The reconstruction of Roncesvalles Avenue presents an opportunity for a demonstration project of a natural relationship between trees and storm water management. We also see it as the kind of project that would meet many of the requirements for carbon-offset trading agreements. Planting trees in a way that incorporates storm water management, along with other environmental benefits carries significant upfront costs, but equally significant long-term savings.
Beginning in June of 2009 through 2010, the City of Toronto will do a major reconstruction of the Roncesvalles road bed. The work includes replacing streetcar rails, sanitary sewers, water mains and sidewalks.
Our priority is to make sure the work includes proper tree planting conditions which incorporate storm water management. We see Roncesvalles as an ideal demonstration project for a green infrastructure system that combines the beauty of a mature tree canopy, with storm water management, along main streets across Toronto – a goal in keeping with the City of Toronto’s urgent imperative to double the urban tree canopy. Many other Canadian cities face similar challenges, making this proposal relevant across the country.
A mature tree canopy is vital to managing storm water run-off, a growing issue for the Toronto region which is expected to receive heavier and more precipitous rain storms due to climate change. Tree canopies slow down the rate at which water is absorbed into the ground, while the root system, when combined with a storm water system, takes up a great deal of water during heavy rainfalls, dramatically reducing the overflow into the combined sewer system
Street trees provide many other benefits -- absorbing carbon dioxide, filtering pollutants which cause respiratory problems, and providing cooling during summer, as well as UV protection. And of course trees are beautiful and well loved.
On the west side of Roncesvalles, which is primarily residential, the existing construction standards are adequate because there are few underground utilities and plenty of space for trees. However, the east side of Roncesvalles which is lined with businesses, is another story. This is where most of the underground utilities – gas lines, water mains, fibre optic cables, and so on – are located. Here, the current standard, based on conventional construction methods and materials, does not allow trees to flourish. In fact, the average boulevard tree in Toronto survives only 5 to 10 years, a pale shadow of the mature tree it would become under better growing conditions. And the sidewalk itself is often broken up, tarred and patched by utility crews within weeks of being laid
Fortunately, there are new methods and materials compatible with both the highest standards for sidewalk construction and tree planting They also resolve the conflict around the maintenance and repair of underground utilities whenever they are located in proximity to tree roots.
As part of its reconstruction budget, the City sets aside a minimal amount for trees. We recognize this will not be adequate to allow trees to flourish on Roncesvalles’ east side.
We are seeking funds to create, as part of the planned reconstruction, the appropriate infrastructure, using new methods and materials, to ensure a healthy tree canopy and natural storm water management.