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Monitoramento da din?mica costeira da praia de Ponta NegraChacon, Aline Freitas 23 December 2013 (has links)
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Previous issue date: 2013-12-23 / This dissertation includes the monitoring of coastal environmental dynamics at three points
distinct from Ponta Negra beach, located on the South Coast of Natal, capital of Rio Grande
do Norte, in the period June 2012 to May, 2013. For this, the following hypotheses were
developed: Which actors morphodynamic and/or anthropogenic responsible for the changes in
the study area? And yet, the configuration of the morphodynamic state of the beach,
dissipative, reflective or intermediate? Faced with these questions , studies on the beach
environment has its relevance as they may clarify the risks and responsibilities of
anthropogenic intervention and also assist managers in more targeted action regarding the
protection of praiais systems, since once committed, it is very difficult recover the
environmental framework of the area, being greatly more feasible the development of
multidisciplinary work plans that can guide human actions possible in search of an
understanding to the harmonious interaction between society and the beach system. Its main
goal is the understanding of the processes of coastal dynamics, methodological procedures
that supported the implementation of this research were based on the object of study related
literature associated with the collection of data resulting from beach profiles made monthly in
spring tides (full moon), the hydrodynamic data and statistical quantification data (%) and
size classification of sediment sediment after laboratory analysis. The results obtained from
annual comparative tables of beach profiles, associated sedimentological analysis, indicated a
positive sediment budget, tending to equilibrium for Point 01 and Point 02 negative. Have to
Step 03 were added to the hydrodynamic data, which allowed also on a comparative
framework, the perception of a depositional dynamics, with a tendency to decrease the
accumulation of material at the end of the annual cycle. These data also allowed for the point
03, the calculation of the volume of material transported by the longshore current was around
104.280 m?/m, plus the Dean parameter which established a morphological state of the
dissipative beach with specific prevalences for point 03. Thus, given the results presented in
this work in a timely monitoring of coastal dynamics is expected that managers and public
authorities can articulate multidisciplinary work plans, always aiming actions that seek
understanding and effective commitment to the recovery of the harmonious interaction
between society and Ponta Negra beach environment / Esta disserta??o contempla o monitoramento da din?mica ambiental costeira em tr?s pontos
distintos da praia de Ponta Negra, situada no Litoral Sul de Natal, capital do Rio Grande do
Norte, no per?odo de junho de 2012 a maio de 2013. Para tanto, foram levantadas as seguintes
hip?teses: Quais os agentes morfodin?micos e/ou antropog?nicos respons?veis pelas
mudan?as ocorridas na ?rea de estudo? E ainda, como se configura o estado morfodin?mico
da praia, dissipativo, refletivo ou intermedi?rio? Diante destes questionamentos, estudos sobre
o ambiente praial tem sua relev?ncia, pois podem esclarecer os riscos e responsabilidades da
interven??o antropog?nica e ainda auxiliar gestores, em a??es mais direcionadas no que tange
? prote??o dos sistemas praiais, visto que uma vez comprometido, ? muito dif?cil recuperar o
quadro ambiental da ?rea, sendo sobremaneira mais vi?vel a elabora??o de planos
multidisciplinares de trabalhos que possam orientar poss?veis a??es humanas na busca de um
entendimento para o conv?vio harmonioso entre a sociedade e o sistema praial. Tendo como
principal objetivo o entendimento dos processos da din?mica costeira, os procedimentos
metodol?gicos que deram suporte a execu??o dessa pesquisa foram fundamentados em
literaturas correlatas ao objeto de estudo, associados ? coleta de dados decorrentes dos perfis
praiais realizados mensalmente nas mar?s de siz?gia (Lua cheia), dados da hidrodin?mica e
dados estat?sticos de quantifica??o (%) e classifica??o granulom?trica dos sedimentos ap?s
an?lises sedimentol?gicas laboratoriais. Os resultados obtidos a partir de quadros
comparativos anual dos perfis praiais, associados ? an?lise sedimentol?gica, indicaram um
