For this project, we ultimately decided to use natural rainfall to water the trees. Because the rainfall is already concentrated by the hard surfaces of streets and paving, it makes sense to redirect the water to the trees as a sustainable water source which can continuously maintain itself.

The tree wells were designed as a part of the stormwater system as a preliminary interception, before draining into the traditional storm inlets. Also incorporated into the tree well was an interception to collect trash and soils from street runoff. This is a critical item which limits the potential pollution of the tree root system from street runoff. The first half-inch of water is diverted into the tree wells directly through the curb’s gutter. Then, after the box fills up, the water overflows directly into the storm drain system. The top of the tree’s root ball is covered in gravel to prevent erosion from heavy remains. The bottom of the box is open to allow for drainage, and the sides are open to allow for tree root growth into the available green spaces. The trees will be planted in structured soils to allow for roadway construction and sidewalk construction over the trees, minimizing settlement. No irrigation is required as the natural rainfall provides the soil moisture.