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Street-side swale and adjacent pervious concrete sidewalk in Seattle, US. Stormwater is infiltrated through these features into soil, thereby reducing levels of urban runoff to city storm sewers.

Green Infrastructure or blue-green infrastructure is a network providing the “ingredients” for solving urban and climatic challenges by building with nature.[1] The main components of this approach include stormwater management, climate adaptation, less heat stress, more biodiversity, food production, better air quality, sustainable energy production, clean water and healthy soils, as well as the more anthropocentric functions such as increased quality of life through recreation and providing shade and shelter in and around towns and cities. Green infrastructure also serves to provide an ecological framework for social, economic and environmental health of the surroundings.

Background: terminology

Ideas for green urban structures began in the 1870s, with concepts of urban farming and garden allotments.[1]

Green Infrastructure is a concept originating in the United States in the mid-1990s that highlights the importance of the natural environment in decisions about land-use planning.[2][3] However, the term does not have a widely recognised definition.[4][5] Also known as “blue-green infrastructure” [6] or “green-blue urban grids” [1] the terms are used by many design-, conservation- and planning related disciplines and commonly feature stormwater management, climate adaptation and multifunctional green space.

The term "green infrastructure" is sometimes expanded to "multifunctional" green infrastructure. Multifunctionality in this context refers to the integration and interaction of different functions or activities on the same piece of land.

The United States Environmental Protection Agency (EPA) has extended the concept of “green infrastructure” to apply to the management of stormwater runoff at the local level through the use of natural systems, or engineered systems that mimic natural systems, to treat polluted runoff.[7][8] This use of the term "green infrastructure" to refer to urban "green" best management practices (BMPs), although not central to the larger concept, does contribute to the overall health of natural ecosystems.

However, it is apparent that the term “blue-green infrastructure” is applied in an urban context and places a greater emphasis on the management of stormwater as an integral part of creating a sustainable, multifunctional urban environment.[6]

The Rise of Green Infrastructure

The Formative Years:1850-1900

  • Henry David Thoreau writes of the "importance of preserving some portions of nature herself unimpaired."
  • The idea of greenbelt is introduced to England.
  • Man and Nature, by George Perkins Marsh, is published [9]

Experimentation and evolution: 1900-1920s

  • The Bronx River Parkway becomes the first parkway designed for recreation motor use.[10]

Context: the role of water

Many cities are facing severe water uncertainties, such as floods, droughts and upstream activities on trans-boundary rivers. The increasing pressure, intensity and speed of urbanisation has led to the disappearance of any visible form of water infrastructure in most cities.[11]

One fifth of the world’s population, 1.2 billion people, live in areas of water scarcity. Climate change and water-related disasters will place increasing demands on urban systems and will result in increased migration to urban areas. Cities require a very large input of freshwater and in turn have a huge impact on freshwater systems. Urban and industrial water use is projected to double by 2050.[12]

In 2010 the UN declared access to clean water and sanitation a Human Right.[13] New solutions for improving the sustainability of cities are being explored. Good urban water management is complex and requires not only water and wastewater infrastructure, but also pollution control and flood prevention. It requires coordination across many sectors and between different local authorities and changes in governance that lead to more sustainable and equitable use of the urban water resources.[12]

Types of Green Infrastructure

Urban Forests

Forests in cities, also known as urban forests, are an important component of urban green infrastructure systems. Urban forests use appropriate tree and vegetation species, instead of noxious and invasive kinds, which reduce the need of maintenance and irrigation. In addition, native species also provide aesthetic value while reducing cost. Diversity of plant species should also be considered in design of urban forests to avoid monocultures; this makes the urban forests more durable and resilient to pests and other harms. In the United States, a federal legislation known as The Energy Conservation Through Trees Act, authored by Congresswoman Doris Matsui of Sacramento, encourages residents to plant shade trees to reduce heating and cooling costs.

