Mimicking nature is the big idea behind rainwater collection on Burke Mountain. To protect the health of streams, the design works to put water where it needs to go. See how a flexible design slows down the water to prevent stream damage.
“One of the key elements of making a watershed work is addressing rainwater; allowing it to filter through the soils, allowing the proper biological processes,” says Coquitlam mayor Richard Stewart. “Rather than (using) large catch basins and taking the water out by storm sewer.”
Under many new Burke Mountain roadways are large pipes, directing some run off to the Pitt River and the Deboville Slough, which are both large enough to handle extra runoff without erosion issues.
“We also don’t want to starve those creeks entirely, so the diversion pipes have flow splitters which bleed off some of the flow back towards the creeks,” explains Melony Burton of the City of Coquitlam Engineering Department. “We have water quality ponds which take the diverted flow and sediments and pollutants get settled out and the clean water is able to carry on to the creek.”
Rain is also diverted to roadside rain gardens and underground trenches filled with rocks. A test in 2011 revealed that 90% of the water soaked into the ground.
“The purpose is to really mimic the natural hydrology,” says Burton. “Get it into the ground and let is travel slowly and evenly back to the creeks the way nature intended.”
Rain barrels and extra topsoil are also part of the City’s directives to developers, as ways to absorb and hold rain.
“We’ve have a unique opportunity up here, with Burke Mountain being a green field development,” says Melony Burton. “Having the space and the foresight to act proactively, rather than reactively with our drainage and storm water and rain water management.”
For Mayor Stewart, the approach brings two important benefits to his city.
“By really focusing on the health of the watershed, we can end up with a much healthier environment and a better community.”