Green infrastructure, or blue-green infrastructure, is a system that helps solve problems in cities and with the climate by working with nature. This system includes managing rainwater, preparing for changes in the weather, reducing hot temperatures, supporting plant and animal life, growing food, improving air quality, creating energy from natural sources, keeping water clean, and maintaining healthy soil. It also helps people by offering places to relax, providing shade, and offering protection in and around cities. Green infrastructure supports the health of the environment, communities, and the economy. Recently, experts and activists have also emphasized the need for green infrastructure that helps all people have fair access to natural benefits, instead of making some groups less able to use them.

Green infrastructure is part of a larger group called "Sustainable and Resilient Infrastructure," which is described in standards like SuRe, a guide for building strong and lasting infrastructure. Green infrastructure can also refer to "low-carbon infrastructure," such as systems that use renewable energy or public transportation (see "low-carbon infrastructure"). Blue-green infrastructure is often part of "sustainable drainage systems" or "sustainable urban drainage systems" (SuDS or SUDS), which help manage water in cities while also improving nature and making areas more pleasant for people to live in.

Introduction

Nature can help protect communities from problems like flooding, extreme heat, and poor air, soil, and water quality. When people use natural systems, such as prairies, to manage these issues, it is called "green infrastructure." Prairies have soil that soaks up water and plants that remove pollutants. Green infrastructure works at many different sizes, but it is most often linked to systems that manage rainwater in an efficient and cost-effective way, such as green stormwater infrastructure. These systems support the health of the environment, society, and economy.

"Blue infrastructure" refers to urban systems that involve water, such as rivers, lakes, ponds, and coastal areas. Blue infrastructure often works together with green infrastructure in cities and is sometimes called "blue-green infrastructure." Natural water features like rivers and lakes can be part of a city's design, or new water areas can be added. Coastal cities may use parts of the shoreline in their planning, such as harbors, piers, and quays. Blue infrastructure helps support water life, including insects, frogs, and birds. It also provides extra benefits for people who live near these water areas, which are sometimes called "blue spaces."

Terminology

Ideas for green urban structures began in the 1870s with plans for urban farming and garden spaces. Other terms used are stormwater best management practices, source controls, and low impact development (LID) practices.

Green infrastructure ideas started in the mid-1980s with plans to manage stormwater more effectively, aiming to reduce runoff, prevent erosion, and help underground water storage. In 1987, changes to the U.S. Clean Water Act added rules to manage pollution from urban areas, requiring practices that handle runoff where it starts. In 1990, the U.S. Environmental Protection Agency (EPA) created rules for municipal storm sewer systems ("MS4"), requiring large systems to develop stormwater pollution plans and use "source control practices." An EPA handbook from 1993 listed best practices, such as using plants, filters, and materials that let water soak into the ground. Rules for smaller cities were added in 1999. MS4s serve over 80% of the U.S. population and drain water for 4% of the land.

Green infrastructure focuses on using the natural environment in land-use planning. However, the term does not have a single, clear definition. It is also called "blue-green infrastructure" or "green-blue urban grids" and is used by many fields, including design, conservation, and planning. These terms often include stormwater management, climate adaptation, and green spaces that serve many purposes.

Sometimes, the term "green infrastructure" is expanded to "multifunctional" green infrastructure. This means combining different uses, such as managing stormwater and providing public spaces, on the same land.

The EPA expanded the term "green infrastructure" to describe managing stormwater using natural or man-made systems that copy nature. This helps protect ecosystems, even though it is not the main focus of the broader concept.

The term "blue-green infrastructure" is often used in cities and emphasizes managing stormwater as part of creating sustainable, multifunctional urban areas. At the building level, "blue-green architecture" applies similar ideas on a smaller scale, using water from sources like rainwater and grey water for building greening.

As mentioned, the term Green Infrastructure (GI) now includes topics like walking, cycling, and renewable energy, which can confuse stormwater experts. To clarify, the term Green Stormwater Infrastructure (GSI) was created in the 2010s by stormwater professionals in the U.S. GSI specifically refers to stormwater management and separates it from other GI topics. GSI includes small-scale measures, like stormwater curb extensions, tree well filters, and pervious pavement, as well as large projects that manage runoff over hundreds of acres. Many U.S. cities and regions have created guides, such as the GSI Handbook by the Santa Clara Valley Urban Runoff Pollution Prevention Program in California.

