Parts 1 and 2 of this case study offered a detailed summary of wet weather inflow and infiltration (I/I) reduction pilot projects undertaken by Civica for the City of Toronto. Part 2 specifically delved into technical, financial, and SWOT analyses. Part 3 will address the project management strategy and sewer capacity analysis, concluding with recommendations for future strategic planning of wastewater management in the City.
Project Management and Sewer Capacity Analysis
Project Management Strategy
Contracting and Procurement
The City of Toronto was advised to conduct a comprehensive audit on City-level water I/I using the existing sewer flow monitoring data. Key performance indicators (KPIs) mentioned in the below Sewer Capacity Management section would help identify and rank where efforts to minimize I/I should be concentrated. For the most efficient results, prioritizing areas for I/I reduction was suggested before any studies began. This strategic approach would maximize the City’s return on investment by first addressing locations with the greatest potential for I/I reduction. To manage this process, the City would be divided into manageable areas of about 200 hectares each. Those areas showing the highest I/I rates could be broken down further for a more detailed I/I reduction investigation, into smaller sections of roughly 50 hectares. It was recommended that the City follow a transparent public bidding process for contracting services related to the investigation, remedy, and assessment of I/I issues.Example I/I Prioritization for City of Toronto
Implementation Plan
The City’s I/I program was designed in three key stages: Phase 1: I/I Investigation and Quantification:
Project management
Pre-repair water flow monitoring
Identifying I/I sources with field tests (e.g., smoke, dye testing, CCTV during rain)
Ongoing project monitoring
Comprehensive reporting
Phase 2: I/I Source Remediation (Construction):
Consulting for remediation planning (includes design, stakeholder interaction, and construction oversight)
Approved construction team roster for various I/I repairs
Phase 3: Verification of I/I Reduction:
Post-repair flow monitoring
Hydraulic model updates and calibration
Phase 2 would utilize a pre-qualification process to ensure a roster of competent contractors for I/I repair needs as they arose.
Schedule and Approach
To identify and tackle I/I sources effectively, shifting to a proactive “find and fix” method was proposed. By merging phases 1 and 2 and prioritizing swift identification and repair, the City would focus on easily correctable problems like residential downspouts, catch basins, and pipe defects using tried-and-true techniques, such as smoke, dye testing, and CCTV. This strategy would eliminate repetitive tendering by utilizing a pre-approved construction list for immediate repairs. Constant measuring of flow rates before and after fixes would ensure the actions are making a difference. If required, further scrutiny using advanced methods could follow to pinpoint any remaining concerns. This streamlined process would boost efficiency and stretch every dollar further in I/I reduction efforts.
Sewer Capacity Management
Key Performance Indicators (KPIs)
KPIs are essential for measuring the success and guiding the efficiency of both existing and future municipal I/I projects. Relevant KPIs include I/I reduction quantification (peak flow and % reduction), cost-effectiveness, time effectiveness, and resident participation. Based on the results from specific areas like Wirral Court and Area 9, the KPIs would be refined to meet the goals of each unique project. The City would then utilize these KPIs to compare projects, pinpoint effective strategies, and identify the best areas for future initiatives. Ultimately, these insights help prioritize investment in projects that deliver the greatest benefits while enjoying strong community support.
