No abstract

Fossil fuels still prevail over other energy sources in the world's consumption energy matrix. Thus, oil transportation and operations over maritime routes have been in high demand for a long time. Although oil spill accidents caused by these activities have reduced significantly over the last few decades, they still cause great concern. From this perspective, this paper presents simulation analyses of oil spill case studies using Telemac-3D hydrodynamic model coupled with an oil model. Hence a location susceptible to such accidents was selected and three real oil spills were simulated, for each of which there were official technical monitoring reports available. The obtained results contribute to the knowledge of oil pollution susceptibility in environmentally sensitive areas, as well as provide information concerning oil slick behaviour. Additionally, similarities between the modelled results and the technical reports were confirmed. These findings are useful for contingency planning and responding to these probable accidents.

O Saco da Mangueira é uma enseada semifechada com acesso a região estuarina daLagoa dos Patos-RS. Esse sistema possui uma área de 227km2 e recebe pequenas descargas deágua doce provenientes dos arroios Vieira e Simão, porém o maior aporte de água que esta enseadarecebe provém do estuário da Lagoa dos Patos. Nesta região são realizadas várias atividades,como pesca artesanal de camarão e atividades de lazer. A análise da hidrodinâmica nesta regiãoé importante, pois a circulação do fluxo de água entre a enseada e o estuário promovem a entrada denutrientes e evitam condições anóxicas no ambiente. O objetivo principal deste estudo é investigara hidrodinâmica do local usando o modelo de simulação numérica TELEMAC-3D validado comdados medidos em campo. Os resultados demonstram que a dinâmica do Saco da Mangueira estáfortemente relacionada com a dinâmica estuarina, sendo controlada pelo efeito não-local do vento.A elevação do nível do mar e os gradientes de pressão entre os pontos analisados proporcionam adireção do fluxo de água, associados aos ventos, ocasionando eventos de enchente de água salgada(ventos de sudoeste) e vazão de água doce (ventos de nordeste) no Saco da Mangueira.

A modelling system was utilised to simulate the movement and behaviour of oil slicks for two types of hydrocarbons, a diesel and another residual, considering hydrodynamic variations. Susceptible areas to oil touching were found in adjacent regions of two vessel manoeuvring zones, in two types of zones, one in a marine coastal and another in an estuarine environment. The evaporation rates were calculated for an estimate of the mass losses. For the maritime zone, the oil particles reached the vicinity of the beaches in approximately 4 to 8 hours after the beginning of the spill simulations, while for the estuary in approximately 1 hour. For the scenarios with diesel oil, mass losses oscillated between 13 to 16% in the estuarine region, and between 23 and 29% in the marine coastal zones. The evaporation rates for scenarios with residual oil, between 2 and 5%, were considerably lower than for diesel (15 and 22%), especially for spills simulated in the estuarine region, where the oil particles reached the lagoon banks after 1 hour. Mass losses by evaporation were more intense in marine coastal areas than for oil spills simulated in estuarine regions, possibly due to the more intense hydrodynamic conditions and the longer time that the oil needs to reach the coast. The fluctuations of observed environmental conditions justify the need for a robust number of simulations for reducing the uncertainties related to the oceanographic and meteorological variability that affect oil spill movement.

Beaches are suffering morphological changes due the interaction between energetics components and local sedimentary supply imbalance. The understanding of the wave climate is an essential source of information for the composition of coastal planning projects. The main goal of this work is to estimate the longshore sediment transport (LST) in various sectors of the Brazilian Coast, and to identify the annual average and its dominant direction. For this study was considered the period between 1979 and 2015, applying computational modeling to investigate the waves behavior, and empirical formulas to calculate LST rates. The results showed a great discrepancy in the wave climate along the Brazilian Coast, and presented similarities rates between the estimation of LST and previous studies for different sectors analyzed. The sector where transport rates have been higher understanding the Northeast region, specifically between Alagoas and Rio Grande do Norte states. The opposite of it was observed in the Southern part of Bahia. The dominant direction of sediments, mainly caused by the waves, was directed to South between Rio de Janeiro and Bahia states, and in some parts of Sergipe. Transportation to the north comprises the South and Southeast regions, as well as a considerable area of the Northeast and the entire Northern Region. In this sense, information related to wave behavior and sediment transport along the Brazilian Coast is presented, unlike studies available in the literature that are carried out locally and approach only specific regions. Thus, the results presented can be considered in future projects, involving the sustainable management of coastal zones.