Several of the recent large oil spills have had markedly different environmental impacts on the coastal zone of the affected areas. The effects of the BRAER spill on the adjacent coasts of the Shetland Island were almost negligible, whereas the Kuwait oils released by Iraq during the 1991 war literally blanketed the nearby Saudi coast with a major environmental dislocation. The EXXON VALDEZ spill was the focus of a large volume of public and media attention, yet the shorelines of Prince William Sound, and the adjacent waters, had virtually recovered in the space of two years. The public perception of the impact of spilled oil is often very different from the reality as documented by long-term scientific studies. The purpose of this poster session is to examine and compare the effects of recent spills in order to put the risk of severe environmental damage to the coastal zone in an appropriate context.
LESSONS LEARNED: 1. THE AMOUNT OF SHORELINE OILING OF SPILLED OIL AND THE SCALE The Exxon Valdez and Desert Storm spills show clearly that there is no direct relationship between the amount of oil that is spilled and the area that is affected by the spilled oil. Following the intentional destruction of oil facilities in Kuwait, an estimated 1.37 million bbl (220 km3) of oil was released.
Oceanographic controls prevented the widespread dispersion and transport of this vast amount of oil, so that only 644 km of coast were oiled. A shoreline loading for this spill averages out at about 2000 bbl (320m3)/km. As a result of the natural oceanographic containment the impact was very heavy, but localized in terms of the effects on a Gulf-wide basis.
This containment process is not uncommon and also explains the similarly heavy, but restricted, oiling on the Brittany coast following the Amoco Cadiz spill (Murray, 1982).
By contrast to these very localized, high-loading situations, the oil spilled from the Exxon Valdez involved an estimated 72 000-84 000 bbl (1 1.5–13.5 km3) of oil (Wolfe et al., 1993) spread out along 783 km of shoreline in Prince William Sound, an Abridged and adapted from Owens, 1993.
Bainbridge Island, Washington, 981 10, U.S.A. * Present Address: OCC Ltd., Suite 302, 755 Winslow Way East, arithmetic average of about 92–107 bbl (15–17 m3)/ km. This spill incident involved rapid and widespread dispersion by currents within the Sound, so that oiling generally was widespread but light; only 140 km of shoreline in the Sound was documented as ‘heavy’ oiling conditions, with greater than 6 m-wide band of oil on the shore (Owens, 1991). The documented recovery discussed below is more easily understand in this context of the degree of oiling and natural oceanographic dispersion. The widespread dispersion of oil in the Gul