When a key water main was damaged by river scour—or high water flow resulting from snow and ice melt—in 1997, Metro Vancouver decided a new approach was needed.

The 40-year-old main, which links Coquitlam to Surrey and points beyond the Fraser River, was successfully repaired the following year, but the incident made it clear that the line would eventually have to be replaced.

Enter the new $240-million Port Mann Water Supply Tunnel, which more than doubles the existing main’s capacity and runs for one kilometre below the floor of the Fraser, starting at Maquabeak Park on the river’s north side, in Coquitlam, and terminating at the CN Thornton Yard in Surrey, on the south side.

Read the full article on canadianundergroundinfrastructure.com