A Lagrangian/Eulerian oil spill model for continental waters

Abstract

The application of the European Water Framework Directive on water quality for human consumption and industrial activities creates a need for water quality assessment and monitoring systems. The MIGR'HYCAR research project was initiated to provide decisional tools for risks connected to oil spills in continental waters. In this paper, the focus is set on a numerical model to simulate oil spill in continental waters and to estimate polycyclic aromatic hydrocarbons (PAHs) toxicity in the aquatic environment. A Lagrangian/Eulerian approach is proposed. The Lagrangian model describes the transport of an oil spill near the free surface. The oil spill model enables to simulate the main processes driving oil plumes: advection, diffusion, evaporation, dissolution, spreading and volatilization. Though generally considered as a minor process, dissolution is important from the point of view of toxicity. To model PAHs dissolution in water, an Eulerian advection–diffusion model is used. Laboratory experiments were conducted to characterize the numerous kinetics of dissolution and volatilization processes. Model validation was carried out with the following test cases: transport processes based on the well-documented seawater spill (advection), weathering processes based on laboratory experiments cited in the literature (spreading and evaporation processes) and artificial river test measurements (dissolution and volatilization).