UPDATE: Spokesperson Dave Conway says that BC Hydro was first alerted to signs of possible instability in the area of the crack on February 11th, and that the tension crack first appeared on February 18th. Conway says that the crack, which is located upstream of the future site of the dam near Garbage Creek, is not spreading.
He added that the appearance of such stress fractures is not uncommon, and that geotechnical specialists are examining the fracture to determine the best course of action.
FORT ST. JOHN, B.C. – A quarter mile-long crack has formed in the north bank of the Peace River near the site of the future Site C dam.
In a release shortly after 11:00 Friday morning, BC Hydro says that the crack appeared during construction of a haul road that will support the excavation of the north bank of the Peace River valley. Hydro says that the plan is to remove unstable soil and create stable slopes for eventual dam construction. According to Hydro, tension cracks are not unexpected in the area, but that this particular crack is significant due to its 400-metre length.
BC Hydro and its contractor have installed instruments to measure and monitor stability around the tension crack. The Crown Corporation added that there was some initial movement of soil, it the crack has since stabilized. The area where the crack formed was already slated to be removed as part of the planned excavations. Hydro adds that its next step is to determine how to continue soil removal, which will need to be undertaken carefully to maintain the stability of the slope.
The project’s independent engineer and technical experts are still assessing the tension crack, while the 30 road construction workers have been reassigned to other work.