balan?o sedimentar positivo, tendendo ao equil?brio para o Ponto 01 e negativo para o Ponto
02. J? para o Ponto 03 foram adicionados dados referentes ? hidrodin?mica, os quais
possibilitaram, tamb?m diante de um quadro comparativo, a percep??o de uma din?mica
deposicional, com tend?ncia ? redu??o do ac?mulo de material ao final do ciclo anual. Esses
dados possibilitaram tamb?m, para o Ponto 03, o c?lculo do volume de material transportado
pela corrente de deriva litor?nea que girou em torno de 104.280 m?/m, al?m do par?metro de
Dean que estabeleceu um estado morfol?gico da praia com predomin?ncias dissipativa
espec?fico para o Ponto 03. Assim, diante dos resultados expostos por este trabalho de
monitoramento pontual da din?mica costeira espera-se que gestores e autoridades p?blicas
competentes possam articular planos multidisciplinares de trabalhos, objetivando sempre
a??es que busquem entendimento e comprometimento efetivo para a recupera??o do conv?vio
harmonioso entre a sociedade e o ambiente praial de Ponta Negra
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Natural and Anthropogenic Influences on the Morphodynamics of Sandy and Mixed Sand and Gravel BeachesRoberts, Tiffany 01 January 2012 (has links)
Beaches and coastal environments are dynamic, constantly shaped and reshaped by natural processes and anthropogenic modifications. The morphodynamics and influence of natural and anthropogenic factors of two different coasts at various temporal and spatial scales are discussed.
To quantify the performance of several beach nourishment projects at annual temporal and kilometer spatial scales on three adjacent microtidal low-wave energy barrier islands in west-central Florida, a total of 5,200 beach and nearshore-profiles spaced at 300 m were surveyed monthly to bi-monthly from 2006-2010. Beach nourishment performance is most significantly influenced by the interruption of longshore sediment transport by complex tidal-inlet processes. More specifically, the tidal-inlet processes influencing adjacent beach nourishment performance includes longshore transport interruption resulting from divergence induced by wave refraction over an ebb-tidal shoal, flood-tidal currents along the beach, and total littoral blockage by structured inlets. A morphologic indicator of a large longshore transport gradient within the study area is the absence of a nearshore sandbar. These non-barred beaches are characterized by persistent shoreline erosion and were almost exclusively located in areas with a large longshore transport gradient. The more typical beach state along the three barrier islands was one exhibiting a migratory bar and relatively stable shoreline. The presence of a sandbar indicates the dominance of cross-shore processes, with onshore migration during calm wave conditions and offshore migration during energetic wave conditions. The onshore and offshore migration of the sandbar is closely related to non-stormy summer and stormy winter seasonal beach changes, respectively.
The morphodynamics of a mixed sand and gravel beach in Delaware were investigated based on 740 beach profiles surveyed almost monthly from 2009 to 2011, 60 sediment cores, and 550 surface sediment samples collected at various alongshore and cross-shore transects. Inter-seasonal temporal scales of storm-induced beach changes and post-storm recovery were examined based on a hurricane, a typical energetic winter storm, and an extremely energetic storm resulting from the rare collision of a hurricane and winter storm ("Nor'Ida") occurring within a 3-month period in 2009. The mixed sand and gravel beaches in Delaware are characterized by monotonically increasing water depths lacking a sandbar under all wave conditions. A distinctive beach cycle was identified consisting of a built-up berm profile and depleted nearly-planar storm profile, with a time-scale related to the frequency and intensity of storm impact and duration of intra-storm recovery instead of simple seasonality. The sedimentological characteristics of the storm deposit associated with Nor'Ida demonstrated substantial cross-shore variation ranging from sandy-gravel and gravelly-sand within the storm swash zone (near the pre-storm dune edge) to well-sorted medium to coarse sand seaward of the storm swash zone, suggesting that storm deposits along mixed beaches demonstrate a variety of sedimentological characteristics. A new dynamic beach cycle model is proposed for the non-barred mixed sand and gravel beach with temporal variability controlled by storm occurrence and inter-storm duration.
