One principle of green infrastructure involves reducing and treating stormwater close to its source. Urban transportation right-of-ways integrated with green techniques are often called “green streets”. Green Streets achieve multiple benefits, such as improved water quality and more livable communities, through the integration of stormwater treatment techniques which use natural processes and landscaping. Green streets can incorporate a wide variety of design elements. Although the design and appearance of green streets will vary, the functional goals are the same: provide source control of stormwater, limit its transport and pollutant conveyance to the collection system, and provide environmentally enhanced roads.
Green Streets are designed to:
- Mimic local hydrology prior to development
- Provide multiple benefits along the street right of way including:
- Integrated system of stormwater management within the right of way
- Volume reductions in stormwater which reduce the volume of water discharged via pipe into receiving streams, rivers and larger bodies of water
- Key linking component in community efforts to develop local green infrastructure networks
- Aesthetic enhancement of the transit right of way
- Improves local air quality by providing interception of airborne particulates and shade for cooling
- Enhanced economic development along the transit corridor
- Improved pedestrian experience along the street right of way.
Numerous approaches are available for creating Green Streets including:
- Alternative Street Designs (Narrower Street Widths)
- Bioretention Curb Extensions and Sidewalk Planters
- Permeable Pavement
- Sidewalk Trees and Tree Boxes
Here's information on Portland, Oregon's green streets program and green streets photos from the Low Impact Development Center.
Information is also available regarding several green streets projects, including a "green street" in Tacoma, Washington, the Growing Vine Street project in Seattle, Washington and the Baker Beach Green Street project in San Francisco. There are several more green infrastructure projects underway in San Francisco.
Here is a video Green Streets: The Road to Clean Water from U.S. EPA.
Closely related to Green Streets are Green Alleys, which are proliferating in Los Angeles and Chicago, as well as in several other cities.
References and Additional Resources
Enhancing Sustainable Communities With Green Infrastructure U.S. EPA, 2014.
Water Environment Research Foundation - Using Rainwater to Grow Livable Communities
Beachapedia - Low Impact Development