From Wikipedia, the free encyclopedia
Green Infrastructure or
blue-green infrastructure is a network providing the “ingredients” for solving urban and climatic challenges by building with nature. 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. Green Infrastructure is considered a subset of Sustainable and Resilient Infrastructure, which is defined in standards such as
SuRe
- the Standard for Sustainable and Resilient Infrastructure. However,
green infrastructure can also mean "low-carbon infrastructure" such as
renewable energy infrastructure and public transportation systems (See
"low-carbon infrastructure").
[4] Blue-Green infrastructure can also be a component of
'sustainable drainage systems' or
'sustainable urban drainage systems' (SuDS or SUDS) designed to manage water quantity and quality, while providing improvements to biodiversity and amenity.
Introduction
Green infrastructure
Nature can be used to provide important services for communities by protecting them against
flooding or excessive heat, or helping to improve
air,
soil and
water quality. When nature is harnessed by people and used as an infrastructural system it is called “green infrastructure”.
Green infrastructure occurs at all scales. It is most often associated
with stormwater management systems, which are smart and cost-effective.
However, green infrastructure is really a larger concept and is closely
associated with many other things. Green infrastructure also serves to
provide an ecological framework for social, economic and environmental
health of the surroundings.
Blue infrastructure
"Blue infrastructure" refers to urban infrastructure relating to water.
Blue infrastructure is commonly associated with green infrastructure in
the urban setting and may be referred to as "blue-green" infrastructure
when in combination. Rivers, streams, ponds and lakes may exist as
natural features within cities, or be added to an urban environment as
an aspect of its design. Urban developments on coasts may also have
pre-existing features of the coastline specifically employed in their
design. Harbours, quays, piers and other extensions of the urban
environment may also be added to capture benefits associated with the
marine environment. There may considerable co-benefits to health and
wellbeing of populations with access to blue spaces in the urban
context.
Benefits
Some
people might expect that green spaces are excessive to maintain and
extravagant in nature, but high-performing green spaces can provide real
economic, ecological and social benefits. For example:
- Urban forestry in an urban environment can supplement managing storm water and reduce the energy usage costs and runoff in result.
- Bioretention systems can work to create a green transportation system.
In result, high performing green spaces work to create a balance between built and natural environments.
- Higher abundance of green space in communities or neighborhoods
is observed to have higher frequencies in participation of physical
activity among elderly men.
- More green space around one's house is associated with better mental health.
Economic effects
A
study in 2012 that focused on 479 green infrastructure projects across
the United States, found that 44% of green infrastructure projects
reduced costs compared to the 31% that increased the costs. The most
notable cost savings were due to reduced storm
water runoff and decreased
heating and
cooling costs.
Terminology
Green infrastructure concepts originated in mid-1980s proposals
for best management practices that would achieve more holistic
storm water quantity management goals for runoff volume reduction,
erosion prevention, and aquifer recharge. In 1987, amendments to the U.S.
Clean Water Act
introduced new provisions for management of diffuse pollutant sources
from urban land uses, establishing the regulatory need for practices
that, unlike conventional drainage infrastructure, managed runoff "at
source." Under the Act, the
U.S. Environmental Protection Agency
(EPA) published regulations for municipalities in 1990, requiring the
development of storm water pollution prevention plans and the
implementation of "source control practices". The EPA's 1993 handbook,
Urban Runoff Pollution Prevention and Control Planning,
identified BMPs to consider in such plans, including vegetative
controls, filtration practices and infiltration practices (trenches,
porous pavement).
Green Infrastructure is a concept that highlights the importance of the natural environment in decisions about
land-use planning. However, the term does not have a widely recognized definition. Also known as “blue-green infrastructure” or “green-blue urban grids”
the terms are used by many design-, conservation-, and planning related
disciplines and commonly feature storm water 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 EPA extended the concept of “green infrastructure” to apply to the management of
storm water
runoff at the local level through the use of natural systems, or
engineered systems that mimic natural systems, to treat polluted
runoff.
This use of the term "green infrastructure" to refer to urban "green"
BMPs contributes to the overall health of natural ecosystems, even
though it is not central to the larger concept.
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 storm water as an integral part of creating a sustainable,
multifunctional urban environment.
The Role of Water: Blue Spaces and Blue Infrastructure
Proximity and access to water have been key factors in human settlement through history.
