Evaluation of the consequences of various response options using modeling of fate, effects and NRDA costs of oil spills into Washington waters

Abstract

Oil spill fate and effects modeling and analysis were performed to evaluate the implications of spill response options being considered by the Washington State Department of Ecology in their rulemaking related to oil spill preparedness (WA State Contingency Plan Rule). The impacts of potential spills in Washington's outer coast, sound and river environments were modeled varying response options and operational timing, including use of conventional mechanical containment and recovery operations; dispersant application with concurrent mechanical containment and recovery; and in-situ burning with concurrent mechanical containment and recovery. US Coast Guard federal response capability standards, current Washington State standards, and potential theoretical higher response capability standards were simulated for scenarios involving spills of crude oil, bunker fuel and diesel into Washington waters (in the Strait of Georgia, Strait of Juan de Fuca, outer coast, and lower and upper Columbia River). The modeling was performed in probabilistic mode, i.e., by randomly varying location along tanker routes, spill date, and time, and so environmental conditions during and after the release among potential conditions that would occur. The model results were analyzed to estimate mean, standard deviation (SD), and 5th. 50th and 95th percentile results for surface water and shoreline oiling, water column and sediment contamination, biological impacts, and natural resource damages (NRD). NRD costs were based on the Washington Compensation Schedule and Oil Pollution Act (OPA) NRD procedures involving compensatory restoration scaling and associated costs. Response costs and socioeconomic damages were evaluated in a companion study by D.S. Etkin (Environmental Research Consulting). The fates, impacts and NRD cost results for two scenarios are presented here: those for the outer coast spills assuming (1) only protective booming and (2) protective booming plus the mechanical removal up to Washington State standards. The results of these and other scenarios are being incorporated into a rulemaking process and cost-benefit analysis by the Department of Ecology.