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FACTORS AFFECTING THE PERSISTENCE OF STRANDED OIL ON LOW ENERGY COASTS

1985; Atlantis Press; Volume: 1985; Issue: 1 Linguagem: Inglês

10.7901/2169-3358-1985-1-359

2169-3366

Edward H. Owens,

Oil Spill Detection and Mitigation

ABSTRACT Mechanical dispersion by waves is usually considered to be the primary factor that controls the persistence of spilled oil reaching the coast. This assumption is accurate for stable coasts that are not subject to net erosion or accretion and beaches where oil would not be buried by onshore, offshore, or alongshore movement of sediments. On high energy coasts, oil can be rapidly buried or eroded, depending on the stage of beach changes. Similarly, oil stranded on coasts subject to rapid net accretion or erosion is likely to be buried or dispersed. Rapid shoreline changes can occur in areas of low wave energy, so wave energy levels cannot be used alone as an indicator of oil persistence. Sections of the North American Beaufort Sea coast are undergoing net long term changes on the order of 10 meters per year, despite the short (3 month) open water season and the small fetch areas. Beach migration or cliff retreat on these low energy coasts often has a net rate on the order of one meter per month. In these situations, the changes in shoreline location due to sediment erosion and transport reflect the integrated effect of coastal processes and the materials on which the processes act. Rates of shoreline changes can be used as an indicator to estimate the residence time of stranded oil, irrespective of the shoreline character or the wave energy levels at the shoreline. Wave energy levels alone are an inadequate basis for estimating the residence time of stranded oil.