API - REPORT 79-28
Review of the State-of-the-Art of Probabilistic Oil Spill Simulation
|Publication Date:||10 June 1980|
Oil spills in the marine environment have been steadily increasing over the past decade primarily due to the greater amounts of petroleum being transported by tanker from the Middle East and Indonesia to Europe and the Western Hemisphere. By far, the greatest amount of petroleum entering the marine environment is from marine transportation, with river runoff second, and natural sources third (see Figure 1-1). It is estimated that all sources of petroleum combined introduce on the order of 106 metric tons of petroleum hydrocarbons annually in to the oceans, the fate of which is of considerable concern to decision-makers and the general public .
There have been a number of significant oil spills over the past decade or so which have resulted in the release of millions of metric tons of petroleum hydrocarbons to the environment. The first of these, the Torrey Canyon in 1967, covered the south coast of Great Britain with more than 50,000 metric tons of Kuwait crude. The Santa Barbara blowout in 1969 released several thousand metric tons of crude resulting in fairly widespread damage to biological and recreational resources in the nearby coast of California. More recently the Argo Merchant disaster (25,025 metric tons) and the Amoco Cadiz grounding (220,000 metric tons) have exacerbated an already festering problem. The recent and most disasterous spill of all is the Ictoc I spill off the Gulf Coast of Mexico which has been estimated to have released over 100 million gallons of crude from the well, causing millions of dollars of damage to the business and an unestimatable amount of damage to the marine environment. The slick associated with this blowout typically measured 10 km x 30 km and constantly changed direction, making cleanup virtually impossible.
The need to control such massive discharges has been recognized for many years and has been the object of engineering, scientific, and regulatory efforts for equally as many years. The concern over determining the fate of spilled petroleum hydrocarbons has come to the fore with the emergence of the environmental movement, basically marked by the passage of the National Environmental Policy Act of 1969. Federal decision-makers at all levels became more acutely aware of the need to predict the fate and effects of such potentially harmful materials and began to infuse substantial amounts of money into related environmental studies. The U.S, Coast Guard (spills from ships), the U.S. Environmental Protection Agency (spills from all sources, but emphasis on terrestial and riverine sources), the U.S. Department of Interior (OCS Oil and Gas), and the National Oceanic and Atmospheric Administration (Oil Spill Response) all have developed various levels of expertise in predicting the fate and effect of petroleum hydrocarbons released in to the environment. Hundreds of millions of dollars have been spent on gathering baseline and related impact data, with the bulk of the funding coming from the Interior Department. The state of affairs at the present time can best be exemplified, albeit sadly, by the case of the Argo Merchant wherein a two-dimensional, non-weathering type model (in fact models) was used to predict the fate of the spilled hydrocarbons. The same is true for the OCS oil and gas risk analyses that are performed for each OCS lease sale and for a number of post-lease decisions. Significant policy and operations decisions concerning the future of our domestic energy picture are premised on the use of these> types of models which are far from optimum and which tend to portray an environmental hazard picture which is not accurate.
An assessment of the state-of-the-art in modeling the fate of oil spills is long overdue, and will contribute significantly to the quality of decisions that are made at all levels of industry and government. The product of the study proposed herein will assist in the planning of future environmental data gathering efforts, thereby enhancing the value of dollars spent, and will improve the accuracy and consistency of decisions made in the short term. The in-depth experience of Raytheon Environmental and Oceanographic Services (EOS) and its consultants will go far in expediting this study and ensuring a meaningful, immediately usable, and cost effective product.