Groundwater models can be useful tools to support decisions regarding the management of public water supply wells. Scientific progress and the availability of increasingly powerful computer resources provide a continuous opportunity for improving the way numerical models are applied for this purpose. In this thesis, numerical groundwater models were applied to address relevant questions regarding the management of water supply wells in two distinct glacial aquifers in southern Ontario, Canada. The objective is to propose science-based methods that can be applied in day-to-day practice in the context of source water protection. Three specific issues were addressed: (1) Time lag in the unsaturated zone: A simplified method was proposed to assess the importance of the unsaturated zone in delaying the effects of changes at ground surface on water supply wells (i.e., unsaturated zone time lag). This assessment is important because it influences field and modelling efforts to estimate well vulnerability to contamination and impacts due to changes in land use. The proposed method is based on estimations of travel time in the saturated and unsaturated zones, and provides a formal framework for an intuitive approach. For the studied case, the delay in the unsaturated zone was deemed to be significant, representing on average ~ 11 years or ~ 53% of the total travel time from ground surface to receptor. Travel times were estimated using approaches with different levels of sophistication, to evaluate the usefulness of simplified calculations. Such calculations lead to the same overall conclusion as more sophisticated and time-consuming approaches. However, when assuming limited knowledge of soil properties, common at earlier stages of most investigations, these simplified techniques generated inconclusive results. (2) Uncertainty in capture zone delineation: A simple method was proposed to address the issue of uncertainty in capture zone delineation. This method considers uncertainty at two different scales: local (parametric) and global (conceptual). Local-scale uncertainty is addressed by using backward transport simulation to create capture probability plumes, with probabilities ranging from 0 to 100%. Global-scale uncertainty is addressed by considering more than one possible representation of the groundwater system (i.e., multiple model scenarios). Multiple scenario analysis accounts for more than one possible representation of the groundwater system, and it incorporates types of uncertainty that are not amenable to stochastic treatment (e.g., uncertainty due to conceptual model, to different model codes and boundary condition types). Finally, the precautionary principle is used to combine capture probability plumes generated by different scenarios. As a result, two maps are generated: One for wellhead protection, and another for selection of priority areas for implementation of measures to improve water quality at the supply well. For the studied case, three models with different spatial distributions of recharge but with similar calibrations were considered, exemplifying the issue of non-uniqueness. The two maps obtained by the proposed method were significantly different, indicating that recharge distribution represents a major source of uncertainty in capture zone delineation. (3) Effects of agricultural Beneficial Management Practices (BMPs) in supply wells: A numerical model framework was used to estimate the effects of measures to reduce nitrate leaching to groundwater from agricultural activities (i.e., Beneficial Management Practices, or BMPs). These measures were implemented in 2003 (~ 10 years ago) at the Thornton well field (Woodstock, Ontario, Canada) to improve well water quality. This case study is based on extensive field work characterization from previous research, and allows the discussion of practical issues related with data collection and interpretation (e.g., different techniques for generating mass loading distributions were compared). Regional flow was simulated in a 3D larger-scale saturated flow model, while variably-saturated flow and transport were simulated in a 3D smaller-scale, more refined grid. A vertical 1D model was used to define the discretization in the unsaturated zone of the variably-saturated flow and transport model. Results indicate that the adoption of BMPs in selected areas can be an effective strategy to improve water quality in supply wells impacted by non-point source contaminants. For the Thornton well field, the currently adopted BMPs are estimated to reduce concentrations from ~ 9.5 to ~ 7.5 mg NO3-N/L. Water quality at the wells are predicted to respond after 5 to 10 years after implementation of BMPs, and are expected to stabilize after 20 to 30 years Management scenarios with further reductions in nitrate concentration are expected to further reduce concentrations by ~ 0.4 to ~ 0.8 mg NO3-N/L. The proposed framework can be adapted to design and evaluate BMPs for similar problems and for other non-point source contaminants. Some insights were common to all three issues discussed and can be useful to practitioners involved in source water protection studies: (1) Reliable recharge estimations are essential for the management of water supply wells; and (2) The use of multiple models should be encouraged to increase the understanding of different aspects of the system, assess uncertainty and provide independent checks for model predictions.

