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About Green Streets

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Green streets reduce sewer overflows and backups by slowing and absorbing stormwater runoff from sidewalks and streets. Also known as rain gardens or bioswales, green streets are important to the City’s sewer and stormwater systems. They also help prevent pollution from washing into our rivers.
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What Are Green Streets?

Green street planters, also known as rain gardens or bioswales, are landscaped areas between the street and the sidewalk that use plants and soil to slow, filter, and clean stormwater running off streets and sidewalks. Traditional stormwater management directs runoff into pipes. A green street manages stormwater before it enters the sewer system. Environmental Services builds and maintains green streets all around Portland.

How Do Green Streets Benefit the Community?

Green streets help prevent combined sewage overflows to the Willamette River and Columbia Slough by keeping some of our stormwater out of the sewer and stormwater systems. Green streets help:

  • Prevent sewer backups into streets and basements.
  • Protect water quality in rivers and streams by removing up to 90 percent of pollutants from the stormwater runoff before it flows into a waterbody.
  • Replenish groundwater supplies.
  • Absorb carbon and improve air quality.
  • Improve neighborhoods by adding green space, and vegetated curb extensions can help improve pedestrian and bicycle safety by calming traffic.
  • Protect our investments in Portland’s stormwater and sewer systems.

How Are Green Street Locations Chosen?

Environmental Services prioritizes the placement of green streets where there is a need to reduce stormwater runoff flowing into the sewer system, protect water quality in nearby streams, and protect properties from sewer backups.

Other considerations for placement of green streets include:

  • Width of planting strips. 
  • Age and size of existing street trees. 
  • Parking impacts. 
  • Underground utilities.

Some green street planters that use existing planting strips do not impact parking. Green streets that need a new curb extension may remove two to three parking spaces. When this is the case, Environmental Services will work with adjacent property owners to try and limit parking impacts.

What Kinds of Plants Are in a Green Street?

Environmental Services selects plants that can tolerate wet soil in the winter and dry conditions in the summer. The plants are a mix of native and non-native varieties that grow 2-3 feet high. Rushes and sedges are commonly used. Flower bulbs add color. Street trees are planted whenever possible. Our community outreach team works with adjacent property owners whenever possible to select bulbs and trees and to help with the planting design. 

Who Maintains Green Streets?  

Environmental Services maintenance crews visit green streets as needed but at least twice a year. 

Regular maintenance includes:

  • Removing sediment, leaves, or trash that can block water from flowing into the green street.
  • Pruning or replacing plants.
  • Watering.

If you would like to report green street maintenance concerns like trash, clogged inlets, or plant concerns, find more information on how to report green street maintenance issues.

To report problems that threaten public safety or public property, including substance spills, call 503-823-1700.

How Can I Get Involved?

You can help support Portland’s green streets in two ways. 

The first is to be a good green street neighbor. This means:

The second way is to volunteer as a Green Street Steward and adopt a green street. Stewards perform more regular maintenance on their adopted green streets. Learn more about being a Green Street Steward.