FORT ST JOHN, B.C. -A new milestone was reached for BC Hydro and the Site C project with the completion of the Peace River diversion tunnel excavations.

The completion of the excavation of the two large diversion tunnels that are located on the north bank of the river was December 24, 2019. According to BC Hydro, the tunnels are approximately 750 metres long and 11 metres in diameter.

BC Hydro shares, that later this year, the tunnels will be used to reroute the Peace River around the dam site, allowing for the construction of the earth-fill dam across the main river channel.

Excavations on the two tunnels began in summer 2018 and breakthrough on the upper half of the tunnels (known as the “crown”) occurred in summer 2019. Since that time, efforts focused on excavating the lower half the tunnels (known as the “bench”).

BC Hydro shares the concrete tunnel lining process is, on average, about 50 percent complete in the tunnels. By using a custom-built slip form that enables concrete to cure in a perfect circle outside the form. At the same time, construction of the structures that will house the inlet gates are nearing completion; construction of the outlet gate structures will be completed once the concrete lining forms have been removed from the tunnels.

According to BC Hydro, they remain on schedule to begin diverting the Peace River in September 2020. River diversion will be in place until the Site C reservoir is filled in 2023.