This thesis involves the design of an early warning source water monitoring station for a riverine source of drinking water. These stations provide downstream water utilities with advanced notification of contamination events so they have time in which to implement a response. Many threats facing riverine water supplies, such as accidental spills, are uncertain in nature. Therefore, designing a monitoring station for the detection of these events requires a probabilistic modelling approach. Sources of uncertainty considered in this research include the location, mass and duration of a spill event as well as the flow at the time of the spill and the water quality model parameters. Probability distributions for each of these uncertainties were defined and a Monte Carlo experiment was conducted. The design objectives include maximizing the probability of detection and maximizing the probability of having a threshold amount of warning time. These objectives are in conflict with each other because the probability of detection improves as the station moves closer to the intake and the amount of warning time increases as the station is located further upstream. Values for the competing objectives were calculated for a number of potential monitoring station locations at multiple sample intervals and the tradeoff solutions were analyzed. This methodology was applied to the Hidden Valley Intake which services the Regional Municipality of Waterloo’s Mannheim Water Treatment Plant. The Hidden Valley Intake is located in Kitchener, Ontario and withdraws up to 72 ML of water per day from the Grand River. Based on an analysis of the Monte Carlo simulation results for the case study application, it was found that locating the monitoring station near the Victoria Street Bridge, approximately 11 km upstream of the intake, represents the best tradeoff in the design objectives. Sampling at least once per hour is recommended to increase the amount of warning time. The impact of various sources of uncertainty was also explored in this thesis. It was found that the flow at the time of a spill and the spill location are the only sources of uncertainty that significantly impact the probability distributions of relevant model results.

This thesis involves the design of an early warning source water monitoring station for a riverine source of drinking water. These stations provide downstream water utilities with advanced notification of contamination events so they have time in which to implement a response. Many threats facing riverine water supplies, such as accidental spills, are uncertain in nature. Therefore, designing a monitoring station for the detection of these events requires a probabilistic modelling approach. Sources of uncertainty considered in this research include the location, mass and duration of a spill event as well as the flow at the time of the spill and the water quality model parameters. Probability distributions for each of these uncertainties were defined and a Monte Carlo experiment was conducted. The design objectives include maximizing the probability of detection and maximizing the probability of having a threshold amount of warning time. These objectives are in conflict with each other because the probability of detection improves as the station moves closer to the intake and the amount of warning time increases as the station is located further upstream. Values for the competing objectives were calculated for a number of potential monitoring station locations at multiple sample intervals and the tradeoff solutions were analyzed. This methodology was applied to the Hidden Valley Intake which services the Regional Municipality of Waterloo’s Mannheim Water Treatment Plant. The Hidden Valley Intake is located in Kitchener, Ontario and withdraws up to 72 ML of water per day from the Grand River. Based on an analysis of the Monte Carlo simulation results for the case study application, it was found that locating the monitoring station near the Victoria Street Bridge, approximately 11 km upstream of the intake, represents the best tradeoff in the design objectives. Sampling at least once per hour is recommended to increase the amount of warning time. The impact of various sources of uncertainty was also explored in this thesis. It was found that the flow at the time of a spill and the spill location are the only sources of uncertainty that significantly impact the probability distributions of relevant model results.