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Din?mica Costeira dos Campos petrol?feros Macau/Serra, litoral setentrional do Estado do Rio Grande do NorteChaves, Marcelo dos Santos 10 October 2005 (has links)
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Previous issue date: 2005-10-10 / This thesis describes the general behavior of the northern shore of the State of Rio Grande do Norte relating beach profile morphology with hydrodynamic and sedimentological parameters. The Macau and Serra Oil Field are inserted on this area and are under accelerated coastal erosion. At these oil fields are installed oil wells from PETROBRAS, nowadays located directly in the shoreline, under constant attacks of coastal processes (e.g. waves, tides and currents), which promote an intense morphodynamic variability of this sandy coast. The area was monitored for 24 months in three different stations (P01, P02 and P03). The methodology applied involved current techniques of beach profiles, hydrodynamical processes, remote sensing and geophysics. A synthesis of results obtained through the use of different time scales (monthly, lunar cycle, seasonal, annual) from a coastal dynamics study is presented. The average wind direction corresponded to 77?Az (NE). The steepness of the berm and of the shoreface, as well as coastal current direction, do not present major changes, with an average of 36? for the steepness of the berm, 15? for the shoreface and 15? for the coastal current direction. This data set allows us to infer that the months of larger coastal erosion were November/2000 and April/2001, because of the largest wave parameter during this time. The months of worse coastal erosion in this area are related with the increasing wavy energy. This in turn, seems to be related to seasonal climatic variations, with the wave energy and tide currents speed increasing during months of minor precipitations (June to January). The months of worse coastal erosion were September and November, when the largest wave parameters and speed currents are measured in the area. Since these months are included on the period of minor precipitations, we related the coastal erosion to seasonal climatic variations. The results obtained during these 24 months of monitoring confirms a situation of accentuated erosion, mainly in Profile 03 (Barra do Corta-Cachorro), where the wave height, period, and coastal current speed are always larger than the values found in Profile 02 (Macau5). Probably these values are more expressive in Profile 03, because it does not present any natural structure of protection against the wave impacts, as the barrier island located at Ponta do Tubar?o, or the sand banks in front of Macau5. The transport of the sediments occurs from East to West, and the sand accumulation is more pronounced on Profile 03 intertidal zone, where there are embrionary dunes in dryer months. The tidal currents speed, on the other hand, is more accentuated in the Macau5 area (Profile 02). At Ponta do Tubar?o, the tidal currents presented a preferential direction for NE, at times of flood, currents and for NW, at times of ebb current; at Barra do Corta-Cachorro the direction of the currents were predominantly for NW, independent of the tide phase, coinciding with the preferential direction of the longshore current. This currents inversion at Ponta do Tubar?o is attributed to the presence of the Ponta do Tubar?o island barrier and by the communication channel of the lagoon with the sea. The tide currents are better observed in protected areas, as in the Ponta do Tubar?o, when they present inversion in their direction accordingly to the flood and ebb tide. In open areas, as in Barra do Corta-Cachorro, the tide currents are overprinted by the longshore currents. Sediment analysis does not show important modifications in grain size related to seasonality (dry- and rainy seasons). On the foreshore and backshore zones, the sediments vary from fine to medium sand, while in the shoreface they very from fine to very sands. The grains are mostly spheres, varying from sub rounded to sub angled. Quartz is the main component alongside Feldspat and heavy minerals as accessory components. Biogenic content is also present and mainly represented by mollusks fragments. The calculated sediment transport show values around 100 m3/day. The morphodynamic studies indicated that this is a reflexive area from October