Sargassum fluitans and natans, types of brown algae, wash up on Galveston Island, Texas annually from May to August. Sargassum smells bad, hurts tourism and impairs sea turtle hatchings. Coastal managers are confronted with the difficult choice of cleaning Sargassum off the beach or leaving it alone. The current beach management practice is to rake the algae with tractors and deposit it at the base of the dunes. The environmental impacts of raking and ecological benefits of Sargassum are unknown. The Galveston Island Park Board of Trustees (GIPBT) used to rake all beaches under their management before Hurricane Alicia in 1983. Then, citizens started to complain that raking was causing erosion. Now, there are people who argue for both raking and leaving the beach alone. Environmental policies require complex decisions that take into consideration social, economical, ecological, and cultural values. The GIPBT initiated the Sargassum Policy Committee to gain knowledge of different stakeholder values and scientific research to develop beach management. The first study analyzed elevation changes over a year period on raked and unraked beaches on both the West and East end of Galveston Island. The Analysis ofVariance results indicated that there is not a difference in elevation changes between the raked and unraked beaches over a year.The second study analyzed the effects of Sargassum on the dune plant Panicum amarum. Plants were asexually grown in a greenhouse in sand without (control) and with Sargassum. The effects of small versus large amounts, top versus mixed with sand and washed versus unwashed Sargassum were tested. The results indicated that the addition of Sargassum increased plant growth. The treatments with large amounts of Sargassum and unwashed treatments showed significant growth changes at the 95% confidence level. The last component analyzed the collaborative potential of the Sargassum Policy Committee through observations of meetings and surveys of the members. Daniel and Walker’s Progressive Triangle was used to assess the relationship, procedural and substance dimensions of collaborative learning. Then, suggestions were made for increasing collaboration. The combination of scientific research and stakeholder values has resulted in the creation of sound beach management.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-09-14T19:25:48Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Athos Farias Menezes 2016.pdf: 6385036 bytes, checksum: a2522df55623cf13d58d7d17b4302fb7 (MD5) / Made available in DSpace on 2016-09-14T19:25:48Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Athos Farias Menezes 2016.pdf: 6385036 bytes, checksum: a2522df55623cf13d58d7d17b4302fb7 (MD5) Previous issue date: 2016-03-23 / Facepe / A erosão costeira é um fenômeno natural encontrado em diversos ambientes litorâneos em todo o mundo. No entanto a ocupação antrópica desordenada pode potencializar o processo erosivo, como é o caso do litoral do estado de Pernambuco, onde 43,8% da população está localizada no ambiente litorâneo que se estende ao longo de 13 municípios. Observando esta problemática, o presente trabalho foi desenvolvido com o intuito de avaliara vulnerabilidade à erosão costeira através do processamento de imagens de satélite de alta resolução e sistemas de informações geográficas (SIG),a partir de indicadores ambientais e antrópicos. A presente pesquisa foi dividida em três etapas, a primeira visa caracterizar a vulnerabilidade à erosão costeira em escala local nas praias de Piedade (município de Jaboatão dos Guararapes) e Paiva (município do Cabo de Santo Agostinho), ressaltando as diferentes características atribuídas as mesmas. Na primeira praia destacou-se a intensa urbanização, com mais de 60% de interferência antrópica nos setores avaliados, enquanto a segunda se demonstrou conter um bom desenvolvimento de áreas vegetais preservadas mais de 55% do total analisado. Na segunda etapa, foi mostrado o uso dos geoindicadores em escala regional para todo o litoral pernambucano, destacando cenários de intensa vulnerabilidade nas cidades do núcleo metropolitano, enquanto em praias de baixa presença antrópica, como no setor sul, foram destacados baixos índices