What is a tree trench?
- Tree trenches can be though of as vertical raingardens. They consist of a system of piping for water storage, structural soils and a tree.
- Tree trenches manage stormwater runoff and promote the use of trees in urban areas mimicking natural watershed functions.
- By holding water after rain events in tree trenches we accomplish the task of filtering runoff, reducing flooding, and providing irrigation for the tree. And they are beautiful!
The city of New London has installed these tree trenches along 1st Avenue to help keep the water clean. On the surface, a stormwater tree trench looks just like a series of street trees planted along the sidewalk. 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 storm drain leading to the stormwater tree trench. The runoff is stored in the empty spaces between the stones, watering the trees and slowly infiltrating through the bottom. If the capacity of this system is exceeded, stormwater runoff can bypass it entirely and flow into an existing storm drain. This system will help filter water and return the filtered water back to the lakes, streams, rivers, and ground water.
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