"Working Green Infrastructure" and
Quality of Life
Most people look to decreased density as a way to lessen the impacts
of imperviousness on stream quality. But the assumption is giving
way to new thinking. This summer, ground will be broken on a [250
ha] site in Surrey, BC, that will accomplish high density [11 units
per acre] while achieving low effective impermeable surface. Dubbed
Headwaters Sustainable Development Demonstration Project, the 15,000-member
community endeavor is championed by Patrick Condon, [James Taylor
Chair of Landscape and Livable Environments at the University of
On a recent lecture tour of the Portland metropolitan region, where
the regional government is working with stakeholders to develop
a regional stream-protection program, Condon noted that lower densities
encourage urban sprawl, create inordinate costs and burdens of providing
infrastructure, price lower-income citizens out of the market, create
segregation by income, and result in flight from the urban center,
longer commutes, higher gas consumption, and more air pollution.
Older developed areas have about a quarter the amount of infrastructure
per person as suburban areas.
"The health of individual sites has everything to do with the ecological
health of a region", remarked Condon, adding that standards for
community design should consider air quality as well as water quality.
He proposed six development policies to achieve community environmental
1. Provide different dwelling types in the same neighborhood.
Achieve this through small residential lots and multi-storey, mixed-use
commercial and residential development. Older commercial developments
are approaching redevelopment and will be future valuable land resources
in urban areas.
2. Ensure that everyone should have access to transit and shops
within a five-minute walking distance.
Achieve this with 10 dwelling units per acre (25 people) and mixed-use
development. 3. Require dwellings to present a friendly face to
4. Plan interconnected street systems that give way to natural
Circulation systems should allow pedestrians to cross stream but
keep the road crossings to a minimum. Providing a system of interconnected
roads should encourage dispersed surface traffic.
5. Develop lighter, greener, cheaper, smarter infrastructure.
Minimize road widths and structure footprints and maximize infiltration
opportunities. Aim for 300-ft. blocks and 50-60% canopy in the developed
area. Outslope streets to drain to an infiltration BMP that performs
at 0.04 in./hr. during winter conditions. Provide 130-ft greenways
to buffer artificial surface drainages in linear riparian parks
that serve as bike and pedestrian pathways. Use open-graded street
pavements, soft shoulders, and common driveway lanes, Use "wet roofs'
to hold rainfall and evaporate it back into the atmosphere. Avoid
curbs and piped drainage systems.
6. Develop natural drainage systems where surface runoff infiltrates
back into the soil. A 200-year-old Douglas fir tree can hold
a thousand gallons of stormwater on its needles. Dennis King and
Lisa Wainger of the University of Maryland's Center for Environmental
Science have devised a method to identify and determine the economic
values of "services," such as stormwater detention, provided by
natural resources (www.ecosystemvaluation.org/). In addition to
the production and recreation services that natural resources provide.
King and Wainger count municipal uses such as ground water recharge,
purification of drinking water, and pollution prevention. To this
mix of active services, they add aesthetics and opportunities for
research and education. But the lists gets more interesting when
passive services are considered; for example, the avoided costs
of flooding, the avoided cost of health care, and the regional effects
of natural resources on regulating climate and air quality.
As the decades of the new century rush by and increasing numbers
of people need places to live and work, the very quality of life
in our cities will depend on how we have valued the natural resources
that sustain these urban environments. The urgently beating hearts
will be the hearts of our own children, and the new lights sparking
up on the vast landscape are the communities of a future that is