What
is Green Infrastructure?
An interconnected network of green space and other
environmental assets that conserves the functions of the natural ecosystem and
provides associated benefits to people. (Adapted from the Conservation Fund, Ed
McMahon and Mark Benedict)
Definition
“Green Infrastructure Work Group” US
“an
interconnected network of waterways, wetlands, woodlands, wildlife habitats,
and other natural areas; greenways, parks and other conservation lands; working
farms, ranches and forests; and wilderness and other open spaces that support
native species, maintain natural ecological processes, sustain air and water
resources and contribute to the health and quality of life for America’s
communities and people.”
Definition: “The Town and Country
Planning Association”, UK
“The
sub-regional network of protected sites, nature reserves, green spaces, and
greenway linkages”. The linkages include river corridors and flood plains,
migration routes and features of the landscape, which are of importance as wildlife
corridors.”
Concept Of Green Infrastructures
·
“Green infrastructure” refers to
natural and engineered ecological systems that act as living infrastructure,
integrating natural vegetation and soils into a community’s infrastructure
through a variety of techniques, approaches, technologies, and practices.
·
Green infrastructure is planned and
managed primarily for storm water control, but it also provides additional social,
economic, and environmental benefits. It can be a useful tool for
communities that are looking to protect their natural water resources and storm
water management systems from the impacts of development and urbanization.
·
Green infrastructure methods can be
implemented practically anywhere soil and vegetation can be worked into a
landscape.
Green
Infrastructure Hubs and Corridors
The two main physical
components of green infrastructure networks are hubs and corridors.
Hubs
• Hubs are large blocks of unfragmented
natural areas that anchor the network.
•
They provide space for native plants and
animal communities and an origin or destination for wildlife, people,
water, nutrients, and energy moving through the system.
Corridors
•
Corridors connect these hubs and tie the
system together, providing conduits for movement, for plants,
animals, water, and nutrients.
•
Corridors have also been shown to
mitigate the effects of habitat fragmentation and enhance the
overall resiliency of natural systems in the face
of natural and human disturbances
The Green Infrastructure has its
origin (John Olmsted and Frederick Law Olmsted Jr. 1903) in 2 main important
concepts which are:
1. Linking
parks and other green space for the benefit of people.
2. Preserving
and linking natural areas to benefit biodiversity and encounter habitat
fragmentation.
However, throughout years new concept had been
adding. Green Infrastructure today is influenced by 4 main factors :
1. Linking
parks for people;
2. Linking
natural areas to counter fragmentation and preserve biodiversity;
3. Identifying
and protecting interconnected open spaces systems to benefit wildlife and
ensure a sustainable future;
4. Building
upon the excitement and appeal of the modern-day greenways movement
TYPES
of Green Infrastructure?
1. Green
Roofs
2. Rain
Gardens
3. Porous
and Pervious Pavements
4. Vegetated
Swales
5. Pocket
wetlands
6. Planter
Boxes
7. Green
Parking
8. Rain
Barrels
9. Downspout
Disconnection
10. Community
Forestry and Trees
1.
Green
Roof
Green roofs are roofs of buildings that are covered
with vegetation and soil, either partially or completely. Green
roofs are layered systems, with a waterproof membrane, drainage mat, root
barrier, growing medium, and vegetation.
2.
Rain
gardens
Rain gardens also called bioretention basins, are
planted topographic depressions that are designed to absorb rainwater that
drains from impervious areas, such as roofs, parking areas, streets, walkways,
and compacted lawn areas.
3.
Porous
and pervious pavements
Porous and pervious pavements, also called permeable
pavements, are paving methods that allow rainwater to infiltrate through them into
the soil below.
4.
Vegetated
swales
• Vegetated
swales, also known as bioswales, are wide, shallow channels that are covered on
the side slopes and bottom by a dense stand of native vegetation. Vegetated
swales are designed to promote infiltration, reduce the flow velocity of
stormwater runoff, and trap particulate pollutants and silt. They can be either
natural or constructed, and are often used around parking lots so that
pollution from automobiles that is picked up in stormwater can be treated
before entering the watershed.
5. Pocket
wetlands
• Pocket
wetlands receive, retain, and treat stormwater that has drained from a limited
impervious area. Not only do they reduce stormwater runoff, but they also
provide for the filtering of pollutants. Additionally, pocket wetlands are
aesthetically pleasing and can even serve as a small wildlife habitat. Pocket
wetlands do not require as much space as other stormwater treatment, so they
can be very helpful in congested urban areas.
6. Planter Boxes
• There
are two types of planter boxes: contained planters and infiltration planters. Contained
planters are planter boxes that are placed over impervious surfaces. They hold
trees, shrubs, and ground cover. Infiltration planters are containers or
structures with open bottoms that contain a layer of gravel, soil, and
vegetation.
