Stormwater Bumpouts

A bumpout is a landscaped extension of the street curb. Runoff water is directed underneath the system to be stored, infiltrated, and absorbed by plants, such as grasses, perennials, and shrubs.

Stormwater Bumpout on Queen Lane

A bumpout is a vegetated curb extension that protrudes into the street at mid-block or at an intersection. The system is composed of a layer of stone topped with soil and plants. An inlet or curb-cut directs runoff into the bumpout structure where it can be stored, infiltrated, and absorbed by the plants. Excess runoff is permitted to leave the system and flow to an existing inlet. The vegetation of the bumpout will be short enough to allow for open sight lines of traffic. Aside from managing stormwater, bumpouts also help with traffic calming. When located at crosswalks, they provide a safety benefit by reducing the pedestrian crossing distance.

Diagram of a mid-block stormwater bumpout
Diagram of a corner bumpout
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