ISSUE 18

Development of an interdisciplinary water risk assessment framework: The state of Ontario’s watersheds

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Jason T
Jason Thistlethwaite
School of Environment, Enterprise and Development

Guneet
Guneet Sandhu
School of Environment, Enterprise and Development

Introduction

Water is a complex resource that provides critical social, economic, cultural and ecological functions that support human wellbeing, economic development and environmental sustainability. These functions are increasingly at risk due to factors, often exacerbated by climate change, that affect the availability, quality and accessibility of water over time and space. As risk influences a system's ability to respond and adapt, risk assessment and analysis is a central component of sustainable water management. While academic, policy and practitioner interest water risk assessment are growing, there remains a gap for systems-based, social-ecological frameworks.

The Province of Ontario, Canada is often perceived as water abundant, but does have local water challenges. The objective of this Ontario case study was to develop and apply an interdisciplinary water risk assessment framework using quantitative and qualitative water risk data at the subwatershed scale to inform sustainable water management decisions, policies, and practices. In addition, it was hoped that the study framework could be methodologically generalized as a model for other geographical regions.

Methodology

The study developed a theoretical framework to integrate biophysical and social variables (Figure 1) for water risk assessment and management. The assessment stage of the framework was then applied to 38 subwatersheds in Ontario (Figure 2) using two stage secondary quantitative and qualitative data analysis.

Figure 1 framework

Figure 1: Framework for water risk assessment and management

Study subwatersheds in Ontario, Canada

Figure 2: Study subwatersheds in Ontario, Canada

Six water risk indicator databases were developed for each subwatershed based on secondary data. The selection of sub-indicators was conceptually informed by the literature and theoretical framework (Table 1). In the second stage, sub-indicators were measured in categorical values on a binary scale of Yes/No, ordinal scales such as High/Moderate/Low or counts. Categorical values were converted into numerical values before aggregating cumulative risk scores. Scores were then converted to differentiated risk ratings for each subwatershed or sector.

Table 1: Water risk indicators and sub indicators

Risk Indicators	Risk Sub-indicators
Biophysical Water Quantity Risk	Identification of subwatersheds under “high” and “moderate” surface water and groundwater stress.
Biophysical Water Quality Risk	Identification of subwatersheds under “very poor,” “marginal,” and “fair” surface water quality based on monitored biophysical parameters. Moderate-high aquifer vulnerability to contamination. Active and suspected legacy contaminated sites. Identification of chronic subwatershed wide water quality issues.
Regulatory Trends	Identification of relevant Federal and Provincial water management laws, regulations, policies, and agreements. Amendments to extant water laws and regulations that indicate increasing stringency and evolving changes. Prevalence of regulatory risk drivers that pose risk to water-use sectors Identification of authority level, municipalities, subwatersheds, and sectors in water-related laws, regulations, and policies.
Public concern and perception of water issues and news media coverage	Identification of public concern and perception. Prevalence of water-related campaigns and initiatives by NGOs or citizen-led groups. Identification of water issues covered in the news media.
Water-user conflict potential and legacy access issues	Potential for conflict based on density or spatial concentration/clusters of permit to take water holders, past low flow conditions, high population and economic growth regions and public and media attention. Prevalence of in-effect or lifted long-term and/or in-effect short-term drinking water advisories.
Sector-specific risk assessment	Identification of sector-specific impacts based on nature of water use and effluent discharge. Identification of “High”, Moderate,” “Low” focus of specific sectors in the public concern and media coverage database.

Outcomes

The study found that 50% and 66% of the investigated subwatersheds had at least one quaternary watershed at high and moderate surface water quantity stress respectively, while 55% and 63% had at least one quaternary watershed at high and moderate groundwater quantity stress respectively. The analysis found 63% of the subwatersheds had a very high and high water quality risk rating (Figure 3).

Cumulative water quality risk ratings

Figure 3: Cumulative water quality risk ratings

The study found that all 12 regulatory risk drivers were present, 33% at high prevalence and 67% at moderate prevalence, in the Provincial and Federal water management framework (Table 2).

Table 2. Regulatory trend assessment results

Prevalence rating	Regulatory risk drivers
High prevalence	Consideration for the environment (allocation, extraction). Implications for effluent treatment/management costs. More stringent regulatory standards. Regulatory uncertainty due to ongoing amendments.
Moderate prevalence	Increased difficulty in obtaining water withdrawal/operations permit. Subwatershed based water management. Possibility of short-term or long-term changes to water withdrawal limits/monitoring. Potential Impact from evolving laws and rights like UNDRIP. Regulation of discharge quality/volumes. Requirements for permits, extraction charges, monitoring and reporting. Violations resulting in fines, enforcement orders and/or penalties. Water efficiency, conservation, recycling or process requirement.
Low prevalence	Nil

Eighty-two percent of the subwatersheds were found to be at very high and high conflict potential (Figure 4). Out of 70 water-using sectors, 50% were found to be at very high and high risk, 31% at moderate risk and 19% at low and very low risk (Table 3).

Water-related conflict potential ratings

Figure 4: Water-related conflict potential ratings

Table 3. Results of sector-specific water risk assessment

Risk and Impact Rating	Water using sectors
Very high	Aggregate Commercial golf courses Manufacturing (ie, water bottling; concrete, non-metallic mineral, agricultural chemicals) Mining, Oil and gas extraction
High	Agriculture Commercial snow making Dams and reservoirs (other than power production) Manufacturing (ie, food and beverage, primary metal, pulp and paper, wood, petroleum and coal, plastics and rubber, fabricated metal, computer and electronics, transportation equipment, furniture) Pipeline testing Power production, thermoelectric (including nuclear), hydroelectric
Moderate	Commercial (ie, aquaculture, mall/business) Construction dewatering Livestock Manufacturing (ie, textile, leather, machinery) Recreation Remediation Wind Power Production Water supply

Based on a thematic analysis of news media coverage, key water issues included:

Unsafe drinking water in First Nations communities;
Great Lakes water quality issues and protection initiatives;
Regulatory changes and water governance issues;
Potential negative impacts from industrial extraction/discharge and oil pipelines;
Nuclear waste burial;
Droughts and low flow conditions;
Groundwater management issues (i.e., quantity and contamination);
Intra-basin and inter-basin bulk water transfer pipelines;
Privatization and commoditization of water;
Overarching threats to water security (e.g., climate change, population growth, urban development);
Infrastructure issues (e.g., lead, leaky pipes, insufficient wastewater treatment, combined sewer outflows).

Conclusions

The study advanced water risk assessment by applying social-ecological perspectives, interdisciplinary approaches to risk theory and mixed methods to provide a comprehensive evaluation of water security. The study revealed multiple hotspots for biophysical and social risk categories across the Great Lakes watershed. Results indicated that while water quantity stress varies across Ontario, water security risks tend to be equally driven by the multidimensional aspects of water quality, regulatory stringency and public perception. The study suggested that, considering all risk indicators, the overall water security risk for a subwatershed can deviate from those indicated by highly aggregated assessments.

The study found high and moderate risk potential in at least 50% of the investigated subwatersheds under all water risk categories, empirically challenging the myth of water abundance in the Great Lakes watershed in Ontario. The interdisciplinary water risk assessment framework developed can help integrate water risks in multisector decisions, policies, and practices supporting a more water secure and climate-resilient society and economy. While spatially scoped to populous subwatersheds of Ontario, this framework can be methodologically generalized to other geographical regions by using local data.