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Avaliação de Impactes Ambientais dos Processos Erosivos Costeiros no Setor Rabo de Peixe- Ribeira Grande, ilha de S. Miguel, Açores
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Abstract(s)
A Região Autónoma dos Açores, constituída por ilhas e ilhéus, apresenta uma extensa faixa costeira, sendo, por isso, alvo privilegiado da ação erosiva marinha, do oceano Atlântico. Dependendo das características geológicas das formações costeiras, da tipologia da agitação marítima e da orientação e morfologia da orla costeira, a ação erosiva pode ser intensificada. Estas zonas são frequentemente habitadas e ocupadas por infraestruturas, tais como estradas e portos. O recuo da linha de costa causado pela ação erosiva resulta na destruição dos terrenos emersos e das infraestruturas que os ocupam, dando origem, por vezes, a fortes impactes ambientais, nomeadamente os de cariz económico e social.
A aposta na gestão integrada da componente ambiental contribui para a diminuição ou eliminação de impactes ambientais adversos, assim como na melhoria da qualidade de vida das pessoas e na prevenção de riscos.
Este trabalho tem como objetivo o estudo da evolução dos processos de erosão costeiros recentes, praia e arriba, no setor Rabo de Peixe – Ribeira Grande, para um período de análise de 11 anos (2006 – 2017), e a avaliação dos impactes ambientais resultantes desses processos, nomeadamente a contabilização das habitações e as infraestruturas demolidas, assim como proceder ao cálculo da área costeira perdida e a taxa de recuo associada.
Em síntese, os resultados obtidos apontam, numa frente costeira de 13,2 km e numa faixa de 563.503 m2, para uma perda total de 279 edifícios entre 2006 e 2017, sendo que mais de 50% deste valor corresponde a habitações. A freguesia de Rabo de Peixe foi aquela onde se verificou a maior perda de habitações junto ao litoral, cerca de 137, parte delas associada à perda de área costeira de 9.289 m2, o que corresponde a um recuo médio da frente costeira de 1,41 m em 11 anos e uma taxa de recuo média de 0,13 m/ano. Os restantes setores de arriba analisados apresentam perdas de edificado menos expressivas.
Os impactes ambientais negativos sociais e económicos para a área de estudo são muito significativos para o curto período em avaliação, 2006-2017. Assumindo que um valor atual de 106 euros por metro quadrado da área, estimam-se perdas de 2.014.424 euros, apenas considerando a área perdida. Estes impactes irão muito provavelmente ser agravados com as alterações climáticas, nomeadamente pelo aumento da agitação marítima e pela subida do nível médio das águas do mar. Entre as medidas mais eficazes para mitigar os efeitos dessas alterações climáticas referem-se o ordenamento do território, nomeadamente a proibição de novas edificações e a deslocalização de pessoas das zonas de perigo, e a execução de obras de reforço costeiro, designadamente as obras aderentes.
Abstract: The Autonomous Region of the Azores, made of nine islands and several islets, has an extensive coastal area, being, therefore, the target for terrain erosion processes by sea waves action. Depending on the coastal geological characteristics, the typology of the sea turbulence, and the orientation and morphology of the coastline, the erosive action could be severe. These areas are often inhabited and occupied by infrastructure such as roads and ports. The retreat of the coastline caused by erosive action results in the destruction of the emersed lands and local infrastructures, sometimes giving rise to large economic losses with a strong social impact. The commitment to the integrated management of the environmental component contributes to the reduction or elimination of adverse environmental impacts, as well as to the improvement of people's quality of life and risk prevention. This work aim study is the evolution of recent coastal erosion processes, beach and cliff, in the Rabo de Peixe – Ribeira Grande sector, for an analysis period of 11 years (2006 – 2017), and the assessment of the environmental impacts resulting from these processes, namely the accounting of demolished housing and infrastructure, as well the calculation of coastal lost area and the associated retreat rate. In summary, the obtained results point to a coastal front of 13.2 km and a range of 563.503 m2, for a total loss of 279 buildings between 2006 and 2017, more than 50% of this value corresponds to housing losses. The parish of Rabo de Peixe was the one where there was the greatest loss of housing along the coast, about 137, part of them associated with the loss of coastal area of 9.289 m2, which corresponds to an average retreat of the coastal front of 1,41 m in 11 years and an average retreat rate of 0,13 m/year. The remaining cliff sectors analyzed have less significant building losses. The negative social and economic environmental impacts for the study area are very significant for the short period under evaluation, 2006-2017. Assuming a current value of 106 euros per square meter of the area, losses of 2.014.424 euros are estimated, just considering the area itself. These impacts will most likely be aggravated by climate change, namely the ongoing increase in maritime agitation and the rise in the mean sea level. Among the most effective measures to mitigate the effects of climate change are land planning, including the prohibition of new buildings and the relocation of people from danger zones, and the execution of coastal reinforcement works, including adherent coastal infrastructures.
Abstract: The Autonomous Region of the Azores, made of nine islands and several islets, has an extensive coastal area, being, therefore, the target for terrain erosion processes by sea waves action. Depending on the coastal geological characteristics, the typology of the sea turbulence, and the orientation and morphology of the coastline, the erosive action could be severe. These areas are often inhabited and occupied by infrastructure such as roads and ports. The retreat of the coastline caused by erosive action results in the destruction of the emersed lands and local infrastructures, sometimes giving rise to large economic losses with a strong social impact. The commitment to the integrated management of the environmental component contributes to the reduction or elimination of adverse environmental impacts, as well as to the improvement of people's quality of life and risk prevention. This work aim study is the evolution of recent coastal erosion processes, beach and cliff, in the Rabo de Peixe – Ribeira Grande sector, for an analysis period of 11 years (2006 – 2017), and the assessment of the environmental impacts resulting from these processes, namely the accounting of demolished housing and infrastructure, as well the calculation of coastal lost area and the associated retreat rate. In summary, the obtained results point to a coastal front of 13.2 km and a range of 563.503 m2, for a total loss of 279 buildings between 2006 and 2017, more than 50% of this value corresponds to housing losses. The parish of Rabo de Peixe was the one where there was the greatest loss of housing along the coast, about 137, part of them associated with the loss of coastal area of 9.289 m2, which corresponds to an average retreat of the coastal front of 1,41 m in 11 years and an average retreat rate of 0,13 m/year. The remaining cliff sectors analyzed have less significant building losses. The negative social and economic environmental impacts for the study area are very significant for the short period under evaluation, 2006-2017. Assuming a current value of 106 euros per square meter of the area, losses of 2.014.424 euros are estimated, just considering the area itself. These impacts will most likely be aggravated by climate change, namely the ongoing increase in maritime agitation and the rise in the mean sea level. Among the most effective measures to mitigate the effects of climate change are land planning, including the prohibition of new buildings and the relocation of people from danger zones, and the execution of coastal reinforcement works, including adherent coastal infrastructures.
Description
Dissertação de Mestrado, Ambiente, Saúde e Segurança, 08 de novembro de 2023, Universidade dos Açores.
Keywords
Erosão Alterações Climáticas Risco Geológico Impactes Ambientais
Citation
Botelho, Ana Rita Moniz. (2023). "Avaliação de Impactes Ambientais dos Processos Erosivos Costeiros no Setor Rabo de Peixe- Ribeira Grande, ilha de S. Miguel, Açores". 125 p. (Dissertação de Mestrado em Ambiente, Saúde e Segurança). Ponta Delgada: Universidade dos Açores, 2023. Disponível em http://hdl.handle.net/10400.3/7034