History

Green infrastructure as a term was first used in the early 1990s, though the idea existed long before that. The first known use of the term was in a 1994 report by Buddy MacKay, who led the Florida Greenways Commission. He wrote about the Florida Greenways Project, an infrastructure project started in 1991. MacKay explained, "Just as we plan roads, water, and electricity for communities, we must also plan and manage green spaces like parks and natural areas."

In ancient China, gardens from the Shang Dynasty (1600–1046 BC) were examples of sustainable lawns. These gardens were designed to let native plants grow naturally, creating safe spaces for wildlife in cities.

In ancient Greece, the concept of green infrastructure began with the creation of agoras. Agoras were public spaces where people gathered to talk. Some agoras included natural elements like trees and plants, blending nature with human activity.

A common urban feature is the lawn, which is usually made of short grass and sometimes plants. While modern artificial lawns can harm the environment, older lawns helped support biodiversity and native plants. These past examples influence modern designs for more sustainable lawns.

In medieval Europe, flower meads were lawns filled with flowers and plants. These were sustainable and helped support pollinators like bees. Later, in the Edwardian Era, lawns with thyme plants were used to attract insects. In the 20th century, "enamelled meads" were created in England for both beauty and to manage stormwater.

During the Renaissance, public areas like parks and gardens became common in cities. These spaces were used for relaxation and socializing, and they also helped improve the appearance of cities. They also provided fresh air and reduced heat in urban areas.

Green infrastructure can be traced back to the 17th century in Europe, starting in France. French cities used nature to organize public spaces and grow food near people. Large open areas were created to give calm, beautiful spaces for the wealthy to enjoy. These areas also included promenades, which were gardens where people could escape city life and relax.

French city planners focused on making cities green by combining urban design with nature. They often included gardens and green spaces in city plans to show how people and nature could coexist.

In 18th-century France, citizens asked to remove old city walls to build new gardens and green walkways. This added more green spaces to cities. Town halls and city centers were decorated with rare plants and trees brought from other countries. These gardens made cities look more beautiful.

In 1847, George Perkins Marsh warned about the harm of deforestation. He later wrote a book called Man and Nature in 1864 about protecting forests. Around the same time, Henry David Thoreau wrote Walden in 1854, arguing that cities should have parks to protect nature. Frederick Law Olmsted, a landscape architect, agreed and designed parks like Boston’s Emerald Necklace in 1887. This park system helps protect wildlife and manages water.

In Europe, Ebenezer Howard promoted the garden city movement to balance development with nature. He designed cities with greenbelts and tree-lined roads to connect urban and rural areas.

In the late 1800s, the U.S. government started protecting land and nature. This began with the 1864 law to preserve Yosemite Valley as a public park and the creation of the first U.S. national park in 1872.

In the 19th century, industrial leaders wanted to improve workers’ lives by creating clean environments and outdoor spaces. This idea continued into the 20th century with green spaces in industrial areas, gardens, and suburbs.

The Anaconda Copper Mining Company caused environmental harm in Montana, but a refinery in Great Falls used the surrounding land to create a green space for recreation. This area included a golf course, flower beds, picnic spots, a pond, and walking paths.

The role of water: blue spaces and blue infrastructure

Water has always been an important reason why people choose to live in certain places. Water and the land around it help with moving goods, trading, and creating energy. It also gives people things like drinking water, food, and opportunities for activities such as swimming or sightseeing. Many of the world's biggest cities are near rivers, lakes, or oceans. Cities have built systems like canals and harbors to use the benefits of water while reducing risks from problems like flooding. However, cities now face serious water challenges, such as floods, dry periods, and activities on rivers that cross borders between countries. As cities grow quickly, many water-related structures are no longer visible. Coastal areas are becoming more populated, and many cities have changed old canals, riverbanks, and docks due to changes in how goods are traded worldwide. Scientists have recently studied how improving areas near water can help people's health. A review from 2017 found that being near water areas, like lakes or rivers, is linked to better mental health and more physical activity.

One-fifth of the world’s people, or about 1.2 billion, live in places where water is not enough. Climate change and water-related disasters will increase the need for water in cities and cause more people to move there. Cities use a lot of fresh water and affect water systems greatly. Water use for cities and industries is expected to double by 2050.

In 2010, the United Nations said that clean water and sanitation are basic human rights. Scientists are looking for new ways to make cities more sustainable. Managing water in cities is complicated and needs more than just pipes and sewers. It also requires controlling pollution, preventing floods, and working together across different groups and governments to use water more fairly and wisely.

