Methodology
Least Cost Path Including Alberta
Due to Alberta data being rather limited to UBC students (not much more than digital elevation models (DEM) were available for easy access), most of the analysis focused on British Columbia.
Using a
DEM of Canada (acquired from Geogratis) and a provincial boundaries
shapefile (acquired from the G: drive) to clip BC and Alberta, a DEM of
these two provinces was obtained. Then, using this DEM, a slope surface
was obtained and this was coupled with the Cost Distance and Cost Path
tools (with the locations of Kitimat and Bruderheim as starting and
finishing points) to eventually create a least cost path spanning
across the two provinces.
Finally, by georeferencing a route map JPEG from the Northern Gateway official website, a "proposed route" path was digitized and this was overlain next to the slope-generated path created.
Cost Surface and Least Cost Analysis
The path creation part of the project was focused only within British Columbia due to the difficulty in attaining data pertinent to the project within Alberta. An image of the proposed pipeline was acquired from the Northern Gateway Pipeline website (2009) and was then digitized in order to create a layer for the proposal. Once digitized, the locations of where the proposed pipeline crosses the border and where the pipe ends in Kitimat were used to create two point shape files with the editor tool.
These start and end point positions then allowed us to establish an area of interest base map from a base map of British Columbia. This would minimize the size of the files produced from any GIS work and eliminate any analysis being done on areas interest. The area of interest used a rectangular shape, longer in the East-West directions than in North-South and was chosen arbitrarily by assuming that the least cost path would not travel too far in the North or South directions.
Any vector files acquired were converted to raster in order to create the appropriate raster cost surfaces later on. All of the resulting raster data was then intersected such that only data within the area of interest was kept. Once this was done, all of the layers for the parameters in our analysis were reclassified so that their “value” was actually an arbitrary cost that was based on either assumed relative construction costs or environmental/societal impacts. This was done for the production of all 3 raster surfaces. The cost values can be viewed in the Cost tables below.
The raster calculator was then used to produce a single cost raster surface that would be used to produce the cost distance and the cost back link raster layers. Once this process was complete, a least cost path was created.
The table which contains the cost values used in the multi-criteria least cost analyses can be found here.
Cost surface created for path 2
Socioeconomic Analysis
Data for this portion was obtained from Abacus, Statistics Canada, and the UBC Geography server.
Shapefiles of dissemination areas (DAs) and census subdivisions (CSDs) of BC were taken and intersected by our area of interest (the area near which the Enbridge pipeline is proposed to pass through).
The Statistics Canada data tables used in this analysis that containing information for dissemination areas and census subdivisions were initially too large to be imported into ArcMap. Relevant categories and areas needed to be queried for just BC. After this was done, the tables were small enough to be exported and used. Once opened in ArcMap, the tables were joined with the intersected DA and CSD shapefiles. With this join, choropleth maps were created for average income, unemployment, and aboriginal populations.
The Enbridge and cost polylines were then overlaid over the choropleth maps so that socioeconomic observations of each path could be done.
Slope
Steep slopes increase construction costs significantly and also increase the risk of environmental damage by allowing any of the materials carried by the pipeline to spread downhill if a spill were to occur.
Elevation
High elevations may be undesired in construction but environmentally, high elevation regions may pose similar threats as slopes. A spill in a high elevation location is likely to spread to a lower elevation location if a slope is nearby.
Provincial Parks
Provincial parks are protected by law against degradation thus a pipeline should not cross provincial park boundaries. Parks were thus given a relatively high importance value so that the pipeline would not cross.
Agricultural Land Reserve
Encompasses only 5% of the province’s land. The Provincial Agricultural Land Commission (2002) defines the Agricultural land reserve (ALR) as:
“…a provincial zone in which agriculture is recognized as the priority use. Farming is encouraged and non-agricultural uses are controlled. It includes private and public lands that may be farmed, forested or vacant land. The Agricultural Land Reserve takes precedence over, but does not replace other legislation and bylaws that may apply to the land.”
“Local and regional governments, as well as other provincial agencies, are expected to plan in accordance with the provincial policy of preserving agricultural land.”
“The Agricultural Land Commission Act sets the legislative framework for the establishment and administration of the agricultural land preservation program.”
ALR was assigned a medium to medium high importance value. It is not ideal to cross ALR’s because they are protected by law but history shows that governments are willing, in certain cases, to let ALR’s be used for purposes other than agriculture. This is exemplified by the fact that BC’s ALR’s have seen a net loss of over 35,000 hectares since the program was started (Brouwers. 2010).
Municipalities
Structures have already been developed within these areas therefore the pipeline would have difficulty crossing. Also, people tend to protest potentially dangerous projects like this if they are being built near their homes. In choosing Municipalities as areas where the pipeline should not cross, it is understood that they are very general parameters in the sense that not the whole municipality contains built structures. This still works because of the coarseness of the scale being used for the analysis.
Lakes
Lakes cannot easily cross a pipeline because of construction costs. Environmental risk is very significant near lakes therefore lakes will be given a highest cost values. The Regional District of Fraser– Fort George (2002) set a minimum distance of 30-150m from water bodies for the installation of sewage disposal systems. Since the Regional District of Fraser – Fort George is within our area of interest we took this information into account and generalized our entire area of Interest. We assumed that an oil leak from a pipeline would have a similar minimum distance restriction and thus gave all large water bodies a 100m buffer.
Watersheds
These are areas where municipalities get their drinking water resources. The pipeline must avoid going near these areas so they will be assigned high costs.
Old Growth Forests
These forests are important to biodiversity and are also considered important to the BC Ministry of Forests. About 4 million hectares of old growth forests are protected in BC (BC Ministry of Forests, 2003). The old growth forest map is patchy therefore the pipeline should be able to get around it easily. None the less, old growth forests will be given a relatively high importance value such that the pipelines in our analysis may not cross.
Endangered Species and Ecosystems
This layer is relatively small but was given a very high cost value due to the protection and care taken in these areas by conservationists.