• They
are designed to allow stormwater runoff to temporarily pool on top of the soil
and then slowly infiltrate into the ground.
• Stone,
concrete, brick, plastic lumber, or wood can all be used to construct
infiltration planters.
7.
Green
Parking
Green parking refers to parking lot design that
incorporates green infrastructure instead of only considering purely functional
requirements. Green parking involves managing stormwater on‐site, providing
generous landscaped areas, planting trees, enhancing pedestrian and cycling
infrastructure, and reducing the urban heat island effect.
8. Rain Barrels
• Rain
barrels, also called rainwater tanks, are water containers that are used to
collect and store rain water. The rainwater is usually collected from rooftops
via rain gutters. Rain barrels help to reduce the amount of untreated
stormwater runoff into wastewater systems and surface waters. The water stored
in rain barrels can be recycled for many uses, including water gardens, washing
cars, agriculture, and home use.
• They
can also simply store stormwater to be released at a future time.
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9.
Downspout
Disconnection
• Downspout
disconnection systems redirect stormwater from traditional collection systems
to vegetated areas. By doing so, green infrastructure components can manage the
runoff and stormwater volume is removed from collection systems. A street
bump-out, or curb extension, is an extension of typical curb that creates an
open space that is used to temporarily store and filter runoff.Street
bump-outs reduce stormwater flow velocity and volume, as well as improve water
quality, with vegetation and possibly infiltration. A
street bump-out can be implemented in any street of adequate width. In
addition to enhancing street aesthetics and providing stormwater management,
street bump-outs provide traffic calming, which improves pedestrian safety.
10. Community
Forestry and Trees
Trees and
forests are essential elements of a community’s green infrastructure. These
include not only public and private forest lands but also community forests:
the canopy of trees in our communities’ yards, parks, roadsides and
streetscapes, commercial centers, common areas, and public spaces. They provide
many environmental and economic benefits to property owners, communities, and
watersheds.
The Benefits Of Green Infrastructure?
Green
infrastructure systems benefits us in many ways. The clean water you drink may
have been naturally purified by the roots of a forest; the trees in your front
yard trap dust and harmful gases from the air you breathe; and the medicine you
take comes from unique plants and flowers. We need to recognize these benefits of nature,
or green infrastructure networks, and understand how they affect our health and
our economy. (The Nature Conservancy). Green infrastructure delivers vital
public health and safety benefits through wildfire suppression, safe drinking
and agricultural water, healthy food production, and protection from flood
hazards and storm dangers. Furthermore, the implementation of green
infrastructure & it’s management can create jobs and opportunities for
Federal funding.
The
Health Benefits of Green Infrastructure
v Absorbs
air pollution. Reduces urban core temperatures. (USFS)
v Streams
and aquifers filter & clean the water before it is treated.
v Provides
fresh, healthy food at low-costs at an ever-increasing number of farmer’s
markets & community gardens.
v Increases
physical activity and correlates to a decreased incidence of doctors visits and
depression. Reduces obesity. (President’s Council on Fitness)
v Maintains
opportunities for children to experience and explore nature.
The
Social Benefits of Green Infrastructure
v Reduces
stress. Increases quality of life and family enjoyment.
v Increases
interaction in the community. Enhances community character.
v Safer
public spaces as a result of increased activity. (Trust for Public Land)
v Evidence
shows urban trees and green spaces decrease rates of violence and crime in
urban areas and other neighborhoods. (USFS)
The
Environmental Benefits of Green Infrastructure
v Protects
habitat, carbon storage, aquifer recharge. Preserves views.
v Reduces
risk of wildfire and other ecological impacts. (USFS)
v Reduces
transportation costs and emissions output. Minimizes inversion. (EPA)
v Federal
law requires improvements for stormwater discharge. (EPA)
The
Economic Benefits of Green Infrastructure
Ø Green
Infrastructure corresponds strongly to property values.
v Homes
adjacent to parks are worth 22% more. (Donjek Inc, 2009)
v Nearby
recreation areas and parks raise home values 15 - 20%. (ibid)
v Permanently
protecting forests raises property values 19 - 35%. (ibid)
v Green
Infrastructure is attractive to businesses & residents.(RNA)
v Supports
local businesses and tourism. Green Infrastructure sells homes. (ibid)
The
Economic Benefits of Green Infrastructure
A
Green Infrastructure Network provides Environmental Services.
v Cities
can use Green Infrastructure to reduce public costs for stormwater management,
flood control, transportation, and other forms of built infrastructure.
v Utilizing
and enhancing existing Green Infrastructure reduces the need for newly built or
increased infrastructure such as water treatment plants, sewer systems, and
detention ponds.
