Mill Creek trunk rehabilitation

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Project overview
Timelines
What to expect during construction
Causes of possible schedule delays

The Mill Creek combined sewer trunks carry wastewater from a large part of south Edmonton towards the Gold Bar Wastewater Treatment Plant, and also convey rainwater and snowmelt from some of Edmonton’s older south side neighborhoods. This line services approximately 58,000 sanitary connections in south Edmonton. Segments of the combined sewer trunk have been observed to be in very poor condition.

Inspections have identified that the existing tunnel running through the Ritchie and Old Strathcona neighborhoods, as well as under the Mill Creek Ravine, requires replacement to ensure it continues to reliably meet the needs for south Edmonton.

The project began in mid-March 2023 and is expected to be completed in summer 2026.

Map of Mill Creek with coloured lines indicating where the new tunnel construction will take place, as well as sewer redirect and trunk decommissioning.

Project overview

The Mill Creek combined trunks carry wastewater from a large part of south Edmonton towards the Gold Bar Wastewater Treatment Plant, and also convey stormwater and snowmelt from some of Edmonton’s older south side neighbourhoods. This line services approximately 58,000 sanitary connections in south Edmonton.

The Mill Creek combined trunk services the Edmonton region highlighted on the map.

In 2020, crews had identified large holes in the trunk as well as a deteriorated manhole. An emergency repair was completed in Mill Creek Ravine, which involved impacts to the trail system, tree removal and heavy equipment being transported and utilized on site.

Further inspections were completed to evaluate the remainder of the trunk’s condition. Due to the poor condition and location of the line, a new trunk was needed to replace the existing trunk and ensure the system continues to reliably meet the needs of the City of Edmonton. Once the new trunk has been constructed, a portion of the existing trunk in Mill Creek Ravine will be abandoned.

The selected alignment of the new trunk is located outside of Mill Creek Ravine. The completion of the new trunk will help reduce the risk of significant environmental impacts to the ravine in the event of a trunk failure.

Timelines

This project will be completed in three stages; work began in March 2023 on Stage One and we estimate the entire project will be finished in summer 2026.

Please note that these timelines are estimates and are pending approvals, material procurement/availability, construction conditions and weather.

Stage one construction (complete)

Mid-March 2023 to mid-2025

During Stage One of the project, crews constructed a 30-meter deep shaft at Worksite #1 for the tunnel boring machine (TBM), which was used for the construction of the new tunnel. A retrieval shaft in was constructed at Worksite #2 in Tubby Bateman Park. Construction of the new tunnel is now complete.

Stage two construction (complete)

Summer 2025 to fall 2025

Crews completed open-trench work along 80 Avenue, between 96 Street and 97 Street, to connect the existing sewer to the new trunk.

Stage three construction

December 2025 to summer 2026

Stage Three construction began in early December 2025, including decommissioning of the old sanitary trunk that previously served the local network. This work was completed in two phases.

Phase one - access shaft construction

Crews constructed a 20-metre-deep access shaft into the old sanitary trunk, as there was insufficient space for crews and equipment to safely access through the existing manhole. A portion of 80 Avenue west of 97 Street was closed to accommodate the shaft location.

Shaft construction was completed in mid-February 2026. Once the access shaft was complete, crews began Phase Two to decommission the old sewer.

Phase two - sewer decommissioning

Crews began sewer decommissioning in late February 2026. This work involved redirecting the remaining sanitary flows into the newly constructed sanitary tunnel and filling the old sewer line with concrete by pouring through designated manholes.

This phase was completed in the first week of May 2026.

Current work – site restoration

Crews are currently completing permanent pavement and landscaping restorations in areas affected by construction, returning streets, sidewalks, and green spaces to their original condition.

Restoration activities include reinstating laydown areas with topsoil and sod, reinstalling fencing, repairing sidewalks and other features removed during construction, and completing permanent roadwork at key locations along 80 Avenue, including the intersections at 96 Street and 97 Street.

Work is being completed in phases to reduce traffic disruption, with only one intersection closed at a time. Restoration began in mid-May 2026 and is expected to continue through the end of July 2026. Some restored green spaces, such as the Mill Creek School laydown area, may remain closed for an extended period to allow grass to establish.

Further notification will be provided if needed and will include any updates on traffic impacts, timelines, and schedules.

Please note, timelines are estimates and may change based on weather, progress, and construction conditions.

Community disruption

EPCOR will work with residents to understand individual impacts related to this work, such as garbage pick-up, accessibility issues, and other needs. We will work to determine mitigations on a case-by-case basis.

What to expect during construction

A generator and frost heater, used to prevent freezing inside the shaft overnight, will be running continuously. Residents may experience general noise from the construction and equipment used for material delivery, excavation, soil removal, and surface restoration.

Residents may experience sewer odours once the shaft is connected to the sanitary tunnel.

Detours will be created for any sidewalk/pedestrian crossing closures.

Lighting structures will be place low within the worksite to minimize light from spilling outside the worksite.

As the construction is in close proximity to Mill Creek School, the site will use secure fencing and site hoarding material to block visibility and deter activity around the site.

Worksite #1 will remain in use during Stage Three construction. Once construction is complete, the greenspace will be sodded and the soccer posts returned to their original locations. The field will remain closed to the public until the landscaping establishes and will reopen once it passes final inspections from the City of Edmonton.

Typical hours of work will be from 7:00 a.m. to 7:00 p.m., Monday to Saturday. If required, these hours may be extended, and construction may occur on Sundays from 9:00 a.m. to 5:00 p.m.

Causes of possible schedule delays

While we always do our best to plan construction and abide by construction timelines communicated to the public, unexpected events can potentially occur which may delay the schedule.

Questions?

Your questions are important to us.

Contact EPCOR

Phone: 780-412-4200
Email: epcorprojects@epcor.com

Mill Creek trunk rehabilitation

Project overview

Project background

Project importance

Timelines

Stage one construction (complete)

Background

Stage two construction (complete)

Background

Stage three construction

Background

Impacts

​What to expect during construction

Noise c​ontrol

Odour

Sidewalks/walkways/pedestrian crossings

Light poll​ution

Worksite s​ecurity

Laydown area

Working hours

​Causes of ​​possible schedule delays

What to expect during construction

Causes of possible schedule delays