The climate is changing, and we have already begun to feel and see the impacts. In York Region, climate change has driven average temperatures higher, increased rainfall and led to more extreme weather events. Three recent extreme rainfall events in the region (June 23, 2017, January 11, 2020 and September 22, 2021) saw more than 60mm of rain fall in less than 12 hours resulting in basement flooding and sewage overflows (York Region Climate Change Action Plan 2022). By 2050, average annual precipitation across York Region is predicted to increase by more than 59mm with more frequent storms also expected (Historical and Future Climate Trends in York Region 2015).
These projections have implications for the way municipalities manage water in our urban landscapes. In urban areas where there are more impermeable surfaces like roads, houses and parking lots, rainwater and snowmelt cannot easily infiltrate the ground. To avoid flooding, stormwater management networks move water from where it falls to where it can be released back into the natural environment. That said, a future where we see more rainfall and extreme rainfall events will put stress on stormwater infrastructure and put homes and properties at risk of flood damage. The end cost of repairing homes, properties and worn-down stormwater infrastructure from the impacts of climate change will be high.
Infrastructure development in urban areas has created a landscape of impermeable hard surfaces, which makes it difficult for water to infiltrate the ground. Stormwater management networks help redirect water when it falls but these same networks can become overwhelmed after heavy rainfall, leading to flooding as seen in the image above. "Toronto Flash Floods June 2013" by Mark Watmough, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons
When water is not absorbed into the ground, it is mainly channelled through grey infrastructure. It runs into storm drains (as seen in the image above) then through a network of pipes that carry it to local waterways or wastewater treatment facilities. Stormwater can also be managed by green infrastructure such as rain gardens, green roofs, rain barrels, permeable paving and even urban trees! "Storm Drain" by Robert Lawton, CC BY-SA 2.5 <https://creativecommons.org/licenses/by-sa/2.5>, via Wikimedia Commons
So, what can we do? Look no further than the Town of Newmarket and its property owners, who have been taking steps to tackle stormwater management through improving green infrastructure (natural vegetation and green technologies).
Addressing climate change and its impacts requires mitigation and adaptation strategies. One effective strategy that combines both is planting trees to reduce stormwater runoff. Trees provide stormwater management services through three main hydrological (water) processes: interception, transpiration and infiltration.
- Interception: The leaves, branches and trunks of trees intercept, evaporate (when rainwater turns to water vapour) and absorb rainwater, reducing the amount that reaches the ground.
- Transpiration: Tree roots draw water up from the soil, transfer it up through the tree to use in photosynthesis (a tree’s food-making process) and release it into the atmosphere in a gaseous form through the leaves and stems.
- Infiltration: Trees help divert stormwater by soaking it up through their roots, which creates soil conditions that promote better storage and movement of water through the soil.
Planting trees also means less urban land is converted into impermeable hard surfaces, allowing water to be better absorbed into the ground where it falls. On average, a tree reduces stormwater runoff by 720 litres!
Many Ontario municipalities, including the Town of Newmarket, know that green infrastructure, such as urban trees, will continue to play an important role in the future of managing increased stormwater. Since 2017, the Town of Newmarket has partnered with the Regional Municipality of York and LEAF to offer homeowners discounted trees through the Backyard Tree Planting Program. Through this special partnership, Newmarket property owners can receive an additional $100 Newmarket Stormwater Management Rebate for planting a tree on their property through the Full Service, Do-It-Yourself or Multi-Unit program (please note that at this time, business properties do not qualify). There is a limit of one rebate per property per year, while supplies last. Every tree planted through this partnership will contribute to Newmarket’s urban forest while also having the potential to divert thousands of litres of stormwater.
A basswood tree planted in Newmarket. In 2024, the Newmarket Stormwater Rebate has the potential to divert 36,000 litres of stormwater! © 2021 Adriana Rezai-Stevens / LEAF
Help fight climate change and tackle stormwater runoff with our Backyard Tree Planting Program! While all property owners within our service areas benefit from this subsidized program, Newmarket residents receive additional savings through the Newmarket Stormwater Rebate. Apply online today to get started on planting a tree this fall.
Jess Wilkin is the Residential Planting Programs Operations Supervisor and an ISA certified arborist at LEAF.
LEAF offers a subsidized Backyard Tree Planting Program for private property. The program is supported by the City of Toronto, the Regional Municipality of York, the City of Markham, the Town of Newmarket, the Regional Municipality of Durham, the Town of Ajax, the Township of Brock, the Municipality of Clarington, the City of Oshawa, the City of Pickering, the Township of Scugog, the Town of Whitby and Ontario Power Generation.