Benefits of Urban Forests

  • Energy Use: According to a study conducted by the Lawrence Berkeley National Laboratory and Sacramento Municipal Utility District, it was found that urban trees can provide up 47% energy savings.
  • Urban Heat Island: Maximum air temperature for tree groves were found to be lower than that of open areas without trees. This is because of a process called evaporative cooling.
  • Water Management: Urban forests helps with city water management on diverting storm water from water channels. Trees intercept a large amount of rainfall that hit them.
  • Air Pollution: Trees hold carbon, which improve air quality in cities.
  • Property Values: Having more trees increases property value, which suggests that people value greenery and trees wherever they are. This implicates that trees contribute to the preferred living conditions. Urban greenery can also improve mental health and well-being. [14]

Constructed Wetlands

Constructed wetlands are manmade wetlands, which work as a bio-filtration system. They contain wetland vegetation and are mostly built on uplands and floodplains. Constructed wetlands are built this way to avoid connection or damage to natural wetlands and other aquatic resources. There are two main categories of constructed wetlands: subsurface flow system and free water surface system. Proper planning and operating can help avoid possible harm done to the wetlands, which are caused by alteration of natural hydrology and introduction of invasive species.

Benefits of Constructed Wetlands

  • Water efficiency: Constructed wetlands try to replicate natural wetland ecosystems. They are built to improve water efficiency and water quality. They also create wildlife habitats by using natural processes of plants, soils, and associated microorganisms. In these types of wetlands, vegetation can trap parts of suspended solids and slow down water flow; the microorganisms that live there process some other pollutants.
  • Cost-effective: Wetlands have low operating and maintenance costs. They can also help with fluctuating water levels. Aesthetically, constructed wetlands are able to add greenery to its surrounding environment. It also helps to reduce unpleasing odors of wastewater.[15] [16]

Planning approach

The Green Infrastructure approach analyses the natural environment in a way that highlights its function and subsequently seeks to put in place, through regulatory or planning policy, mechanisms that safeguard critical natural areas. Where life support functions are found to be lacking, plans may propose how these can be put in place through landscaped and/or engineered improvements.[17]

Within an urban context, this can be applied to re-introducing natural waterways [18] and making a city self-sustaining particularly with regard to water, for example, to harvest water locally, recycle it, re-use it and integrate stormwater management into everyday infrastructure.[19]

The multi-functionality of this approach is key to the efficient and sustainable use of land, especially in a compact and bustling country such as England where pressures on land are particularly acute. An example might be an urban edge river floodplain which provides a repository for flood waters, acts as a nature reserve, provides a recreational green space and could also be productively farmed (probably through grazing). There is growing evidence that the natural environment also has a positive effect on human health[20]

In the United Kingdom

In the United Kingdom, Green Infrastructure planning is increasingly recognised as a valuable approach for spatial planning and is now seen in national, regional and local planning and policy documents and strategies, for example in the Milton Keynes and South Midlands Growth area.[21]

In 2009, guidance on green infrastructure planning was published by Natural England, and can be accessed online at [1] This guidance promotes the importance of green infrastructure in 'place-making', i.e. in recognizing and maintaining the character of a particular location, especially where new developments are planned.[22]

In North West England the former Regional Spatial Strategy had a specific Green Infrastructure Policy (EM3 - Green Infrastructure) as well as other references to the concept in other land use development policies (e.g. DP6).[23] The policy was supported by the North West Green Infrastructure Guide.[24] The Green Infrastructure Think Tank (GrITT) provides the support for policy development in the region and manages the web site that acts as a repository for information on Green Infrastructure.[25]

The Natural Economy Northwest programme has supported a number of projects, commissioned by The Mersey Forest to develop the evidence base for green infrastructure in the region. In particular work has been undertaken to look at the economic value of green infrastructure, the linkage between grey and green infrastructure and also to identify areas where green infrastructure may play critical role in helping to overcome issues such as risks of flood or poor air quality.

