Navegando por Assunto "Erosão costeira"

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Acesso aberto (Open Access)
Conflitos socioambientais e erosão costeira: o caso de Ajuruteua, Bragança – PA
(Universidade Federal do Pará, 2018-12-20) RANIERI, Andreza Souza; BASTOS, Rodolpho Zahluth; http://lattes.cnpq.br/0697476638482653; LOPES, Luis Otávio do Canto; http://lattes.cnpq.br/1013147545099173
The coastal erosion on Ajuruteua Beach has been intensifying over the last years.The beach advances about five meters annually, destroying the streets and houses that were inserted there improperly. The current work purposes to study the fields of coast line management at Ajuruteua, Bragança – PA aiming to create new instruments that can contribute to building solutions to minimize social and environmental problems arising from the process of appropriation and use of the beach.Through three chapters with distinct and complementary themes and by semi-structured interviews, analysis of documents and exploratory fields, this work has succeeded in pointing the main actors of the conflicts in the region and how they are related to coastal erosion besides the analysis of the process of municipal Coastal Management and of these main gaps. Taking into account these analyzes it was possible to carry out a participatory cartography as a participatory tool of how the community perceives its own territory and the significant characteristics of it. Among such limitations, has been shown that Ajuruteua suffer the issue of management competences since there is currently no body entirely responsible for the beach. This problem rise a conflict in competences influencing directly the community there, in reason of not even the port owners knew who is in charge of the beach. In view of the importance of this work mainly from the participatory mapping that serve as an instrument to empower and strengthen the Ajuruteua community.
Acesso aberto (Open Access)
Os efeitos dos manguezais e das intervenções humanas na dinâmica sedimentar das praias de SalinópoliS, PA
(Universidade Federal do Pará, 2025-03-07) PÉREZ MARTINEZ, Julián David; COHEN, Marcelo Cancela Lisboa; http://lattes.cnpq.br/8809787145146228
Salinópolis, on the coast of Pará, has become an important tourist hub, expanding its infrastructure along the coastal zone. This area is considered sensitive to sea-level rise. Therefore, identifying the area most vulnerable to coastal erosion is extremely important, especially due to the growth of coastal urban areas, which can interfere with sediment balance, intensifying erosion processes. This master's thesis aims to identify the effects of mangroves and coastal urban expansion on sediment balance along the beaches of Salinópolis. This study was carried out through a spatio-temporal analysis based on satellite (2003 – 2023) and drone data (2019-2024). The data revealed that the urban area expanded (627 ha), while the mangrove area fluctuated, increasing from 3630 ha to 3889 ha between 2003 and 2023. Erosion was identified along the beaches, particularly at Praia do Farol Velho (erosion = 432,625 m³, sedimentation = 217,259 m³). Praia do Atalaia (erosion = 115,415 m³, sedimentation = 462,630 m³) and the Maçarico/Corvina beaches (erosion = 640,389 m³, sedimentation = 801,670 m³) showed a trend of sediment accumulation. Erosion has predominantly occurred in the lower intertidal zone, while sedimentation has occurred in the supratidal zone and the upper intertidal zone. Residences, particularly in Farol Velho, may accentuate this process and Praia do Atalaia, which are currently located in the intertidal and supratidal zones in front of the mangroves. The walls built to protect these residences from waves and current action have also functioned as a barrier to retain sediments at the upper intertidal/supratidal transition. In much of Praia do Farol Velho, without these walls, there has been erosion in the intertidal zone, with a retreat of the coastline by about 100 meters between 2009 and 2023. However, the Maçarico/Corvina beaches have mangroves in front of the urban infrastructure, with sediment accumulation predominantly in the supratidal zone and the upper part of the intertidal zone. Human interventions on these beaches have not impacted the sedimentary dynamics until 2023. This beach provides a good example of how coastal infrastructure projects should be planned, using mangroves as protection against the action of waves and currents. However, the construction of beach access walkways in 2024 altered the hydrodynamic flow of a tidal channel, trapping tidal waters and creating muddy intertidal zones with porewater salinities close to 70 ‰. This process has already killed approximately 7 ha of mangrove. These data provide valuable insights to guide more efficient public and private investments, avoiding construction in high-risk areas or those that harm the mangroves, offering crucial information about coastal erosion and its impacts on urban infrastructure in the beaches of Salinópolis, especially in the face of sea-level rise.
Desconhecido
Geoindicadores de vulnerabilidade à erosão em praias estuarinas, costa amazônica, Pará.
