A tree trench is a system of trees that are connected by an underground infiltration structure. On the surface, it looks like a row of ordinary street tree pits, but underground there is a system to manage incoming runoff.
A stormwater tree trench is a system of trees connected by an underground infiltration structure. On the surface, a stormwater tree trench appears like a series of street tree pits. However, under the sidewalk, there is an engineered system to manage the incoming runoff. This system is composed of a trench dug along the sidewalk, lined with a permeable geotextile fabric, filled with stone or gravel, and topped off with soil and trees. Stormwater runoff flows through a special inlet leading to the stormwater tree trench. The runoff is stored in the empty spaces between the stones, watering the trees and infiltrating through the bottom. If the capacity of this system is exceeded, stormwater runoff can bypass it entirely and flow into an existing street inlet.