September 15, 2018
Leaning on a white metal railing near the top of the 10-storey cavern known as the powerhouse, Stephen Watson from BC Hydro explains the scope and scale of the new underground power generating station for the John Hart dam.
"It's pretty hard to get a full understanding of how big this project is until you are standing here," Watson says.
BC Hydro has spent years and $1.1 billion on this new generating station for the 1940s-era dam located about five kilometres outside Campbell River on northern Vancouver Island.
A giant yellow crane spans the width of the underground powerhouse, which is roughly as wide as a football field.
The crane slides back and forth on rails, lifting buckets of concrete and lowering them down several more storeys to turbines that are located even further underground.
Construction crews drilled and blasted out enough rock to fill about 120 Olympic-sized swimming pools
Water held back by the John Hart dam will tumble down a new eight-metre wide tunnel that is 100 metres underground. The volume of water passing through the tunnel could fill an Olympic-sized swimming pool every 20 seconds.
From there, the water will be directed through the turbines in the powerhouse, generating enough electricity to power about 80,000 homes.
When the project comes online in October, BC Hydro hopes it will have a reliable, state-of-the-art power generation facility that can withstand the sizable earthquake expected to rock the B.C. coast in the years to come.
The dam and original power generating station date back to the 1940s.
The John Hart dam has a rich history dating back to the days when mining and forestry were just beginning to drive the Vancouver Island economy.
"This was the first large generation source outside of Vancouver and Victoria," Watson says.
The dam and original generating station came online in 1947. In the years that followed, the powerhouse was expanded to house six turbines.
Water from the dam currently runs down giant above-ground pipes. Parts of those pipes are still made of wood.
After more than 70 years of service, it's time for an upgrade, Watson says.
"It's like an old car. It's great when you first buy it and it runs for a long time, but it needs to be replaced."
BC Hydro initially looked at retrofitting the existing above-ground power generating station, but bringing the 1940s building and pipes up to modern seismic standards proved difficult and even more expensive.
At that point, engineers started looking deep under the soil at the surface to the solid bedrock below, Watson says.
BC Hydro worked with project contractor InPower BC back in 2014 to start blasting the tunnel that leads from the dam to the powerhouse.
Four years later, water is flowing through that tunnel, and two out of the three generators, supplied by General Electric, are online. The third is expected to be ready in time for the new powerhouse to be officially commissioned in October.
Although it will have three turbines instead of six, the facility has more efficient equipment and will generate 10 per cent more power than the old generating station.
The new power house was moved underground to help it withstand an earthquake.
Although the new power station has been built to withstand a sizable earthquake, the seismic risk of the John Hart dam itself remains for those who live in and around Campbell River.
About four to six metres of water could flood large areas downstream, and even the city's downtown core, within about 40 minutes, if the dam was to breach during an earthquake.
BC Hydro wants the dam to be able to withstand the catastrophic earthquake that is expected to hit the West Coast in the coming years, including Vancouver island.
"Right now, it can't do that," Watson says.
There are two other dams further up the watershed that also need to be upgraded to withstand earthquakes.
Until those dam upgrades are done, the risk of flooding remains for Campbell River.
BC Hydro has been working with the city and the Strathcona Regional District on an awareness campaign for those who live, work and play downstream.
Signs along the river indicate people need to get to higher ground if they experience an earthquake that is powerful enough to knock them off their feet.
The signs also show areas of the city that would be devastated by flood waters, should the dam fail.
Work is expected to get underway to seismically upgrade the John Hart dam in either 2021 or 2022, Watson says.
"There is certainly an interim risk of a dam failure."
The push for a new generating station at the John Hart dam wasn't just about a seismic upgrade. BC Hydro also needed to reduce environmental risk to the river.
About 95 per cent of the water flow in the Campbell River comes out of the generating station.
If the turbines in the old powerhouse went offline for any reason, water flow could be cut off. That could be catastrophic for fish and fish habitat downstream.
The new system has special bypass pipes that allows hydro to keep a consistent flow in the river, even if the turbines are not operating.
"It's one of highest environmental risks, for BC Hydro and the province," Watson says. "It gives BC Hydro much more water management abilities here at the dam."