The high risk was identified in a new study by the crown corporation that found the effects of ground shaking due to an earthquake on its facilities on Vancouver Island and along Bridge River near Lillooet, B.C. could be more severe than previously thought.
The Jordan River dam area, which is already recognized as a tsunami zone, has now been identified by the study as the highest seismic-prone area in B.C. and possibly even in Canada.
A BC Hydro spokesperson said it was not feasible to reduce the reservoir level, because it was crucial to produce the demand for power at peak times in Victoria, and it would have been too costly to rebuild the dam system.
As a result, BC Hydro is taking the unprecedented step of offering to buy the 11 homes at fair market value, she added.
The model used to study potential hazards to hydropower facilities in the event of a major earthquake is the first of its kind in North America, said BC Hydro in a news release, and is the culmination of six years of work by a cross-section of experts, including seismologists, physicists and geologists.
The new 3,500-page document will be available to local governments and other agencies who are interested in assessing ground movement and what it could mean for their infrastructure.
Hydro plans upgrades
BC Hydro also stressed that generally the seismic risk at its largest power generation facilities in the north and southeast has decreased or remains the same.
"The new model shows us that nothing has changed for the biggest dams in the province," said BC Hydro vice-president Chris O'Riley. "We have an updated action plan that addresses the hazards raised for Vancouver Island. This includes investing $700 million on Vancouver Island dam safety upgrades over the next ten years."Hydro said it is advancing the design and review of the John Hart dam safety upgrade and will undertake new public education and awareness campaigns in the Campbell River and the Jordan River areas.
The crown corporation said it is also modifying its operations at the Downton Reservoir for Lajoie dam and undertaking further studies at Terzaghi and Seton dams to determine if action is required.