New urban garden helps manage storm water in Thunder Bay
CBC News | Posted: July 7, 2015 8:56 PM | Last Updated: July 8, 2015
City officials say the engineered green space filters runoff, prevents pooling and adds beauty
City officials in Thunder Bay say a new green space along one of the city's busiest streets will beautify the route and also deal with storm water runoff.
The city unveiled the Memorial Avenue "low impact development," Tuesday afternoon.
From the High Street intersection, it looks like an urban garden, but dig a little deeper, and project engineer Aaron Ward said there's a lot more going on underneath the newly-planted trees and shrubs.
"It's not just a garden, it's actually an engineered rain garden," he said.
Multiple layers of ground cover, like gravel and mulch, organic-rich soil and sand are designed to filter storm water that is directed into the space by curb cutouts and small concrete culvert-like structures. A network of pipes underneath the garden then takes the water away.
The quick-draining materials in the ground also prevent water pooling, according to the city.
The green space's proximity to a main artery and a well-used parking lot is good for aesthetics, Ward said, but it also means the garden can do the most good.
"We have a fairly large parking lot area of hard surface runoff that can be contaminated runoff," he said."Prior to this facility being in place, that water used to go straight into our catch-basin system and right into Lake Superior."
The site will also prevent water from rushing into the storm sewers faster than the system can handle it, Ward added.
The city has set up a number of similar green sites; another one is right across the road.
Using these sites, instead of relying solely on gutters and storm drains, is something that's going to become more prevalent, said Werner Schwar, Thunder Bay's coordinator of park planning.
"The time is coming it will be legislated," he said. "Storm water is becoming more and more of an issue with climate change and higher volume precipitation events."