to April, and intermediate from May to September. The Relative Tide Range-RTR for this area is 4 < RTR < 15, and so classified in the mixed wave-tide group. Having this exposed we can affirm that the more active natural factors in this area are the currents, followed by the tides and the winds. The anthropic factors are exclusively local and punctual (Macau and Serra Oil Field). Taking in account the economic importance of the area, as well as the intensity of coastal processes acting on this shore, it is important a continuity of the monthly environmental monitoring looking for variations on longer-period cycles. These data have been stored on the geo-referenced database of the projects MARPETRO and PETRORISCO (REDE 05), aiming to model the coastal and sea environment, susceptible to oil spills and their derivatives / Esta tese contempla a caracteriza??o da din?mica costeira dos campos petrol?feros de Macau e Serra, localizados no litoral setentrional do Estado do Rio Grande do Norte. Estes campos petrol?feros est?o inseridos em uma costa de mesomar? sob a a??o da eros?o costeira. As instala??es do campo Macau foram constru?das no in?cio dos anos 80 do s?culo passado a uma dist?ncia de aproximadamente 800 m do mar. Atualmente, encontram-se localizadas na linha de costa, sob ataque constante dos processos costeiros (ondas, correntes, mar?s), que promovem uma intensa variabilidade morfodin?mica.Diversas medidas t?m sido aplicadas para proteger esta linha de costa contra a eros?o nos po?os petrol?feros. Entretanto, estudos de monitoramento n?o haviam sido efetuados anteriormente. A metodologia utilizada envolveu a utiliza??o de dados de sensoriamento remoto (tratamento digital de imagens orbitais e fotografias a?reas), processos costeiros (ventos, correntes, ondas e mar?s, inclusive o padr?o de circula??o local), perfis praiais, an?lises sedimentol?gicas e geof?sicas (batimetria) para caracteriza??o da din?mica costeira local em diferentes per?odos (mensal, ciclo lunar, semestral) em tr?s pontos distintos (P01, P02 e P03). Os resultados deste estudo mostram que enquanto a praia na regi?o da Ponta do Tubar?o apresentou-se est?vel com tend?ncia a deposi??o, na regi?o do Macau5 e Barra do Corta-Cachorro ocorreu uma tend?ncia ? eros?o. Isto ? confirmado atrav?s da evolu??o desta linha de costa realizada com base nas imagens Landsat de 2000, 2001, 2002 e 2003 (monitoramento anual). Observa-se tamb?m que durante o ciclo lunar de mar?o 2002 (in?cio do per?odo chuvoso) a ?rea em estudo n?o apresentou diferen?as durante as quatro fases da lua. Entretanto, no ciclo lunar de outubro 2003 (per?odo seco e ventos fortes), apenas o Perfil 01 n?o apresentou diferen?as significativas. O Perfil 02 apresentou maior deposi??o na fase de lua cheia e o Perfil 03 uma maior deposi??o na lua nova, com presen?a de barras arenosas. Os resultados da hidrodin?mica costeira mostraram que na regi?o da Ponta do Tubar?o, devido ? prote??o exercida pela ilha-barreira, as ondas s?o atenuadas e as correntes de mar? exercem um papel importante no interior da laguna. No per?odo de mar? vazante as correntes mostraram uma dire??o geral para NW, coincidindo com o sentido da deriva litor?nea, enquanto no per?odo de mar? enchente ocorre uma invers?o no sentido da corrente para E-NE. Na ?rea do Macau5 e Barra do Corta-Cachorro, que n?o s?o abrigadas pela ilha-barreira, os valores de temperatura, condutividade e velocidade da corrente aumentaram com a profundidade e o sentido preferencial das correntes foi para NW, independente da fase de mar?. O volume de sedimentos transportados pela deriva litor?nea ? da ordem de uma centena de metros c?bicos ao dia. A an?lise mensal dos dados granulom?tricos indica, no geral, uma grande homogeneidade nos resultados obtidos (acima de 90%), mostrando que n?o houve modifica??es no tamanho dos gr?os em rela??o ? sazonalidade (per?odo de chuvas e per?odo seco). Nos tr?s perfis monitorados (P01, P02 e P03), tanto a p?s-praia quanto o estir?ncio, foram classificados pela m?dia como areia fina a m?dia. Apenas a antepraia ? classificada como areia fina a muito fina. Os gr?os s?o predominantemente esf?ricos, sub-angulosos a sub-arredondados. Composicionalmente quartzo ? o mineral vi predominante, podendo ocorrer tamb?m micas, feldspatos, fragmentos de rocha e minerais pesados (< de 5% cada), bem como componentes bi?ticos. Quanto a morfodin?mica a ?rea em estudo foi classificada