Water, along with the spaces around it, create a potential for
transport, trade, and power generation. They also provide the human
population with resources like recreation and tourism in addition to
drinking water and food. Many of the world’s largest cities are located
near to water sources, and networks of urban "blue infrastructure", such
as canals, harbors and so forth, have been constructed to capture the
benefits and minimize risks. Globally, cities are facing severe water
uncertainties such as floods, droughts, and upstream activities on
trans-boundary rivers. The increasing pressure, intensity, and speed of
urbanization has led to the disappearance of any visible form of water
infrastructure in most cities. Urban coastal populations are growing,
and many cities have seen an extensive post-industrial transformation
of canals, riversides, docks, etc. following changes in global trading
patterns. The potential implications of such waterside regeneration in
terms of public health have only recently been scientifically
investigated.
A systematic review conducted in 2017 found consistent evidence of
positive associations between exposure of people to blue space and
mental health and physical activity.
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.
In 2010 the
United Nations declared that access to clean water and sanitation is a human right.
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 urban water resources.
Types of green infrastructure
Urban forests
Urban forests
are forests located in cities. They 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.
Benefits
- 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 to 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
implies that trees contribute to the preferred living conditions of
people.
- Public health: Urban greenery can also improve mental health and well-being.
- Creating Urban forest affects Public Health in many ways, as
mentioned above urban heat islands are created by the condensation of
heat due to the materials and infrastructure used in metropolitan areas,
which can negatively impact human health. Urban forests provide natural
shading structures at a fraction of the cost of artificial shading
structures and it counters the negative health impacts of increasing
global temperatures.
Beyond countering the negative impacts of man-made infrastructure,
green infrastructure has the potential to enhance existing ecosystems
and make them more stable, which has been historically done in
traditional Japanese agriculture.
Green infrastructure in an urbanized area can help restore and enhance
the resiliency of an ecosystem to natural disturbances and disasters
that disrupt the lives of residents.
Building new urban forests in an existing metropolitan area creates
new labor jobs that do not require a high level of education, which can
decrease unemployment in the working class which benefits society.
Furthermore, green infrastructure helps states to implement the
principles of the 1992 Rio Declaration on Environment and Development
that was designed to alleviate the social and economic consequences of
environmental degradation.
Constructed wetlands
Constructed wetlands are man-made
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
- 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.
Green roofs and green walls
Green roofs
improve air and water quality while reducing energy cost. The plants
and soil provide more green space and insulation on roofs. Green and
blue roofs also help reducing city runoff by retaining rainfall
providing a potential solution for the storm water management in highly
concentrated urban areas. The social benefit of green roofs is the rooftop agriculture for the residents.
Green Alleys
The Trust for Public Land is working in partnership with the City of Los Angeles' Community Redevelopment Agency, Bureau of Sanitation, the
University of Southern California's Center for Sustainable Cities, and
Jefferson High School by converting the existing 900 miles of alleys in the city to green alleys.
The concept is to re-engineer existing alleyways to reflect more light
to mitigate heat island effect, capture storm water, and make the space
beautiful and usable by the neighboring communities. The first alley, completed in 2015, saved more than 750,000 gallons in its first year.
The Green alleys will provide open space on top of these ecological
benefits, converting spaces which used to feel unsafe, or used for
dumping into a playground, and walking/biking corridor.
Green School Yards
The Trust for Public Land has completed 183 green school yards across the 5 boroughs in New York.
Existing asphalt school yards are converted to a more vibrant and
exciting place while also incorporating infrastructure to capture and
store rainwater: rain garden, rain barrel, tree groves with pervious
pavers, and an artificial field with a turf base.
The children are engaged in the design process, lending to a sense of
ownership and encourages children to take better care of their school
yard. Success in New York has allowed other cities like Philadelphia and Oakland to also convert to green school yards.
Low Impact Development
Low
impact development (also referred to as green storm water
infrastructure) are systems and practices that use or mimic natural
processes that result in the infiltration, evapotranspiration or use of
stormwater in order to protect water quality and associated aquatic
habitat. LID practices aim to preserve, restore and create green space
using soils, vegetation, and rainwater harvest techniques. It is an
approach to land development (or re-development) that works with nature
to manage storm water as close to its source as possible.
Many low impact development tools integrate vegetation or the existing
soil to reduce runoff and let rainfall enter the natural water cycle.
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.