(Universidade Federal do Pará, 2022-04-19) NOVAES, Gabriela de Oliveira; RANIERI, Leilanhe Almeida; http://lattes.cnpq.br/3129401501809850; https://orcid.org/0000-0002-9870-4879
The coastal zone (CZ) is a region responsible for various ecological functions, and also object of concern due to its uses and anthropic pressures, which affect its balance and environmental integrity. The beach is one of the most important environments in CZ, due to its intense use by the human population, having ecological function for many organisms and being a natural protection against physical forcers (waves, tides and chains). The anthropogenic occupation on a particular beach can aggravate coastal erosion (natural process of the morphological amendment of the environment, due to the interaction with physical agents). This occurs on the island of Mosqueiro, object of study of this work, where erosive processes have been intensified in recent decades, combined with urbanization. Observing this problem, the present research aims to analyze vulnerability to erosion on the Amazonian estuarine beaches of the Mosqueiro Island, well as evaluating the degree of coastal risk to which they are exposed. Using geoindicators, index and classification of local vulnerability were obtained. Being the index composed of coastal variables: morphology and granulometry of the beach, sedimentary swing, variation of the coast line, cliffs, natural barriers; and continental variables: land elevation, vegetation, coastal engineering structures, percentage of occupation and soil permeability. Then it was carried out: (a) collection of topographic data and sealing samples on 16 beaches; (b) observational analysis with Checklist of geoindicators of coastal erosion in loco and through satellite images; c) treatment of data collected in the field and by remote sensing; d) Use of the coastal vulnerability index to evaluate erosion on the beaches; and, e) identification of risk degree in these beaches. The results demonstrate that 8 of the 16 analyzed beaches are classified with high vulnerability (IVC: 5,0-7,4) and accentuated coastal risk, and that the presence of active cliffs, wall of arrimation and high occupation next the beaches stood out as favoring ones for this result. The data indicated high human occupation (> 70% on most beaches), since several forms of land use are frequent on the island, whether for homes or establishments (shops, restaurants, inns), which raises local risk for the occurrence of damage caused by erosion. In general, the adapted method of this study for Amazonian estuarine beaches, proved to be an interesting tool to be used in urban planning and to minimize future impacts of coastal erosion. It provides information that can aid in decision-making focused on coastal management and choosing which mitigatory measures can be carried out. Thus, the importance of this analysis and continuous coastal monitoring is reinforced through the use of geoindicators.
Acesso aberto (Open Access)
Mudanças morfológicas em praias da costa Leste da ilha do Marajó e os níveis de vulnerabilidade à erosão
(Universidade Federal do Pará, 2021-06-29) SOUSA, Maria Bárbara Pereira de; RANIERI, Leilanhe Almeida; http://lattes.cnpq.br/3129401501809850; https://orcid.org/0000-0002-9870-4879
The coastal zone is a transition area between the sea and the continent, being one of the most vulnerable geographic spaces on the planet. In view of this, the assessment of morphological changes and coastal vulnerability to erosion is essential, as it contributes to the planning of protective and mitigating actions against impacts that occur on the environment, whether natural or anthropic. Thus, the work aims to verify the morphological changes in beaches on the east coast of Ilha de Marajó/PA and their levels of vulnerability to erosion at different time scales. For this purpose, two field campaigns (dry and rainy seasons) were carried out at Barra Velha beach (municipality of Soure) and Praia Grande (municipality of Salvaterra). The methodology consisted of a semi-quantitative analysis, determined by parameters of human and natural occupation evaluated on the beaches. Remote sensing techniques (medium period data) and in situ data collection (short period data) were used. According to the results obtained, Barra Velha beach was classified as dissipative in the two periods studied and most profiles topographic showed an erosive trend from the dry to the rainy period. Praia Grande showed behavior of intermediate to reflective beaches in both the dry and rainy seasons. The sedimentary accretion phase of this beach occurred during the rainy season, reflecting an atypical pattern for beach morphodynamics. Barra Velha beach exhibited moderate erosion vulnerability in the northwest sector and high vulnerability in the southeast sector, mainly due to the high erosion rate over the 16 years studied. Praia Grande, on the other hand, presented a moderate degree of vulnerability to erosion, being considered a more stable beach, combined with coastal protection works. On both beaches, the coastal risk was low due to the low level of occupation close to the coastline. It is believed that the results of this research can contribute to future studies on the theme of vulnerability to erosion in areas that are little or very anthropized and, for possible actions of coastal management in the Amazon region, considering their environmental particularities.