como reflexiva (erosiva) nos meses de outubro a abril e como intermedi?ria (inst?vel) nos meses de maio a setembro, tanto no Perfil 02 (Macau5), como no Perfil 03 (Barra do Corta-Cachorro). Aplicando o modelo de Masselink e Turner (1999) para uma varia??o m?dia de mar? de siz?gia de 3 m, a varia??o relativa de mar? - RTR (Relative Tide Range) obtida para as praias da ?rea em estudo esteve na sua maior parte entre 4 e 15, permitindo ser classificadas como praias mistas, denotando a influ?ncia das ondas e mar?s para a regi?o. Na zona submersa pr?xima ? costa as linhas batim?tricas apresentam um trend principal paralelo ? linha de costa na por??o oeste da ?rea, enquanto que na por??o leste, apresenta uma varia??o, pela complexidade morfol?gica influenciada pela Ponta do Tubar?o. Na baixa-mar ? poss?vel observar os bancos de areia expostos. O entendimento das causas da eros?o costeira e monitoramento dos processos costeiros obtidos nesta tese permitiu a quantifica??o e caracteriza??o das mudan?as na linha de costa, essenciais para elabora??o de mapas de sensibilidade ambiental ao derramamento de ?leo
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Caracteriza??o da din?mica ambiental da regi?o costeira do munic?pio de Galinhos, litoral setentrional do Rio Grande do NorteLima, Zuleide Maria Carvalho 10 March 2004 (has links)
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Previous issue date: 2004-03-10 / This doctorate thesis concerning on the Characterization of the Environmental Dynamics of the Coastal Area of the Municipal district of Galinhos, Septentrional Coast of Rio Grande do Norte State, is located in the influence area of the Guamar? Petroliferous Pole, having as general objective the understanding of the active coastal dynamics in the region of Galinhos, whose specific objectives were: To study the variation of the coast line in the decades of 1954, 1967,1988, 1996, 2000, from remote sensing products; To elucidate the hypothesis of the region of Galinhos to have been an old system of islands barriers, using as basic tool the penetration radar in the soil - GPR; To monitor and to characterize the coastal dynamics of the study area starting from monthly data of beach profiles, sedimentological analysis, hydrodynamic data and environmental characterization data; which were used to feed the database of the N-NE network of Environmental Monitoring of Areas under Influence of the Petroliferous Industry;(REDE05/FINEP/CNPq/CTPETRO/ PETROBRAS). This research is justified, of the environmental point of view, by involving the mangrove ecosystem considered one of the most delicated environments of the State. From the viewpoint of the petroleum exploration, the systems of islands barriers are favorable for hydrocarbons reservoirs and, consequently important targets to the oil and gas industry, becoming this region attractive in comparison with similar lithified environments. With the results of the variability study in the position of the coast line in the Municipal district of Galinhos/RN from the analysis of remote sensing images, it was possible to investigate the changes in the coast line in temporal scale; the use of directional filters allowed to emphasize linings in the direction NE and to identify submerged features such as sandwaves. The use of GPR enabled the confirmation of paleochannels existence and thus confirmed the hypothesis that the Galinhos spit was formed from an old system of islands barriers. The results of the granulometric analyses indicated that in the summer period the
sediments in the profiles A and B in the foreshore portion were classified with the granulometry of sand with scattered gravel and in the shoreface were constituted by sand, but in the winter period these same morphologic compartments were constituted by sand with sparse gravel and siltic sand respectively. In the profile C, in the summer and in the winter, the shoreface and foreshore compartments presented predominantly constituted by sand with sparse gravel. The hydrodynamic results showed that the largest wave heights were registered in the month of February (62 cm) and the highest period of 1,00 m/s in the month of May, the sense of the coastal currents was kept among the quadrants SW and NW, and the winds coming from NE were predominant. The analysis of the beach profiles demonstrated that in the profile A, although it had occurred erosion and deposition during the monitored months, the morphology of the referred profile was kept constant. In the profiles B and C, there were abrupt changes in the morphology, during the monitored months, having been identified a cyclic pattern in the features
