What is Green Infrastructure?

How can you use green infrastructure to protect and improve your community’s water?

Green infrastructure (GI) consists of a range of methods to reduce stormwater flows to sewer systems and surface waters. Unlike water treatment plants, green infrastructure mimics nature by using soil, plants, and other elements to detain or absorb stormwater. Restoring natural areas also provides new spaces for play, habitats for wildlife, and a host of other benefits.

The seven examples below will introduce you to different types of green infrastructure, and examples of organizations in urban areas that are using green infrastructure to improve water quality in their communities.

Bioretention Basins & Rain Gardens

Bioretention basins and rain gardens are depressed areas that collect stormwater from nearby buildings, streets and other impervious surfaces. The plants and soil allow stormwater to soak into the ground, filter pollutants and provide wildlife habitats.

The terms are sometimes used interchangeably. However, a bioretention basin more commonly refers to a large depressed area on a commercial property. Rain gardens are often associated with gardens on residential properties.

Aim High: The 12,000 Rain Gardens in Puget Sound Campaign

A massive undertaking is underway in the Seattle/Puget Sound region: install 12,000 rain gardens to clean millions of gallons of polluted runoff.

Dr. Aaron Clark, Director of Strategic Partnerships for Stewardship Partners, explained how the campaign got its name. “The decision to center a numeric goal, and a big one, was a public engagement decision. 12,000 Rain Gardens would clean up 160 million gallons of polluted runoff in the Puget Sound Region, we estimated. Being part of a big effort that would make a real impact on our region’s water quality, wildlife and quality of life seemed compelling. Ambitious but achievable with built in accountability and metrics.”

Since the campaign launched in 2011, residents, businesses and the government have installed over 6,000 rain gardens. Clark believes the campaign’s bold name helped the campaign leaders engage broad audience and draw media attention.

To track and communicate the campaign’s progress, Stewardship Partners created the online portal, Sound Impacts. The portal also helps Clark’s team with a thorny problem: how to collect data from every rain garden owner. “Seeing how your own project or the collection of projects you’ve worked on fits into a bigger picture of environmental improvement and recovery is a pretty powerful draw too.” The 12,000 Rain Gardens in Puget Sound Campaign confirms there is strength in numbers.

Blue & Green Roofs

Blue and green roofs are designed to absorb stormwater and slow the speed that it drains from a roof.

A green roof uses vegetation, soil, and a waterproofing membrane. The vegetation also absorbs heat energy, and provides a habitat for animals and insects. A blue roof does not have vegetation, and instead uses rocks, geotextiles and plastics to retain water.

How Green Infrastructure Provides Sweet Rewards to the Osborne Association

Transformation is in the DNA of the Obsorne Association. Since 1933, the organization has committed to transforming the criminal justice system while creating opportunities for impacted families and communities.

In 2012, the Osborne Association embarked on a new transformation: to change its unordinary roof into an integrated blue and green roof. The NYC Department of Environmental Protection helped subsidize the $700,000 undertaking with a $288,000 green infrastructure grant.

The Osborne Association’s home in the Bronx is a nondescript, three-story building constructed in 1925. The building’s roof had to be reinforced in order to withstand the green infrastructure’s weight, which also created an opportunity to add new insulation.

Next, the roof began to take shape. The blue roof system consisted of 2×2 foot stainless steel trays. Chunks of granite in the trays would slow stormwater from draining from the roof. To keep the roof low maintenance, the green roof squares were planted with sedum, a family of perennial plants that can survive 30 days without water.

Lastly, the team installed a monitoring system to measure the system’s impact. They placed a rain gauge in the center of the roof and water flow meters at each exit drain. The result was an integrated blue and green roof system design that was lighter and required lower maintenance than most green roofs.

Today, the roof is “on auto-pilot” and is “maintenance-free” according to Dr. Todd Patton, the Osborne Association’s Medical Director. Data from the monitoring system shows the roof absorbs 43% of water that hits its surface.

An apiary, also known as a bee yard, is the roof’s newest edition. Dr. Patton, who is a beekeeper, as well as a doctor, oversees the four bee hives. He says the bees enjoy water from the blue roof trays. Plus, their honey provides gifts of appreciation to staff members and donors.

The Osborne Association’s roof transformation is a great model for building owners who are looking to reduce their building’s impact on the local watershed.

Cisterns & Rain Barrels

A cistern is a large vessel designed to catch and hold stormwater. A system of pipes directs water from roofs and impermeable surfaces into the cistern, which can be located above or below ground.

A rain barrel is similar to a cistern, but typically much smaller. The EPA rates cisterns and rain barrels as particularly valuable in arid regions to reduce demands on limited water supplies.

Lafayette Residents Rush to Receive Subsidized Rain Barrels

In 2013, the Lafayette Utilities System launched a rain barrel giveaway program to reduce stormwater runoff into the Bayou Vermilion Watershed. Each year, 300 lucky residents of Lafayette, Louisiana can reserve a subsidized rain barrel from The Great American Rain Barrel Company.

The rain barrels hold 55 gallons of water that can be used for gardening or other outdoor purposes. Plus, the rain barrels are part of an upcycling scheme, a process where unwanted products are creatively reused. The Great American Rain Barrel Company sources used barrels from a food importing business, which previously stored olives and other imported goods.

Your community may have a rain barrel giveaway program, too. Contact your local government to learn more.

Perforated Pipes & Stormwater Chambers

In a perforated pipe system, parallel perforated pipes buried in gravel store stormwater and then release it into the ground.

A stormwater chamber, instead, uses open-bottom, perforated plastic chambers surrounded by stone.

