The goal of green infrastructure is to maintain, mimic or recreate a natural, environment – that relies on soils and plants to do the work; keep a balanced system.
Features include planters, bump outs, curb cuts, bioswales and permeable surfaces that use vegetation and soil to interact with runoff, slow down and sink in the flow of water.
Types of green infrastructure
Green infrastructure can take many forms. Some examples include bioswales along the street, rain gardens in your yard or business common area, pervious driveways and sidewalks, and vegetated rooftops.
In Arizona, the latter is difficult to cultivate successfully. However, it has been done. And, rain gardens that utilize drainage from the roof, driveway, or sidewalk are trending nationally.
With the help of a local municipality and non-profit organization, you can find a suitable mix of plant and organic matter that thrive with minimal supplemental water and labor. Where space is constricted and you need to achieve volume reduction (that is, decrease the amount of water leaving your property), it may be preferable to build an interlocking permeable paver system as a driveway or parking area. Multi-layered or compartmentalized structures store, promote infiltration, and diminish runoff.
Bioswales are small depressions that can be supplied with rainwater via a curb cut or core that allows water to flow into the swale and water plants, and also helps replenish ground water.
Benefits of green infrastructure
In the urban environment, cityscapes become highly impervious. Parking lots, driveways, and roads minimize infiltration, and increase the quantity and velocity of stormwater runoff.
These hardscapes curb vegetative growth. As a result, the force of gravity and slope of the land push stormwater quickly to the lowest point in the valley (like our rivers and washes), which can cause erosion.
With the stormwater runoff goes all the dirt and grime from city living, such as oils, metals, nutrients, pesticides, and pet waste, which pollutes nature.
Green infrastructure can help to slow down stormwater and infiltrate more into the ground. Green infrastructure absorbs some of the pollutants commonly found in stormwater. And trees, which can be a part of a well-designed green infrastructure project, also slow stormwater flow and provide shade, which can reduce the urban heat island effect.
When designed, installed and maintained correctly, green infrastructure can dampen or lessen peak flooding (takes some of the water off the road); it can reduce ambient temperatures by a couple degrees; and may also increase property values.
Where can I find it?
GI is found all around the Valley. Some good examples in Phoenix include Primera Iglesia United Methodist Church located at 1st and Grant Streets; Civic Space Park located at Central Avenue and Fillmore; ASU’s Taylor Mall located on Taylor Street, from Central Avenue to 3rd Street; and Manzanita Park, located at 39th Avenue and Sunland.
If you are interested in learning more about how you may implement Green Infrastructure at home, visit Phoenix.gov/stormwater, or contact the Watershed Management Group at Watershedmg.org.
