BC Hydro finalized the buyout of all but one of the properties below the Jordan River Diversion Dam on Vancouver Island, British Columbia, Canada, according to published reports.
The 103-year-old dam is a concrete buttress dam, 232-m long and 40-m high, located on the Jordan River about 2.8 km downstream from the Bear Creek Dam and impounds Diversion Reservoir. It is part of the Jordan River hydroelectric system that includes: The Bear Creek, Elliott and Jordan River Diversion dams; and a 170-MW generating station.
The system was originally completed in 1911 and redeveloped in 1971.
The Jordan Dam is on the Juan de Fuca Plate — a tectonic plate generated from the Juan de Fuca Ridge and is subducting under the northerly portion of the western side of the North American Plate at the Cascadia subduction zone (CSZ). The CSZ is the most active seismic region in the Pacific Northwest, according to researchers.
Published research indicates the CSZ fault — a 1,000-km-long dipping fault that stretches from Northern Vancouver Island to Cape Mendocino, Calif. — will eventually move, causing an earthquake.
This led BC Hydro to buy properties that would likely be destroyed by a dam collapse in the event of a magnitude 8 or 9 earthquake.
The Jordan River community is one of several Juan de Fuca communities that make up an unincorporated rural Electoral Area under the jurisdiction of the Capital Regional District (CRD).
Juan de Fuca’s Electoral Area Director, Mike Hicks, said everyone — except for one person — living in 11 private residences has negotiated a buyout. BC Hydro also finalized the purchase of a CRD campground for over C$3 million, he said.
Jordan River used to have more than 1,000 residents, but now has just over 100.
According to BC Hydro’s Seismic Study and Action Plan, released Dec. 5, 2014, the expected ground motion at Jordan River Dam in an extreme event — an 8 to 9 magnitude earthquake — is much greater than previously thought due to its 40 km proximity to the CSZ.
Fortifying or repairing the Jordan River facility to survive an 8 to 9 magnitude seismic event is neither possible nor economically feasible, according to BC Hydro. Additionally, decommissioning the dam or lowering the level of the reservoir are not viable options because the system produces about 35% of hydroelectricity generated on the island.