Hydro warns of flooding in the event of a major earthquake

Downtown Campbell River and Campbellton will be under a lot of water in the event of a major earthquake

Downtown Campbell River and Campbellton will be under a lot of water in the event of a major earthquake.

BC Hydro says that flood water from a dam breach caused by a major earthquake could arrive within 30 minutes to an hour and flood large areas of Campbell River – some areas near the river up to 11 metres deep.

“Under normal conditions the three dams in the Campbell River system are in good shape and well managed for public safety and flood control,” says BC Hydro’s Stephen Watson.

“We also need to plan for a worst-case scenario where a major earthquake could damage our dam system and release water downstream. The good news is that BC Hydro has a plan over the next 20 years plus to bring the John Hart and Strathcona dams up to current seismic guidelines. Until that work is complete, these two dams may not withstand a major earthquake.”

A public information campaign is about to be launched with details about the flood risk and evacuation procedures to help community members plan for a major, worst-case scenario earthquake.

Howie Siemens, the emergency coordinator for the Strathcona Regional District, said there may not be a lot of time to react once a major earthquake hits so information is being shared to help the community be prepared.

“Mapping information from BC Hydro, including water arrival times and depths from a potential dam failure, has helped us develop emergency plans over the years,” says Siemens.

“Now, for perhaps the first time in the province, BC Hydro is releasing a map to the public so we can all be better prepared.”

On Dec. 3, the City of Campbell River issued letters to all the residents and businesses within the potential flood or evacuation area.

The letter includes two brochures with an evacuation area map for the region and the city.

The brochures show the possible water arrival times and depths, and tips to prepare so the community is ready to react.

The brochures are also posted on the BC Hydro, city and Strathcona Regional District’s websites, and paper copies are available at City Hall, recreational facilities, the Strathcona Regional District office at 301-990 Cedar Street and Strathcona Gardens.

Frequently asked questions are also answered on the city and Strathcona Regional District websites.


Information sessions


The letter includes information about public education workshops, hosted by the city, set for Dec. 11 and 15. Two separate sessions will run on Dec. 11 (one at 2 p.m. and one at 6:30 p.m.) at the Tidemark Theatre.

Seating is limited to 400 people per session and will be filled on a first-come basis.

A third session at the Tidemark will run on Dec. 15 at 2 p.m. Presentations by BC Hydro and members of the community emergency preparedness team will provide information on how to prepare for this risk.

The sessions will last about two hours, with the first hour being about presentations and information, and the second hour providing for questions and answers from various experts on a panel. The expert panel will feature representatives from the city, regional district, BC Hydro and Emergency Management BC.

The City of Campbell River and Strathcona Regional District’s Emergency Coordinator will then conclude the presentation session with a talk about emergency planning and developing response plans in the event of a major earthquake.

“To be really clear, we are only talking about a major earthquake that could damage our dams,” Watson emphasizes. “This is the kind of earthquake that causes considerable damage to ordinary buildings, including partial collapse. This isn’t about a moderate earthquake but a major one with longer and stronger ground movement, with its epicentre near Campbell River.”


Dams could pose a threat


Watson says it is unlikely that one of the dams would fail immediately following a major earthquake. Yet we need to plan for the worst case scenario.

“BC Hydro’s immediate plan in the event of a major earthquake is to conduct an emergency reservoir drawdown, which would send more water downstream and potentially cause some flooding along the immediate river area,” Watson adds. “Our information and follow-up modelling of the Campbell River system dams have found that the downstream risks are significant should a major earthquake hit the area before our dam safety seismic upgrades are completed,” Watson adds. “People also need to know that there is a plan, a good plan, to upgrade those dams to a 1-in-10,000 year major earthquake level.”


Be prepared


While the focus for this public information campaign is on what to do in the event of a major earthquake, people in Campbell River also need to remember that a series of major storms could also flood similar areas of the city.

“A major earthquake or a major flood event should be part of people’s personal or business emergency preparedness plan if you live or work within the evacuation area,” says Siemens.

“We should all plan responsibly, so we can feel ready for the worst case scenario.”

People are encouraged to attend one of the three workshops for more information.

For more on emergency preparedness planning, contact Siemens at 250-830-6702 or HSiemens@strathconard.ca, and for questions about BC Hydro’s Campbell River hydroelectric system, contact Stephen Watson at 250-755-4795 or steve.watson@bchydro.com

More information about BC Hydro dam safety is available online at: www.bchydro.com/damsafety