Types of green infrastructure

Urban forests are forests found in cities. They are an important part of urban green spaces. These forests use tree and plant species that are not harmful or invasive, which helps reduce the need for frequent maintenance and watering. Native species also add beauty to the area and lower costs. Including a variety of plant species in urban forests is important to avoid having only one type of plant, which makes the forests stronger and better at resisting pests and damage.

• Energy use: A study by the Lawrence Berkeley National Laboratory and Sacramento Municipal Utility District found that shade trees planted near homes can save up to 47% of energy used for heating and cooling.
• Urban heat island mitigation: Areas with tree groves have lower maximum air temperatures than open areas without trees. This happens because trees cool the air through processes like evaporation from plant leaves, shading from tree canopies, and changes to the surface that help cool the air.
• Water management: Urban forests help manage city water by reducing the amount of stormwater that flows into water channels. Trees catch a lot of rainwater before it reaches the ground.
• Property values: Adding more trees and greenery in cities can increase the value of nearby homes and businesses.
• Public health: Green spaces in cities improve mental health and well-being. Urban forests help reduce the effects of heat islands, which are areas that become very hot due to city materials and structures. Trees provide natural shade at a lower cost than artificial structures and help counter the health risks of rising temperatures. Green spaces can also make ecosystems more stable, as seen in traditional Japanese farming. Green infrastructure in cities can help ecosystems recover from natural disasters and create jobs that do not require advanced education, reducing unemployment. Green spaces also support agreements like the 1992 Rio Declaration, which aims to reduce the negative effects of environmental harm on society.

Constructed wetlands are manmade wetlands that act as natural filters. They include plants and are usually built on land that is not part of natural wetlands or water areas. This helps protect natural wetlands from damage. There are two main types of constructed wetlands: those where water flows underground and those where water flows on the surface. Proper planning and management help prevent harm caused by changes to natural water systems or the introduction of non-native plants.

• Water efficiency: Constructed wetlands mimic natural wetlands to improve water quality and efficiency. They use plants, soil, and microorganisms to trap pollutants and slow water flow.
• Cost-effective: Constructed wetlands have low costs for operation and maintenance. They can handle changes in water levels and add greenery to their surroundings. They also reduce unpleasant smells from wastewater.

Green roofs improve air and water quality and lower energy costs. In some areas, green roofs have been linked to higher albedo, which reflects more sunlight and lowers temperatures, reducing energy use. Plants and soil on green roofs add green space and insulation. Green and blue roofs also help manage stormwater by holding rainwater, which can reduce runoff in crowded cities. Green roofs can also help grow food on rooftops for residents.

Green roofs capture rainwater and carbon pollution. About 40% to 80% of rain that falls on green roofs can be stored. The water is released slowly, reducing the amount of runoff that enters water systems at once.

Blue roofs are not considered green infrastructure but collect and store rainwater to reduce the sudden flow of runoff into sewers. They use detention ponds or basins to hold rainwater before it is released slowly into sewers or waterways. Blue roofs also help reduce energy costs for cooling and lower the urban heat island effect when used with reflective roofing materials.

Rain gardens are a way to manage stormwater by capturing water. They are shallow, planted areas that collect rainwater from roofs or pavement and let it slowly soak into the ground.

Regular lawn grass is not effective at controlling runoff, so alternatives are needed to reduce harmful runoff and slow water flow for absorption. In homes, rain gardens can reduce runoff by 30%. A typical size for a rain garden on a private property is between 150 and 300 square feet. The cost per square foot is about $5 to $25, depending on the plants used and the slope of the land. Native plants from wetland and river areas are best for removing toxins from runoff.

Stormwater basins collect rainwater in vegetated depressions to reduce runoff, prevent erosion, filter water, and stop flooding. Newer designs use more plants instead of mowed grass, making them more sustainable. These designs, called bioretention basins, are especially good at removing pollutants and absorbing sediment. Stormwater basins are a key part of the "sponge city" concept for managing floods.

Downspout disconnection is a type of green infrastructure that separates roof downspouts from sewer systems and redirects rainwater to permeable surfaces. This helps store stormwater or let it soak into the ground. It is especially useful in cities with combined sewer systems, where heavy rain can cause basement backups and sewer overflows. To reduce rainwater entering these systems, organizations like the Milwaukee Metropolitan Sewerage District have updated rules to require downspout disconnection in residential areas.