Numerical Modelling
Effective management of water systems starts with tracking I/I rates. Utilizing upcoming data and a refined numerical model allows for better quantification of I/I changes. This model sharpens with each data update, allowing the City to assess and hone the impact of repair strategies, such as disconnecting foundation drains or sealing points of entry. With the May 12, 2000 event, for instance, flow rates were compared under different scenarios—before and after hypothesized I/I repairs and against the City’s standards in Area 9—to gauge the effectiveness of interventions. Implementing this approach helped in monitoring the improvements in service from I/I mitigation and informing any further action that might be required to meet objectives.Modelled Flow Conditions – May 12, 2000
I/I Rate Linear Regression Tool
Linear regression analysis is a straightforward and cost-effective method to measure the success of efforts aimed at reducing I/I rates in sewer systems. By comparing the I/I rate—measured in liters per second per hectare (L/s/ha)—to the peak rainfall intensities, the City can see how well rehabilitation projects are performing. For example, on May 12, 2000, the baseline I/I rate in the study area was recorded at 1.16 L/s/ha. However, with planned remedial actions, the aim was to reduce this significantly to 0.53 L/s/ha—more than a 50% decrease in the peak flow rate. Achieving this target would be a sign of a successful intervention, and the flow rates during rain events would continue to be tracked to ensure they align with expectations. As progress was made and the I/I rates dropped, models would be refined to better understand the improvements and plan future steps.Wirral Court Existing vs Target I&I Projections
Stakeholder Engagement Strategy
Engaging with stakeholders is crucial for successful I/I source remediation work. This involves regular updates, direct answers to resident queries, and securing agreements from property owners for work on their land. The preferred approach was face-to-face interactions to build trust, ensuring property owners were directly involved and satisfied with the outcomes. A strong relationship and transparent communication would help aid the process, meeting everyone’s expectations.
Identify Program Stakeholders
To initiate private remediation efforts, it is essential to recognize and confer with all parties involved. For the project, this included the property owner, Toronto Water, engineering teams, the assigned contractor, consultants, and regulatory bodies.
Engagement Mediums
Several engaging methods of outreach were suggested to connect with various groups:
Implementing a dynamic media campaign with radio segments, newspaper articles, and effective use of PR to bring about upbeat media attention.
Creating and sharing informative resources such as brochures, newsletters, and detailed fact sheets. These could be distributed directly to individuals or posted online for easy access.
Produce short, understandable videos that break down the technical aspects of the project for everyone’s benefit.
Organizing meetings and workshops with city departments and community groups to gather valuable feedback and refine our strategic plans.
Hosting public events to inform the community about the project’s developments.
Actively using social media platforms like X (formerly Twitter) and Facebook to share progress updates, tackle issues, and guide followers to the project’s website for further information.
Providing consistent updates to City Council members and high-ranking staff to ensure they are well-informed about the project’s achievements and milestones.
Property Owner Participation
Voluntary participation in the I/I reduction program fosters a collaborative spirit between the City and property owners, enhancing the program’s appeal and encouraging more owners to join. Offering I/I source disconnection work without cost is a compelling incentive that benefits and motivates homeowners. Based on Civica’s success and practices of Southern Ontario municipalities like the City of London and Halton Region, effective engagement strategies are crucial. By diversifying communication channels, the Toronto program would gain visibility, and ongoing dialogues with property owners would ensure smooth execution, especially during necessary disconnection activities. A detailed tracking database for participating and non-participating property owners would allow the City to monitor progress and maintain updated records through the course of future I/I reduction endeavours.
Recommendations for Future City Planning
The City gained insights into the impact of I/I from private properties on its wastewater systems. To improve future planning, the following measures were recommended for adoption:
Establish a Toronto-Focused I/I Reduction Program: This initiative will zero in on reducing unnecessary water entering wastewater systems specifically at Wirral Court and Area 9.
Perform a City-Wide Wastewater Audit: Use flow and rainfall data coupled with performance metrics to identify and prioritize critical catchment areas needing I/I reduction.
Engage Stakeholders Effectively: An extensive engagement program should accompany the rollout of I/I reduction initiatives, continuing through all phases of implementation.
Develop a Comprehensive I/I Reduction Strategy: Implement voluntary programs that incentivize property owners to disconnect I/I sources, enhancing collaboration and program success.
Evaluate Program Outcomes: Analyze data before and after I/I remediation to assess the effectiveness of efforts and adjust strategies accordingly.
Strategize Based on Pilot Projects: Formulate a City-wide I/I strategy, selecting priority zones for immediate and future action based on lessons learned from pilot projects.
Through these recommendations, the City would reduce the burden on its wastewater systems and move towards more sustainable water management.
