Este estudo tem como objetivo a previsão de impactos gerados por tempestades sobre os sistemas praial e de dunas frontais nas costas Leste (praias expostas) e Norte (praias abrigadas) da Ilha de Santa Catarina. A área de estudo abrange as praias entre a Barra da Lagoa e a Praia da Daniela. As respostas da costa frente aos eventos de tempestades foram classificadas em quatro diferentes regimes: Espraiamento (Swash), Colisão (Collision), Sobrelavagem (Overwash) e Inundação (Inundation). A delimitação entre cada regime é baseada na mais alta e mais baixa elevação vertical do nível d’água em relação às características morfológicas da duna frontal (base e crista). Para a Costa Leste, onde as praias são expostas à incidência de ondas, a máxima elevação do nível do mar foi definida pela soma do wave runup, maré astronômica e maré meteorológica, calculada para quatro distintos períodos de retornos (5, 10, 25 e 50 anos). A mais baixa elevação do mar foi definida como sendo a elevação na qual a praia é, na maior parte do tempo, continuamente submersa. Enquanto que para a Costa Norte, onde as praias são abrigadas da incidência das ondas, a máxima elevação do nível do mar durante eventos de tempestades foi calculada levando-se em consideração a soma das marés astronômica e meteorológicas para cada período de retorno analisado; enquanto que a mínima elevação foi representada pelo nível mais alto da maré astronômica. Em ambas as costas, foram adicionados os valores de elevação do nível do mar baseados nas previsões de pior caso do relatório do Painel Intergovernamental de Mudanças Climáticas. De acordo com este estudo a elevação do nível médio do mar vem ocorrendo em uma taxa de 4 mm/ano com uma aceleração anual de 0,019 mm/ano². Os resultados mostram que para a maioria das praias expostas não houve mudança de regime entre os períodos de retorno analisados. As exceções foram a porção central da praia dos Ingleses que apresentou passagem do regime de sobrelavagem (5 e 10 anos) para o regime de inundação (25 e 50 anos) e a Praia Brava que foi classificada como sujeita ao regime de colisão para o período de retorno de 5 anos passando a ser classificada como submetida ao regime de sobrelavagem para os demais períodos. O regime de sobrelavagem foi predominante para as praias abrigadas, sendo este o único regime registrado em toda a Costa Norte para o período de 50 anos. / This study aims to forecast the impacts of storms on the beache and foredune system along the East (exposed beaches) and North (sheltered beaches) coast of Santa Catarina Island. The study area covers the beaches between Barra da Lagoa and Daniela Beach. The coastal storm response were classified into four different regimes: Swash, Collision, Overwash and Inundation. The limits between regimes are based on the highest and lowest vertical elevation of the water level in relation to the elevation of geomorphic features of the foredune (base and crest). To the East Coast the maximum rise in sea level was defined as the sum of the wave runup, astronomical tide and storm surge, calculated for four different return periods (5, 10, 25 and 50 years). The lowest elevation of the sea is defined as the elevation at below which the beach is, most of the time, continuously subaqueous. On the North Coast the maximum rise in sea level during storm events was calculated taking into account the sum of astronomical and meteorological tides; the minimum level was defined as the maximum vertical range of astronomical tide for each return period. On both coasts the sea level rise (SLR) based on worst-case of the Climate Change Intergovernmental Panel report predictions was added to the maximun and minimum sea level elevation. According to this study the increase on the mean sea level has been occurring at a rate of 4 mm/year with an annual acceleration of 0.019 mm/ano². The results show that most of the exposed beaches did not change their regimes between the return periods analyzed. The exceptions being the Central-North portion of Ingleses, that went from overwash (RP 5 and 10 years) to inundation (RP 25 and 50 years) and Brava which changed from collision (RP 5 years) to overwash regime (RP 10, 25 and 50 years). Overwash was the predominant regime on sheltered beaches, being the only recorded regime for the 50-year return period.

