No abstract

Numerical models have been widely used to simulate and predict the behavior and transport of oil spills in marine environments. Their behavior is governed by physical, chemical and biological processes which are related to the hydrocarbon properties, hydrodynamic and weather conditions, and other environmental variables. The transport and interactions of oil particles were evaluated in simulations reproducing two oil spills recorded in the northern part of the Southern Brazilian Shelf (SBS). The numerical simulations were performed using the ECOS (Easy Coupling Oil System) model coupled to the three-dimensional hydrodynamic module TELEMAC3D. The hydrodynamic model provides the variables needed by oil spill model to calculate and infer the properties and behavior of the oil slick. The results indicate that the local wind forcing is the most important factor in determining the oil fate, followed by the intensities and directions of coastal currents. Regarding the events, in 2012 the oil reached the coast after 10 hours of the leak while in 2014 it was transported towards the ocean. The simulation strategy used in this article did not prove to be appropriate for estimates of the oil risk in the region, due to the distinct susceptibility responses between the events simulated.

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.

Facing great obstacles to eradicate environmental hazards generated by oil spills, it is crucial to establish actions against such accidents. In this context, the focus of this study is to analyze oil spills at the harbor region of Rio Grande, Rio Grande do Sul. The Easy Coupling Oil System (ECOS) model was used to model the oil spills under different environmental conditions simulated by the hydrodynamic model Telemac-3D, with the intention to identify the main forces controlling the movement of the oil slicks over a year of averaged hydrodynamic conditions from 2003 to 2015. The computational domain comprises the Patos Lagoon, the harbor area of Rio Grande and the Southern Brazilian Shelf. For the oil spill simulations, eight distinct events were defined considering both flood and ebb conditions in the estuarine region of the Patos Lagoon. The oil spill simulations showed that, in ebb conditions, the oil slick movement is mainly ruled by the currents, moving towards the outflow. After a few hours, the wind action makes the slick move towards the margins of the waterway. In flood conditions, on the other hand, the oil slick drifts to the interior of the estuary, following the dominant currents and the local winds.

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.