Within an urban context, this can be applied to re-introducing natural waterways
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.
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.
United Kingdom
In 2009, guidance on green infrastructure planning was published by Natural England.
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.
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). The policy was supported by the
North West Green Infrastructure Guide.
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.
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
was launched. The Toolkit is available under a Creative Commons
license, 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.
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.
Green Infrastructure is being promoted as an effective and efficient response to projected climate change.
United States
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 storm water 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.
One example of these green infrastructure programs in use is the
National Pollutant Discharge Elimination System (NPDES). It was established in 1972 to reduce stormwater runoff pollution across the United States by distributing permits to facilities (or groups of facilities) to regulate their allowable point source pollution. Under the
Clean Water Act, the NPDES may be managed by localities, which has prompted many cities and counties to delegate
Best Management Practices (BMPs) to local builders for slowing and filtering surface runoff from their projects.
Though green infrastructure is yet to become a mainstream practice, many US cities have initiated its implementation. 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.
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.”
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.
The communities selected were: Austin, Texas; Chelsea, Massachusetts;
the Northeast Ohio Regional Sewer District (Cleveland, Ohio); the City
and County of Denver, Colorado; Jacksonville, Florida; Kansas City,
Missouri; Los Angeles, California; Puyallup, Washington; Onondaga County
and the City of Syracuse, New York; and Washington, D.C.
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 storm water 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.
Other 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.
Currently, an international standard for green infrastructure is
developed: SuRe® – The Standard for Sustainable and Resilient
Infrastructure is a global voluntary standard which integrates key
criteria of sustainability and resilience into infrastructure
development and upgrade. SuRe® is developed by the Swiss
Global Infrastructure Basel Foundation (GIB) and the French bank
Natixis as part of a multi-stakeholder process and will be compliant with
ISEAL guidelines.
GIB has also developed the SuRe® SmartScan, a simplified version of the
SuRe® Standard which serves as a self-assessment tool for infrastructure
project developers. It provides them with a comprehensive and
time-efficient analysis of the various themes covered by the SuRe®
Standard, offering a solid foundation for projects that are planning to
become certified by the SuRe® Standard in the future. Upon completion of
the SmartScan, project developers receive a spider diagram evaluation,
which indicates their project’s performance in the different themes and
benchmarks the performances with other SmartScan assessed projects.
Examples
ABC Water Design Guidelines by PUB 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 in 2011 contains planning and design considerations
for the 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 storm water 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.
Storm water Management, Surrey, British Columbia
Farmers
claimed that flooding of their farmlands was caused by suburban
development upstream. The flooding was a result of funneled runoff
directed into storm drains by impervious cove, which ran unmitigated and
unabsorbed into their farmlands downstream. The farmers were awarded an
undisclosed amount of money in the tens of millions as compensation.
Low density and highly paved residential communities redirect storm water
from impervious surfaces and pipes to stream at velocities much greater
than predevelopment rates. Not only are these practices environmentally
damaging, they can be costly and inefficient to maintain. In response,
the city of
Surrey
opted to employ a green infrastructure strategy and chose a 250-hectare
site called East Clayton as a demonstration project. The approach
reduced the storm water flowing downstream and allows for infiltration of
rainwater closer if not at its point of origin. In result, the
storm water system at East Clayton had the ability to hold one inch of
rainfall per day, accounting for 90% of the annual rainfall. The
incorporation of green infrastructure at Surrey, British Columbia was
able to create a sustainable environment that diminishes runoff and to
save around $12,000 per household.
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
greywater.
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.
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).
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.
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.
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.
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.
Hammarby Sjöstad, Stockholm, Sweden
In the early 1990s,
Hammarby Sjöstad had a reputation for being a run-down, polluted and unsafe industrial and residential area.
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.
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.
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.
