SUPPORTING NATURAL HERITAGE SYSTEMS: GREEN TOOLKIT

NRU
March 22, 2017
Leah Wong

Local stormwater systems are under stress from population growth and increased frequency of extreme weather events due to climate change. To avoid costly upgrades, municipalities can introduce small-scale green infrastructure projects that also generate environmental, social and economic benefits, according to new research.

The Friends of the Greenbelt Foundation recently enlisted a University of Toronto planning studio team to develop a theoretical green infrastructure master plan for a community in the Greenbelt to show the potential benefits of small-scale interventions. The students’ research is being used as the basis for green infrastructure design guides that will be distributed to municipalities within the Greenbelt.

“We are working with the Green Infrastructure Ontario Coalition to turn elements of the report into a design guide that we think would be useful for smaller and more rural municipalities,” Friends of the Greenbelt Foundation research manager Tom Bowers told NRU. “We are going to turn the [students’] design palette and planning approach into a guidance document that will be more generic.”

The studio team of Master’s planning students Anni-Claudine Buelles, Kelsey Carriere, Holly Wacker and Jennifer Williamson reported on the potential use of smallscale green infrastructure, such as rain gardens, bioswales and retention ponds, in Mount Albert in East Gwillimbury. Carriere told NRU that they selected Mount Albert because of its varied landscapes and the town’s commitment to environmental protection.

Mount Albert is one of four communities in East Gwillimbury that has been designated to accommodate future growth. With three new subdivision developments in the works for Mount Albert, the students saw an opportunity to incorporate green infrastructure projects as the community grows over time.

Increasing the population of rural communities can strain municipal infrastructure, such as water treatment facilities and stormwater systems. By implementing green infrastructure projects, Bowers said municipalities can postpone, or even eliminate, the need to upgrade conventional infrastructure.

The students developed a planning framework to introduce green infrastructure in different parts of the community. Carriere said they developed seven zones—private residential, transportation rights of way, public lands and parks, the downtown core, institutional and commercial, future developments and agriculture—to show what types of green infrastructure are best suited to the various elements of the community.

“We took a whole palette of potential green infrastructure elements, from rain gardens to bioswales to constructed wetlands to green roofs, and categorized them into what areas they would be most suitable and useful,” said Carriere. “You get an appropriate palette of green infrastructure design elements that would be appropriate to implement in [each type] of zone.”

For a town’s main street, for example, the team identified the type of green infrastructure that could take up minimal space and be used in conjunction with traffic calming strategies. For example, the introduction of “bulb-outs” that extend beyond a conventional curb to slow traffic around street corners could also be designed to collect stormwater, according to Carriere.

“Instead of [runoff] going into a storm sewer it can go into a rain garden. A tree can be planted there to create a shaded area and seating [added],” said Carriere. “All of a sudden you have a focal point for your town where there was previously just a storm sewer.”

Carriere said there are a range of benefits associated with green infrastructure projects. For example, bioswales, the shallow vegetated open channels designed to slow down the flow of stormwater, can be designed for double duty as beautiful public spaces.

Bowers said one of the challenges of implementing green infrastructure is that there are so many different options from which to choose. By splitting a community into different zones, as the students did, choices can be made based on what is best suited for a particular area.