THE USE OF RECEPTOR MODE TRAJECTORY ANALYSIS TECHNIQUES FOR CONTINGENCY PLANNING

Abstract

ABSTRACT Spill trajectory models and computer analysis techniques have been used effectively in spill response programs. In addition to providing movement and spreading forecasts, these models also can be used to explore alternative operational scenarios. In many cases these same, basically deterministic, model formulations have been used to study hypothetical spills in a region where development is proposed, and the results used in contingency planning activities. When deterministic trajectory forecast models are used in this manner, a number of assumptions are necessary about the statistical nature of the dominant physical transport processes and the location of potential spill sites. This paper describes a new modeling procedure in which high-value target, or receptor, areas first are determined. These areas may be defined by using various environmental sensitivity mapping schemes. With this information, the model performs an inverse set of trajectory calculations and presents the output as two maps. The first map provides the quantitative probability distribution that a pollutant could reach the high-value receptor site from anywhere in the modeled region; i.e., it is a threat zone map. The second map provides time of travel information for this distribution. An example of the model's use is presented, and ways in which its map output may be used directly in regional response and contingency plans are discussed.