What is Green Infrastructure?
Runoff from stormwater continues to be a major cause of water pollution in urban areas. It carries trash, bacteria, heavy metals, and other pollutants through storm sewers into local waterways. Heavy rainstorms can cause flooding that damages property and infrastructure.
Historically, communities have used gray infrastructure—systems of gutters, pipes, and tunnels—to move stormwater away from where we live to treatment plants or straight to local water bodies. The gray infrastructure in many areas is aging, and its existing capacity to manage large volumes of stormwater is decreasing in areas across the country. To meet this challenge, many communities are installing green infrastructure systems to bolster their capacity to manage stormwater. By doing so, communities are becoming more resilient and achieving environmental, social and economic benefits.
Basically, green infrastructure filters and absorbs stormwater where it falls. In 2019, Congress enacted the Water Infrastructure Improvement Act, which defines green infrastructure as "the range of measures that use plant or soil systems, permeable pavement or other permeable surfaces or substrates, stormwater harvest and reuse, or landscaping to store, infiltrate, or evapotranspirate stormwater and reduce flows to sewer systems or to surface waters."
Green infrastructure elements can be woven into a community at several scales. Examples at the urban scale could include a rain barrel up against a house, a row of trees along a major city street, or greening an alleyway. Neighborhood scale green infrastructure could include acres of open park space outside a city center, planting rain gardens or constructing a wetland near a residential housing complex. At the landscape or watershed scale, examples could include protecting large open natural spaces, riparian areas, wetlands or greening steep hillsides. When green infrastructure systems are installed throughout a community, city or across a regional watershed, they can provide cleaner air and water as well as significant value for the community with flood protection, diverse habitat, and beautiful green spaces.
- Downspout Disconnection
- Rainwater Harvesting
- Rain Gardens
- Planter Boxes
- Permeable Pavements
- Green Streets and Alleys
- Green Parking
- Green Roofs
- Urban Tree Canopy
- Land Conservation
This simple practice reroutes rooftop drainage pipes from draining rainwater into the storm sewer to draining it into rain barrels, cisterns, or permeable areas. You can use it to store stormwater and/or allow stormwater to infiltrate into the soil. Downspout disconnection could be especially beneficial to cities with combined sewer systems.
- Philadelphia Rain Check PRogram Metal Downspout Planters
- Milwaukee Downspout Disconnection
- Portland, OR, Downspout Disconnection Program
Rainwater harvesting systems reduce stormwater pollution by slowing runoff and collecting rainfall for later use. The variety of systems range from the backyard rain barrel and the commercial building cistern to ground level pits, acquifers and even nets that capture dew and fog. These types of systems have been implemented world-wide.
- District of Columbia Riversmart Homes
- San Mateo County Home Rain Barrel Program
- Philadelphia Rain Check Program for Rainwater Harvesting
- Milwaukee Metropolitan Sewerage District Rain Barrels
- New York City Rain Barrel Giveaway Program
- Arizona Municipal Water Users Association
- Burnsville, MN, Stormwater Retrofit Study (PDF)(18 pp, 2.7 MB, About PDF)
- 12,000 Rain Gardens in Puget Sound
- Use of Pervious Concrete Eliminates over $260,000 in Construction Costs in Sultan, WA
- Designing Impervious: A Minnesota city eschews storm drains for pervious streets
- EPA Region 3 Green Streets, Green Jobs, Green Towns (G3) Program
- Seattle Public Utilities GSI Projects
- Syracuse Green Street: Concord Place (PDF)(2 pp, 220 K, About PDF)
- Los Angeles Green Street: Elmer Ave
- The Chicago Green Alley Handbook (PDF)(24 pp, 3.7 MB, About PDF)
- Ipswich River Watershed Demonstration Project in Wilmington, MA
- Toronto Design Guidelines for “Greening” Surface Parking Lots (PDF)(40 pp, 9.6 MB, About PDF)
- King County, WA, Green Roof Case Study Report (PDF)(31 pp, 1 MB, About PDF)
- Green Roof and Wall Projects Database