de vulnerabilidade, enquanto no setor norte foram atribuídos valores moderados. Na terceira etapa deste trabalho trabalho foi apresentado a utilização da interpretação de imagens de alta resolução espacial e métodos automáticos e semiautomáticos na identificação dos geoindicadores na Praia do Forte Orange (município da Ilha de Itamaracá) evidenciando feições sedimentares oriundas do Canal de Santa Cruz, mas com a presença de feições erosivas. De forma geral este trabalho visualiza destacar a importância de métodos alternativos na identificação de áreas com potenciais erosivos, a partir de dados orbitais que acarretarão em uma otimização do tempo para na tomada de decisões públicas acerca dos ambientes litorâneos. / The coastal erosion is a natural phenomenon found in many coastal environments worldwide. One of the causes of unorganized human occupation near coastal areas is erosion. An example of erosion caused by anthropogenic activities is found in the coastal areas of Pernambuco State, Brazil, where 43.8% of the state population live nearthe state’s coastal environments, extending over 13 cities. The current study is divided in three chapters and focuses on the coastal beaches vulnerability evaluation and identification of the vulnerability of coastal erosion caused by anthropogenic and environmental factors, using tools as high resolution satellite images and geographic information systems. First part aims to characterize the vulnerability of beaches to coastal erosion in a local scale.The areas of study are Piedade (city of Jaboatão dos Guararapes) and Paiva beaches (city of Cabo de Santo Agostinho) in Pernambuco State, Brazil, with geomorphological and dynamic characteristics variablity. Piedade beach has intensive urbanization, indicating more than 60% of anthropogenic interference in all evaluated sectors, while Paiya beachis covered by vegetation approximately 55% of total area. In second part, several geoindicators were analyzed in a regional scale along the Pernambuco’s coastline. Different scenarios of high vulnerability were examined in the cities of the metropolitan area, on beaches of low and high anthropogenic activities. The first results, showed low indication of vulnerability at the southen sectorcompared to the northen sector which showed moderate risk of erosion. Finally, in section three,high resolution satellite images were used to identify geoindicators by automaticand semi-automatic approaches in order to identify erosional features. In this chapter the study the Forte Orange beach (city of Ilha de Itamaraca) highlighting sedimentary features of the Canal de Santa Cruz and the presence of erosional features. This research highlights the importance of alternative identification methods for areas under potential erosion risk. The proposed methods in this study are very efficient and can produce accurate and fast results, which can be valuable to the public, environmental agencies, porotection and decision makers of coastal environments.

Storms have been impacting coastal morphodynamics directly due to its intensifying effects over the years. Climate change has caused an exponential impact on storms and therefore morphodynamic changes in the coasts. A specific land that has constantly been threatened is Dauphin Island, a barrier island in Alabama. Over time, it has experienced a total land loss of 100 ft of shoreline over the past of 3 decades and an overall 16% land loss of the island due to the intensifying effects of storms due to a changing climate. In this study, we use Hurricane Ivan as an example. In order to analyze the effects of a future scenario we incorporate the effects of sea level rise. Therefore, we compare three different scenarios of Hurricane Ivan including its current scenario in 2004, current scenario with sea level and future scenario with sea level. Increases in storm surge include wind speed, minimum central pressure and translation speed. These are all factors affecting the breaching in the barrier island. We aim to show how climate change can intensify the effects of hurricanes and impact coastal erosion by comparing a future climate with current climate. We use Hurricane Ivan in Dauphin Island as a case study.

