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Tuesday, Dec 05, 2017

Phasing construction of 37th Street storm trunk sewer helps meet schedule for Southwest Ring Road project in Calgary

37th Street Storm Trunk


As part of the Calgary Southwest Ring Road project, Alberta Transportation needed to construct a new stormwater management trunk sewer within the 37 Street SW right-of-way, south of Lakeview Drive SW with a new outfall to the Glenmore Reservoir / Elbow River, to replace the existing storm trunk that crosses the Tsuut’ina Nation Lands. 

To meet Alberta Transportation’s schedule and in collaboration with the City, Associated Engineering as the Prime Consultant, proposed to divide the project into two phases. This approach met Alberta Transportation’s schedule and allowed the City and Associated Engineering to perform their due diligence by conducting the necessary environmental assessments in the park area. These included a biophysical impact assessment and fish habitat assessment. 

Contract 1, the northern portion of the project, comprised 1.4 kilometres of 2400 millimetre diameter trunk sewer from Lakeview Drive to 66 Avenue. Contract 2 spans from 66 Avenue through North Glenmore Park to the Glenmore Reservoir.   

Project Manager, Nadeer Lalji, tells us,  “The storm trunk was installed through a combination of tunnelling and open cut methodologies.”  To limit tunnelling construction to specialized, qualified contractors with relevant experience, Associated Engineering pre-qualified tunnelling and microtunnelling contractors, and incorporated this list of qualified contractors in the tender documents.   

The City also requested the stormwater to be treated prior to discharge to the river.  The project team investigated several treatment options at various locations. These included source control practices, such as bioretention, mechanical treatment, and stormwater ponds. 

Nadeer says, “After evaluating these options using a triple bottom line analysis considering the economic, social, and environmental impacts, we recommended an oil-grit separator and a new stormwater pond in North Glenmore Park.” 

Construction for Contract 1 began in mid-August 2015 and was substantially completed by the end of 2015, well ahead of the mid-2016 deadline. The storm trunk in Contract 1 was installed by microtunnelling and open-cut excavation. At the time of construction, this was the largest microtunnelling installation in Calgary. Contract 1 was located close to the community of Lakeview. Associated Engineering conducted extensive public engagement, including mail-outs, open houses, community association meetings, phone calls, and online weekly blog updates during construction to keep stakeholders informed. During construction, noise testing was conducted to confirm acceptable levels of noise. 

Contract 2 includes 1.6 kilometres of 2400 millimetre diameter storm trunk sewer, a diversion structure to an offline oil-grit separator, a piled slope stabilization wall to support an unstable slope, an energy dissipation structure, and a new outfall to the Glenmore Reservoir. These works will be completed in 2018.  Associated Environmental conducted the biophysical impact assessment, fish habitat assessment, and obtained approval from the Department of Fisheries and Oceans to enable the work through the park.

Key staff involved on the project include Nadeer Lalji, Corinne Arkell, Gabriel Jean, Risto Protic, Duane Strayer, Eliman Camara, Karen Prezelj, Joe Lisella, Justin Hick, Matt Freeman, Joe Lisella, Ryan Jalowica, Alvin Chan, Owen James, and Jason Bennett.