PROJECT SUMMARY

The City of Calgary required a Fisheries and Oceans Canada (DFO) offsetting plan to offset the unavoidable aquatic effects from the temporary instream berms for the 12 Street Southeast Bridge Replacement Project. Matrix Solutions Inc. devised a plan to create and enhance fish habitat by removing excessive angular riprap that was placed in a side channel of the Bow River in the 1970s. Our plan involved removing 650 tonnes of this riprap, repositioning some of the larger pieces of riprap to create fish habitat features and enhancing riparian vegetation on the adjacent bank. This offsetting plan was submitted to the DFO in 2016, and the construction took place in spring 2017, concurrently with bridge construction. Post-construction monitoring was conducted in 2017, 2018, and 2019.

OUR ROLE

Our scope of work included:

• developing the concept plan

• completing detailed river engineering and aquatics design

• obtaining all regulatory approvals

• preparing the tender package and managing construction

• completing 3 years of post-construction monitoring (e.g., underwater snorkel surveys) to meet the conditions of the Fisheries Act Authorization for the 12 Street Southeast Bridge Replacement Project

OUTCOME

This cost-effective fish habitat offsetting project met or exceeded all of the DFO’s offsetting requirements. It supports local fisheries’ management objectives, balances project impacts from the temporary instream berms of the bridge, and is generating self-sustaining benefits. Underwater snorkel surveys show that multiple fish species at various life stages are utilizing the habitat and that riparian plantings are providing shade along the riverbank.