Bioswales are stormwater systems that offer an alternative to traditional sewers. Like rain gardens, bioswales are vegetated or mulched channels often placed in narrow spaces in cities. They absorb or carry stormwater.

Planning approach

The Green Infrastructure approach studies the natural environment to understand how it works and then creates rules or planning policies to protect important natural areas. If certain natural functions are missing, plans may suggest ways to fix them using natural or man-made improvements.

In cities, this approach can help restore natural waterways and make cities more self-sustaining, especially with water. For example, cities can collect rainwater locally, reuse it, and include stormwater management in everyday structures.

This method is important for using land efficiently and sustainably, especially in crowded places like England, where land is in high demand. An example is a river floodplain near a city, which can store floodwater, serve as a nature reserve, provide space for recreation, and even support farming through grazing. Research shows that natural environments can also improve human health.

In the United Kingdom, Green Infrastructure planning is now widely used in national, regional, and local policies. For example, it is included in plans for the Milton Keynes and South Midlands Growth area.

In 2009, Natural England released guidelines to help with Green Infrastructure planning. These guidelines emphasize the role of Green Infrastructure in "place-making," which means helping to keep the unique character of a place, especially when new buildings are planned.

In North West England, a past plan called the Regional Spatial Strategy included a Green Infrastructure Policy (EM3) and other policies related to land use. This policy was supported by the North West Green Infrastructure Guide. The Green Infrastructure Think Tank (GrITT) helps develop policies in the region and manages a website with information about Green Infrastructure.

The Natural Economy Northwest program supported projects led by The Mersey Forest to study the value of Green Infrastructure. Work included looking at how Green Infrastructure connects with traditional infrastructure, such as stormwater systems, and identifying areas where it can help solve problems like flooding or poor air quality.

In March 2011, a Green Infrastructure Valuation Toolkit was created. This toolkit, available for free, helps measure the economic benefits of Green Infrastructure projects. It has been tested in areas like the Liverpool Green Infrastructure Strategy.

In 2012, the Greater London Authority released the All London Green Grid Supplementary Planning Guidance (ALGG SPG). This plan suggests creating a network of green spaces and waterways to improve travel, flood management, health, and economic and social benefits.

Green Infrastructure is promoted as a way to address future climate change challenges.

Green Infrastructure may include goals related to the diversity of natural landscapes.

In the United States, programs managed by the EPA and partners aim to improve water quality by managing stormwater runoff more effectively. These efforts reduce pressure on traditional drainage systems, such as underground pipes and surface water channels, which are common in cities. Better stormwater management is expected to reduce overflows in sewers, lower urban flooding risks, and provide other environmental benefits.

Although Green Infrastructure is not yet widely used, many U.S. cities are starting to use it to meet requirements for MS4 permits. Cities do this by offering programs that encourage private property owners to create or improve Green Infrastructure. There are about 555 such programs nationwide. For example, Philadelphia has installed permeable pavements in parks, rain gardens at schools, and wetlands to manage stormwater. These improvements help reduce the amount of water entering the city’s aging sewer system during rainstorms.

In Maryland, a program called "GreenPrint" uses maps to show the ecological importance of every piece of land in the state. This tool helps protect environmentally important areas and supports future land use decisions. GreenPrint Maryland was created in 2001 to preserve lands critical to the state’s natural resources.

In 2011, the EPA announced a plan to protect water and build better communities through Green Infrastructure. Ten communities were selected as partners: Austin, Texas; Chelsea, Massachusetts; Northeast Ohio Regional Sewer District (Cleveland, Ohio); Denver, Colorado; Jacksonville, Florida; Kansas City, Missouri; Los Angeles, California; Puyallup, Washington; Onondaga County and Syracuse, New York; and Washington, D.C.

The Federal Emergency Management Agency (FEMA) also supports Green Infrastructure as a way to manage urban flooding.

Since 2009, Singapore’s Public Utilities Board has published two editions of the ABC (Active, Beautiful, Clean) Waters Design Guidelines. The latest version (2011) includes planning and design ideas for integrating drains, canals, and reservoirs with the environment. The Public Utilities Board encourages landowners, developers, and the public to use ABC Waters features in their projects for recreation and education.

Key benefits of the ABC Waters Concept include:
– Treating stormwater naturally near its source using plants and soil, which helps keep water clean before it reaches rivers and reservoirs.
– Improving biodiversity and making areas more attractive.
– Bringing people closer to water and creating spaces for recreation and learning.