Subsurface Systems Pass the Test in a Bronx Housing Complex

The New York City Department of Environmental Protection (DEP) installed subsurface systems at a housing complex in the Bronx. During a 2-year pilot period, DEP used a variety of techniques to characterize how the subsurface systems impacted water quantity and quality, and soil quality.

First, the research team installed flow turbines at inflow and outflow pipes to measure flow rates. They also mounted a rain gauge to measure local precipitation. Lastly, they took water and soil samples to test levels of diesel, metals and other materials.

The monitoring system captured data for 20 months, weathering 5-day long storms and punishing amounts of rain. In a 2012 report, DEP reached a number of positive conclusions. The stormwater chambers frequently retained nearly all runoff it received. The perforated pipes reduced peak flows by more than 60%. Plus, the systems required minimal routine maintenance. As a result of the successful pilot, DEP created its Guidelines for the Design and Construction of Stormwater Management Systems.

Permeable Pavements

Permeable pavements are designed with materials that allow water to seep in and be absorbed into the ground. Pervious concrete, porous asphalt, or permeable interlocking pavers like the bricks shown in the photo are all examples of permeable pavement materials.

The EPA notes permeable pavements are a cost effective solution for flood or ice-prone areas with costly real estate.

Permeable Pavers Reduce Flooding in a Brooklyn Community Garden

Families and neighbors have been gathering in the Gil Hodges Community Garden in Brooklyn for decades. However until recently, heavy storms would cause the area to flood, and poison the space with industrial pollution.

In 2014, the New York Restoration Project (NYRP) received a $329,000 grant through the NYC Green Infrastructure Grant Program. The grant helped NYRP renovate the park with permeable pavers, a rain garden and a storm drainage detention system. In total, the green infrastructure should manage 150,000 gallons of stormwater annually.

According to Gary Dearborn, NYRP’s Chief of Capital, the permeable pavers and other green infrastructure improvements made an immediate impact by significantly reducing flooding in the area.

The renovation also added playful elements. A 2013 article in The Brooklyn Daily Eagle describes “[a] fragrance walk, inspired by Jo Malone London, featuring lush, textural and aromatic plants, including sweetbay magnolia, ruby spice summersweet, orange azalea and mountainmint.”

The sweeping redesign inspired both the community and NYRP. Dearborn reports, “the experience NYRP gained [with] Gil Hodges Garden was later used on another Green Infrastructure Grant project in the Bronx, and has since become a standard practice for all our garden renovations.” The Gil Hodges Community Garden is a standout example of great design and function.

Riparian Buffers

A riparian buffer is a vegetated area next to a body of water. The grasses, shrubs, trees, and other plants provide a number of benefits: fight erosion, filter pollutants from the water, provide shade, and support aquatic life.

How to Use EnviroAtlas to Measure the Impact of Riparian Buffers in Your Neighborhood

The US Environmental Protection Agency created a series of tools called EnviroAtlas to measure the impact of ecosystem services. Ecosystem services, also known as environmental services, are benefits natural areas provide to maintaining ecosystem health, and human well-being. One tool, the EnviroAtlas Interactive Map, provides access to over 400 maps, and analysis tools. You can use the EnviroAtlas Interactive Map to find the location of riparian buffers in your neighborhood.

1. Open the EnviroAtlas Interactive Map and choose the community you want to study from the Community Selection menu. There are 30 communities to choose from in the United States, and the list keeps growing.

EnviroAtlas community selection menu

2. Select “Land Cover: Near-Water” from the EnviroAtlas Data menu

EnviroAtlas data menu

3. Select “Estimated vegetated cover in stream and lake buffer (percent). Red indicates 20% or less of the area within 15m of a water body has vegetation. Dark green indicates that figure is over 80%.

EnviroAtlas Land Cover Near Water menu

You can also combine the environmental data in EnviroAtlas with demographic data to inform community organizing and planning decisions. For example, EnviroAtlas created an example story map of how to prioritize tree planting in specific neighborhoods to support healthy child development. Follow the story map to learn how to layer several data sources to create a rich, interactive map that tells the story of your community.

Street Trees & Tree Trenches

A tree trench holds stormwater to prevent it from entering the storm sewer system, and irrigates trees.

Street trees provide multiple benefits in addition to reducing stormwater, including: improved water quality, reduction in urban heat island effects, improved air quality, increased tree canopy, and habitat creation.

Street Tree Monitoring in Gowanus Increases Civic Engagement

There are 3,000 street trees surrounding the Gowanus Canal in New York City. Collectively, they provide $360,000 yearly in environmental services including energy savings, carbon dioxide capture, air quality improvement, rainwater capture, and aesthetic improvements.

The Gowanus Canal Conservancy (GCC), a local environmental non-profit, is using Temboo’s Kosmos IoT System to collect data on street trees’ stormwater absorption rates. “Street trees are more widely accepted by the community and much easier to permit and install than other forms of green infrastructure, such as right of way rain gardens and bioswales. Our intention for the monitoring solution was to identify criteria that would allow us to compare stormwater performance of tree pits to green infrastructure,” said Amy Motzny, Watershed Manager at GCC.

two people planting street tree bed

First, soil moisture sensors buried under the street trees send data to a Raspberry Pi gateway device that is hosted on a volunteer’s home WiFi network. Then, the gateway then passes it along to the Kosmos Cloud.

As a result of collecting and reporting on soil moisture data, GCC can advocate for more and better green infrastructure investment. The volunteers who are conducting the monitoring along with GCC have taken a personal stake in the project and are even planning on applying for a grant for a weather station to expand the scope of the application. Overall, street tree monitoring has become an impetus for environmental action and behavioral change in the neighborhood.

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To learn how to measure the impact of your green infrastructure project through environmental sensor data, check our case studies or email us at hey@temboo.com.