1. SIMBAR Oil Spill Boom and Contingency Plan Modelling Objectives Optimal usages of booming in practice Partners –EIGSI Engineering School La Rochelle, Project Coordinator –CEDRE Expertise Center, Centre de Documentation de Recherche et d’Expérimentations sur les Pollutions Accidentelles des eaux, Brest –ULR La Rochelle University, Hydrodynamic LEPTAB –CETMEF French Administration, Centre d’Etudes Techniques Maritimes et Fluviales, Département Environnement Littoral et Cours d'Eau (DELCE), Division environnement marin et littoral (DEML) Brest-Plouzané –EDF R&D LNHE Laboratoire National d’Hydraulique et Environnement Chatou Contact Frédéric Muttin EIGSI La Rochelle muttin@eigsi.fr Web site Simbar : http://simbar.eigsi.fr Acknowledgements The financial support of the French Administration on Environment and Sustainable Development, Ministère de l’Ecologie et du Développement Durable (MEDD), is gratefully acknowledged, grant n° CV 13 2003, Accord n°CV 03000142, date 15/03/2004. The project SIMBAR is a member from 2003 of the French research network RITMER on Accidental Maritime Pollutions and theirs Ecological Impacts. Key words: Oil pollution, Coastal water, Recommendations, Technological Innovations, Environmental technologies, Oil Spill Boom

2. The problem addressed on booms Boom efficiency is limited by different physical effects of oil leakage under the boom (entrainment, submersion,…). CEDRE gives the different physical properties needed. Three kinds of oil were studied: light, heavy and emulsion. A standard boom geometry is used for design improvements: diameter of the float 55 cm, skirt height 75 cm de hauteur. An exploratory study over more than 20 parameters on the design of a boom has been conducted: elasticity of the fabric, size of the chain, leach and mooring members. The boom modeling The main objective is to propose a complete modeling of the boom. Fluid mechanics and solid mechanics are involved. Based on model result, recommendations on boom design are given. The current limit on the boom efficiency must be more than the actual limit 0.35 – 0.5 m/s. The objective is to increase the limit to 1 m/s. The concept of oil deviation by boom is study. The mechanical stress on the boom is concentrated on the chain on the bottom of the skirt. The validation The mooring device of a boom used buoyancies, mooring lines, anchors or dead-masses. The French response team CETMEF will use the result of the research to improve the POLMAR plan. The boom plan of the river Elorn (Brest bay) is used as case study. The boom computation uses both tide and river current pressures. The boom plan length is 1030 m. The vertical angle of the skirt, around 10°, plays a central role in the oil contingency. The double mooring device on both parts of the boom is useful when the tide inverses the current direction. The numerical simulation of the flows (oil and water) used the method SPH. The simulations in 2D have been made with a uniform current and with a monochromatic wave. A current higher than 0.35 m/s will give oil leakage under the boom. LNHE works on the fluid flow computation around the boom (SPARTACUS). The boom efficiency is limited by submersion or entrainment of oil under the boom. CEDRE gives the physical parameters of oils and booms. The visualisation of the flow permits to identify the efficiency limit of the contingency by booms. The University of La Rochelle provides boom tests in a channel. EIGSI computes the structural behaviour of boom plan on the coastal sea zone.