Este estudo tem como objetivo a previsão de impactos gerados por tempestades sobre os sistemas praial e de dunas frontais nas costas Leste (praias expostas) e Norte (praias abrigadas) da Ilha de Santa Catarina. A área de estudo abrange as praias entre a Barra da Lagoa e a Praia da Daniela. As respostas da costa frente aos eventos de tempestades foram classificadas em quatro diferentes regimes: Espraiamento (Swash), Colisão (Collision), Sobrelavagem (Overwash) e Inundação (Inundation). A delimitação entre cada regime é baseada na mais alta e mais baixa elevação vertical do nível d’água em relação às características morfológicas da duna frontal (base e crista). Para a Costa Leste, onde as praias são expostas à incidência de ondas, a máxima elevação do nível do mar foi definida pela soma do wave runup, maré astronômica e maré meteorológica, calculada para quatro distintos períodos de retornos (5, 10, 25 e 50 anos). A mais baixa elevação do mar foi definida como sendo a elevação na qual a praia é, na maior parte do tempo, continuamente submersa. Enquanto que para a Costa Norte, onde as praias são abrigadas da incidência das ondas, a máxima elevação do nível do mar durante eventos de tempestades foi calculada levando-se em consideração a soma das marés astronômica e meteorológicas para cada período de retorno analisado; enquanto que a mínima elevação foi representada pelo nível mais alto da maré astronômica. Em ambas as costas, foram adicionados os valores de elevação do nível do mar baseados nas previsões de pior caso do relatório do Painel Intergovernamental de Mudanças Climáticas. De acordo com este estudo a elevação do nível médio do mar vem ocorrendo em uma taxa de 4 mm/ano com uma aceleração anual de 0,019 mm/ano². Os resultados mostram que para a maioria das praias expostas não houve mudança de regime entre os períodos de retorno analisados. As exceções foram a porção central da praia dos Ingleses que apresentou passagem do regime de sobrelavagem (5 e 10 anos) para o regime de inundação (25 e 50 anos) e a Praia Brava que foi classificada como sujeita ao regime de colisão para o período de retorno de 5 anos passando a ser classificada como submetida ao regime de sobrelavagem para os demais períodos. O regime de sobrelavagem foi predominante para as praias abrigadas, sendo este o único regime registrado em toda a Costa Norte para o período de 50 anos. / This study aims to forecast the impacts of storms on the beache and foredune system along the East (exposed beaches) and North (sheltered beaches) coast of Santa Catarina Island. The study area covers the beaches between Barra da Lagoa and Daniela Beach. The coastal storm response were classified into four different regimes: Swash, Collision, Overwash and Inundation. The limits between regimes are based on the highest and lowest vertical elevation of the water level in relation to the elevation of geomorphic features of the foredune (base and crest). To the East Coast the maximum rise in sea level was defined as the sum of the wave runup, astronomical tide and storm surge, calculated for four different return periods (5, 10, 25 and 50 years). The lowest elevation of the sea is defined as the elevation at below which the beach is, most of the time, continuously subaqueous. On the North Coast the maximum rise in sea level during storm events was calculated taking into account the sum of astronomical and meteorological tides; the minimum level was defined as the maximum vertical range of astronomical tide for each return period. On both coasts the sea level rise (SLR) based on worst-case of the Climate Change Intergovernmental Panel report predictions was added to the maximun and minimum sea level elevation. According to this study the increase on the mean sea level has been occurring at a rate of 4 mm/year with an annual acceleration of 0.019 mm/ano². The results show that most of the exposed beaches did not change their regimes between the return periods analyzed. The exceptions being the Central-North portion of Ingleses, that went from overwash (RP 5 and 10 years) to inundation (RP 25 and 50 years) and Brava which changed from collision (RP 5 years) to overwash regime (RP 10, 25 and 50 years). Overwash was the predominant regime on sheltered beaches, being the only recorded regime for the 50-year return period.