Coastal erosion can be described as the landward or seaward propagation of coastlines. Coastal processes occur over various space and time scales, limiting in-situ approaches of monitoring change. As such it is imperative to take advantage of multisensory, multi-scale and multi-temporal modern spatial technologies for multi-dimensional coastline change monitoring. The research presented here intends to showcase the synergy amongst remote sensing techniques by showcasing the use of coastal indicators towards shoreline assessment over the Kommetjie and Milnerton areas along the Cape Town coastline. There has been little progress in coastal studies in the Western Cape that encompass the diverse and dynamic aspects of coastal environments and in particular, sediment movement. Cape Town, in particular; is socioeconomically diverse and spatially segregated, with heavy dependence on its 240km of coastline. It faces sea level rise intensified by real-estate development close to the high-water mark and on reclaimed land. Spectral indices and classification techniques are explored to accommodate the complex bio-optical properties of coastal zones. This allows for the segmentation of land and ocean components to extract shorelines from multispectral Landsat imagery for a long term (1991-2021) shoreline assessment. The DSAS tool used these extracted shorelines to quantify shoreline change and was able to determine an overall averaged erosional rate of 2.56m/yr. for Kommetjie and 2.35m/yr. for Milnerton. Beach elevation modelling was also included to evaluate short term (2016-2021) sediment volumetric changes by applying Differential Interferometry to Sentinel-1 SLC data and the Waterline method through a combination of Sentinel -1 GRD and tide gauge data. The accuracy, validation and correction of these elevation models was conducted at the pixel level by comparison to an in-field RTK GPS survey used to capture the current state of the beaches. The results depict a sediment deficit in Kommetjie whilst accretion is prevalent along the Milnerton coastline. Shoreline propagation and coastal erosion quantification leads to a better understanding of geomorphology, hydrodynamic and land use influences on coastlines. This further informs climate adaptation strategies, urban planning and can support further development of interactive coastal information systems.

Louisiana’s wetlands are losing land in response to sea level changes, anthropogenic influences and natural marine processes. Historical satellite image analysis reveals that between 2005 and 2015, fifteen tidal creeks in Barataria Bay, Louisiana eroded at the rate of 1.80 m/yr (± 1.98 m), and the open water area behind these creeks enlarged at the rate of 530.00 m2/yr (± 204.80 m2). This research revealed that selected tidal creeks within the estuary have cross-sectional areas larger (2639% larger) than established ocean-inlet equilibrium models would predict. This work suggests that tidal prism to tidal creek cross-sectional area relationships in Barataria Bay are most strongly shaped by creek exposure to waves and secondarily by tide range and currents. A trend of increased inlet erosion rates due to large fetch distances is evident, but impacts from storm driven subtidal variations also play an important role.

O objetivo deste trabalho é avaliar as variações espaço-temporais da dinâmica morfo-sedimentar do sistema praial de Ilha Comprida-SP. Assim, para reconhecer os padrões de onda encontrados na região, resultados do modelo global de ondas WAVEWATCH III foram utilizados. Da mesma forma, levantamentos de campo periódicos foram realizados em cinco diferentes setores com obtenção de dados morfológicos e sedimentares. Simulações com o modelo numérico MIKE21 SW foram realizadas para reconhecer as tendências de transporte e distribuição de força de onda. Os resultados mostraram uma tendência geral de transporte para NE, com maiores valores para a região sul em relação a norte, com dois setores principais de divergência residual: centro-sul e norte. A divergência centro-sul apresenta um aumento e uma migração para sul nos meses mais energéticos, enquanto que a divergência norte apresenta uma manutenção espacial ao longo das estações. A distribuição de força de onda mostrou-se mais elevada nos setores centro-sul e norte, coincidindo com os pontos de divergência. Dados granulométricos mostraram baixa variabilidade temporal, mas possuem diferenças espaciais que refletem a hidrodinâmica local. Os dados volumétricos apresentam maiores valores médios nos setores centro-norte e menores no centro-sul e norte. De modo geral, os resultados mostram que ao longo de uma linha de costa exposta a um mesmo padrão de ondas, sua variabilidade é um reflexo de alterações hidrodinâmicas locais. Tais conclusões são importantes para o conhecimento do estado atual das praias e de sua evolução. / The aim of this study is to evaluate the spatial-time variations on the beach system of Ilha Comprida-SP. Therefore, the wave reanalysis database from the global wave generation model WAVEWATCH III was used to recognize the wave pattern for the region. Furthermore, periodic field works at five different sectors have been conducted to collect morphological and sedimentological data. The numerical model MIKE 21 SW has been applied to propagate waves onshore and recognize the transport tendency and the nearshore wave power distribution. Results show a transport trend to the NE, with the southern sector being larger than the northern sector in magnitude, with two main residual longshore drift divergence spots: in the central-southern and northern regions. Moreover, the central-southern divergence spot become larger and migrated to the south during the most energetic months, while the northern divergence spot kept its position throughout the year. Wave power results show two main areas with higher values that coincide with the observed longshore divergence spots. Sediment data presents low temporal variability, although spatial variations have been found reflecting the hydrodynamic conditions. The volumetric data shows largest values in the central-northern sector, being smaller in the central-southern and northern regions. In summary, the findings show that along this wide open stretch of coastline, exposed to the same offshore wave regime, its variability is a result of local hydrodynamic conditions. These results help in further understanding the island\'s long term evolution and current state of its beaches.

