Seismic hazards & our dams
World-class safety program bolstered by six-year study
A six-year study has given BC Hydro powerful new tools to calculate seismic hazards in British Columbia.
We now better understand the potential location and impact of where major earthquakes will occur in B.C., and we're using the information to better assess and focus on seismic upgrades at our generation facilities.
BC Hydro has for many decades assessed seismic hazards at our dams and related facilities, and seismic upgrades are ongoing. A 2013 independent external audit by two international experts found that BC Hydro has a strong dam safety program and a robust risk assessment process consistent with international best practices.
But in recent years, we've recognized that with new information about earthquakes in B.C. now available, it was time to update our assessment model.
With the goal of creating a best-in-class model for calculating earthquake hazards in B.C., BC Hydro leaned on international seismic experts as part of a six-year, $10 million Probabilistic Seismic Hazard Analysis (PSHA) study. In the process, we've become the first non-nuclear utility in North America to elevate seismic hazard assessment of its dams using processes similar to those used by the U.S. Nuclear Regulatory Commission.
What the study tells us
The PSHA study includes two key findings:
- For most of BC Hydro's 40 dam sites, including dams on the Peace and Columbia rivers systems that account for 80% of BC Hydro's total generating capacity, earthquake hazard levels are about the same as earlier assessment methods suggested
- For some dam sites, on Vancouver Island and at Bridge River, the hazards are higher than earlier calculated
For more details on our dam safety program, download the Keeping Our Systems Safe booklet [PDF, 10.2 MB]
For a look at the Jordan River system, where the seismic hazard is the highest among BC Hydro facilities, see our Jordan River page.
$2 billion in upgrades to make our facilities even safer
We have a long-term dam safety action plan to help reduce the potential downstream risks to people, property and infrastructure in the event of a major seismic event.
We're investing around $2 billion over 10 years on our seismic upgrade program, while also working with emergency responders and others to better plan for how to respond to a major earthquake.
We're spending $700 million on Vancouver Island dam safety upgrades. This is in addition to the $1-billion John Hart project that will also address seismic concerns in the Campbell River area, which is nearing completion.
The Campbell River system includes the John Hart Dam, Strathcona Dam and Ladore Dam.
Also on Vancouver Island, the Jordan River system includes the Jordan River Diversion Dam and the smaller Elliott and Bear Creek Dams. Even though the Jordan Diversion Dam was upgraded in 1991 and the Bear Creek reservoir level was reduced in 1993 to minimize the possible consequences of a dam failure during a major earthquake, new information from the seismic hazard (PSHA) study puts the Jordan River system at the highest seismic hazard within BC Hydro's system.
What we're doing in the Lower Mainland
We recently completed the Ruskin Dam and Powerhouse upgrade project. Construction on the 80-year facility began in April 2012. Improving seismic stability was an important driver for the project. As part of a rigorous dam safety program across BC Hydro, the Ruskin Dam needed to be brought up to modern-day requirements and safety standards. The new Ruskin Dam is designed to withstand a 1-in-10,000 year earthquake.
The dams and related facilities that make up the Bridge River system, located in the southern Interior near Lillooet, are safe and well managed. The seismic hazard (PSHA) study confirmed there is an increased seismic hazard at Terzaghi Dam.
A study is underway at Terzaghi to assess the dam's performance, and at Seton, a study will be prioritized in future work plans to assess the dam's performance.
There's a slight decrease in hazard at La Joie Dam. However, until we complete upgrades to the dam, we've taken the additional step of reducing the peak level of the reservoir.
Emergency planning and communication
Following a 2012 Disaster Preparedness Audit, BC Hydro has improved its oversight of emergency management planning, updated earthquake response and recovery plans, and increased training for BC Hydro employees in the event of a major earthquake.
We'll also be increasing our emergency planning at our facilities and ensuring that strong lines of communication are in place with local emergency response agencies. We'll work with these groups to ensure communities understand the location of evacuation areas in the event of a major earthquake that may cause a dam failure.