CBC/Radio-Canada employs an array of technology and infrastructure to deliver its programming from coast-to-coast-to-coast across the country. In keeping with its Environmental Policy, when searching for the most appropriate technical means to fulfill its broadcasting mandate, the Corporation carefully considers the potential impact that its choices will have on the environment. It is a question of doing business in a socially responsible way.
In June 2011, CBC/Radio-Canada set out to improve its transmission tower sites in Steveston, British Columbia. One of the first steps was to undertake an environmental assessment (EA) to identify potential adverse environmental effects on the tidal area of Steveston; propose any necessary mitigation measures; and predict residual adverse effects following mitigation. The EA was performed by an external company which concluded that the project was not likely to cause any significant adverse environmental effects. The EA was made available to the general public upon request.
An additional step was to place a notice in a local newspaper, inviting residents to a Public Information Meeting on June 18, 2011, at the community centre. The purpose and process for the project were discussed, with no issues or objections raised by those attending the meeting.
The project went ahead successfully and as planned.
Here is the story.
Since 1968, CBC/Radio-Canada has had four 61-metre AM transmission towers on CBC-owned and -leased land in the Village of Steveston, British Columbia. The site is located on the edge of the Sturgeon Bank of the Georgia Depression within the Strait of Georgia, and is surrounded by the Sturgeon Bank dyke system. Most of the site is at sea level and is subject to the tides. Nearby are the Alaksen National Wildlife Area and George C. Reifel Bird Sanctuary.
To maintain the towers’ structural safety, in 2011 it became necessary to replace aging timber piles used as guy anchors for the towers. Given the site’s favourable AM transmission, tower relocation was not desirable. Therefore, the Corporation looked for the best product and the least intrusive installation method, and chose 24 new, galvanized steel helical screw-type anchor piles with a lifespan of 45-50 years. The existing guy wires were to be transferred to the new anchor pile positions.
The ideal time for carrying out the project at this site was June, to coincide with the lowest tides of the year.
Understanding the physical characteristics of the site and the surrounding environment was critical to predicting environmental outcomes. For instance, the area’s geology includes the following: the bedrock is granite; the surficial soils are Fraser River Sediments; the subsurface soil and sediment consist of a surface layer of black clayey silt over sandy silt and a medium sand that extends down 30 metres. In considering what to do with the old anchor material after changing to the new, it was realised that abandoning the timber piles was the best and least invasive choice. Removing them would have caused soil disturbance and the possibility of habitat destruction for aquatic and intertidal species. At the same time, there would be very little disturbance during the installation of the steel anchor piles, and no surface soil or sediment would be removed.
Knowing about species at risk in the vicinity was also crucial in order to avoid creating additional pressures. The EA focused on five species, in particular, pointing out the largest, pre-existing threats to each one:
The EA considered other species in the area, as well, even though they were not covered by the Canadian Species at Risk Act. These included aquatic vegetation (salt grasses and seaweeds typical of intertidal zones), fish and migratory birds.
The EA concluded that, with appropriate mitigation during construction, potential adverse effects would be temporary and insignificant.
So, what were the mitigation strategies employed during construction?
There were several general strategies: construction work was conducted during daylight hours to minimise the possibility of accidents related to reduced visibility; fuelling of machinery was conducted on dry land off-site to minimise the chances of inadvertent petroleum spills; and all equipment was kept in good operating condition and inspected for potential hydraulic and fuel leaks prior to operation. Were any mishaps to occur, there was an Environmental Emergency Reaction Plan (EERP) in place, and a containment boom and response kit readily available to deal with any spills or accidental releases.
There were also specific mitigation strategies. For instance, to avoid potential adverse effects on birds of the increased noise during construction, all work was completed outside of migratory and breeding seasons. In the case of fish and fish habitat, sediments suspended in the water were unavoidable but also minimal, short-term and localised.
CBC/Radio-Canada concluded its work at Steveston, British Columbia, by leaving the site clean for the enjoyment of residents and the safety and protection of local flora and fauna. All in all, the Corporation successfully completed this project in an environmentally and socially responsible way, in keeping with its Environmental Policy.
For more information about CBC/Radio-Canada’s “green” practices, please take a look at our annual Environmental Performance Reports, published on our corporate website for all Canadians to see.