Striking a Balance Between In-River Construction Practices and Aquatic Resource Values Such As Species at Risk to Facilitate Instream Pier Construction on the Fraser River, British Columbia

The Fraser River is one of the world’s largest salmon producers, and home to four genetically unique stocks of white sturgeon (Acipenser transmontanus). White sturgeon in the upper Fraser River and its tributary the Nechako River, are listed as Endangered under Canada’s Species at Risk Act.  In 2005, the Province of BC announced a commitment to 4-lane 440 kilometres of Highway 97 between Cache Creek and Prince George, including the twinning of the Simon Fraser Bridge in Prince George.  This resulted in a new 400 metre span over the Fraser River that included construction of two new instream piers.  Construction methodologies for this project necessitated implementation of appropriate techniques for site isolation to mitigate risks to aquatic resources including white sturgeon and pacific salmon.  These mitigation measures required acceptance by regulators through federal and provincial permitting processes.  Isolation was also important to the construction process itself, as many pier components had to be completed in a dry site.  Instream isolation measures and construction procedures were designed to accommodate a wide array of flow scenarios including the freshet period.  Designing and implementing these procedures within the Fraser River (Canada’s fifth largest river by volume), posed a significant challenge in this project.