolution and long-term coastline change dataset is of crucial impor tance to improve the knowledge on mesoscale evolution of the Portuguese south-eastern coast, from Ancão to Vila Real de Santo António (VRSA), a 55 km long coastal stretch. The evolutionary trend, from 1950 to 2015, points to a general seaward progradation at the western (Barreta island) and eastern (Cacela peninsula – VRSA) sectors, and mostly an erosional trend at the central barrier island system (Culatra, Tavira and Cabanas islands). Moreover, a considerable average landward displacement of approximately 130 m is observed at Cabanas island. Regarding overall coastline movement, seaward displacement prevails, with a prograding coastline occupying approximately 54% of the studied sector even though this is mostly associated with human intervention on the coast. The exception is the Manta Rota - Monte Gordo sector where accumulation is likely related to natural processes. Considering the significant influence man-made interventions have had on the coastline evolution, it is believed that the natural evolutionary pattern would point to an overall erosional trend in the islands sector and a progradational trend from Manta Rota to VRSA beach.
- Patterns of sediment distribution on the Portuguese southeastern coastPublication . Nave, Silvia; Rebêlo, LuísSUMÁRIO: A granulometria dos sedimentos pode fornecer informações importantes sobre a origem e evolução dos ambientes sedimentares da zona costeira. Este trabalho apresenta a distribuição espacial da granulometria dos sedimentos no sotavento algarvio, resultante da análise de 395 amostras recolhidas em 133 perfis posicionados ao longo de uma faixa de 55km, desde a península do Ancão até Vila Real de Santo António. A análise preliminar dos resultados, apresentados em função do valor da média e agrupados nas classes normalizadas da escala de tamanho de grão (classificação de Wentworth), revela a ausência das classes granulométricas de areia muito fina e fina, mesmo na zona dunar, onde a classe de areia média domina no sector leste, e a de areia grosseira, no sector ocidental. O padrão geral de distribuição espacial da granulometria dos sedimentos exibe uma variação distinta ao longo da área de estudo, decorrente da exposição aos principais agentes forçadores (ondas e correntes).
- Patterns of sediment distribution on the Algarve leeward coast, PortugalPublication . Nave, Silvia; Rebêlo, LuísABSTRACT: Sediment grain size gives important information on the origin and evolution of coastal sedimentary environments. This work reports the sediment grain size spatial distribution longshore and cross-shore the Southeastern Algarve coastal area, assessed through the analyses of 395 samples collected in 133 profiles, positioned along a 55 km continuous sector, from Ancão peninsula to Vila Real de Santo António. The results are presented as the mean value of grain size and were clustered into the normalized classes of the Wentworth grain-size scale. The preliminary analysis reveals that the very fine and fine sand clusters are absent for the entire transect, even at the dune area, where the smallest average grain size is within the range of medium sand in the eastern sector and coarse sand at the western edge. General trends in the spatial distribution of sediments exhibit a distinctive variation resulting from the exposure to forcing agents along the study area.