A manifestação de danos em infraestruturas costeiras decorrente da ação de ondas tem estimulado avaliações de vulnerabilidade para fins de gestão integrada da costa. Os municípios costeiros do Estado de Santa Catarina concentram 28% de sua população e sua interface com o oceano é predominantemente composta por praias arenosas dominadas por ondas. Impactos costeiros relacionados a processos dominados por ondas, sobretudo às escalas local e regional, podem ser ainda mais danosos do que os ocasionados por processos naturais de larga escala (p. ex., a subida do nível do mar). A abordagem utilizada neste estudo consiste na definição de um índice multicritério de vulnerabilidade a ondas de maior frequência de ocorrência e de tempestade para o litoral de Santa Catarina. O índice de vulnerabilidade (IVC) foi obtido a partir da integração entre o índice de capacidade adaptativa, composto por variáveis socioeconômicas e de ocupação (área ocupada, distância entre a ocupação e a linha de costa, número de residentes, renda por residente e número de domicílios de uso ocasional), e o índice de suscetibilidade - composto por variáveis do meio físico (altura significativa de onda, gradiente de deriva litorânea potencial, largura de praia, elevação e declividade). A dinâmica costeira resultante da incidência de ondas sobre as manchas urbanas na área em perigo é analisada através de produtos de modelagem numérica, integrados às demais variáveis em ambiente de Sistema de Informação Geográfica (SIG). A relevância das variáveis na composição do índice foi avaliada pelo método de decisão multicritério AHP (analytic hierarchy process). As variáveis e os índices foram representados em cinco classes de vulnerabilidade (muito baixa, baixa, média, alta e muito alta) nos setores do Plano Estadual de Gerenciamento Costeiro (GERCO/SC). Com base na opinião de especialistas, as variáveis físicas foram consideradas mais relevantes do que as socioeconômicas. Os setores mais suscetíveis e vulneráveis são: centro-sul, sul, norte, centro-norte e centro, respectivamente. Já os setores de menor capacidade adaptativa são: centro-norte, centro, norte, centro-sul e sul, respectivamente. A baixa presença de residentes e ocupações na área em perigo, bem como as maiores distâncias entre a ocupação e a linha de costa - variáveis utilizadas na determinação da capacidade adaptativa e que favorecem a redução da vulnerabilidade - apresentaram um papel secundário na determinação do IVC para os setores centro-sul e sul. Os setores ao norte do Estado são menos suscetíveis e vulneráveis, todavia se encontram intensamente ocupados em praias com menores larguras de faixa de areia, terrenos planos e com baixa declividade (segmentos de maior suscetibilidade). A maior ocorrência de danos por erosão e inundação, atualmente observada ao norte do Estado, pode ser facilmente revertida caso haja a expansão de áreas ocupadas próximo às linhas de costa dos setores centro-sul e sul, tendo em vista a alta suscetibilidade e os baixos valores de renda e de segunda-moradia encontrados ao sul do Estado. / The occurrence of coastal infrastructure damage due to wave action has been promoting vulnerability assessments for integrated coastal management. Santa Catarina\'s coastal municipalities concentrate 28% of the state\'s population and the interface between the coastline and the ocean is predominantly composed by wave-dominated sandy beaches. Coastal impacts related to wave-dominated processes, especially at local and regional scales, can produce more damaging effects than large-scale natural processes (e. g., sea level rise). The approach suggested in this study consists of defining a vulnerability multicriteria index, for Santa Catarina\'s coastline, to waves with higher frequency of occurrence and to storm wave events. The coastal vulnerability index (IVC) was obtained by integrating the adaptive capacity index, composed by socioeconomic and occupational variables (constructed area, distance between human settlements and shoreline, number of residents, income per capita and number of households for occasional use), and the susceptibility index - consisting of environmental variables (significant wave height, potential longshore drift gradient, beach width, coastal elevation and slope). The resulting coastal dynamics from nearshore wave incidence is analyzed through the application of a numerical model, integrated with the other variables by geoprocessing techniques in a Geographic Information System (GIS) environment. The variables\' relevance in the index formula was obtained by the analytic hierarchy process (AHP). Variables and indices were hierarchized in five vulnerability classes (very low, low, medium, high and very high) and represented in the