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WCEL
> Issues > Urban Growth and
Development > Smart Bylaws Guide > Part
2
Smart Bylaws Guide – Part 2
2. Incorporate the Green Infrastructure and Working Lands
Into Communities
Green infrastructure refers to the ecological processes, both
natural and engineered, that provide economic and environmental
benefits in urban areas. Municipalities are returning to the
benefits of green infrastructure because they are often less costly
than hard infrastructure, and offer aesthetic and recreational
benefits. Using the green infrastructure to manage common processes,
such as stormwater, keeps water on the land longer, thus recharging
streams, aquifers and water reservoirs more fully. Street trees,
greenways and rooftop gardens, the “urban forest,” help mediate
summer heating in developed areas while also improving air quality,
and providing habitat for many species. Green infrastructure in
neighbourhoods, such as ponds and greenways, are seen as amenities
and increase property values. Finally, maintaining working lands is
important both for the economy and for their contribution to the
green infrastructure of a region.
The green infrastructure includes:
- ditches, rivers, creeks, streams and wetlands that retain and
carry stormwater, improve water quality, and provide habitat;
- parks and greenways that link habitat and provide recreation
opportunities;
- working lands such as agricultural or forested areas;
- aquifers and watersheds that provide drinking water;
- engineered wetlands and stormwater detention ponds that retain
stormwater and improve infiltration; and
- trees, rooftop gardens and community gardens that clean air
and cool urbanized areas in the summer.
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Examples of ecosystem services and saving include:
- Pollution abatement and heat attenuation – The tree canopy
in Portland, Oregon absorbs approximately two million pounds of
pollutants from the atmosphere each year. This service is worth
an estimated $4.8 million (US). Conversely, over the past 25
years, the Puget Sound region has lost 37 percent of its tree
canopy and high vegetation. This cover would have removed
approximately 35 million pounds of pollutants annually, a value
of $95 million; and
- Stormwater management – The lost tree cover in Puget Sound
has resulted in a 29 percent increase in stormwater flows during
peak events. Replacing the lost retention capacity with
reservoirs and engineered solutions would cost $2.4 billion ($2
per cubic foot).
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Using the green infrastructure more fully points towards infrastructure and
servicing practices that use land and resources more efficiently. This
includes:
- Drainage standards based on infiltration, environmental protection, and
community amenity;
- Utility alignments for more compact roads where bicycle and pedestrian
infrastructure are built in;
- Road standards tailored to specific uses, lower speed limits, and
community amenity goals such as achieving 40 percent tree canopy at
maturity;
- Traffic calming built into road designs;
- A connected (grid) road network;
- Pavement structure allowing for permeable paving in certain circumstances;
- Unique road and servicing standards for projects near working lands;
- Significant street trees and boulevard plantings;
- Low maximum driveway standards;
- District heating systems;
- District water recycling systems;
- Water & sewer infrastructure requirements for subdivisions of high
performance (green) buildings (in some cases allowing for smaller pipe
sizing); and
- Dark sky outdoor lighting standards and energy efficiency requirements.
To maintain the ecological functioning of the green
infrastructure, both the quality and quantity of its land and water
are important. Connecting public and private natural areas for water
infiltration and habitat creates a green infrastructure network that
serves as the foundation for built communities.
Water, and the watercourses that hold and convey it, are a
precious commodity. Many communities are facing water shortages, as
well as enormous costs for accessing additional sources of water.
Scientific evidence now shows that paving more than ten percent of a
watershed affects its biological productivity. Municipalities are
moving beyond only using setbacks and water quality guidelines for
protecting watercourses to taking an integrated stormwater
management planning approach that applies watershed goals at a site
specific and neighbourhood level. The objective is to put as much
water back into the ground to support aquifers and streams while
protecting and enhancing riparian habitat.
Over the past 50 years, the landscape has been flattened or filled
to accommodate new development. The new value placed on the green
infrastructure is changing this approach to one that tailors
development to existing and desired natural processes.
“The shape of blocks is not random. In a sustainable community,
the block design should satisfy two imperatives: (1) merge blocks
with the landscape; and (2) maintain a high degree of
interconnectivity and permeability. The recommended maximum standard
block length for interconnectivity is 180 metres. Interconnected
blocks are easy to understand and to get around in; they are also
welcoming. Blocks modified by the landscape are distinguishable from
one another and make unique and – literally – distinguished
neighbourhoods. Capitalize on the site by allowing natural features
to shape the block without eroding interconnectivity.”
Patrick M.Condon, Jacqueline Teed and Sara Muir with Chris
Midgley. Site
Design Manual for BC Communities (2002)
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Working lands (land used for agriculture, forestry or other
resource industries) are both the backbone of many rural and
near-urban economies, and important components of the green
infrastructure. Crucial to sustaining working lands is to ensure
that uses within agriculture and resource zones support an economy
based on a working landscape, and that these lands are buffered from
more urban uses. Large lot zoning, buffer specifications, and
explicit regulations on accessory activities for processing, sales
and other uses help to maintain the viability of farming and
resource industries.
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Between 1976 and 1996, the Greater Toronto Area (population 4.5
million) lost about 60,000 hectares (148,000 acres) of farmland,
most of which was classed as prime agricultural land. Thanks to the
Agricultural Land Reserve, from 1974 to 2000, British Columbia (population 4
million) lost significantly less: 13,193 hectares of prime
agricultural land (32,600 acres), with no net loss of farmland.
Likewise, 2.7 percent of BC’s land base provides over $1.4 billion
or 78 percent of the Province’s total gross farm receipts.
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In addition to supporting working lands, working watersheds that
provide communities with drinking water require special management
approaches. Through integrated management and using recycled water,
working watersheds are better able to continue to supply an adequate
quality and quantity of water.
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Residential development in rural areas costs more to serve than
it generates in tax revenue. Farms generate $1 in revenue for every
$0.21 of services needed, but rural residential uses generate only
$1 for every $1.20 in services used.
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For More Information
West Coast's Green
Infrastructure Guide (PDF 983 Kb) West Coast's Protecting
the Working Landscape of Agriculture (PDF 725 Kb)
GreenInfrastructure.net Maryland's Green Infrastructure
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