Emeryville, California, US
EPA supported the city of
Emeryville, California in the development of "Stormwater Guidelines for Green, Dense Redevelopment." Emeryville, which is a suburb of
San Francisco,
began in the 1990s reclaiming, remediating and redeveloping the many
brown fields within its borders. These efforts sparked a successful
economic rebound. The city did not stop there, and decided in the 2000s
to harness the redevelopment progress for even better environmental
outcomes, in particular that related to storm water runoff, by requiring
in 2005 the use of on-site GI practices in all new private development
projects. The city faced several challenges, including a high water
table, tidal flows, clay soils, contaminated soil and water, and few
absorbent natural areas among the primarily impervious, paved parcels of
existing and redeveloped industrial sites. The guidelines, and an
accompanying spreadsheet model, were developed to make as much use of
redevelopment sites as possible for handling storm water. The main
strategies fell into several categories:
- Reducing the need, space and storm water impact of motor vehicle
parking by way of increased densities, height limits and floor area
ratios; shared, stacked, indoor and unbundled automobile parking; making
the best use of on-street parking and pricing strategies; car-sharing;
free citywide mass transit; requiring one secure indoor bicycle parking
space per bedroom and better bicycle and pedestrian roadway
infrastructure.
- Sustainable landscape design features, such as tree preservation and
minimum rootable soil volumes for new tree planting, use of structural
soils, suspended paving systems, bioretention and biofiltration
strategies and requiring the use of the holistic practices of
Bay-Friendly Landscaping.
- Water storage and harvesting through cisterns and rooftop containers.
- Other strategies to handle or infiltrate water on development and redevelopment sites.
Gowanus Canal Sponge Park, New York, US
The
Gowanus Canal, in
Brooklyn, New York, is bounded by several communities including Park Slope, Cobble Hill, Carroll Gardens, and Red Hook. The canal empties into
New York Harbor.
Completed in 1869, the canal was once a major transportation route for
the then separate cities of Brooklyn and New York City. Manufactured gas
plants, mills, tanneries, and chemical plants are among the many
facilities that operated along the canal. As a result of years of
discharges, storm water runoff, sewer outflows, and industrial
pollutants, the canal has become one of the nation's most extensively
contaminated water bodies. Contaminants include PCBs, coal tar wastes,
heavy metals, and volatile organics. On March 2, 2010, EPA added the
canal to the its Superfund
National Priorities List
(NPL). Placing the canal on the list allows the agency to further
investigate contamination at the site and develop an approach to address
the contamination.
After the NPL designation, several firms tried to redesign the
area surrounding the canal to meet EPA's principles. One of the
proposals was the Gowanus Canal Sponge Park, suggested by DLANDstudio,
an architecture and landscape architecture firm based in Brooklyn. The
firm designed a public open space system that slows, absorbs, and
filters surface water runoff with the goal of remediating contaminated
water, activating the private canal waterfront, and revitalizing the
neighborhood. The unique feature of the park is its character as a
working landscape that means the ability to improve the environment of
the canal over time while simultaneously supporting public engagement
with the canal ecosystem. The park was cited in a professional award by
the
American Society of Landscape Architects, in the Analysis and Planning category, in 2010.
Lafitte Greenway, New Orleans, Louisiana, US
The
Lafitte Greenway in
New Orleans, Louisiana, is a post-
Hurricane Katrina revitalization effort that utilizes green infrastructure to improve water quality as well as support wildlife habitat. The site was previously an industrial corridor that connected the
French Quarter to
Bayou St. John and
Lake Pontchartrain. Part of the revitalization plan was to incorporate green infrastructure for environmental sustainability.
One strategy to mitigate localized flooding was to create recreation
fields that are carved out to hold water during times of heavy rains.
Another strategy was to restore the native ecology of the corridor,
giving special attention to the ecotones that bisect the site.
The design proposed retrofitting historic buildings with storm water
management techniques, such as rainwater collection systems, which
allows historic buildings to be preserved. This project received the Award of Excellence from the
American Society of Landscape Architects in 2013.
Geographic Information System applications
A
Geographic Information System (GIS) is a computer system for that allows users to capture, store, display, and analyze all kinds of spatial data on Earth. GIS can gather multiple layers of information on one single map regarding streets, buildings, soil types, vegetation, and more.
Planners can combine or calculate useful information such as impervious
area percentage or vegetation coverage status of a specific region to
design or analyze the use of green infrastructure. 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 analysis of many layers of geographic information.
Green Infrastructure Master Plan
According
to the Green Infrastructure Master Plan, developed by Hawkins Partners,
civil engineers use GIS to analyze the modeling of impervious surfaces
with historical Nashville rainfall data within the CSS (combined sewer
system) to find the current rates of runoff.
GIS are able to help planning teams analyze potential volume reductions
at the specific region for green infrastructures, including water
harvesting, green roofs, urban trees, and structural control measures.
