The purpose of this study is to identify the riskiest tanker route associated with the Northern Gateway Pipeline and then identify which route presents the largest number of vulnerable ecologically important areas if an oil spill occurs. The identified factors are combined in an MCE analysis using the Model Builder processes (Figure 3), the pairwise comparisons (Table 1), and suitability equation (Equation 7) all found in objective 2 in the Research Approach for each of the two UTM zones the study area crosses. The resulting MCE model statistics of the two UTM zones are compared and provide a measure of spatial error inherent in the study. A range of -74 to 80 is given showing that the analysis has an approximate 154m range of error. Figures 4 - 6 represent the constraints and Figures 7 - 12 represent the criteria found and used in the MCE analysis. Each route is run through the MCE model and is combined together in Figure 13 giving the oil spill risk model for the study area. The MCE model is analyzed by examining the statistics of each route to determine the route that encompasses the largest percentage of areas identified as having extreme risk (areas with a suitability score of 75% to 100%). The Southern 1 tanker route is therefore deemed the most hazardous route for tankers, as seen in Figure 14, as it has 7676 of cells in the 75%-100% range, followed by the Northern route, 6273, and then Southern 2 route, 3746 (refer to Table 3 for all route cell assignments). This study notes that all cells identified as low risk are equal to 0, due to the fact that the cells are beyond all of the study constraints. Thus, these values are not included in Figure 14.
The analysis of all tanker routes and the associated proximity of ecologically important areas ascertains the most environmentally hazardous tanker route (refer to Table 4 for all vulnerable areas associated for each route). The Southern 1 tanker route is the riskiest route, as identified by the MCE, and it is found that a total of 46 ecologically important areas are vulnerable to an oil spill if it travels a distance of 25km, as seen in Figure 15 Part B. Within 25km of the Southern 2 tanker route, 43 ecologically important areas are identified as vulnerable, as seen in Figure 15 Part C, as well as 51 ecologically important areas are identified within 25km of the Northern tanker route, as seen in Figure 15 Part A.
Figure 4: Map showing the depth constraint of a depth lower than 23.10001m.
Figure 5: Map showing the water constraint to not allow the MCE to be performed on land.
Figure 6: Map showing the route constraint to not allow the MCE to be performed past a 10km buffer on each side of the route to account for freedom of boat travel in the ocean.
Figure 7: Map showing the route depth criterion, shallow is deemed high risk.
Figure 8: Map showing the proximity to land criterion, smaller distances are deemed high risk.
Figure 9: Map showing the marine traffic criterion, the more traffic the higher the risk.
Figure 10: Map showing the marine hazards criterion, the closer to the hazard the higher risk.
Figure 11: Map showing the marine obstructions criterion, the closer to the obstruction the higher risk.
Figure 12: Map showing the wave height criterion, the larger the wave height the higher risk.
Figure 13: Map showing the MCEs for all routes.
Figure 14: Map showing the proposed Southern 1 route MCE with the Slice tool used to divide the route cells into percentages of relative risk.
Figure 15: Map showing the ecologically important areas that would be affect by an oil spill traveling 25km off each proposed route. Part A is the Northern route, Part B is the Southern 1 route and Part C is the Southern 2 route.
Figure 16: Map showing the riskiest proposed route for the tanker with the relative MCE and the route that pertains the most vulnerable areas of ecological importance, with the relative vulnerable areas.