A carregar...
Publicação
Caracterização morfodinâmica e sedimentar da praia de Carcavelos
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 3.3 MB | Adobe PDF |
Autores
Orientador(es)
Resumo(s)
O presente trabalho incidiu sobre a praia de Carcavelos, situada na freguesia de Carcavelos.
Esta praia foi estudada à microescala temporal para caracterizar a sua morfodinâmica sazonal, entre Outubro de 2014 e Junho de 2015, tendo como objetivo fundamental o estudo da variabilidade sazonal, no que se refere à morfologia e conteúdo sedimentar, com apoio de dados oceanográficos.
Realizaram-se dez campanhas de campo, estabelecendo-se cinco pontos de apoio ao longo do passeio marítimo, a partir dos quais foram levantados, periodicamente, quatro perfis topográficos, transversais à orientação da praia. Como complemento foram ainda realizados dois levantamentos topográficos integrais da praia, bem como recolhidas amostras de sedimentos, representativas das diferentes unidades morfossedimentares, posteriormente analisadas e trabalhadas em laboratório.
Os resultados sugerem que a praia de Carcavelos é uma praia de baixa a média energia. Durante o período de monitorização, foram registados 17 episódios de tempestade. No entanto, a agitação junto à costa não excedeu uma altura significativa de 3m, sendo a sua direção predominantemente de Sudoeste.
Os sedimentos são essencialmente provenientes de deriva litoral, não existindo uma contribuição sedimentar significativa das ribeiras que desaguam nesta praia. Estes são areia média a bem calibrada, revelando grande homogeneidade do ponto de vista textural e composicional, no espaço e no tempo.
Relativamente à morfologia, concluiu-se que a praia é dominada por organização morfológica intermédia, entre os extremos reflectivo e dissipativo, mais próximos do extremo dissipativo em épocas de agitação mais intensa, e estádios mais próximos dos reflectivos em condições de agitação menos intensas.
A praia de Carcavelos apresenta uma elevada capacidade de recuperação volumétrica, não ocorrendo variações significativas no stock sedimentar. Este variou, no período de estudo, menos de 13% em relação ao seu valor médio. Estas variações ocorreram predominantemente no domínio da baixa-praia, domínio este que se vai reajustando de acordo com as condições de agitação marítima prevalecentes.
The present work studies the beach of Carcavelos in the town of Carcavelos. This beach was studied at a micro time-scale, from October 2014 until June 2015, in order to characterize its seasonal morphodynamics with the main goal to study the seasonal variability, morphology and sedimentary content, with support from oceanographic data. Ten field work campaigns were conducted establishing five support points along the waterfront from which four topographical profiles were produced transversal to the beach's length. To supplement, two integral topographic profiles of the beach were produced as well as sampling of the different morfosedimentary units present in the beach, subsequently analysed in laboratory. The results suggest that Carcavelos beach is low-medium energy beach. During the monitoring period there were 17 registered storm events. However the sea wave regime near the coast is predominantly from the southwest with significant height below the 3 meters. The sediments are essentially from longshore drift and there is no significant contribution from the small rivers that drain into the beach. These sediments are essentially medium-well calibrated sand revealing high textural and compositional homogeneity, both in space and time. In terms of morphology, it was concluded that the beach is dominated by an intermediate morphological arrangement, standing between the reflective and dissipative extremes, although closer to the dissipative extreme in higher intensity sea wave regime seasons and closer to the reflective stages in lower intensity sea wave regime seasons. Carcavelos beach presents itself with a high volumetric recovery capacity. In the period of study, the sedimentary stock changed less than 13% over the average. These variations occurred mainly in the lower beach domain of the beach since it readjusts according to the prevalent sea wave regime.
The present work studies the beach of Carcavelos in the town of Carcavelos. This beach was studied at a micro time-scale, from October 2014 until June 2015, in order to characterize its seasonal morphodynamics with the main goal to study the seasonal variability, morphology and sedimentary content, with support from oceanographic data. Ten field work campaigns were conducted establishing five support points along the waterfront from which four topographical profiles were produced transversal to the beach's length. To supplement, two integral topographic profiles of the beach were produced as well as sampling of the different morfosedimentary units present in the beach, subsequently analysed in laboratory. The results suggest that Carcavelos beach is low-medium energy beach. During the monitoring period there were 17 registered storm events. However the sea wave regime near the coast is predominantly from the southwest with significant height below the 3 meters. The sediments are essentially from longshore drift and there is no significant contribution from the small rivers that drain into the beach. These sediments are essentially medium-well calibrated sand revealing high textural and compositional homogeneity, both in space and time. In terms of morphology, it was concluded that the beach is dominated by an intermediate morphological arrangement, standing between the reflective and dissipative extremes, although closer to the dissipative extreme in higher intensity sea wave regime seasons and closer to the reflective stages in lower intensity sea wave regime seasons. Carcavelos beach presents itself with a high volumetric recovery capacity. In the period of study, the sedimentary stock changed less than 13% over the average. These variations occurred mainly in the lower beach domain of the beach since it readjusts according to the prevalent sea wave regime.
Descrição
Tese de mestrado em Ciências do Mar, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2015
Palavras-chave
Carcavelos Praia Morfodinâmica Sedimentos Teses de mestrado - 2015