Implementation
Barriers
Lack
of funding is consistently cited as a barrier to the implementation of
green infrastructure. One advantage that green infrastructure projects
offer, however, is that they generate so many benefits that they can
compete for a variety of diverse funding sources. Some tax incentive
programs administered by federal agencies can be used to attract
financing to green infrastructure projects. Here are two examples of
programs whose missions are broad enough to support green infrastructure
projects:
- The U.S. Department of Energy
administers a range of energy efficiency tax incentives, and green
infrastructure could be integrated into project design to claim the
incentive. An example of how this might work is found in Oregon’s Energy
Efficiency Construction Credits. In Eugene, Oregon, a new biofuel
station built on an abandoned gas station site included a green roof,
bioswales and rain gardens. In this case, nearly $250,000 worth of tax
credits reduced income and sales tax for the private company that built
and operated the project.
- The U.S. Department of Treasury
administers the multibillion-dollar New Markets Tax Credit program,
which encourages private investment for a range of project types
(typically real estate or business development projects) in distressed
areas. Awards are allocated to non-profit and private entities based on
their proposals for distributing these tax benefits.
Benefits
This
Storm Water Curb Extension in Emeryville, California provides a
pedestrian safety element as well as storm water quality benefits. It
uses Bay-Friendly Landscaping and recycled water for irrigation.
Some people might expect that green spaces are excessive to maintain
and extravagant in nature, but high-performing green spaces can provide
real economic, ecological and social benefits. For example:
- Urban forestry in an urban environment can supplement managing
storm water and reduce the energy usage costs and runoff in result.
- Bio-retention systems can work to create a green transportation system.
- Stormwater Curb Extensions can increase pedestrian safety by
increasing visibility and reducing crossing distances at intersections.
In result, high performing green spaces work to create a balance between built and natural environments.
Economic effects
A
study in 2012 that focused on 479 green infrastructure projects across
the United States, found that 44% of green infrastructure projects
reduce costs compared to the 31% that increased the costs. The most
notable cost savings were due to reduced storm water runoff and decreased
heating and cooling costs.
A comprehensive green infrastructure in Philadelphia is planned
to cost just $1.2 billion over the next 25 years, compared to over $6
billion for "grey" infrastructure (concrete tunnels created to move
water). Under the new green infrastructure plan it is expected that:
- 250 people will be employed annually in green jobs.
- Up to 1.5 billion pounds of carbon dioxide emission to be avoided or
absorbed through green infrastructure each year (the equivalent of
removing close to 3,400 vehicles from roadways)
- Air quality will improve due to all the new trees, green roofs, and parks
- Communities will benefit on the social and health side
- About 20 deaths due to asthma will be avoided
- 250 fewer work or school days will be missed
- Deaths due to excessive urban heat could also be cut by 250 over 20 years.
- The new greenery will increase property values by $390 million over
45 years, also boosting the property taxes the city takes in.
A green infrastructure plan in New York City is expected to cost $1.5
billion less than a comparable grey infrastructure approach. Also, the
green storm water management systems alone will save $1 billion, at a
cost of about $0.15 less per gallon. The sustainability benefits in New
York City range from $139–418 million over the 20 year life of the
project. This green plan estimates that “every fully vegetated acre of
green infrastructure would provide total annual benefits of $8.522 in
reduced energy demand, $166 in reduced CO2 emissions, $1,044 in improved
air quality, and $4,725 in increased property value.”
Ongoing Initiatives
One program that has integrated green infrastructure into construction projects worldwide is the
Leadership in Energy and Environmental Design (LEED) certification. This system offers a benchmark rating for
green buildings and neighborhoods, credibly quantifying a project’s environmental responsibility. The LEED program incentivizes development that uses resources efficiently.
For example, it offers specific credits for reducing indoor and
outdoor water use, optimizing energy performance, producing renewable
energy, and minimizing or recycling project waste. Two LEED initiatives
that directly promote the use of green infrastructure include the
rainwater management and heat island reduction credits. An example of a successfully LEED-certified neighborhood development is the 9th and Berks Street
transit-oriented development (TOD) in
Philadelphia, PA which achieved a
Platinum level rating on October 12, 2017.
Another approach to implementing green infrastructure has been developed by the
International Living Future Institute. Their
Living Community Challenge assesses a community or city in twenty different aspects of sustainability. Notably, the Challenge considers whether the development achieves net positive water and energy uses and utilizes replenishable materials.