Groundwater models can be useful tools to support decisions regarding the management of public water supply wells. Scientific progress and the availability of increasingly powerful computer resources provide a continuous opportunity for improving the way numerical models are applied for this purpose. In this thesis, numerical groundwater models were applied to address relevant questions regarding the management of water supply wells in two distinct glacial aquifers in southern Ontario, Canada. The objective is to propose science-based methods that can be applied in day-to-day practice in the context of source water protection. Three specific issues were addressed: (1) Time lag in the unsaturated zone: A simplified method was proposed to assess the importance of the unsaturated zone in delaying the effects of changes at ground surface on water supply wells (i.e., unsaturated zone time lag). This assessment is important because it influences field and modelling efforts to estimate well vulnerability to contamination and impacts due to changes in land use. The proposed method is based on estimations of travel time in the saturated and unsaturated zones, and provides a formal framework for an intuitive approach. For the studied case, the delay in the unsaturated zone was deemed to be significant, representing on average ~ 11 years or ~ 53% of the total travel time from ground surface to receptor. Travel times were estimated using approaches with different levels of sophistication, to evaluate the usefulness of simplified calculations. Such calculations lead to the same overall conclusion as more sophisticated and time-consuming approaches. However, when assuming limited knowledge of soil properties, common at earlier stages of most investigations, these simplified techniques generated inconclusive results. (2) Uncertainty in capture zone delineation: A simple method was proposed to address the issue of uncertainty in capture zone delineation. This method considers uncertainty at two different scales: local (parametric) and global (conceptual). Local-scale uncertainty is addressed by using backward transport simulation to create capture probability plumes, with probabilities ranging from 0 to 100%. Global-scale uncertainty is addressed by considering more than one possible representation of the groundwater system (i.e., multiple model scenarios). Multiple scenario analysis accounts for more than one possible representation of the groundwater system, and it incorporates types of uncertainty that are not amenable to stochastic treatment (e.g., uncertainty due to conceptual model, to different model codes and boundary condition types). Finally, the precautionary principle is used to combine capture probability plumes generated by different scenarios. As a result, two maps are generated: One for wellhead protection, and another for selection of priority areas for implementation of measures to improve water quality at the supply well. For the studied case, three models with different spatial distributions of recharge but with similar calibrations were considered, exemplifying the issue of non-uniqueness. The two maps obtained by the proposed method were significantly different, indicating that recharge distribution represents a major source of uncertainty in capture zone delineation. (3) Effects of agricultural Beneficial Management Practices (BMPs) in supply wells: A numerical model framework was used to estimate the effects of measures to reduce nitrate leaching to groundwater from agricultural activities (i.e., Beneficial Management Practices, or BMPs). These measures were implemented in 2003 (~ 10 years ago) at the Thornton well field (Woodstock, Ontario, Canada) to improve well water quality. This case study is based on extensive field work characterization from previous research, and allows the discussion of practical issues related with data collection and interpretation (e.g., different techniques for generating mass loading distributions were compared). Regional flow was simulated in a 3D larger-scale saturated flow model, while variably-saturated flow and transport were simulated in a 3D smaller-scale, more refined grid. A vertical 1D model was used to define the discretization in the unsaturated zone of the variably-saturated flow and transport model. Results indicate that the adoption of BMPs in selected areas can be an effective strategy to improve water quality in supply wells impacted by non-point source contaminants. For the Thornton well field, the currently adopted BMPs are estimated to reduce concentrations from ~ 9.5 to ~ 7.5 mg NO3-N/L. Water quality at the wells are predicted to respond after 5 to 10 years after implementation of BMPs, and are expected to stabilize after 20 to 30 years Management scenarios with further reductions in nitrate concentration are expected to further reduce concentrations by ~ 0.4 to ~ 0.8 mg NO3-N/L. The proposed framework can be adapted to design and evaluate BMPs for similar problems and for other non-point source contaminants. Some insights were common to all three issues discussed and can be useful to practitioners involved in source water protection studies: (1) Reliable recharge estimations are essential for the management of water supply wells; and (2) The use of multiple models should be encouraged to increase the understanding of different aspects of the system, assess uncertainty and provide independent checks for model predictions.