of the foreshore zone sometimes forming longitudinal sandy bars and in other times forming berm. These results evidenced, therefore, that studies of this nature are of fundamental importance for the coastal zoning, aiming subsidies to the organs managers in the closing of
decisions as for the implantation of enterprises in the area, and for the industry of the petroleum through generation of information that subsidize the implementation and location of petroliferous structures adequate to this environment / Esta tese de doutorado sobre a caracteriza??o da din?mica ambiental da regi?o costeira do munic?pio de Galinhos, Litoral Setentrional do Rio Grande do Norte, acha-se inserida na ?rea de influ?ncia do P?lo Petrol?fero de Guamar?, tendo como objetivo geral o entendimento da din?mica costeira atuante na regi?o de Galinhos, cujos objetivos espec?ficos foram : estudar a varia??o da linha de costa nas d?cadas de 1954, 1967, 1988, 1996 e 2000, a partir de produtos de sensoriamneto remoto; elucidar a hipotese da regi?o de Galinhos ter sido um antigo sisitema de ilhas barreiras, utilizando como ferramneta b?sica o radar de penetra??o no solo - GPR; monitorar e caracterizar a dinamica costeira da ?rea em estudo a partir de dados mensais da perfis praiais, analise sedimentologica, dados hidrodin?micos e dados de caracteriza??o ambiental; este conjunto de dados foram utilizados para alimetar o banco de dados da Rede NNE de monitoramneto ambiental das ?reas sob influ?ncia da industria petrol?fera (REDE05/FINEP/CNPq/CTPERO/PETROBRAS). Esta pesquisa se justifica, do ponto de vista ambiental,
por envolver ecossistemas de alta fragilidade como dunas, praias e manguezais. Do ponto de vista da explora??o do petr?leo, os sistemas de ilhas barreiras s?o prop?cios para reservat?rios de hidrocarbonetos e, por conseguinte, alvos importantes para a ind?stria do petr?leo e g?s tornando
esta regi?o atrativa na compara??o com dep?sitos similares litificados. O estudo da variabilidade na posi??o da linha de costa no Munic?pio de Galinhos/RN a partir da an?lise de imagens de sensores remotos, foi poss?vel investigar as mudan?as na linha de costa em escala temporal; a
utiliza??o de filtros direcionais permitiu enfatizar lineamentos de dire??o NE e identificar fei??es submersas tais como sandwaves. A utiliza??o do GPR possibilitou a comprova??o da exist?ncia de paleocanais confirmando a hip?tese de que o spit de Galinhos foi formado a partir de um antigo sistema de ilhas barreiras. Os resultados das an?lises granulom?tricas indicaram que no per?odo de ver?o os sedimentos nos perfis A e B na por??o de estir?ncio foram classificados como de granulometria areia com cascalho esparso e na antepraia foram constitu?dos por areia, j? no per?odo de inverno estes mesmos compartimentos morfol?gicos apresentaram-se com areia com cascalho esparso e areia siltosa respectivamente No perfil C, tanto no ver?o como no inverno, os compartimentos de estir?ncio e antepraia apresentaram-se predominantemente por areia com cascalho esparso. Os resultados hidrodin?micos mostraram que as maiores alturas de
onda foram registradas no m?s de fevereiro (62 cm) e o maior per?odo de 1,00 m/s no m?s de maio, o sentido das correntes litor?neas se manteve entre os quadrantes SW e NW, e os ventos provenientes de NE foram predominantes. A an?lise dos perfis praiais demonstrou que no perfil A, embora tenha ocorrido tanto eros?o como deposi??o durante os meses monitorados, a morfologia do referido perfil permaneceu constante. Nos perfis B e C, ocorreram mudan?as bruscas na morfologia, durante os meses monitorados, tendo sido identificada uma ciclicidade nas fei??es da zona de estir?ncio ora formando barras arenosas longitudinais ora formando berma. Estes resultados evidenciaram, portanto, que estudos desta natureza s?o de fundamental import?ncia para o zoneamento costeiro, dando subs?dios aos ?rg?os gestores na tomada de decis?es quanto ? implanta??o de empreendimentos na regi?o, e para a ind?stria do petr?leo
atrav?s de gera??o de informa??es que subsidiam a implementa??o de estruturas petrol?feras adequadas ao ambiente estudado
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