Filling the reservoir
One of the last steps in building the Site C dam is to fill the reservoir. Reservoir filling will take about four months, widening the Peace River by an average of two to three times.
Site C reservoir filling is underway
Reservoir filling began on August 25, 2024.
Filling the reservoir allows us to put the generating station, spillways, turbines and generators into operation. Over a period of up to four months, water will rise by up to three metres per day, creating permanent changes to the shoreline.
For public safety, we strongly urge people to stay away from the reservoir and the surrounding slopes during reservoir filling and for at least one year after.
Existing public boat launches are closed until at least spring 2026. Ensuring safety during the gradual filling process and afterwards remains our primary concern.
Reservoir filling progress
Watch this video to see the Site C reservoir area.
On August 28, we closed the first of two diversion tunnels. Water is now only flowing downstream of Site C through the second tunnel, which has constriction rings in place. Water levels will continue to rise in the coming weeks.
As of August 30, the water at the Site C dam had risen by 11.5 metres since the start of fill. The depth at the dam site is more than 20 metres.
In early September, we plan to close the remaining diversion tunnel, once the reservoir reaches the spillway low-level gates. At that point, water will be able to pass through the spillway to ensure water continues to safely pass downstream, maintaining our minimum flow requirement.
Above: The Site C dam on August 29, 2024.
See more photos of reservoir filling progress in our gallery.
As expected, debris is accumulating behind the debris boom. We will begin to remove debris in the coming weeks, and that work will continue through fall.
Wildlife monitoring and Indigenous cultural monitoring are taking place in the reservoir area.
What to expect during reservoir filling
- The Site C reservoir will cover 5,550 hectares of land, with a total surface area of about 9,330 hectares.
- The 83-kilometre-long reservoir will be, on average, two to three times the width of the current Peace River. The mouths of the Moberly River, Halfway River and Cache Creek will also widen.
- The final depth of the reservoir will vary: 52 metres close to the dam, 36 metres at Halfway River, and 18 metres near Hudson's Hope.
- Water levels will rise at a varying rate of 0.3 metres to three metres per day.
Watch the video below to learn more about how we fill the reservoir.
See more videos about reservoir filling, slope stability, boater safety, and more.
Reservoir filling unaffected by drought
The water used to fill the Site C reservoir comes from the upstream Williston Reservoir. The water is used to generate energy at WAC Bennett Dam, and then Peace Canyon, before it enters the Site C reservoir.
In an average year, water flowing into the Williston Reservoir can fill Site C up to 20 times. Even in another drought, Williston generation discharges more than 10 times the water needed to fill Site C.
Timing reservoir filling to protect wildlife
Reducing impacts to wildlife is a top priority during Site C reservoir filling. We've taken comprehensive measures to avoid, reduce or offset potential impacts on wildlife in the reservoir area.
Starting reservoir filling in the last week of August helps avoid the bird nesting period in spring and summer, the typical spring mammal birthing period, and the winter black bear hibernation period.
If you see an animal in distress, please contact the B.C. Conservation Officer Service through the Report All Poachers and Polluters (RAPP) Hotline at 1-877-952-7277.
The following activities were completed before reservoir filling began:
- Highway 29 realignment
- Earthfill dam built and fit for service
- Regulatory authorization
- Convert the diversion tunnels
- Approach channel, spillways, and tailrace at the dam site
While filling the reservoir is one of the last activities require to complete the dam, clearing the area began years in advance. We have removed trees and vegetation from the dam site and the reservoir area to ensure boater safety and reduce impacts to dam construction and operations.
Reservoir clearing and debris management activities have taken place and continued through 2024. This includes road construction, logging, hauling timber to local mills and waste wood burning.
We recognize the importance of this final step, and the impacts on local communities and Indigenous peoples. We’ll continue to communicate expected changes and timing of reservoir filling with Indigenous Nations and all stakeholders in the Peace Region, including local government and residents.
Prior to filling the reservoir, more than 20 regulatory approvals were met. In addition to these authorizations, reservoir filling considers BC Hydro’s operation of the Peace River system, both up and downstream impacts, environmental and weather constraints, as well as the construction progress.
Resources
Filling the reservoir factsheet PDF • 3.8 MB
Site C reservoir safety factsheet PDF • 376 KB