In March 2011, a prototype Green Infrastructure Valuation Toolkit[26] was launched. The Toolkit is available under a Creative Commons licence, and provides a range of tools that provide economic valuation of green infrastructure interventions. The toolkit has been trialled in a number of areas and strategies, including the Liverpool Green Infrastructure Strategy.[27]

In 2012, the Greater London Authority published the All London Green Grid Supplementary Planning Guidance (ALGG SPG) which proposes an integrated network of green and open spaces together with the Blue Ribbon Network of rivers and waterways. The ALGG SPG aims to promote the concept of green infrastructure, and increase its delivery by boroughs, developers, and communities, to benefit areas such as sustainable travel, flood management, healthy living and the economic and social uplift these support.[28]

Green Infrastructure is being promoted as an effective and efficient response to projected climate change.[29]

Green Infrastructure may include geodiversity objectives.[30]

In the United States

Alley renovated with permeable paving located in Chicago, Illinois.

Green infrastructure programs managed by EPA and partner organizations are intended to improve water quality generally through more extensive management of stormwater runoff. The practices are expected to reduce stress on traditional water drainage infrastructure--storm sewers and combined sewers—which are typically extensive networks of underground pipes and/or surface water channels in U.S. cities, towns and suburban areas. Improved stormwater management is expected to reduce the frequency of combined sewer overflows and sanitary sewer overflows, reduce the impacts of urban flooding, and provide other environmental benefits.[31][32]

For example, the City of Philadelphia has installed or supported a variety of retrofit projects in neighborhoods throughout the city. Installed improvements include:

Some of these facilities reduce the volume of runoff entering the city's aging combined sewer system, and thereby reduce the extent of system overflows during rainstorms.[33]

Another U.S. example is the State of Maryland's promotion of a program called GreenPrint. GreenPrint Maryland is the first web-enabled map in the nation that shows the relative ecological importance of every parcel of land in the state.

Combining color-coded maps, information layers, and aerial photography with public openness and transparency, Greenprint Maryland applies the best environmental science and Geographic Information Systems (GIS) to the urgent work of preserving and protecting environmentally critical lands. A valuable new tool not only for making land conservation decisions today, but for building a broader and better informed public consensus for sustainable growth and land preservation decisions into the future.

The program was established in 2001 with the objective to “preserve an extensive, intertwined network of land vital to the long term survival of our native plants and wildlife and industries dependent on clean environment and abundant natural resources.”[34]

In April 2011, EPA announced the Strategic Agenda to Protect Waters and Build More Livable Communities through Green Infrastructure and the selection of the first ten communities to be green infrastructure partners.[35][36] The communities selected were: Austin, TX; Chelsea, MA; the Northeast Ohio Regional Sewer District (Cleveland, OH); the City and County of Denver, CO; Jacksonville, FL; Kansas City, MO; Los Angeles, CA; Puyallup, WA; Onondaga County and the City of Syracuse, NY; and Washington, DC.[37]

The Federal Emergency Management Agency (FEMA) is also promoting green infrastructure as a means of managing urban flooding (also known as localized flooding).[38]

In Singapore

Since 2009, two editions of the ABC (Active, Beautiful, Clean) Waters Design Guidelines have been published by the Public Utilities Board (PUB), Singapore. The latest version (2011) contains planning and design considerations for the holistic integration of drains, canals and reservoirs with the surrounding environment. PUB encourages the various stakeholders — landowners, private developers to incorporate ABC Waters design features into their developments, and the community to embrace these infrastructures for recreational & educational purposes.

The main benefits outlined in the ABC Waters Concept include:

  • Treating stormwater runoff closer to the source naturally, without the use of chemicals through the use of plants and soil media, so that cleaner water is discharged into waterways and eventually our reservoirs.
  • Enhancing biodiversity and site aesthetics.
  • Bringing people closer to water, and creating new recreational and community spaces for people to enjoy.[39]

In fragile states

A 2012 paper by the Overseas Development Institute reviewed evidence of the economic impacts of green infrastructure in fragile states.

