Green Infrastructure

Green Infrastructure: A Holistic Guide


Green infrastructure refers to natural or nature-based systems that provide benefits like cleaning water, reducing flooding, improving air quality, and removing carbon dioxide from the air. Examples include parks, green roofs, rain gardens, trees, and community farms. This guide explains what green infrastructure is, how it helps communities, different types and designs, costs and savings, jobs created, and how everyone can support more green infrastructure in their hometowns.

What is Green Infrastructure?

Green infrastructure uses plants, soils and natural processes to manage rainwater, pollution, air quality and more. It is the opposite of “gray infrastructure”, which uses pipes, treatment plants, and machines. Green infrastructure creates healthier communities by:

  1. Slowing and absorbing rainwater to prevent flooding
  2. Filtering out pollution from rainwater before it reaches rivers, lakes and oceans
  3. Removing carbon dioxide from the air to fight climate change
  4. Cooling neighborhoods by providing shade and emitting water vapor
  5. Making cities more beautiful with natural sights like flowers and trees

Unlike pipes and treatment plants, green infrastructure gets better over time as plants grow. It requires less maintenance and energy too. Both gray and green infrastructure are important, but green infrastructure offers more benefits.

Green Infrastructure

Examples of Green Infrastructure

There are many types of GI . Some common examples include:

Parks and Open Space – Parks, meadows and natural areas allow rainwater to soak into the ground instead of running off streets into storm drains. Parks also improve air quality and provide shade.

Rain Gardens – Shallow landscaped pits filled with native plants and compost soak up rainwater from roofs, driveways and streets that would otherwise carry pollution into local waters. The plants and soil filter out pollutants.

Bioswales – Bioswales are rain gardens along streets and parking lots designed to capture and filter stormwater runoff. Native plants slow and filter the water while also making neighborhoods prettier.

Green Roofs – Rooftops covered with a lightweight soil mix and hardy succulent plants absorb and evaporate rainwater. Green roofs last longer than conventional roofs by protecting materials from sun and weather.

Urban Tree Canopy – Trees along streets, in parks and residential yards capture and store rainwater while also removing carbon dioxide and cooling air temperatures through shade and evapotranspiration.

Community Gardens – Gardens grown by local volunteers on vacant lots provide community green space while generating healthy local food options in urban areas.

These are just some examples of green infrastructure that enhances communities through natural processes.

Green Infrastructure


Cost Savings and Economic Benefits

While costs vary by project type and scale, GI often saves money over time:

  1. Reduces flooding by absorbing more rainwater, preventing cleanup and repair costs. Every $1 spent on green infrastructure can save $7 in flood damages.
  2. Lowers urban temperatures which reduces demand for air conditioning, cutting electricity bills.
  3. Requires less maintenance than mechanical gray infrastructure. A bios wale costs 50-80% less than a storm water treatment facility.
  4. Improves health through cleaner water and air, reducing medical expenses. Chicago estimates that each additional tree saves $68 in health costs.
  5. Raises property values by up to 15% due to improved aesthetics, wildlife habitat, and recreation opportunities.
  6. Creates more jobs per $ invested compared to gray infrastructure. Each $1 million spent on green infrastructure produces 10-31 more job years than $1 million spent on gray infrastructure.

Green infrastructure costs more upfront but pays back over time through many savings and benefits.

Community Benefits Beyond Cost Savings

In addition to saving money, it improves communities:

  1. Cleaner water – Rain gardens, bioswales, green roofs, and urban forests filter out pollution and reduce contaminated runoff.
  2. Less flooding – Absorbing and holding more rainwater locally decreases flood severity, road closures, and property damage.
  3. Cooler neighborhoods – Evapotranspiration and shade from vegetation cools down heat islands in urban areas up to 9°F.
  4. Cleaner air – Trees remove air pollutants like ozone, nitrogen oxides, sulfur dioxide and particulates. 1 acre of trees removes 2.6 tons of particulates annually.
  5. Habitat – Parks and rain gardens create urban wildlife habitat and biodiversity hotspots for birds, pollinators and many species.
  6. Recreation – Green spaces give people places to play, exercise and socialize for better physical and mental health.
  7. Local food– Community gardens provide fresh produce and plants in neighborhoods lacking grocery stores.