Examples

A good example of green infrastructure used on a large scale is the Beijing Olympic site. First built for the 2008 Summer Olympics and later used for the 2022 Winter Olympics, the site covers a large area of old industrial land being redeveloped in the northern part of the city between the 4th and 5th ring roads. The main green infrastructure feature is the "Dragon-shaped river," a system of water storage areas and wetlands covering more than 500,000 square meters. From above, the system looks like a traditional Chinese dragon.

This system helps reduce the amount of nutrients in water coming from a nearby wastewater recycling facility. Farmers claimed that their farmlands flooded because of development upstream. The flooding happened when water from hard, impermeable surfaces ran off into storm drains and flowed into their farmlands. The farmers received an undisclosed amount of money in the tens of millions as compensation. Areas with low building density and many paved surfaces send stormwater into streams faster than before development. These practices harm the environment and are costly to maintain. In response, the city of Surrey used a green infrastructure strategy on a 250-hectare site called East Clayton. This approach reduced stormwater flowing downstream and allowed rainwater to soak into the ground near where it fell. The system could hold one inch of rain each day, which covers 90% of the area’s yearly rainfall. Green infrastructure in Surrey helped create a sustainable environment, reducing runoff and saving about $12,000 per household.

The former factory site at Nya Krokslätt is located between a mountain and a stream. Danish engineers, Ramboll, designed a system to slow and guide stormwater using methods like plants, ponds, streams, and soak-away pits. Green and blue areas around buildings help delay and clean water from roofs and greywater. The design includes energy-efficient buildings and blue-green infrastructure to support ecosystems in the city.

Since 1991, the city of Zürich has required all flat roofs (except those used as terraces) to be covered with plants. This policy helps increase biodiversity, store rainwater, and reduce the speed of water flow. Green roofs also help control temperature extremes and improve air quality. These roofs act as stepping stones for plants and animals, connecting with natural areas and helping maintain urban green spaces.

In the Ruhr District of Germany, Duisburg-Nord is a landscape park that includes old industrial structures and natural biodiversity. Architects Latz + Partner designed a water park using the old River Emscher, divided into five sections: Klarwasserkanal, Emschergraben, Emscherrinne, Emscherschlucht, and Emscherbach. Rainwater is collected through barriers and water channels to gradually supply the old river. This ensures water remains in the river even during dry periods, supporting plant and animal life. The park also includes overgrown areas with diverse plant and animal species, some of which are endangered. The plan also made the water system visible to help people connect with it.

The Greenhouse Project started in 2008 when parents and teachers wanted to teach children about food, the environment, and sustainability. The project uses greenhouses on school rooftops with hydroponic farms, solar panels, rainwater collection systems, weather stations, and worm composting. Topics include nutrition, water use, land use, climate change, biodiversity, and sustainable development. Students learn how humans and the environment are connected and how to support sustainable living.

In the 1990s, Hammarby Sjöstad was a polluted and unsafe area in Stockholm. Now, it is a new district with strict environmental rules for buildings and infrastructure. The Hammarby Model, developed by Fortum, Stockholm Water Company, and Stockholm Waste Management, uses energy, waste, and water systems to support sustainable living. Examples include using heat from treated wastewater for heating, returning rainwater to nature through green roofs and pools, and recycling sludge from wastewater as fertilizer. This model has inspired projects in cities like Toronto, London, and China.

The EPA helped Emeryville, California, create "Stormwater Guidelines for Green, Dense Redevelopment." Emeryville, near San Francisco, redeveloped old industrial sites in the 1990s, leading to economic growth. In the 2000s, the city required new developments to use green infrastructure for stormwater management. Challenges included a high water table, tidal flows, clay soil, contaminated land, and few natural areas. Guidelines and a spreadsheet model were created to use redevelopment sites for stormwater management. Key strategies included reducing parking needs through higher building density, shared parking, and better public transit. Other strategies included requiring bicycle parking and improving walking and biking paths.

Geographic information system applications

A geographic information system (GIS) is a computer tool that helps people collect, save, show, and study data about places on Earth. GIS can combine many types of information on one map, such as roads, buildings, soil kinds, plants, and more. Planners use GIS to mix or calculate useful details, like the percentage of areas that do not let water pass through or how much green space covers a certain area. This helps them plan or study green infrastructure projects. GIS can also include public participation GIS (PPGIS), which adds information from people in the community. This gives more context beyond just environmental details for planning. As GIS systems improve and are used more often, they become important for creating Green Infrastructure plans. These plans often rely on GIS to study many layers of geographic data. When planning urban green infrastructure projects, GIS systems now use methods from many different fields. This includes looking at social, economic, environmental, and cultural factors of an area. This helps planners create better, more complete plans for projects.

