Proposed Abstract Title

Challenge of Accurate Simulation of Spill Trajectories in Salish Sea – Revisiting the 2003 Pt. Wells Spill

Session Title

Salish Sea Estuarine Circulation, Community perspectives on oil spill planning and response, Reducing Oil Spill Risk in the Salish Sea with a Particularly Sensitive Sea Areas Designation

Description

Salish Sea is a particularly challenging water body for predictive oil spill trajectory simulations. These waters are highly stratified with fjord like long narrow deep channels and presence of mid-channel islands. Availability of real time accurate predictions of near surface currents is therefore essential for minimizing the uncertainty and risks associated with oil spill impact assessment. The Salish Sea model developed by PNNL using FVCOM accommodates complex shoreline geometry and generates hydrodynamic solutions for use in circulation, flushing, and water quality assessments. In this study we evaluate the adequacy of those routinely available (intermediate scale) solutions for use in hind casting and predictive oil spill trajectory modeling. The Pt. Wells Spill that occurred in December of 2003 is used as a case study. The trajectory modeling was conducted using two separate oil fate and transport models, 1. The General NOAA Operational Modeling Environment (GNOME) designed for simulating the trajectory and dispersion of oil at the water surface and 2. Blowout and Offshore Spill Occurrence Model (BLOSOM). The BLOSOM model developed by U.S. DOE’s National Energy Technology Laboratory is a 3D model with the ability to generate jet mixing and buoyant plume dilution and also includes detailed weathering/crude modules. Preliminary tests using GNOME and BLOSOM models showed that use of available hydrodynamic solutions while suitable for large scale water quality assessments may not be sufficient for surface oil transport predictions. Sensitivity tests were conducted with model grid resolution, dispersion coefficients, and wind forcing to improve the hydrodynamic solutions for use in Oil Spill Trajectory predictions. The results were found to be highly sensitive to local wind conditions. The model results using GNOME were compared with BLOSOM and found to be comparable validating the performance of BLOSOM and GNOME with linkage to using Salish Sea Model solutions.

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Challenge of Accurate Simulation of Spill Trajectories in Salish Sea – Revisiting the 2003 Pt. Wells Spill

Salish Sea is a particularly challenging water body for predictive oil spill trajectory simulations. These waters are highly stratified with fjord like long narrow deep channels and presence of mid-channel islands. Availability of real time accurate predictions of near surface currents is therefore essential for minimizing the uncertainty and risks associated with oil spill impact assessment. The Salish Sea model developed by PNNL using FVCOM accommodates complex shoreline geometry and generates hydrodynamic solutions for use in circulation, flushing, and water quality assessments. In this study we evaluate the adequacy of those routinely available (intermediate scale) solutions for use in hind casting and predictive oil spill trajectory modeling. The Pt. Wells Spill that occurred in December of 2003 is used as a case study. The trajectory modeling was conducted using two separate oil fate and transport models, 1. The General NOAA Operational Modeling Environment (GNOME) designed for simulating the trajectory and dispersion of oil at the water surface and 2. Blowout and Offshore Spill Occurrence Model (BLOSOM). The BLOSOM model developed by U.S. DOE’s National Energy Technology Laboratory is a 3D model with the ability to generate jet mixing and buoyant plume dilution and also includes detailed weathering/crude modules. Preliminary tests using GNOME and BLOSOM models showed that use of available hydrodynamic solutions while suitable for large scale water quality assessments may not be sufficient for surface oil transport predictions. Sensitivity tests were conducted with model grid resolution, dispersion coefficients, and wind forcing to improve the hydrodynamic solutions for use in Oil Spill Trajectory predictions. The results were found to be highly sensitive to local wind conditions. The model results using GNOME were compared with BLOSOM and found to be comparable validating the performance of BLOSOM and GNOME with linkage to using Salish Sea Model solutions.