West Coaldale Sanitary Trunk Main Extention Project

What?

The West Coaldale Sanitary Trunk Main Extension Project is a major underground infrastructure project focused on extending and upgrading Coaldale’s sanitary sewer network in west and southwest Coaldale. 

Why?

In 2017, the Town of Coaldale annexed approximately 1,420 acres (574.5 hectares) from Lethbridge County to accommodate projected growth over the next 25 years. The annexation was necessary because the Town’s previous boundaries offered a limited supply of developable land, and additional land was required to support long-term residential, commercial, and industrial needs.

Planning documents associated with the annexation projected that Coaldale’s population could more than double by 2041—from approximately 8,500 residents to over 15,700. The annexation area was planned with a balanced land-use mix, including:

• approximately 939 acres designated for future residential development (primarily on the west and southwest sides of town);
• 173 acres allocated for commercial growth adjacent to Highway 3;
• 144 acres set aside for industrial use on the north side; and
• 202 acres reserved for public use, including parks, on the north and northwest sides.

To service these growth areas, the Town needs to extend and upgrade its sanitary trunk main network to facilitate new development. Coaldale’s topography generally slopes from southwest to northeast, which allows the west growth area to be serviced largely by gravity sewer. This is a significant technical and financial advantage because it reduces (or avoids) the need for an additional sanitary lift station, which would otherwise require substantial capital investment and ongoing operating costs supported by taxpayers.

Following annexation, the Town completed an Infrastructure Master Plan in 2019, which provided high-level recommendations for how to extend servicing into the newly acquired lands. Based on these recommendations, the Town then completed a West Coaldale Trunk Main Preliminary Design Study in 2021 to determine the optimal alignment, pipe sizing, and slope needed to service the west side growth area.

Key technical considerations in the design work included:

• Optimal alignment to serve both new growth areas and existing customers, while supporting asset management objectives and coordinating with other planned capital projects;
• Appropriate pipe sizing for long-term capacity while avoiding oversizing of gravity mains, which can lead to operational challenges (e.g., low-flow conditions and flushing/maintenance issues); and
• Optimal slope and hydraulic performance to maintain effective gravity flow and avoid the need for a new lift station, which carries significant capital and lifecycle operating costs.

When?

2025 Construction Phase (complete)

Work completed in 2025 focused on the Highway 845 corridor between 14 Avenue and 16 Avenue and included:

• Highway 845 crossing at 14 Avenue using trenchless (auger bore) installation to minimize disruption and avoid major traffic impacts.
• Installation of approximately 350 m of 600 mm sanitary trunk main along the west side of Highway 845 between 14 Avenue and 16 Avenue, including tie-ins to the existing system.
• Weather permitting, installation of a 2.5 m gravel pathway in the same corridor, with asphalt surfacing planned for Spring 2026.
• Work was designed to avoid major highway impacts, with only short-term disruption near tie-ins.

2026 Construction Phase (planned)

In 2026, work will shift to 16 Avenue from Highway 845 to 23 Street. Construction is anticipated to occur July–September 2026, with overall completion anticipated in September 2026. Work is expected to include:

• Upsizing the existing sanitary sewer along 16 Avenue to a 600 mm main.
• Connecting/tie-in of service lines for existing residential properties along 16 Avenue.
• Stormwater improvements through extended underground storm infrastructure to improve stormwater collection along the corridor.
• Full road restoration, including restoration of road base and asphalt, with replacement of damaged sidewalks/curbs on an as-needed basis.
• Construction of approximately 615 m of new asphalt pathway along the north side of 16 Avenue to create a continuous connection from the Kin Picnic Shelter to the Rehoboth Garden Centre, including pathway connections tying into the Highway 845 corridor.
• Residents should expect longer-term traffic disruptions on 16 Avenue. The contractor will provide advance notifications and temporary local access arrangements during construction.

A public open house and information session is scheduled for Thursday, March 12, 2026, in the Civic Square Atrium (1801 20 Avenue). The presentation begins at 6:30 p.m., with Town staff available for discussion from 6:30–8:30 p.m.

Thank You for Your Patience

The Town appreciates residents’ patience and cooperation. This work is a foundational investment in Coaldale’s future, supporting growth, improving reliability, and ensuring our underground infrastructure can meet the community’s long-term needs.