One of the three surge towers at the defunct John Hart dam in Campbell River was brought down during a controlled demolition on Friday.
The demolition is part of the decommissioning of the 70-year-old station near Campbell River. The station is being replaced with a $1.1-billion generating station.
During Friday’s demolition of the 90-metre tower, two access roads and surrounding public trails were closed off. For the felling process, some of the eight supporting legs of the tower were cut using linear shape charges, with kicker charges used to ensure full metal separation and displacement.
The felled surge tower is being removed and the steel will be recycled. A second tower may be coming down next week, according to BC Hydro. The third (south) tower is not part of the new hydroelectric facilities but is in good condition. BC Hydro spokesman Stephen Watson said the tower will stay in place due to its communications equipment and visual aid to the local airport.
Watson said there is also heritage value in keeping one tower in place.
“At 90 metres, or 295 feet tall, for a period of time the surge towers were the highest structures on Vancouver Island. The iconic white towers are visible from certain areas of Campbell River, including from boats on the ocean,” Watson wrote in a release.
The towers were in operation from 1947 to 2018 and protected the 1.8-kilometre long penstocks, which led from the dam to the generating station, from short-duration water pressure changes that occur when the flow velocity is increased or decreased. They do this by allowing the water to go up, or conversely come down. The surge tanks were half-filled with water and at the same elevation as the upstream John Hart Reservoir.
The old John Hart facility was officially shut down in October 2018 and the final touches on the new underground hydroelectric facility are being completed.