Custom Box Culverts for Amphibians' Crossing
Half Moon Bay West Phase 3, Ottawa, ON
As the City of Ottawa continues to expand, more challenges are encountered given that the prime land has been developed and the remaining developable land has more restrictive characteristics such as flood plain restrictions and environmental habitat considerations. In the case of the Mattamy Homes Half Moon Bay West and Glenview Homes Flagstaff subdivisions, an existing channel that primarily served to convey flows from the swamp of the Cambrian Woods to the Jock River had to be realigned. The realigned channel would replace the old conveyance route, while providing a travel corridor and habitat for frogs between the swamp and the river. The new channel was required to pass under Flagstaff Drive, a main roadway within the subdivisions. To pass the 100-year flows the hydraulic design of the channel required twin 800 mm diameter CSP culverts. Given the importance of this roadway, CSP was changed to precast as the material of choice to ensure the maximum service life of this critical infrastructure. A precast concrete box culvert with a 1200 mm span x 900 mm rise was selected. The culvert was produced and designed by M CON Products of Ottawa, according to OPSS 1821 standard as well as CHBDC. The overall length of the structure would be 32.5 m with a total of 13 pieces. Due to the dual purposes of the culvert to both convey flow and provide a travel corridor for frogs, the culvert included a unique design feature. It was decided to add a 300 mm x 150 mm shelf inside the culvert along its entire length to allow frogs to traverse the corridor in high flow conditions.
M CON Products' engineering and fabrication teams were able to design the required shelf and fabricate the necessary formwork to achieve the secondary casting which resulted in the creation of a shelf for the amphibians within the precast concrete box culvert. DSEL would like to thank M CON Products for their ability to provide timely design and manufacturing solutions that addressed both the environmental challenges of this development as well as keeping the project on schedule.