Coquitlam-Buntzen Diversion Tunnel
Water Level Changes in the Coquitlam River and Buntzen Lake
In August and September 2022, BC Hydro may need to release more water than usual from the Coquitlam Reservoir to the Coquitlam River as we work to upgrade the tunnel. There may be higher than normal flow and water levels in the river during this time. We ask that the public be extra careful when active around the river since water levels can rise and fluctuate without warning.
Recreational water levels at Buntzen Lake may be impacted this summer. Users are asked to exercise caution and obey safety signs and barriers.
In 1902, the Coquitlam-Buntzen facilities comprised of the Coquitlam Dam, the Coquitlam Diversion Tunnel and Lake Buntzen 1 Powerhouse were built to provide electricity to the city of New Westminster.
The 3.9-kilometre Coquitlam Diversion Tunnel was built and later expanded between 1909 and 1911, to divert water from the Coquitlam Reservoir to Lake Buntzen Reservoir to generate electricity at the Lake Buntzen 1 Powerhouse. The tunnel is also used to control the water level of the Coquitlam Reservoir which provides water for Metro Vancouver and help maintain Buntzen Lake’s water levels for recreation.
What we’re planning
We’ll be replacing the three gates in the tunnel that are used to control the flow of water through the tunnel to modern-day standards and seismic operability. We’ll also be installing new control equipment to allow for remote monitoring of the facilities.
Why we’re doing it
The last major update of the Coquitlam-Buntzen facilities was completed in 1955. To ensure continued reliability of the tunnel so that water can continue to be safely transferred from Coquitlam Reservoir to Buntzen Lake, we’re addressing near end-of-life equipment inside the tunnel.
The Coquitlam-Buntzen facilities are in the City of Coquitlam and the diversion tunnel is located 7 kilometres from the west side of the Coquitlam Dam.
During outages of the tunnel, we’ll be diverting water into the Coquitlam River which passes through the cities of Coquitlam and Port Coquitlam. Please be aware of the potential for sudden fluctuations in water levels and water flows in and around the river.
To do this upgrade work, we’ll need remove the tunnel from service. Using extensive hydrological modelling to study historical weather and inflows into the reservoirs and river, we’ve determined the best approach would be to carry out the work in a series of outages.
- Outage 1 – January 4 to April 15, 2021
- Outage 2 – August 4 to September 30, 2021
- Outage 3 – January 17 to May 15, 2022
- Outage 4 – August to September 2022
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