Groundwater contamination is a significant environmental issue in Canada (Giraldez & Fox, 1995). Groundwater contamination describes the diffusion of toxic chemicals through the surface of a landscape and into the groundwater aquifer (Saidi et al., 2009). A contaminated site is an area that contains an unsafe amount of contaminants as recalled by regulators (De Sousa, 2001). New expansions in development and agriculture have increased the potential for groundwater contamination because different anthropogenic processes influence the permeability of the soil and increase additives to the surface. Therefore, some landscapes are more vulnerable to groundwater contamination than others (Saidi et al., 2009). While the contamination of groundwater resources is rare, it is important to monitor and conduct groundwater surveys in order to prevent social and economic disasters. An example of this within Ontario is the Walkerton Water Tragedy in 2000 (Ivey, De Loë & Kreutzwiser, 2006; Clark et al., 2003). Approximately 25 percent of Ontario residents rely on groundwater resources, therefore preventing groundwater contamination is significant for public health (De Loë, Giantomasso & Kreutzwiser, 2002). In some cases, contaminated groundwater has affected in excess of 400,000 people in individual outbreaks across North America (Ivey et al., 2006). As a result, protecting the integrity of groundwater resources and identifying potential areas vulnerable to contamination has become a priority for municipalities in Ontario (Ivey et al., 2006).
In order to prevent groundwater contamination from occurring, prevention strategies must be assessed and implemented on the landscape. The use of prevention strategies is preferred over remediation strategies as it is a quicker and less expensive method (De Loë et al., 2002). Therefore, prevention methods such as green space conversion are favoured (De Loë et al., 2002). Green space conversion as a prevention strategy includes converting areas of high vulnerability to groundwater contamination into a space that promotes and preserves plant, wildlife and ecological functions (Jim, 2004). An area of green space can contribute to the clean and pathogen free infiltration of surface water into the water table (Jim, 2004). The implementation of green space is a viable solution as it is capable of decreasing the quantity of contaminants that reach the groundwater aquifer.
Areas of high vulnerability to contamination must be identified so that a suitable location for green space conversion can be selected. The DRASTIC model and the MCE model are effective tools for satisfying these two goals. The DRASTIC model is used in assessing groundwater vulnerability to contamination (Wang, He & Chen, 2012). This model is useful in identifying vulnerability to contamination and has shown to be beneficial to decision-makers concerned with protecting and sustaining groundwater quality (Pacheco & Fernandes, 2013). An MCE model is important as it has the capabilities to classify areas as either suitable or unsuitable for a specific job based a number of relevant factors (Erfanian et al., 2013). An MCE model is useful in determining the most suitable area for a reduction in groundwater contamination by implementing green space. (Questad et al., 2014). The GIS-based DRASTIC model and MCE model applications will prove to be beneficial in determining both highly vulnerable areas of groundwater contamination, as well as locations most suitable for the implementation of green space as a form of prevention.
Though the two GIS-based models are useful in determining the area(s) most vulnerable to contamination and the area(s) most suited for green space conversion, there is still research needed in order to determine the best possible location. To identify locations for green space conversion, considerations such as habitat requirements are needed (De Sousa, 2003). Ecological habitat requirements such as locations near pre-existing forests or water bodies should be considered so to promote ecological integrity (De Sousa, 2003). As well, the re-introduction of native flora and fauna should be considered in order to enhance the success of the converted green space (De Sousa, 2003). As it is acknowledged that habitat requirements such as proximity to forests and water bodies should be considered, these will be used as factors within the MCE model. As a result of these habitat requirements, further academic research should be conducted in order to supplement these research gaps.
Purpose of the Research
The purpose of this research is to identify high-risk areas for groundwater contamination within the Grand River Watershed using the GIS-based DRASTIC model and to reduce potential contamination by identifying area(s) suitable for green space conversion using a GIS-based MCE model.
1. To identify factors related to groundwater vulnerability and green space conversion.
2. To adapt the GIS-based DRASTIC model to evaluate areas of high vulnerability to groundwater contamination.
3. To develop a GIS-based MCE model to evaluate the most suitable areas for green space conversion.
4. To apply the DRASTIC model and the MCE model.
5. To evaluate the results of the DRASTIC model and MCE model, and evaluate the strengths and limitations of the models and model outputs.