BC Hydro contractors completed perhaps the most unusual structure associated with the John Hart Power Generating Station replacement project in May — a set of bat houses.
As part of the project, scheduled for completion in 2018, BC Hydro had to identify and mitigate potential environmental impacts, including those on local wildlife.
When biologists identified a small shed slated for demolition was being used as a roost for bats in the spring and summer, crews worked to seal the shed against bat intrusion, using plastic barriers, taping and caulking of gaps.
Then, so as not to leave the bats homeless, the project team constructed four bat houses, elevated above 4.5 metres and facing southeast for maximum sun exposure and warmth.
Crews have also used exclusion work, including mesh and other barriers, to prevent the nesting in construction areas of barn swallows, a federally listed species.
The swallows have been found to be making nests farther along the dam, allowing construction to proceed.
Round the clock
Project operations have moved into a 24-hour-a-day schedule, with blasting proceeding in the main generating station cavern and in the main access tunnel. The main tunnel now reaches more than 150 metres and the powerhouse cavern 65 metres in.
Meanwhile, above the dam, work has begin on the new intake system with construction of crane pads, silt curtains and piles underway for the cofferdam. Work on the cofferdam and intake access earthworks will continue through December of 2016, with power tunnel excavation beginning this September.
Water seepage
For the first time since blasting began on the access tunnels and main generating station cavern, the project has encountered its first water seepage from a seam.
Following a blast in the main access tunnel May 14, a “significant” amount of water began entering the tunnel, BC Hydro spokesman Stephen Watson said.
Pumps were installed to pump the flow to the project’s water treatment plant. From there, outflow was sent to a diversion ditch that flows into Campbell River, with the water monitored throughout the diversion period.
“All the water was treated and the water that goes into Campbell River has been within compliance,” Watson said. “The project team tests for turbidity, pH, and for some nutrients, like nitrogen.
“The water quality in general has been good.”
Watson said water seepage is an anticipated challenge of blasting underground rock, and the incident has not impacted the project schedule or work.
“InPower BC is still working on that (seepage), but the water issue was under control within a few days,” Watson said. “It’s resolved itself.”
Bridge to the future
The Elk Falls Suspension Bridge, opened May 8, has met expectations as a major draw for visitor to the interpretive centre, Elk Falls Provincial Park and the John Hart dam site.
Visitor stats at the info center ballooned in May.
After totaling 442 visitors for the entire month of April, the centre drew 384 in a single day in May and finished with 1,572 visitors for the month, an average of 196 per day.
Have a look
BC Hydro and InPower BC will host a community site visit July 12. Details are still being finalized for the public event, in which people may visit the construction site and view some of the work and equipment.
Access to the tunnels will not be available, though visitors may walk partway down the entrance ramps to view the tunnels.
Access to the project site will be by bus only. BC Hydro will to provide additional details on the community site event as they become available.