sectors from the State Coastal Management Plan (GERCO/SC): north, center-north, center, center-south and south. Based on specialists\' opinion on the determination of vulnerability, physical/environmental variables were considered more relevant than socioeconomic variables. The most susceptible and vulnerable sectors are: center-south, south, north, center-north and center, respectively. Sectors with the lowest adaptive capacity are: center-north, center, north, center-south and south, respectively. The low number of residents and settlements in the endangered area, as well as the greater distances between occupied area and the shoreline - variables used to determine adaptive capacity and that contribute to reduction of vulnerability - played a secondary role in the CVI\'s determination for the center-south and south sectors. The northern sectors of the state are less susceptible and vulnerable; however, they are intensely occupied in beaches with smaller beach width, lower elevation and slope (segments with higher susceptibility degrees). The highest occurrence of erosion and flood damage, currently observed at the north of the state, can easily be reversed in case of expansion of settlements near the center-south and south sectors, as a function of the higher susceptibility degrees and lower income per capita and number of households of occasional use found at the south of the state.

Extreme storms are responsible for rapid changes to coastlines worldwide. During the 2013/14 winter, the west coast of Europe experienced a sequence of large, storm-induced wave events, representing the most energetic period of waves in the last 60 years. The southwest coast of England underwent significant geomorphological change during that period, but exhibited a range of spatially variable and complex morphological responses, despite being subjected to the same storm sequence. The 2013/14 storm response along the southwest coast of England was first used as a natural field laboratory to explain the variability in storm response through the introduction and evaluation of a new classification of how sandy and gravel beaches respond to extreme storms. Cluster analysis was conducted using an unique data set of pre- and post-storm airborne Light Detection and Ranging (LiDAR) data from 157 beach sites and the calculation of volumetric beach changes and a novel parameter, the longshore variation index which quantifies the alongshore morphological variability in beach response. The method used can be applied to any sandy and gravel beaches where topographic data with sufficient spatial resolution is available. Four main beach response types were identified that ranged from large and alongshore uniform offshore sediment losses up to 170 m3 m-1 (at exposed, cross-shore dominated sites) to considerable alongshore sediment redistribution but limited net sediment change (at more sheltered sites with oblique waves). The key factors in determining the type of beach response are: exposure to the storm waves, angle of storm wave approach and the degree to which the beach is embayed. These findings provide crucial information for the development of coastal studies at regional scale, especially along coastal areas where abrupt changes in coastline orientation can be observed. A 10-year time series (2007-2017) of supra- and intertidal beach volume from exposed and cross-shore transport-dominated sites was used to examine the extent to which beach behaviour is coherent over a relatively large region (100-km stretch of coast) and predictably coupled to incident wave forcing. Over the study period, 10 beaches, exposed to similar wave/tide conditions, but having different sediment characteristics, beach lengths and degrees of embaymentisation, showed coherent and synchronous variations in sediment volumes, albeit at different magnitudes. This result is crucial for studying coastal changes in remote coastal areas or in areas where only few topographic data are available. The sequence of extreme storms of the 2013/14 winter, which represents the most erosive event over at least a decade along most of the Atlantic coast of Europe, is included in the data set, and three years after this winter, beach recovery is still on-going for some of the 10 beaches. Post-storm beach recovery was shown to be mainly controlled by post-storm winter wave conditions, while summer conditions consistently contributed to modest beach recovery. Skilful hindcasts of regional changes in beach volume were obtained using an equilibrium-type shoreline model, demonstrating that beach changes are coherently linked to changes in the offshore wave climate and are sensitive to the antecedent conditions. Furthermore, a good correlation was found between the beach