Stormwater to Street Trees

This guide is an introduction to engineered stormwater systems that utilize trees to manage a volume of stormwater.

Cities employ a variety of measures to manage stormwater runoff. However, most do not take advantage of the stormwater utility benefits trees provide.

Trees are typically not considered part of either grey or green stormwater management systems; they are generally, and falsely, considered to be of landscaping value. Planting a tree just for landscaping is not taking advantage of the stormwater utility benefits and other environmental services it provides.

In urban areas, trees are part of the managed municipal infrastructure. A street tree, which is generally a publicly managed tree found growing within the right-of-way, offers unique opportunities to increase the effectiveness of grey and green stormwater systems.

With urbanization on the rise and impervious surfaces dominating urban cores, existing stormwater and sewer systems are often inadequate to handle peak flows. When a system is overtaxed, peak flows can blow manhole covers from the ground and back up stormwater and, in some cases, even sewage into the streets. To reduce pressure on existing systems and increase capacity, cities must consider every available option, especially using trees, to help manage stormwater.

Installing trees in locations that are engineered to retain stormwater is a great way to augment existing stormwater management systems, increasing their capacity and improving water quality while greatly improving urban forest canopy. This guide is an introduction to those engineered systems available, and in use today, that utilize trees to manage a volume of stormwater.

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