DYNAMICS AND IMPACTS OF DEEP WATER OIL SPILL PLUMES

Lead Research Organisation: University of East Anglia
Department Name: Environmental Sciences

Abstract

Following the 2010 Deep Water Horizon oil spill in the Gulf of Mexico there is growing concern within the oil industry, government and by the general public that a similar incident could occur in UK waters. One region where offshore oil exploration is pushing into deeper water is the Faroe-Shetland Channel north of Scotland. Here the shallow shelf sea drops off into the abyss, with water depth increasing from around 200 m to near 1 km over a short distance. There are many dramatic physical process that occur in the channel, including strong along-slope currents; 10s km-scale eddies that spin off the currents; subsurface (internal) waves and extreme surface waves. These processes need to be fully understood and accounted for in ocean forecast models and oil spill dispersion models. These computer models can then be used in to predict the path and decay of oil from potential deep spills in the region and to plan appropriate emergency response measures.

In the UK, the Centre for Environment, Fisheries & Aquaculture Science (Cefas) is tasked with advising the government on the use of oil dispersants and other emergency response measures in the event of oil spill incidents. The Cefas response team first uses ocean forecast models, run by the Met Office, to understand the ocean 'weather' at the spill site. They then run dedicated oil spill models, driven by the predicted currents and water temperature/salinity, to predict the path and decay of the oil spill plume and to assess the likely impact on local beaches, commercially important marine species, and protected conservation species.

For this system to work effectively in an dynamically complex areas such as the Faroe-Shetland Channel, the models will need to be further developed to account for additional physical processes. This joint project between Cefas scientists and physical oceanographers the University of East Anglia (UEA) will investigate the key processes that disperse and mix oil in the Faroe-Shetland Channel region, assess the suitability of the current response system for potential deep oil spills in the Channel, and suggest areas where model development should be focused.

The project will utilise traditional current and temperature/salinity measurements from oceanographic moorings; new measurements from autonomous underwater vehicles known as Seagliders; ocean forecast models in operation at the Met Office and being developed at scientific institutions; and commercial oil spill models run by Cefas. In addition, the project will assess the use of Seagliders as part of a rapid response system for monitoring oil dispersion after a spill.

By working to improve the emergency response system, the project will benefit UK industry by reducing costs and uncertainty when producing oil pollution emergency plans, a critical step in the development of sites. The project will also benefit the UK government by improving the advice given by Cefas on regulatory policy and mitigation measures.

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