Utilidor Replacement – Rankin Inlet, NU

Rankin Inlet is an isolated Nunavut community located on the west coast of Hudson Bay with a rare Arctic water and sewer system built in the 1970’s that is dealing with age-related and environmental deterioration. The Government of Nunavut engaged Dillon Consulting Limited to design system-wide upgrades to mitigate contamination risks, improve reliability, and increase capacity. These solutions leveraged unique Arctic design principles and remote capture technology to deliver upgrades in the challenging construction environment.

Entrusted by the Government of Nunavut (GN), Dillon’s mandate encompasses capital planning, risk management, design, construction administration, and advisory services aimed at resolving critical water and wastewater infrastructure challenges.

The Utilidor, a network of buried water/sewer mains with associated pumping facilities dating back to the 1970s, serves an isolated community situated 300 km north of Churchill. While the system has expanded over the years, many of its original components are still in use. Operations are further complicated by permafrost, necessitating continuous recirculation and heating to prevent freezing along with robust components such as insulated steel manholes which present their own unique operational and maintenance challenges.

The community faced several problems, including groundwater infiltration of wetwells, risks of cross-contamination within combined manholes, insufficient fire flow and water pressure due to tuberculation, and overcapacity within pumping systems.

Dillon undertook a comprehensive evaluation and risk assessment of the infrastructure, identifying upgrades for critical short-term failures and long-term expansion requirements. This entailed extensive financial projections and lifecycle analyses to determine optimal timelines, considering risks associated with a restricted contractor base, exorbitant material transport expenses, and unique stakeholder considerations in the remote Inuit community.

From this assessment, a series of expedited work packages were devised to address the major risks. Given Rankin Inlet’s isolated location, accessible only by air and limited sealifts, project execution was complicated by logistical challenges, a short 4-month construction window, and the scarcity of skilled labor, equipment, and accommodations. Executing such a project in a remote location within accelerated timelines demanded innovative approaches.

Advanced technology was harnessed throughout the project lifecycle to maximize the limited site access. Dillon utilized 360 scans to create immersive digital walkthroughs of facilities, allowing for live collaboration with the Canada-wide client and design team. Community-wide scans using drone LIDAR and photogrammetry expediting the design process and substituted lack of accurate records.

Creative engineering solutions were developed which included:

• Below-grade pump/wetwell replacement with an at-grade system within the existing building footprint while tying into an obsolete PLC system and aged pipes
• Design of innovative partitioned water/sewer manholes to prevent cross-contamination,
• Water main design improvements to mitigate tuberculation, heat loss, and dynamic settlement, and
• Implementation of in-situ steel manhole refurbishment as opposed to typical replacement for greater cost efficiencies and waste reduction.

Dillon’s pioneering approach in the Utilidor Replacement Program establishes a blueprint for future water and wastewater endeavors in challenging Arctic environments.

Awards

• Award of Excellence, Association of Consulting Engineering Companies Canada, 2024

Project Details

Project Partner: Government of Nunavut
Business Unit: Community Planning & Infrastructure
Service Offering: Linear Infrastructure