When rain falls on our roofs, streets, and parking lots, the subsequent water cannot soak into the ground and becomes stormwater runoff. This stormwater drains through gutters and storm sewers, and ultimately is discharged into nearby waterways. Trash, bacteria, oil, heavy metals, and other pollutants from the urban landscape are carried downstream in floodwaters. These floodwaters also can cause erosion in urban streams, resulting in damaged property, infrastructure, and habitat.
In natural areas, water is absorbed like a sponge and filtered by soils and native plants. As a result, stormwater runoff is greatly reduced. Green infrastructure mimics this process and alleviates stormwater, benefiting the environment by soaking up and storing water through the use of native trees, shrubs, and plants. Green infrastructure is often less expensive and an easier alternative to installing grey infrastructure-conventional piped drainage and water treatment systems that flow underground.
Green infrastructure captures and treats stormwater at its source. These processes are effective, economical, and deliver ecological benefits to their community as well as create healthier environments. Green infrastructure is a system of small-scale to larger scale elements integrated into sites which can be woven throughout a community providing habitat, flood protection, cleaner air, and cleaner water.