Mapping Of Oil Residence And Biological Sensitivity Indices Related To Coastal Oil Spills

To deal with an oil spill threatening the coastal marine environment, oil spill planning and response teams require current, simply-presented data on the physical and biological resources of the coast. These data should provide the user the flexibility to make decisions appropriate to real-world, real-time situations at the time of a spill. We describe two separate indices; an Oil Residence Index (ORI) and a Biological Sensitivity Index (BSI). Both indices are presented separately on maps plus accompanying coding and data sheets to show the distribution of physical and biological shore-zone characteristics, plus the spatial and temporal variations in sensitivities of these characteristics to an oil spill. This allows the user to identify specific areas of concern, reasons for the concern, and the relationships between physical and biological features of the coastline. The Oil Residence Index (ORI) is based on physical shoreline characteristics, especially wave exposure levels and beach sedimentation cycles. Explicitly included for the first time is the seasonal influence of wave energy and beach erosion-accretion cycles on the persistence of stranded oil. The Biological Sensitivity Index (BSI) is based on the temporal and spatial presence, abundance, vulnerability and sensitivity to oil of coastal biological resources. The BSI reflects population level responses to oil spills and not only the losses of individuals, i.e., the "body count" assessment approach.