Green Stormwater Infrastructure (GSI)

GSI Oh My! Scavenger Hunt for Creek Week 2023

This Creek Week, we encouraged people to get outside and explore Green Stormwater Infrastructure examples that already exist in their own communities. Below are some of the photos submitted for the scavenger hunt.

What is GSI and why is it used?

Conventional stormwater systems are designed to move stormwater quickly and efficiently away from where it falls. Green Stormwater Infrastructure is a way of constructing our built environment that helps mimic natural systems and slow down, soak up and spread-out stormwater. Green Infrastructure elements can be implemented in multiple scales from the city or neighborhood scale to a watershed scale and can have a wide range of benefits when interwoven throughout a community in different forms.

Types of GSI

Below are a few examples of green stormwater infrastructure that you may have seen in your own city, town or neighborhood.


Image from The B.C. Open Collection

Bioswales are gardens or vegetated areas built in shallow depressions that capture stormwater runoff and allow it to percolate into the soil. These are usually placed in longer and narrower spots than rain gardens such as between sidewalks and the street curb.

EPA Fact Sheet: NPDES: Stormwater Best Management Practice, Grassed Swales (

Green Roofs

Photo by Living Roofs NC

Green Roofs or eco-roofs are a type of green infrastructure designed to capture and absorb stormwater from buildings. Green roofs also help with building insulation and can provide habitat for pollinators and other animals in urban settings.

EPA Fact sheet: NPDES: Stormwater Best Management (

Land Conservation

Photo by NC Coastal Federation

Land conservation is a larger scale method of improving water quality and reducing the impacts stormwater runoff can have on flooding in a watershed. Protecting natural areas such as riparian areas, wetlands, and steep hillsides can help maintain existing vegetation and the natural processes of absorbing stormwater.

EPA Fact sheet: NPDES: Stormwater Best Management Practice, Protection of Natural Features (

Pervious Pavement

Photo by NC Botanical Garden in Chapel Hill

Pervious pavement, also known as permeable pavement, is a type of pavement with high porosity that can be used on sidewalks, roads, and parking lots to help stormwater infiltrate rather than run off. Examples of pervious pavement substrates include some types of bricks, stones, and gravel.

EPA Fact Sheet: NPDES: Stormwater Best Management Practice, Permeable Pavements

Rain Garden

Photo by NC State University

Rain gardens are gardens built in shallow depressions that help capture, filter and infiltrate stormwater during rain events. When properly installed, standing water in a rain garden will be soaked up in 48 hours or less.

EPA Fact sheet: NPDES: Stormwater Best Management Practice, Bioretention (Rain Gardens) (

Rainwater Harvesting

Photo by Webb Home Improvement

Rainwater harvesting techniques contain rainwater before it can accumulate on a surface and become stormwater runoff. This reduces the amount of stormwater that can pick up pollutants and enter a waterway. This is also a great way to collect fresh water to be used later for purposes such as irrigation. Techniques include rain barrels which hold around 55 gallons of water, and cisterns which are much larger and can hold hundreds to thousands of gallons of water.

Stormwater Wetland

Photo by NC State University

stormwater wetland is a constructed ecosystem that is saturated with water and vegetation in a setting with a high amount of stormwater runoff, specifically to retain and treat stormwater by mimicking a natural wetland.

EPA fact sheet: G:\WD\WSSPB\Fact Sheets\Constru (

Trees and Urban Tree Canopy

An urban tree canopy on Queens Street in Charlotte, NC (photo credit Trees Charlotte)

Trees and urban tree canopies can help reduce stormwater runoff by catching water with their leaves and branches, so it runs down to the ground where it infiltrates and is taken up by roots. Trees also help decrease the temperature of stormwater runoff by providing shade and can prevent erosion by stabilizing stream banks with their roots.

EPA Fact sheet: NPDES: Stormwater Best Management Practice, Urban Forestry (

Resources for GSI

Local organizations

Check out your local government or county website to see if they offer Green Infrastructure programs such as rain barrel sales or installation, rain garden workshops or tree and native plant giveaways.

Below are links with to some North Carolina organizations that offer workshops and webinars if you are interested in installing a Green Infrastructure element to your home or community. Click the drop-down list to explore their resources.

Rain It in Video Series

View the Rain It In video series for descriptions of common residential green stormwater infrastructure measures, and consider which may be a good fit for your property.

Grants and Funding

Nature-based Solutions Funding Database:

The National Wildlife Federation (NWF) launched this funding microsite for communities interested in pursuing federal funding and/or technical assistance for nature-based solutions and green infrastructure projects. This site can be accessed here.

319 Grant:

State and local governments, interstate and intrastate agencies, public and private nonprofit organizations, educational institutions, and tribal councils are all eligible to apply for 319 funding. Must be used to help restore waterbodies that are (1) currently impaired by nonpoint source pollution and (2) in areas with approved watershed restoration plans. You can learn more here.

Environmental Justice

It is important to address the equity issues associated with Green Infrastructure. Here are some resources for strategies that can be used for increased equitable implementation of green infrastructure for urban landscapes.

Tree Equity Score

The Tree Equity Score calculates scores based on how much tree canopy and surface temperature align with income, employment, race, age and health factors in the U.S.

Discussion Panel

Discussion Panel on Green infrastructure and Environmental Justice from 1A on NPR: Listen here.

Policy and Planning Tools

Policy and Planning tools for Urban Green Justice written by the Local Governments for Sustainability and The Barcelona Lab for Urban Environmental Justice: PDF can be accessed here.