volume changes and the new climate index WEPA (West Europe Pressure Anomaly), which offers new perspectives for the role and the use of climatic variations proxies to forecast coastline evolution. A process based model, XBeach, was used to model storm response at one macrotidal beach characterized by the largest sediment losses during the 2013/14 sequence of extreme storms. Beach volume changes were modelled over hypothetical scenarios with varying hydrodynamics conditions and beach states to investigate the relative roles of hydrodynamic forcing (i.e., waves and tides), beach antecedent state and beach-dune morphology in beach response to extreme storms. This modelling approach is applicable to any beach system where process based models have been implemented. Beside significant wave height and peak wave period, the beach antecedent state was shown to be the dominant factor in controlling the volumes of sediment erosion and accretion along this cross-shore dominated beach. Modelled volumes of erosion were, on average, up to three times higher along an accreted beach compared to an eroded beach for the same wave conditions. The presence of a dune, being only significantly active during spring tides and storm conditions along this macrotidal beach, was shown to reduce erosion or even cause accretion along the intertidal beach. This work provides a detailed, quantitative insight of the hydrodynamic and morphological processes involved in storm response and beach recovery on a number of spatial and temporal scales. This improved understanding of the potential impact of extreme events will hopefully aid future research efforts and ensure effective management of sedimentary coastlines.

A manifestação de danos em infraestruturas costeiras decorrente da ação de ondas tem estimulado avaliações de vulnerabilidade para fins de gestão integrada da costa. Os municípios costeiros do Estado de Santa Catarina concentram 28% de sua população e sua interface com o oceano é predominantemente composta por praias arenosas dominadas por ondas. Impactos costeiros relacionados a processos dominados por ondas, sobretudo às escalas local e regional, podem ser ainda mais danosos do que os ocasionados por processos naturais de larga escala (p. ex., a subida do nível do mar). A abordagem utilizada neste estudo consiste na definição de um índice multicritério de vulnerabilidade a ondas de maior frequência de ocorrência e de tempestade para o litoral de Santa Catarina. O índice de vulnerabilidade (IVC) foi obtido a partir da integração entre o índice de capacidade adaptativa, composto por variáveis socioeconômicas e de ocupação (área ocupada, distância entre a ocupação e a linha de costa, número de residentes, renda por residente e número de domicílios de uso ocasional), e o índice de suscetibilidade - composto por variáveis do meio físico (altura significativa de onda, gradiente de deriva litorânea potencial, largura de praia, elevação e declividade). A dinâmica costeira resultante da incidência de ondas sobre as manchas urbanas na área em perigo é analisada através de produtos de modelagem numérica, integrados às demais variáveis em ambiente de Sistema de Informação Geográfica (SIG). A relevância das variáveis na composição do índice foi avaliada pelo método de decisão multicritério AHP (analytic hierarchy process). As variáveis e os índices foram representados em cinco classes de vulnerabilidade (muito baixa, baixa, média, alta e muito alta) nos setores do Plano Estadual de Gerenciamento Costeiro (GERCO/SC). Com base na opinião de especialistas, as variáveis físicas foram consideradas mais relevantes do que as socioeconômicas. Os setores mais suscetíveis e vulneráveis são: centro-sul, sul, norte, centro-norte e centro, respectivamente. Já os setores de menor capacidade adaptativa são: centro-norte, centro, norte, centro-sul e sul, respectivamente. A baixa presença de residentes e ocupações na área em perigo, bem como as maiores distâncias entre a ocupação e a linha de costa - variáveis utilizadas na determinação da capacidade adaptativa e que favorecem a redução da vulnerabilidade - apresentaram um papel secundário na determinação do IVC para os setores centro-sul e sul. Os setores ao norte do Estado são menos suscetíveis e vulneráveis, todavia se encontram intensamente ocupados em praias com menores larguras de faixa de areia, terrenos planos e com baixa declividade (segmentos de maior suscetibilidade). A maior ocorrência de danos por erosão e inundação, atualmente observada ao norte do Estado, pode ser facilmente revertida caso haja a expansão de áreas ocupadas próximo às linhas de costa dos setores centro-sul e sul, tendo em vista a alta suscetibilidade e os baixos valores de renda e de segunda-moradia encontrados