Albro Lakes Combined Sewer Separation
Adam Sketchley (DesignPoint Engineering & Surveying Ltd.)

In 2020, Halifax Water hired DesignPoint to complete design of a sewer separation in Dartmouth, Nova Scotia. The combined sewer in question received upstream combined flow as well as the discharge from three lakes: Albro Lake, Little Albro Lake, and Martin Lake. The existing combined sewer ranged in size from 1,050 mm to 1,500 mm and was located along existing public streets. The combined sewer terminated at a Combined Sewer Overflow CSO chamber on Jamieson Street. During periods of high flow, the CSO chamber opens, allowing combined overflow to bypass the adjacent lift station and downstream treatment plant.

This separation project was highlighted in Halifax Wateres Infrastructure Master Plan as an opportunity to both reduce combined sewer overflows and to provide wastewater capacity to facilitate development in a targeted growth node in Dartmouth.

Stormwater and wastewater modelling was completed in Infoworks ICM for both existing conditions and future conditions, accounting for population growth and climate change. Stormwater catchments were developed and included potential future separation areas. The goal was to provide a trunk storm sewer which could facilitate future separations in the area.

An options analysis was completed, considering installing a new storm sewer or installing a combined sewer and converting the existing combined to a storm sewer. It was decided to install a new combined sewer and convert the existing combined to a storm sewer. Based on the modelled flows, design of the combined sewer was completed. The design included a culvert crossing CN tracks, with capacity for both the newly piped storm sewer and overland drainage.

Following design, the project was tendered, with construction completion in 2023.