Upfront construction costs for GI were up to 8% higher than non-green infrastructure projects. Climate Finance was not adequately captured by Fragile states for GI investments, and governance issues may further hinder capability to take full advantage.

GI Investments needed strong government participation as well as institutional capacities and capabilities that fragile states may not possess. Potential poverty reduction includes improved agricultural yields and higher rural electrification rates, benefits that can be transmitted to other sectors of the economy not directly linked to the GI investment.

Whilst there are examples of GI investments creating new jobs in a number of sectors, it is unclear what the employment opportunities advantages are in respect to traditional infrastructure investments. The correct market conditions (i.e. labour regulations or energy demand) are also required in order to maximise employment creation opportunities.

Such factors that may not be fully exploited by fragile state governments lacking the capacity to do so. GI investments have a number of co-benefits including increased energy security and improved health outcomes, whilst a potential reduction of a country’s vulnerability to the negative effects of climate change being arguably the most important co-benefit for such investments in a fragile state context.

There is some evidence that GI options are taken into consideration during project appraisal. Engagement mostly occurs in projects specifically designed with green goals, hence there is no data showing decision making that leads to a shift towards any green alternative. Comparisons of costs, co-benefits, poverty reduction benefits or employment creation benefits between the two typologies are also not evident.[40]

Examples

Nya Krokslätt, Sweden

The site of former factory “Nya Krokslätt” is situated between a mountain and a stream. Danish engineers, Ramboll, have designed a concept of slowing down and guiding storm water in the area with methods such as vegetation combined with ponds, streams and soak-away pits as well as glazed green-blue climate zones surrounding the buildings which delay and clean roof water and grey water. The design concept provides for a multifunctional, rich urban environment, which includes not only technical solutions for energy efficient buildings, but encompasses the implementation of blue-green infrastructure and ecosystem services in an urban area.[6]

Zürich, Switzerland

Since 1991, the city of Zürich has had a law stating all flat roofs (unless used as terraces) must be greened roofed surfaces. The main advantages as a result of this policy include increased biodiversity, rainwater storage and outflow delay, and micro-climatic compensation (temperature extremes, radiation balance, evaporation and filtration efficiency).[41] Roof biotopes are stepping stones which, together with the earthbound green areas and the seeds distributed by wind and birds, make an important contribution to the urban green infrastructure.[1]

Duisburg-Nord, Germany

In the old industrial area of the Ruhr District in Germany, Duisburg-Nord is a landscape park which incorporates former industrial structures and natural biodiversity. The architects Latz + Partner developed the water park which now consists of the old River Emscher, subdivided into five main sections: Klarwasserkanal (Clear Water Canal), the Emschergraben (Dyke), the Emscherrinne (Channel), the Emscherschlucht (Gorge) and the Emscherbach (Stream). The open waste water canal of the “Old Emscher” river is now fed gradually by rainwater collection through a series of barrages and water shoots. This gradual supply means that, even in lengthy dry spells, water can be supplied to the Old Emscher to replenish the oxygen levels.[42] This has allowed the canalised river bed to become a valley with possibilities for nature development and recreation. As a key part of the ecological objectives, much of the overgrown areas of the property were included in the plan as they were found to contain a wide diversity of flora and fauna, including threatened species from the red list. Another important theme in the development of the plan was to make the water system visible, in order to stimulate a relationship between visitors and the water.[1]

New York Sun Works Center, US

The Greenhouse Project was started in 2008 by a small group of public school parents and educators to facilitate hands-on learning, not only to teach about food and nutrition, but also to help children make educated choices regarding their impact on the environment. The laboratory is typically built as a traditional greenhouse on school rooftops and accommodates a hydroponic urban farm and environmental science laboratory. It includes solar panels, hydroponic growing systems, a rainwater catchment system, a weather station and a vermi composting station. Main topics of education include nutrition, water resource management, efficient land use, climate change, biodiversity, conservation, contamination, pollution, waste management, and sustainable development. Students learn the relationship between humans and the environment and gain a greater appreciation of sustainable development and its direct relationship to cultural diversity.[43]