Green infrastructure grows communities that are greener, cooler, healthier and happier.

Examples of Successful Green Infrastructure Projects

Many cities have implemented GI programs that showcase benefits:

  1. Portland, Oregon – Over 448 green streets, 500 eco roofs, and 1,000+ rain gardens capture storm water, save $250 million in hard infrastructure costs, and add wildlife habitat across neighborhoods.
  2. Philadelphia, Pennsylvania – A $2.4 billion green infrastructure plan transformed over 1,600 acres of impervious areas into green infrastructure assets, reducing runoff by 6 billion gallons annually.
  3. Madison, Wisconsin – 350 rain gardens, 125 green alleys, 250 green streets, and more absorb over 250 million gallons of storm water yearly, leading to cleaner lakes.
  4. Seattle, Washington – RainWise program rebates residents for installing rain gardens and cisterns, capturing 5 million gallons annually from over 2000 properties and counting.
  5. New York, New York – Green infrastructure projects across neighborhoods including green roofs, trees, porous pavement and right-of-way gardens reduced drainage flows by 2.7 billion gallons per year.

These leading cities show that GI can be implemented at large scale to transform neighborhoods.

Design Considerations

Key factors to consider when designing GI projects:

Site – Evaluate drainage, soils, slopes and space constraints. Favor slow infiltration over slopes.

Scale – Right-size systems for the drainage area and runoff volume treated. Consider modular designs that can be expanded.

Soils – Amend soils with compost to improve water retention and filtration.

Native Plants – Choose hardy, non-invasive plants suited to sun, soils and climate at the site.

Water harvesting – Collect drainage from downspouts and impervious areas to direct into the system.

Community fit – Seek input on appropriate locations that meet neighborhood needs like recreation and walkability.

Maintenance – Ensure long-term care plans, access for workers, and educational signage.

With careful design green infrastructure can sustainably treat storm water for decades.

Getting Involved in Your Community

Everyone can take action to support green infrastructure locally:

Volunteer – Get involved with groups like park conservancies for hands-on project building and maintenance.

Advocate – Lobby city officials and attend town halls to request integrating green infrastructure in public works budgets and projects.

Educate – Share information on your social networks about the benefits of GI to build support.

Install green infrastructure – Turn your yard into a mini green infrastructure site with rain barrels, garden beds, and shade trees.

Reduce pavement – Replace paved areas on your property with permeable pavers or vegetation to allow storm water infiltration.

Start a community garden – Work with neighbors to convert vacant lots into shared green spaces with native plants.

Map opportunities – Identify high priority locations needing GI  improvements like parking lots and school grounds.

Our voices and actions together can green every community for healthier, more sustainable living.


Green infrastructure leverages natural systems to sustainably manage water and revitalize communities. As climate change increases storms and flooding, expanding green infrastructure protects properties and people while also cleaning the air and beautifying neighborhoods. By getting involved, we can advocate for policies, projects and practices that transform gray cities into green oases benefiting all.

Frequently Asked Questions

What are the most cost effective types of green infrastructure?

Some low cost but high impact options are downspout disconnection to perimeter drainage, converting abandoned lots to pocket parks, green street medians, swales along roads, and planting street trees.

How does green infrastructure relate to sustainability?

Green infrastructure applies concepts of ecological engineering and landscape ecology to handle urban and climatic challenges like storm water management in sustainable ways.

Which plants are best for rain gardens and bioswales?

Native vegetation with deep roots like ferns, sedges, rushes, shrubs and some wildflowers perform well by infiltrating water and filtering pollutants.

How much maintenance does green infrastructure require?

Much less than mechanical systems. Limited occasional weeding, replanting and sediment removal is needed. Design with community upkeep capacity in mind.

Where can I learn more about green infrastructure projects in my area?

Contact local environmental agencies, non-profits, master gardeners groups, government sustainability offices and conservation districts to learn about green infrastructure initiatives near you

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