Green Streets are roadway landscaping designs that reduce and filter stormwater runoff.
Green Streets are part of a County initiative to capture stormwater runoff in neighborhoods with minimal stormwater controls and not enough open space for larger stormwater practices. They use Low Impact Development (LID) and are constructed within the street right-of-ways.
Benefits of Green Streets:
When the County considers installing a Green Street, they take into account factors like utilities, existing drainage patterns, soils, tree impacts, the amount of runoff volume, and many other considerations.
More information is available on the Green Streets brochure.
Types of Green Streets
Rain Gardens and Bioretentions
Tree Box Filters
Pervious Sidewalk, Permeable Pavers & Pavement Removal
Help Maintain Right-of-Way Rain Gardens and Green Streets
Do you have a Green Street in your neighborhood? DEP typically maintains these rain gardens monthly. You can also help DEP by performing a couple small tasks.
Want to learn more about maintaining Right-of-Way Rain Gardens and Green Streets? Email firstname.lastname@example.org
Frequently Asked Questions
Why are you Creating Green Streets in my Neighborhood?
This project is part of the County’s need to meet Federal and State mandates to control and treat stormwater runoff. The goal of Green Streets is to reduce stormwater runoff, minimize pollution, promote infiltration, and restore stream conditions throughout County watersheds and the Chesapeake Bay.
Where are Green Streets Practices?
Green Streets facilities are typically constructed within the street or within the County right-of-way areas (i.e. the grassy strip between the sidewalk and the curb).
What will the Green Streets Practices Look Like?
There are many different looking Green Streets and Low Impact Development features. In the case of a rain garden or bioretention, they are typically bowl-shaped, sometimes sodded, and sometimes landscaped with plants and mulch. Tree box filters look smaller, with a square inlet with a tree or small shrub(s) planted inside a filter box filled with a bioretention soil mix. Typically, landscape designers work with the County to develop aesthetically pleasing designs that help connect a neighborhood together and provide a sense of neighborhood identity.
For additional photos, visit the Stormwater Management Best Practices webpage or the DEP Flickr website. The general Green Streets Photo Album and the Dennis Avenue Green Streets Photo Album are two good examples.
Who is Responsible for Maintaining Green Streets?
DEP is responsible for the maintenance of Green Streets. DEP will monitor the practices monthly to make sure they are functioning properly.
It depends on the type of practice, but generally, stormwater runoff from the roadway is diverted into an inlet opening in the curb, and is filtered through a mixture of highly permeable soils (sand, mulch, compost), then stored in an underlying gravel layer before percolating into the groundwater and/or entering into an underdrain that flows to the storm drain system. Runoff has an opportunity to cool down while the plants help absorb nutrients and microbes around the plant roots help break down pollutants. When certain facilities are full after rain events, water may pond up to six inches before draining within 12 to 48 hours, depending on the type of facility and site conditions.
Where are Examples of Green Streets in the County?
How Can I Learn More?
Email askDEP@montgomerycountymd.gov for information on Green Streets in your community.