Green infrastructure is a cost-effective, resilient approach to managing wet weather impacts that provides many community benefits. Green Infrastructure can reduce the amount of flooding and reduces the polluted runoff that reaches sewers, streams, rivers, lakes, and oceans. Green infrastructure reduces and treats stormwater at its source while delivering 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 projects are maintained by the Office of Sustainability with the help of AmeriCorps Student Volunteers.
Most of our Green Infrastructure projects on campus are also acting as pollinator habitats. Green Infrastructure areas of campus are not only helpful for stormwater management purposes but they are also providing a valuable habitiat to our campus pollinators.
Green Infrastructure can be:
- Rain gardens - are small, shallow, sunken areas of plantings that collect stormwater runoff from roofs, streets, and sidewalks. Also known as bioretention cells, they are designed to mimic the natural ways water flows over and absorbs into land to reduce stormwater pollution.
- Bioswales - are sunken areas of plantings that collect stormwater runoff from roofs, streets, and sidewalks that are designed to slow down rainwater through a curving or linear path to a drain, while also allowing some (but not all) of it to infiltrate.
- Permeable Pavement - infiltrate, treat, and/or store rainwater where it falls. They can be made of pervious concrete, porous asphalt, or permeable interlocking paver
- Urban Tree Canopy - Trees absorb stormwater in their leaves and branches. Many cities have set tree canopy goals to restore the benefits of trees lost when the areas were developed.
- Rainwater Harvesting - 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, aquifers and even nets that capture dew and fog.
- Green Roofs - Green roofs are covered with growing media and vegetation that enable rainfall infiltration and evapotranspiration of stored water. They are particularly cost-effective in dense urban areas where land values are high and on large industrial or office buildings where stormwater management costs are likely to be high.
- Land Conservation - The water quality and flooding impacts of urban stormwater also can be addressed by protecting open spaces and sensitive natural areas within and adjacent to a city while providing recreational opportunities for city residents. Natural areas that should be a focus of this effort include riparian areas, wetlands, and steep hillsides.
- Green streets - are created by integrating green infrastructure elements into their design to store and filter stormwater. Permeable pavement, bioswales, planter boxes, and trees are among the elements that can be woven into street or alley design.
- Downspout Disconnection - 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.
Goals for green infrastructure on campus is to implement and utilize low impact design where possible:
- Install new rain gardens and bioswales on campus with the help of student volunteers and AmeriCorps Students.
- Increase tree canopy in areas along drainage coulees and storm drains.
- Analyze potential for a green roofs installation on either an existing or new building.
- Utilize impermeable pavement options for selected applications
- Combine native pollinator habitats with rain gardens or bioswales in areas where stormwater builds up.
For more information on Green Infrastructure visit the EPA's Green Infrastructure website here.