The proposed Shell Puget Sound Refinery Anacortes Rail Unloading Facility in Washington State is expected to receive six unit trains per week, each containing 60,000–70,000 barrels of conditioned Bakken crude oil. Oil spill trajectory, fate, and effects modeling was performed to evaluate risks from hypothetical releases of crude oil from crude-by-rail unit trains. The oil spill modeling predicted where released oil would move over land and in water, how it would behave within the environment, and how it may impact resources within the area. Hypothetical releases from train derailments were modeled using the OILMAP Land and SIMAP models, two state-of-the-art computational oil spill models that are routinely used internationally by industry, government, and academia. OILMAP Land was used to predict the overland and down slope trajectory and fate of released crude oil on land and within storm water drainage systems. SIMAP was used to characterize the trajectory, fate, and acute biological effects of oil within the water column. Releases were modeled at three representative locations along the rail corridor, including the Swing Bridge over the Swinomish Channel, the Skagit River crossing, and the Edmonds Ferry Terminal. Two environmental conditions were modeled at each location to capture the seasonal and environmental variability in tides, river flow rate, and winds. Two discharge volumes of conditioned Bakken crude oil were modeled. An overlay analysis was used to determine the potentially affected resources located within the oil spill footprint for each respective scenario. A biological effects assessment was conducted to estimate the potential short-term (acute) exposure of organisms to floating oil and subsurface oil contamination to estimate the resulting equivalent area of 100% predicted mortality. To bound the range of potential effects, biological impacts were assessed using two biological sensitivities. In total, 12 physical fates scenarios were modeled (3 locations × 2 environmental conditions × 2 release volumes) with 24 biological scenarios (2 sensitivities). Approximately 50% of the conditioned Bakken crude was predicted to evaporate within 48 hours, while the remaining oil formed surface slicks, oiled shorelines, and entrained within the water column, potentially interacting with SPM and oiling sediments. This assessment was used to quantitatively discuss the consequence side of risk associated with crude by rail releases from unit trains for the proposed Shell Puget Sound Refinery Anacortes Rail Unloading Facility. Results were included in Chapter 5 of the Environmental Impact Statement (EIS) addressing Environmental Health and Risk, as well as a technical report.

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