BURKE MOUNTAIN STORMWATER UPPER DIVERSION

If Burke Mountain was to develop in a sustainable way, stormwater runoff would have to be managed to protect the natural and environmentally sensitive watercourses within the watershed.

Client: City of Coquitlam

Location: Coquitlam, BC

Project Type: Municipal Infrastructure

About This Project

The City of Coquitlam realized that if Burke Mountain was to develop in a sustainable way, stormwater runoff would have to be managed to protect the natural and environmentally sensitive watercourses within the watershed. Additionally, the City needed to address the future development of Burke Mountain and provide a safe solution to protect the public from flooding.

The City retained ISL to lead the design to construction of what became one of the largest stormwater pipe projects in BC. ISL created a complex stormwater management system that conveyed up to 21,000 litres/sec of flow through Burke Mountain, bypassing several environmentally sensitive creeks including Hyde Creek and Smiling Creek, and ultimately dissipating a hydraulic force of 550 kN before safely reaching the DeBoville Slough.

Challenges:

The contractor was not used to working with large diameter HDPE pipe.
Materials were shipped from Texas.
Environmental monitoring and mitigation were extremely important as working on the mountain resulted in very quick runoff response when rainfall occurred. The native soil conditions were easy to work with when dry, however, when they were wet or saturated construction equipment mobility and slope stability were compromised.

Solutions:

Our site reps worked closely with the contractor, showing how the product had to be handled, how it was to be properly fused together and the proper methods for connecting the mechanical joints. Close inspection and quality control were critical in completing the product to a high quality.
Scheduling was critical. ISL allowed the contractor to start the project in multiple locations and provided quality assurance on grades so adjustments could be made to phasing and the project could stay on its critical path.
Proper silt fencing, mitigation of slopes and placing impermeable membranes on them helped mitigatethese issues.