ao sul do Estado. / The occurrence of coastal infrastructure damage due to wave action has been promoting vulnerability assessments for integrated coastal management. Santa Catarina\'s coastal municipalities concentrate 28% of the state\'s population and the interface between the coastline and the ocean is predominantly composed by wave-dominated sandy beaches. Coastal impacts related to wave-dominated processes, especially at local and regional scales, can produce more damaging effects than large-scale natural processes (e. g., sea level rise). The approach suggested in this study consists of defining a vulnerability multicriteria index, for Santa Catarina\'s coastline, to waves with higher frequency of occurrence and to storm wave events. The coastal vulnerability index (IVC) was obtained by integrating the adaptive capacity index, composed by socioeconomic and occupational variables (constructed area, distance between human settlements and shoreline, number of residents, income per capita and number of households for occasional use), and the susceptibility index - consisting of environmental variables (significant wave height, potential longshore drift gradient, beach width, coastal elevation and slope). The resulting coastal dynamics from nearshore wave incidence is analyzed through the application of a numerical model, integrated with the other variables by geoprocessing techniques in a Geographic Information System (GIS) environment. The variables\' relevance in the index formula was obtained by the analytic hierarchy process (AHP). Variables and indices were hierarchized in five vulnerability classes (very low, low, medium, high and very high) and represented in the sectors from the State Coastal Management Plan (GERCO/SC): north, center-north, center, center-south and south. Based on specialists\' opinion on the determination of vulnerability, physical/environmental variables were considered more relevant than socioeconomic variables. The most susceptible and vulnerable sectors are: center-south, south, north, center-north and center, respectively. Sectors with the lowest adaptive capacity are: center-north, center, north, center-south and south, respectively. The low number of residents and settlements in the endangered area, as well as the greater distances between occupied area and the shoreline - variables used to determine adaptive capacity and that contribute to reduction of vulnerability - played a secondary role in the CVI\'s determination for the center-south and south sectors. The northern sectors of the state are less susceptible and vulnerable; however, they are intensely occupied in beaches with smaller beach width, lower elevation and slope (segments with higher susceptibility degrees). The highest occurrence of erosion and flood damage, currently observed at the north of the state, can easily be reversed in case of expansion of settlements near the center-south and south sectors, as a function of the higher susceptibility degrees and lower income per capita and number of households of occasional use found at the south of the state.

Open-coast beach-dune environments are vulnerable to erosion, such as from storms or interruption of littoral drift. Although protected from event-driven wave energy, backbarrier shorelines are also susceptible to erosion, due to tidal currents and boat wakes. A common response to mitigate erosion is to place sediment and restore the environment. For placement on beaches, a significant effort has been made to identify offshore resources available; however, offshore resources have seldom been considered for dune or backbarrier shoreline restoration. This study evaluates the geotechnical sediment properties of offshore sediments in proven borrow areas for beach nourishment and reclassifies them for placement in dunes and along the backbarrier in Palm Beach County, Florida. Two different methods calculate volume of offshore resources available for dune or backbarrier projects, including numerical calculations and interpolation of volume through SURFER. Because existing proven borrow areas are delineated for beach nourishment, less volume of sediment available in these areas for other coastal environments. The results of this study suggest that identifying offshore sediment sources for lower-energy environments would not adversely impact sediment needed for beach nourishment. As coastal environments are increasingly threatened by climate change and sea level rise, sediment resources become scarcer, the need to efficiently and effectively use sediments will be of utmost importance for scientists, engineers, and managers in their efforts to protect coastal habitat and communities. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection