Benefits of Green Infrastructure
Green infrastructure (GI) can provide many ecological, economic and social benefits. The correct GI practice in the right place can improve water quality, reduce runoff volume and peak flows, and recharge groundwater. Green infrastructure provides additional benefits, such as improving air quality, reducing the urban heat island effect, providing wildlife habitat and beautifying communities. These guidelines will highlight the benefits listed below and provide general insight into which benefits are associated with each type of GI practice. Each GI strategy will have an associated matrix providing a generalized evaluation for the following functions and benefits GI can provide:
Stormwater Runoff
Stormwater runoff can be a major cause of transportation-related issues following large storm events or back-to-back storm events. GI can significantly reduce the risk for localized flooding of roads and adjacent or downstream neighborhoods, businesses, or critical facilities. Transportation planners and designers should identify and evaluate the role GI practices can have in reducing peak flows or serving as volume controls. Managing smaller volumes of stormwater as close to the source of runoff, in this case pavement, can be much more cost-effective than large downstream storage and flood control projects.
- Peak Flow Attenuation
- GI can slow stormwater leaving a site, providing relief to the local sewer system and reducing flooding. Implementation of GI can serve as a peak stormwater runoff flow control that reduces runoff rates and lengthens the time stormwater enters the conventional storm sewer system. This can reduce the demands on downstream infrastructure.
- Infiltration
- Infiltrating stormwater runoff can provide both volume control benefits and contribute to recharging the local groundwater. Reducing the volume of stormwater runoff being directed to the sewer system can reduce localized flooding within the area. GI can be designed to provide storage as well as infiltration to mitigate flooding.
- Filtration
- Stormwater runoff is a major contributor of pollution into streams, lakes and waterways. GI can use soil and vegetation or engineered technology to reduce erosion and filter pollutants such as nutrients and sediment.
Air Quality
Many GI practices reduce air pollution in addition to stormwater benefits. Trees and vegetation can remove many air pollutants, such as particulate matter, to reduce health impairments such as asthma and make our communities healthier.
Community Aesthetics
Green infrastructure can provide social benefits and positively impact the community it is located in. GI can improve the quality of life by enhancing more natural surroundings and improving public health, supporting diverse ecosystems, lowering energy consumption, and reducing regional climate impacts.
Heat Island Effect
Urbanized areas can experience heat islands with higher temperatures due to impervious and paved surfaces and reduced vegetation. GI reduces this effect by using vegetation to shade and cool communities and reducing impervious surfaces such as pavement. Vegetation can also sequester carbon, combating climate change.
