The Memorial West Trenchless Sewer Upgrade (MWTSU) represents the City of Vancouver’s first pilot application of micro tunnelling technology for sewer renewal, combined with trenchless rehabilitation of existing infrastructure beneath a major urban park. The project addressed aging combined sewer infrastructure beneath Memorial West Park while limiting impacts to a highly valued public space in the Dunbar neighbourhood.

Rather than relying on conventional open cut excavation, the City elected to pilot a trenchless approach using a micro tunnel boring machine (MTBM) to install a new concrete storm sewer main beneath the park’s primary pedestrian corridor. In parallel, the existing combined sewer was rehabilitated using slip lining, where a smaller pipe was inserted and fixed in place with grout to extend the service life of the aging infrastructure without extensive excavation.

In its public announcement, the City highlighted that the successful tunnel installation and rehabilitation demonstrated the potential for trenchless methods to preserve mature trees, keep much of the park accessible, reduce impacts to nearby residents, and shorten the construction period. GHD provided preliminary design review, detailed design, and construction phase services, supporting delivery of this precedent-setting pilot project.

The project team evaluated traditional open‑cut construction alongside trenchless alternatives and supported the City’s decision to pilot a combined micro‑tunnelling and slip‑lining approach due to the sensitivity of Memorial West Park. This integrated strategy allowed new storm infrastructure to be installed while rehabilitating existing combined sewers, all with minimal surface disturbance.

Micro‑tunnelling was used to construct a new storm sewer main beneath the park’s central pathway, while slip‑lining was applied to the existing combined sewer to extend its service life and support long‑term sewer separation objectives. The approach reduced excavation requirements and limited disruption to trees, park amenities, and surrounding residents.

The design and construction planning process integrated geotechnical, arborist, environmental, archaeological, and stakeholder considerations. During construction, GHD provided technical and construction‑phase support to address site‑specific challenges typical of trenchless installations in constrained urban environments.

The project delivered a separated sewer system beneath Memorial West Park through the City’s first pilot use of micro‑tunnelling combined with trenchless rehabilitation by slip‑lining. The integrated approach preserved mature trees, reduced surface disruption, extended the life of existing infrastructure, and established a precedent for future utility projects in sensitive urban settings.