BC Hydro is weighing its options for a seismic overhaul of the John Hart Dam, a project set to begin once work on the John Hart Generating Station comes to a close.
Stephen Watson, spokesperson for BC Hydro, said the utility is moving forward with major safety upgrades to not just the John Hart Dam, but also the further upstream Strathcona Dam.
Both projects are each estimated to cost hundreds of millions of dollars.
“When the John Hart project is complete, as early as summer 2019, pending regulatory and BC Hydro funding approvals, we plan to start another construction project to upgrade the (John Hart) dam,” Watson said. “The project team has worked through the various options to strengthen the dam for it to withstand a one-in-10,000 year earthquake. We are now going through the feasibility design for those shortlisted options. Throughout this process we have been consulting with First Nations and updating government agencies, local government and stakeholders through our community liaison committee.”
Work will begin first on the John Hart Dam, followed by the Strathcona Dam and, taking into account construction on the generating station which began in 2014, will keep BC Hydro working in the area for up to 20 years.
Mayor Andy Adams said that’s good news for the city which stands to benefit from all the activity.
“BC Hydro provided a general update on their capital projects at the December 2015 City of Campbell River council meeting and we are extremely pleased to see the planning and approval process moving forward for all of these important projects,” Adams said. “These are important safety projects that will keep the residents and business safe and also continue to be an enabler of economic growth for our community. These are major projects that will create hundreds of project-related jobs for 20 plus years.”
The feasibility design stage for the John Hart Dam is expected to be complete in spring, 2017.
“Ultimately, BC Hydro will then select the appropriate upgrade options for the various components of the 810-metre long dam, built in 1947, that includes the intake dam, the middle earthfill dam, the concrete dam and spillway gate system, and the north earthfill dam,” Watson said. “The generating station project, with the new water intake works, will not impact the planned seismic upgrades. In fact, it will allow for them to proceed. The current water intake into the penstocks to the generating station is shallow. With the new water intake and tunnel, it’s much deeper in the reservoir and will allow BC Hydro to lower it to complete the dam upgrades.”
Watson said BC Hydro will need approval from the BC Utilities Commission to undertake the John Hart Dam project and is targeting a project submission around fall of 2018.
Seismic upgrades to the Strathcona Dam are expected to get underway following work on the John Hart Dam.
The Strathcona Dam, built in 1958, is the furthest up the Campbell River and is where about 80 per cent of the water inflows enter the system.
Watson said the Strathcona project was more recently initiated and is not as far along as the John Hart project.
“We are in the process of shortening down the list of potential upgrade options. Then we will begin feasibility design,” he said. “With proposed upgrades to the dam and eventually a new powerhouse at Strathcona, the first step is to design and build a new low level outlet tunnel that will go around the dam and deep into the reservoir. The tunnel may be similar to the new John Hart project tunnel as the Strathcona outlet tunnel will be designed to pass water to lower the reservoir in the event of an earthquake.”
BC Hydro can pass water downstream of the Strathcona Dam by having water go through the generating station or through any of the three spillway gates. However, the spillway gates can be left high and dry like what happened last summer.
Watson said the gates perform well for flood risk management operations but not for lowering the reservoir post-earthquake. This project will provide for that flexibility. As with the John Hart Dam project, Hydro is consulting with First Nations and through its community liaison committee. Hydro expects to submit the Strathcona Dam project to the BC Utilities Commission for approval in late 2018 or early 2019.