As part of the Trans Mountain Expansion Project, substantial work has gone into determining potential environmental impacts and prescribing mitigation methods to reduce these impacts during construction.

Trans Mountain has identified more than 1,000 potential watercourses along the Project footprint between Edmonton and Burnaby. Trans Mountain’s Environment Team has investigated every one to collect data, with the exception of a few locations where the team did not have access to the immediate site.

Within Burnaby, the watercourses crossed by the Project include an unnamed tributary to Eagle Creek, Silver Creek, Stoney Creek, an unnamed creek, Lost/Austin Creek and Holmes Creek. Trans Mountain recognizes the importance of these streams within an urban setting and has a long-standing positive working relationship with local streamkeeper groups who successfully nurture the streams and the fish species they support.

A lot of time and care has gone into determining construction methodology and environmental precautions during Project construction to protect streams. Within Burnaby, the construction team will use a variety of construction methods to minimize impact to local streams including:

Along the pipeline route:

  • Isolated watercourse crossing – stream flow is temporarily rerouted around the natural watercourse for a short duration while trenched construction occurs across the watercourse. Once the trench is constructed and the pipe is installed, the trench is backfilled and channel bed and banks restored, and the water is restored to its natural channel. The typical duration the watercourse is diverted is usually a few hours to a single day for smaller watercourses. During this type of construction, fisheries biologists will salvage fish from the isolated area and release them upstream, if the watercourse is fish-bearing. Water quality is also monitored during construction in all fish-bearing watercourses.
  • Overhead crossing – Trans Mountain will use a unique crossing method for one of the stream crossings in Burnaby as a result of construction space constraints and specific environmental considerations at the crossing location. The pipeline, which is typically buried underground will still be buried within a trench, but will be installed over existing culverts. As a result, there will be no instream works at this crossing location and disturbance of riparian habitat will be minimized. 
  • To address potential environmental impacts associated with construction, Trans Mountain has created a Pipeline Environmental Protection Plan (EPP). This plan outlines the mitigation measures that will be implemented during construction activities of the pipeline and associated components. It also provides instructions for carrying out construction activities in a manner that will avoid or reduce adverse environmental effects.

At Burnaby Terminal:

  • At Burnaby Terminal, Trans Mountain will relocate existing culverted reaches of tributaries to Silver Creek and unnamed tributaries to Eagle Creek as part of construction activities. These watercourses are surface-flowing upslope of the terminal and are currently culverted for some or all of their extent through the terminal.
  • To accommodate expansion of Burnaby Terminal both sets of tributaries will be relocated into new culverts for their full length across the facility. Both Silver Creek tributaries will be diverted into separate culverts, and the unnamed tributaries to Eagle Creek will be diverted into one culvert with a short diversion culvert connecting the two. After this work, the discharge volumes leaving the terminal will remain the same as they were pre-construction.
  • Mitigation efforts will be in place for these watercourse diversions, which include a Water Management Plan, an Erosion and Sediment Control Plan, and environmental monitoring during construction and reclamation of inlet and outlet areas immediately following the diversion to minimize risk of soil erosion.
  • Trans Mountain’s Facilities Environmental Protection Plan outlines our environmental procedures and mitigation measures at the terminal. These include pre-construction environmental resource protection; the prevention of construction-related materials or debris from entering watercourses; and the installation of erosion and sediment control measures to prevent sediment from entering natural drainage systems, watercourses or wetlands.

In order to minimize environmental impacts post-construction, Trans Mountain will implement reclamation activities according to its Reclamation Management Plan. The plan, which was filed with the NEB, promotes the protection of rare plant species and the re-establishment of native plant communities; and will return the area to a condition similar to pre-construction. Trans Mountain has made a number of commitments to continue monitoring our watercourse crossings after construction. For a period of up to five years, we will be periodically returning to each watercourse to ensure our restoration and reclamation measures have been effective. The results will be documented and filed with the NEB.