Hammarby Sjöstad, Stokholm, Sweden

In the early 1990s, Hammarby Sjöstad had a reputation for being a run-down, polluted and unsafe industrial and residential area.[1] Now, it is a new district in Stockholm where the City has imposed tough environmental requirements on buildings, technical installations and the traffic environment. An ‘eco-cycle’ solution named the Hammarby Model, developed by Fortum, Stockholm Water Company and the Stockholm Waste Management Administration, is an integral energy, waste and water system for both housing and offices. The goal is to create a residential environment based on sustainable resource usage.[44] Examples include waste heat from the treated wastewater being used for heating up the water in the district heating system, rainwater runoff is returned to the natural cycle through infiltration in green roofs and treatment pools, sludge from the local wastewater treatment is recycled as fertiliser for farming and forestry.[1] This sustainable model has been a source of inspiration to many urban development projects including the Toronto (Canada) Waterfront, London's New Wembley, and a number of cities/city areas in China.[45]

GIS applications

The continued development of Geographic Information Systems (GIS) and their increasing level of use is particularly important in the development of Green Infrastructure plans. The plans frequently are based on GIS anaysis of many layers of geographic information.

Economic effects

A 2012 study found that 44% of green infrastructure projects reduce costs compared to 31% that increased costs. The study focused on 479 green infrastructure projects from across the US. Reduced stormwater runoff and decreased heating and cooling costs are the most notable cost savings.[46][47]

