District of North Vancouver Evergreen Flume Replacement

The District of North Vancouver retained Water Street Engineering to design the replacement of a deteriorating 1960s wood-stave flume with a modern storm sewer system and upgrade adjacent sanitary and water utilities along Evergreen Place. The existing flume had reached the end of its service life, presented structural and hydraulic limitations, and required an accelerated design schedule to meet construction timelines.

The project scope included:

• 418 meters of new storm sewer,
• 91 meters of sanitary sewer replacement, and
• 440 meters of watermain upgrades.

Key technical challenges included steep slopes that required extra stability measures, energy dissipation for high velocity flow, limited utility separation, and an environmentally sensitive connection to Thain Creek.

The final design was developed in close collaboration with the District and was informed by detailed hydraulic modelling, geotechnical investigations, structural analysis at the headwall connection, and arborist input on tree preservation.

Construction challenges included contaminated soils, tight timelines, utility conflicts, and a significant storm event. The project’s location near two schools necessitated strict schedule adherence to reduce disruptions. The team met these challenges and successfully delivered a cost-effectve, resilient, and environmentally responsible infrastructure upgrade on schedule.