Este estudo tem como objetivo a previsão de impactos gerados por tempestades sobre os sistemas praial e de dunas frontais nas costas Leste (praias expostas) e Norte (praias abrigadas) da Ilha de Santa Catarina. A área de estudo abrange as praias entre a Barra da Lagoa e a Praia da Daniela. As respostas da costa frente aos eventos de tempestades foram classificadas em quatro diferentes regimes: Espraiamento (Swash), Colisão (Collision), Sobrelavagem (Overwash) e Inundação (Inundation). A delimitação entre cada regime é baseada na mais alta e mais baixa elevação vertical do nível d’água em relação às características morfológicas da duna frontal (base e crista). Para a Costa Leste, onde as praias são expostas à incidência de ondas, a máxima elevação do nível do mar foi definida pela soma do wave runup, maré astronômica e maré meteorológica, calculada para quatro distintos períodos de retornos (5, 10, 25 e 50 anos). A mais baixa elevação do mar foi definida como sendo a elevação na qual a praia é, na maior parte do tempo, continuamente submersa. Enquanto que para a Costa Norte, onde as praias são abrigadas da incidência das ondas, a máxima elevação do nível do mar durante eventos de tempestades foi calculada levando-se em consideração a soma das marés astronômica e meteorológicas para cada período de retorno analisado; enquanto que a mínima elevação foi representada pelo nível mais alto da maré astronômica. Em ambas as costas, foram adicionados os valores de elevação do nível do mar baseados nas previsões de pior caso do relatório do Painel Intergovernamental de Mudanças Climáticas. De acordo com este estudo a elevação do nível médio do mar vem ocorrendo em uma taxa de 4 mm/ano com uma aceleração anual de 0,019 mm/ano². Os resultados mostram que para a maioria das praias expostas não houve mudança de regime entre os períodos de retorno analisados. As exceções foram a porção central da praia dos Ingleses que apresentou passagem do regime de sobrelavagem (5 e 10 anos) para o regime de inundação (25 e 50 anos) e a Praia Brava que foi classificada como sujeita ao regime de colisão para o período de retorno de 5 anos passando a ser classificada como submetida ao regime de sobrelavagem para os demais períodos. O regime de sobrelavagem foi predominante para as praias abrigadas, sendo este o único regime registrado em toda a Costa Norte para o período de 50 anos. / This study aims to forecast the impacts of storms on the beache and foredune system along the East (exposed beaches) and North (sheltered beaches) coast of Santa Catarina Island. The study area covers the beaches between Barra da Lagoa and Daniela Beach. The coastal storm response were classified into four different regimes: Swash, Collision, Overwash and Inundation. The limits between regimes are based on the highest and lowest vertical elevation of the water level in relation to the elevation of geomorphic features of the foredune (base and crest). To the East Coast the maximum rise in sea level was defined as the sum of the wave runup, astronomical tide and storm surge, calculated for four different return periods (5, 10, 25 and 50 years). The lowest elevation of the sea is defined as the elevation at below which the beach is, most of the time, continuously subaqueous. On the North Coast the maximum rise in sea level during storm events was calculated taking into account the sum of astronomical and meteorological tides; the minimum level was defined as the maximum vertical range of astronomical tide for each return period. On both coasts the sea level rise (SLR) based on worst-case of the Climate Change Intergovernmental Panel report predictions was added to the maximun and minimum sea level elevation. According to this study the increase on the mean sea level has been occurring at a rate of 4 mm/year with an annual acceleration of 0.019 mm/ano². The results show that most of the exposed beaches did not change their regimes between the return periods analyzed. The exceptions being the Central-North portion of Ingleses, that went from overwash (RP 5 and 10 years) to inundation (RP 25 and 50 years) and Brava which changed from collision (RP 5 years) to overwash regime (RP 10, 25 and 50 years). Overwash was the predominant regime on sheltered beaches, being the only recorded regime for the 50-year return period.

