Upgrade work is due to start early this month on the crests of BC Hydro’s John Hart and Strathcona dams. Scheduled to be completed in December, the work will increase capacity at Campbell river hydroelectric system, allowing the Canadian project to accommodate extreme floods.
The work being done to the dams consists of adding two levels of concrete lock-blocks, with an impermeable membrane, to the upstream side of the dam crests at Strathcona dam and sections of John Hart dam. The work involves locally removing up to 2 m of the crest surface and road materials to get to the dam’s core, placing concrete to form a base, installing the lock-blocks and membrane, then backfilling the excavations and restoring the road surface. The lower row of blocks will be completely buried.
‘The inflow event we are preparing for is a very rare and extreme scenario of inflows into the Campbell River watershed, and we are providing the means to better handle such an event,’ said BC Hydro’s John Hart Plant Manager, Tom Veary
‘BC Hydro will not be storing more water for power generation as a result of the increased dam height,’ he adds. ‘The measures now being implemented will allow us to better accommodate an extremely large flood while we investigate what further measures might be required in the long term.’
At Strathcona dam, an earthfill dam constructed from 1956 to 1958, two levels of lock-blocks will add up to 1.6m in core height. At John Hart, lock-blocks will be installed within the earthfill sections of the dam and will add up to 1.5m in core height.