Source water protection (SWP) is defined as a land use management and planning process aimed at the protection of surface and groundwater sources from contamination. Currently in Saskatchewan, the Water Security Agency is leading much of the planning and management with the goal of safe drinking water sources and reliable water supplies. The Water Security Agency has developed SWP planning initiatives across the southern portion of the province. Rates of SWP plan implementation in Saskatchewan are uneven and dependent on multiple factors. Using document review and key informant interviews, this study identifies factors facilitating and constraining source water protection plan implementation in selected areas and describes capacity building needs for SWP plans implementation in Saskatchewan. Results are discussed based on four capacity areas: financial, institutional, technical and social capacity. The results in this study show that capacity areas in need of improvement include stable financial resources, training opportunities for local watershed groups, public awareness, adequate stakeholder involvement, SWP plan re-evaluation, and information/data access. The result of this research contributes to the understanding of SWP plan implementation relating to capacity building needs at the watershed scale in the prairie region.

Groundwater is an important water resource that must be protected from potential contamination due to anthropogenic activities such as industrial production and agriculture. It is necessary to understand the presence, movement, and persistence of contaminants in aquifers to develop adequate protection plans. Fractured bedrock aquifers with thin overburden cover are very sensitive to contamination, and little is known about transport processes from the ground surface to depth in this setting. Thus, this research was undertaken to improve the understanding of anthropogenic impacts on water quality in a natural fractured bedrock aquifer with minimal overburden protection. This was accomplished through a field-based investigation conducted in an agricultural setting near Perth, Ontario, Canada. The temporal and spatial variations of several contaminants and indicators (including nitrate, E. coli and polybrominated diphenyl ethers) were examined. A unique infiltration tracer experiment was also conducted to simulate the transport of solutes from the ground surface to wells. Results showed that nitrate concentrations were consistent on a daily scale, but varied monthly. In contrast to nitrate, greater bacterial (E. coli) variability was observed daily. E. coli was not identified in some locations for several months. The temporal variability of concentrations is an important consideration for those consuming groundwater in this setting, as concentrations may be acceptable one month while unsuitable another month (or even another day for fecal bacteria). Annual groundwater monitoring will likely not capture maximum concentrations and thus may not protect human health. Polybrominated diphenyl ethers (flame retardants), which had not been previously measured in groundwater, were detected in the study aquifer at concentrations greater than observed in surface water bodies. It is evident that additional surveys of PBDE concentrations in groundwater are warranted. The infiltration tracer experiment showed that solute transport from the ground surface through thin soil to wells in fractured bedrock can be extremely rapid (on the order of hours) although very complex. This is an important consideration for private and municipally owned drinking water systems that draw water from shallow bedrock aquifers. The results of this research demonstrate that protecting water at the source is imperative in order to preserve water quality in sensitive fractured bedrock aquifers with minimal overburden cover. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2009-10-25 21:37:21.418

Collaborative approaches to the governance and management of drinking water sources have gained traction in recent decades as constituting a superior, bottom-up alternative to conventional and adversarial forms of governance, which have largely occurred from the top-down. Collaborative water governance enables local stakeholders to work together to more effectively manage water resources at the watershed level, in an inclusive manner that considers the interests of the various users of the resource. However, despite its promise, collaboration can be difficult to effectively achieve in practice, and scholars assert that some of the normative assumptions underlying the concept do a disservice to the difficulties that actors face in this setting. This research addresses this gap through an empirical analysis of the collaborative approach to drinking water source protection planning and governance that was implemented in Ontario through the enactment of the Clean Water Act in 2006. Three factors prevalent in the literature that are thought to underscore successful collaboration were chosen as the basis of this analysis: representation, public participation, and financial capacity. The author first analyzed the Hansard transcripts on the debates on the Clean Water Act, in order to identify the issues and concerns that were raised by Members of Provincial Parliament (MPPs) relating to these factors, and to examine how the legislation was formulated to include these factors in its collaborative mandate. This analysis revealed that elected officials appeared to view these factors as being important for the success of the program, and that in the end, the legislation was strengthened in terms of its collaborative governance elements, at least on paper. The author then conducted a second directed content analysis of the meeting minutes of three source protection committees across the province, to identify how these committees experienced representation, public participation, and financial capacity throughout their respective collaborative processes. This analysis revealed that some of the elements of the legislated process of collaboration, to which the committees were bound, appeared to exacerbate or in some cases lead to fundamental issues throughout the SWP planning processes. This led the author to ultimately question how much authority was delegated to these committees in actuality in order to carry out SWP on the ground, and thus how truly collaborative and “from the ground up” this program was truly intended to be. The findings suggest that greater attention should be paid in future research to the potential implications of particular design features of mandated forms of collaboration on the ability of collaborative organizations to meet their objectives, particularly when collaborative water governance is transplanted to other contexts.

