Coquitlam
Reservoir
intake replacement limnology
Client
Jacobs Canada
Location
Coquitlam Reservoir, Metro Vancouver
Year
2025
Project management and engineering
Jacobs Canada
Limnology
C. Perrin, S. Bennett
Photography
C. Perrin
Product
ways to maintain high water quality and ecological values during stages of different drawdown
Coquitlam Reservoir is one of three large bodies of water providing drinking water to Metro Vancouver, Canada. To increase availability of existing storage, a deep intake is being designed along with a new water treatment plant. We are examining ways to protect water quality and valued ecological components in the reservoir during different phases of change in drawdown that is expected with use of the new intake.
We start with building a conceptual model. That tells us where are the critical uncertainties and what data is needed to answer questions. We fill the data gaps which in this case mostly comes from seven years of detailed monitoring that was designed by Limnotek in 2016. We parameterize the pathways and explore relationships quantitatively. Then we use visualization tools to show how things work. Output is visual and something everyone can figure out. That approach is key to supporting decisions on reservoir management.
Much of what happens in a reservoir begins upstream. Headwaters build into large streams and rivers that supply the reservoir with water. As the reservoir is drawn down to supply drinking water, the inflowing streams can carve pathways through underlying sediment and produce turbidity. That turbidity can be removed at a downstream treatment plant but it is better to minimize production of that turbidity in the first place. That goal is reached through a keen understanding of river and reservoir interactions. We model those patterns and interpret the limnology to find the best ways to use natural processes to achieve high water quality even before withdrawal to the treatment plant.
