How large does a wave basin need to be to simulate an ocean for oil spill research? It depends

Most marine oil spill research is conducted in facilities varying from large-scale wave basins to laboratory-scale swirling flasks. Since the dynamics of the ocean are very complex, the challenge lies in interpolating the bench-scale data to real world situations. Langmuir cells are one of the major processes observed in all oceans. These cells are a result of wind action, and are from 10 to 50 metres apart. They range from a few metres to many kilometres in length and 4 to 6 metres in width. Any measurement of particle dynamics is influenced by the water depth and is related to wave height. Most wave basins are shallow in terms of wave heights used. As such, both buoyant and sinking particles are influenced by energy reflections from the basin bottom. Likewise, the advection of sub and surface plumes are controlled by different current regimes because of Coriolis forces, and extend to 10 to 20 metres depending on the surface wind. Another aspect that sets open ocean and wave basins sub-surface current systems apart is that the current regime in many wave basins contains components of reflected energy from the end of the basin. Test basins can be used to evaluate the effectiveness of pumps, skimmers and booms in an ocean environment, and the data from a basin can be reliably used for oil spill response. However, even the largest basins are too shallow to be useful for any studies involving the motion of oil in the sub-surface. This includes most of the dispersant studies which detect oil under water. The absolute values of dispersant effectiveness would be incorrect since the sub-surface plumes are truncated on the bottom and their dynamics are very different. 3 refs., 1 tab., 1 fig.