According to the "Green Infrastructure Master Plan" by Hawkins Partners, civil engineers use GIS to study models of impervious surfaces with historical rainfall data in Nashville. This is done within the combined sewer system (CSS), which carries both stormwater and sewage. GIS helps planning teams find out how much water could be reduced in a specific area through green infrastructure projects. These projects include water collection systems, green roofs, city trees, and structures that control water flow.

Implementation

Lack of money is often mentioned as a challenge when trying to build green infrastructure. However, green infrastructure projects can be supported by many different sources of funding because they offer many benefits. Some tax programs run by federal agencies can help bring money to these projects. Here are two examples of such programs:

• The U.S. Department of Energy manages tax incentives for energy efficiency. Green infrastructure can be included in project designs to qualify for these incentives. For example, in Eugene, Oregon, a new biofuel station built on an old gas station site included a green roof, bioswales, and rain gardens. This project earned nearly $250,000 in tax credits, which reduced income and sales taxes for the company that built it.
• The U.S. Department of Treasury runs the New Markets Tax Credit Program, which encourages private investment in projects like real estate or business development in areas that need help. Awards are given to non-profit and private groups based on their plans for using these tax benefits.

Some people might think green spaces are too expensive or hard to maintain, but well-designed green spaces can provide real economic, environmental, and social benefits. For example:
• Urban trees can help manage stormwater and reduce energy costs and runoff.
• Bioretention systems can be used to create green transportation systems.
• Lawn grass is not a good solution for runoff, so alternatives like rain gardens are needed. In homes, rain gardens can reduce runoff by about 30%. A typical size for a rain garden on a private property is between 150 and 300 square feet. The cost per square foot is about $5–$25, depending on the plants used and the slope of the land. Native trees, shrubs, and wetland plants are most helpful for reducing runoff.

Well-designed green spaces help balance built and natural areas. More green space in communities has been linked to increased physical activity among older men and better mental health for people living near green areas.

Studies show that people value the experiences green infrastructure provides, such as beauty, health, and a sense of place. This means green infrastructure should be designed to include these elements, as they improve how communities see its value and quality of life.

A 2012 study of 479 green infrastructure projects in the U.S. found that 44% reduced costs, while 31% increased them. The biggest savings came from less stormwater runoff and lower heating and cooling costs. Green infrastructure is often cheaper than traditional water management methods. For example, Philadelphia’s green plan would cost $1.2 billion over 25 years, compared to $6 billion for a traditional plan.

Philadelphia’s green plan is expected to:
• Create 250 green jobs each year.
• Avoid or absorb up to 1.5 billion pounds of carbon dioxide yearly (equivalent to removing 3,400 cars from roads).
• Improve air quality through trees, green roofs, and parks.
• Help communities with health and social benefits.
• Prevent about 20 asthma-related deaths.
• Reduce missed work or school days by 250.
• Cut deaths from extreme heat by 250 over 20 years.
• Increase property values by $390 million over 45 years, boosting property taxes.

In New York City, a green plan would cost $1.5 billion less than a traditional plan. Green stormwater systems alone would save $1 billion, costing about $0.15 less per gallon. Over 20 years, sustainability benefits in New York City could range from $139–$418 million. Each fully vegetated acre of green infrastructure is expected to provide $8.522 in energy savings, $166 in reduced CO2 emissions, $1,044 in better air quality, and $4,725 in higher property values yearly.

A 2016 study in the United Kingdom found that residents are more willing to pay for green infrastructure that is visibly green, easy to access, and provides multiple benefits on one site. This suggests that designing green spaces to be functional and attractive can increase their value. Encouraging residents to invest in green projects in their areas can create more money for future projects, improving their economic success.

In cities like Chicago, green infrastructure projects aim to improve the environment and livability, but they can also cause social issues like gentrification. This happens when new green spaces in low-income areas raise property values, pushing out current residents. Studies show these projects improve air quality and reduce heat, but benefits often go to wealthier, whiter neighborhoods. In Los Angeles, research found that green infrastructure can lead to "green climate gentrification," where minority communities face larger gaps in green space, housing prices, and environmental quality. The effects of gentrification depend on the community and the types of infrastructure built, such as green spaces or transportation systems.