See also

References

  1. ^ a b c d e f g Hiltrud Pötz & Pierre Bleuze (2012). Urban green-blue grids for sustainable and dynamic cities. Delft: Coop for life. ISBN 978-90-818804-0-4.
  2. ^ The Conservation Fund, Arlington, VA. "Green Infrastructure." Accessed 2009-10-06.
  3. ^ Maryland Department of Natural Resources, Annapolis, MD. Maryland's Green Infrastructure Assessment: A Comprehensive Strategy for Land Conservation and Restoration. May 2003.
  4. ^ http://www.eea.europa.eu/publications/green-infrastructure-and-territorial-cohesion accessed: 09.04.13
  5. ^ http://www.csc.noaa.gov/magazine/2009/03/article2.html accessed: 09.04.13
  6. ^ a b c http://www.ramboll.com/projects/viewproject?projectid=F73AC734-B657-48A0-AE92-0C8A85C8992A accessed: 10.04.13
  7. ^ U.S. Environmental Protection Agency (EPA), Washington, D.C., et al., Green Infrastructure Statement of Intent. 2007-04-19.
  8. ^ EPA et al. "Managing Wet Weather with Green Infrastructure: Action Strategy 2008." January 2008.
  9. ^ Benedict, Mark A., Edward McMahon, and Va. Arlington. Green Infrastructure Linking Landscapes and Communities. Washington, DC: Island, 2006. Print.
  10. ^ Benedict, Mark A., Edward McMahon, and Va. Arlington. Green Infrastructure Linking Landscapes and Communities. Washington, DC: Island, 2006. Print.
  11. ^ http://www.academia.edu/2369268/Water_purificative_landscapes_constructed_ecologies_and_contemporary_urbanism accessed: 10.04.13
  12. ^ a b http://www.un.org/waterforlifedecade/swm_cities_zaragoza_2010/pdf/02_water_uncertainties.pdf. accessed: 09.04.13
  13. ^ http://www.un.org/waterforlifedecade/pdf/facts_and_figures_human_right_to_water_eng.pdf accessed: 09.04.13
  14. ^ "GREEN INFRASTRUCTURE: CITIES".
  15. ^ "Constructed Wetland". Architecture 2030. Retrieved 7 October 2014.
  16. ^ "Constructed Treatment Wetlands" (PDF).
  17. ^ Mark Benedict and Edward T. McMahon (2006). Green Infrastructure, Linking Landscapes and Communities. Washington, D.C.: Island Press. ISBN 1-55963-558-4.
  18. ^ http://www.ramboll.com/megatrend/feature-articles/in-the-cities-of-the-future-water-flows-everywhere accessed 11.04.13
  19. ^ “Blue-Green Infrastructures”. (December 13, 2012). Topos, p.18, 21,22.
  20. ^ Irvine KN, Warber SL. (2002). "Greening healthcare: practicing as if the natural environment really mattered." Altern Ther Health Med. 2002 Sep-Oct;8(5):76-83.
  21. ^ Environment Agency, Bristol, UK
  22. ^ Natural England website 2009
  23. ^ North West Regional Assembly, Wigan, UK. "The North West Plan: Submitted Draft Regional Spatial Strategy for the North West of England." January 2006.
  24. ^ Green Infrastructure Think Tank (GrITT), Warrington, UK. "North West Green Infrastructure Guide." September 2007.
  25. ^ GrITT. "Green Infrastructure North West." Accessed 2009-10-06.
  26. ^ Green Infrastructure Valuation Toolkit - www.ginw.co.uk/projects
  27. ^ Liverpool Green Infrastructure Strategy 2010. www.ginw.co.uk/liverpool
  28. ^ http://www.london.gov.uk/priorities/planning/publications/all-london-green-grid-spg accessed 11.04.13
  29. ^ Green Infrastructure to Combat Climate Change - www.ginw.co.uk/climatechange
  30. ^ Green Infrastructure Planning in the Black Country: Barrow Hill LNR and Russells Hall Hospital, Dudley - http://www.bcll.org.uk/whats_happening/documents/GreenInfrastructurePlanningintheBCBarrowHillCaseStudy.pdf
  31. ^ EPA. "How Does Green Infrastructure Benefit the Environment?" December 15, 2008.
  32. ^ American Rivers, Washington, D.C. "Water infrastructure: Green investments create jobs, save money." 2008-12-17.
  33. ^ Philadelphia Water Department. "Green Stormwater Infrastructure." Accessed 2010-04-27.
  34. ^ State of Maryland, 2001. “Maryland GreenPrint FAQ’s.” Accessed 2011-01-31.
  35. ^ http://cfpub.epa.gov/npdes/home.cfm?program_id=298
  36. ^ http://www.epa.gov/npdes/pubs/gi_agenda_protectwaters.pdf
  37. ^ http://www.epa.gov/npdes/pubs/gi_partner_organizations.pdf
  38. ^ "Reducing Damage from Localized Flooding." U.S. Federal Emergency Management Agency, 2005.
  39. ^ http://www.pub.gov.sg/abcwaters/abcwatersdesignguidelines/Pages/ABCDesignGuidelines.aspx accessed 11.04.13
  40. ^ Lemma, A. Green Infrastructure in Fragile States, October 2012, Overseas Development Institute http://partnerplatform.org/?5amvj9gc
  41. ^ http://www.stadt-zuerich.ch/content/ted/de/index/gsz/angebote_u_beratung/beratung/dachbegruenungen.html
  42. ^ http://en.landschaftspark.de/architecture-nature/water-concept accessed: 12.04.13
  43. ^ http://nysunworks.org/thegreenhouseproject accessed: 12.04.13
  44. ^ http://www.hammarbysjostad.se/ accessed: 15.04.13
  45. ^ http://www.cleanenergyawards.com/no_cache/top-navigation/nominees-projects/nominee-detail/singleprintview/project/66/ accessed: 15.04.13
  46. ^ Berg, Nate. "Green Infrastructure Could Save Cities Billions." The Atlantic. April 24, 2012. http://www.theatlanticcities.com/technology/2012/04/green-infrastructure-could-cities-save-billions/1832/. Accessed: September 18, 2012.
  47. ^ American Society of Landscape Architects, et al. "Banking on Green." http://www.asla.org/ContentDetail.aspx?id=31301 Accessed: September 18, 2012.

Further reading

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