Trees: An essential part of stormwater management

Ever heard of the term “stormwater runoff”? It refers to rainfall that does not seep into the ground and instead flows over the ground surface and into our sewer or drainage systems. In urban and suburban areas, where there is an abundance of sidewalks, roads and other paved areas, stormwater management is becoming an increasingly complicated and costly problem. But, trees can help! Not only are they are a cost-effective way to reduce flooding, they also provide countless co-benefits such as shade, air purification, beauty and privacy.


Our towns, cities and suburbs have a high percentage of impermeable surfaces, such as paved roads, parking lots, driveways and sidewalks, which surround houses, buildings and other built structures that are impermeable themselves. When it rains, we take it for granted that the water runs away into drains. However, a rainfall event can have major environmental and economic impacts when stormwater drains become overwhelmed and lead to flooding. Municipal managers are looking for creative and cost-effective solutions for stormwater management – and that’s where trees can help!



By intercepting rainfall, tree canopies slow down and redirect raindrops as they fall. Some of these raindrops remain on the leaves and branches and later evaporate back into the atmosphere. Other raindrops flow down the branches and tree trunks to the ground below.  If the surface is permeable (such as a garden bed or lawn), the water percolates into the soil rather than running off. Some are taken up by roots systems of the tree and nearby vegetation and the rest continues downward to replenish groundwater. This incredibly valuable ecological service is provided free of charge by the tree! Compare that to the cost of moving and treating huge volumes of stormwater and it’s easy to see why trees are such a cost-effective solution.


Though one tree’s impact may seem limited, the combined effect of urban and suburban trees is impressive. Some forward-thinking municipalities are striving to grow their urban tree canopies on both public and private property. The stormwater benefits, together with many co-benefits such as shade, air purification, beauty and privacy, make the modest planting investment well worth it!




The Town of Newmarket is a model municipality which is creatively managing their stormwater programs. The Town has partnered with LEAF to provide residents with a stormwater rebate, as part of their Stormwater Credit and Recognition Programs. Newmarket residents participating in the LEAF subsidized Backyard Tree Planting program will enjoy an additional $100 rebate, courtesy of the Town of Newmarket. One rebate per property per year is offered, while supplies last. Residential, multi-unit properties, such as townhomes, may also qualify.


Contact LEAF today to learn more about the program and how it can help ensure you get the right tree in the right place at a low cost! Find out more about the LEAF Backyard Tree Planting program here.




Daniela Serodio is the Marketing and Communications Coordinator at LEAF.