Authoritative, top-down forms of environmental governance are presently giving way to more collaborative approaches in which decision making is an ongoing negotiation between government and non-government actors. There is growing consensus that critical environmental concerns—such as contamination of drinking water—relate as much to political, economic and social issues, as to technical and scientific issues. As the trend toward collaborative environmental governance continues, and as science-based knowledge increasingly shares a role in decision-making processes with more “local”, non-scientific knowledge, questions arise concerning how diverse knowledge contributions are understood and engaged in these governance processes. This research explored the relationships between knowledge and collaborative environmental governance processes. The purpose of the research was to identify (1) types of knowledge that individual actors bring into collaborative governance pertaining to water resource protection, (2) uses of that knowledge, and (3) features of collaborative processes that affect the engagement of actor knowledge. Collaborative water governance in New Brunswick provided the context for the research. Most actors did not see a definitive distinction between “expert”, scientific and “local”, non-scientific knowledge; they considered both to be important contributions. Nonetheless, science-based knowledge, especially natural science, was found to be a predominant knowledge type among actors involved in collaborative water governance. Science-based, expert knowledge was more readily used than local knowledge types in the various stages of collaborative governance. Leadership and the definition of actor roles were considered paramount for engaging a wide range of knowledge types in collaborative governance processes.

Source Water Protection (SWP) is recognized as the first barrier in the multi-barrier approach to reduce the risk of drinking water contamination. In Canada, provincial water agencies and municipalities lead most of the water management responsibility based on provincial regulations. However, SWP planning and implementation is variable across jurisdictions and influenced by different factors related to local capacity. Much of the water resources literature is focused on capacity-building limitations faced by small and rural water system operators. The purpose of this research is to investigate capacity-building limitations faced by metropolitan water system operators. Information from a questionnaire and document review in four selected Canadian metropolitan areas was gathered and analysed in this study. The results of this study show variability of SWP planning uptake as well as variability in approach toward SWP implementation. While large metropolitan areas may appear to possess ready access to financial capital, technical capability, and other forms of capacity to undertake SWP, the results of this research indicate the opposite. Metropolitan areas in Canada remain reliant on advanced water treatment and other engineering solutions to provide safe drinking water as opposed to SWP planning that invests in preventative measures through land use planning mechanisms. The results of this research contribute to the knowledge and understanding of SWP particularly as applied to metropolitan Canada.

Authoritative, top-down forms of environmental governance are presently giving way to more collaborative approaches in which decision making is an ongoing negotiation between government and non-government actors. There is growing consensus that critical environmental concerns—such as contamination of drinking water—relate as much to political, economic and social issues, as to technical and scientific issues. As the trend toward collaborative environmental governance continues, and as science-based knowledge increasingly shares a role in decision-making processes with more “local”, non-scientific knowledge, questions arise concerning how diverse knowledge contributions are understood and engaged in these governance processes. This research explored the relationships between knowledge and collaborative environmental governance processes. The purpose of the research was to identify (1) types of knowledge that individual actors bring into collaborative governance pertaining to water resource protection, (2) uses of that knowledge, and (3) features of collaborative processes that affect the engagement of actor knowledge. Collaborative water governance in New Brunswick provided the context for the research. Most actors did not see a definitive distinction between “expert”, scientific and “local”, non-scientific knowledge; they considered both to be important contributions. Nonetheless, science-based knowledge, especially natural science, was found to be a predominant knowledge type among actors involved in collaborative water governance. Science-based, expert knowledge was more readily used than local knowledge types in the various stages of collaborative governance. Leadership and the definition of actor roles were considered paramount for engaging a wide range of knowledge types in collaborative governance processes.