The alongshore variability of beach-dune systems and the response and recovery from extreme storms remains poorly understood. The height and extent of foredunes along barrier islands varies over a range of spatial scales, implying that during extreme storms, the beach-dune system should respond in different ways depending on the elevation and volume of the dunes relative to the storm surge. The purpose of this study is to use Ground-Penetrating Radar (GPR) and vibra-cores to investigate the internal structure of small, intermediate and large dunes along a 2.5 km transect of beach in Padre Island National Seashore, TX with particular attention to storm impacts. A series of dune normal and parallel GPR profiles were collected to capture the variation in beach-dune morphology at the three sites. Site locations were chosen along a transition from dissipative to intermediate beach states. Following the Sallenger (2000) storm impact model, the small dune is defined by low-lying topography that is susceptible to overwash and inundation depending on the size of the storm surge. The large dune is characteristic of the “collision regime”, while the intermediate dune represents a transition between “overwash” and “collision regimes”, with the underlying assumption that all three dunes would be impacted by the same level of surge during a single storm event. Results from the GPR survey suggest that each site contains a bright, laterally continuous radar reflector that is interpreted with the aid of the sedimentary data as an erosional layer. Different characteristic radar facies and sequence boundaries provide evidence as to how each dune evolved through and after the storm. Results from XRF scans and grain size analysis show a direct comparison between the GPR reflectors at the storm surface and spikes in calcium counts from XRF scans to distinct changes in grain size parameters at the same depth. It is argued that the location of each shell layer corresponds to a storm surface generated during a single storm, which means it is possible to interpret different recovery mechanisms. The presence of the storm layer across the backbeach and dunes provides evidence for the height and extent of the surge during the storm event. The data suggests that the small dune was overtopped by the surge, experiencing minimal erosion and recovery. The intermediate dune was completely eroded by the surge, but showed the greatest recovery of all the dune sites. The large dune was scoured at the base with marginal impact along its crest and shows minimal recovery after the storm. These results suggest that the evolution (i.e., transgression) of a barrier island varies considerably over short distances.

This dissertation combines seemingly different studies, which work together to describe the physical characteristics of rip current development and associated social implications at several locations. These fast-moving, concentrated flows of water travel offshore and can be found on any beach with sufficient wave action. Any event of increased wave steepness will erode a large quantity of sediment from the beach. The material deposited offshore eventually makes its way back; during this process, ocean water becomes trapped behind a shore-attached bar resulting in a ridge-and-runnel. These formations are seen at East Hampton, where rip-like currents form as concentrated water drains from the runnel through a breach in the ridge. Camera images from 2010-2016 captured ridge-and-runnel formations and the ensuing currents. These newly described rips behave similarly to bar-gaps; however, they are not directly related to wave action. Coastal scientists consider rip currents to be the number one hazard at most beaches. In Palm Beach County, two traditional rip types were studied: bar-gap and structurally-controlled. Lifeguard incident reports from 2011-2016 were used to correlate wind speeds and wave heights to rip related rescues at three beaches. This research was undertaken in an effort to determine under what conditions most beachgoers become caught in this hazard. Rip currents were seen to be the most dangerous to bathers on days with moderate wind and wave activity. The same beach states that lead to the strongest rips also tend to keep beachgoers from entering the ocean. A social survey at Miami Beach, from 2011 to 2012, quantified beachgoer’s rip knowledge and their recognition of hazards. A significant portion of the respondents showed insufficient knowledge, which indicated they are at-risk of being caught or drowning in a rip current. Frequent exposure to the beach, maturation, and residency were identified as the main contributors to one’s literacy whereas education was the only variable that influenced a beachgoer’s visual recognition of hazard. The information gathered by these surveys can aid in creating better rip current awareness campaigns targeted to demographics that were determined as the most at-risk. An understanding of the physical and social science of rip currents can mitigate the impact of these beach hazards.