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Patrick Condon's strategy for sustainability is premised on six sustainable planning principles developed in a series of design charrettes involving architects, landscape architects, and planners from across the continent.

He holds the James Taylor Chair in Landscape and Liveable Environments at the University of British Columbia (UBC), a position with the goals of developing and illustrating principles for building more sustainable urban environments, even as urban populations double in the next forty years.

Principle One

Increase density and conserve energy by designing compact, walkable neighborhoods.

Studies show that if it takes more than five minutes to walk somewhere, people will probably drive. So this principle brings transit and shops within a five minute walk of houses.

For even a small convenience store to be viable based on people walking five minutes, the streets around it need to contain about ten dwelling units per acre (25 units per hectare). By coincidence, this also seems to be the density necessary for a viable transit system.

Principle Two

Locate different dwelling types in the same neighborhood, and even on the same street.

Zoning, says Condon, has been the single greatest instrument for segregating the North American landscape according to class and income, and "this must change".

If houses of different types and sizes share a street, and rental suites help home owners with their mortgages, then community members can continue to make the neighborhood their home, even as their age, income level, and family circumstances change.

Principle Three

Ensure that buildings present a friendly face to the street.

This means a streetscape free of garage fronts. Instead, lanes provide vehicle and service access to the backs of houses. Streets become pedestrian-oriented places that promote social interaction.

As a bonus, vehicular traffic moves more efficiently when cars aren't pulling out of driveways directly into the street.

Principle Four

Make a system of interconnected streets.

Those cul-de-sacs so beloved of suburban developers make it impossible to walk anywhere in five minutes. A regular street grid or modified grid gives people the chance to take the shortest route to where they're going.

At the same time, interconnected streets reduce the need for major arterial streets that slice through the neighborhood. Arterials are mostly used below capacity, except at rush-hour, when they're jammed. Interconnected streets allow rush-hour overflow to trickle through neighborhoods, moving more traffic with less pavement.

This doesn't necessarily mean heavy traffic tearing through quiet streets. People are generally content to drive slowly through traffic-calmed neighborhoods when the alternative is sitting stuck on a jammed arterial.

Principle Five

Make infrastructure lighter, cheaper, greener, smarter.

The amount of pavement per person has gradually increased to the point where the average suburban dweller now has four times the amount of pavement the average urban dweller has. This corresponds to an increased impact, per person, on both the public purse and the environment.

Pave less, says Condon, not more. Narrower, tree-shaded streets save infrastructure costs while providing a greener, friendlier neighborhood character.

Principle Six

Preserve the natural environment and promote natural drainage systems.

This is the 1/25 of an inch (one millimeter) per hour principle that translates an affordable, walkable neighborhood into an ecologically sustainable settlement pattern. If we want to urbanize an area without destroying its streams and fish, says Condon, we must drain new neighborhoods the same way the natural landscape drains — through infiltration and evaporation.

In a mature forest, 70 percent of the rainfall returns to the ground. It seeps through the earth to a subsurface water table, which flows horizontally to a stream bank. This progress might take a week, or a month, or six months, and by the time the water arrives at the stream, it has been filtered clean.

If water is allowed to infiltrate the earth at a minimum rate of 1/25 of an inch per hour, a measure of porosity averaged over all the surfaces in a given area and an easily-achieved standard, 70 to 90 per cent of the total annual rainfall will be absorbed where it falls in yards, street verges, and lanes. The remaining 10 to 30 per cent will flow overland to a park, where a catchment basin or seasonal pond will give it another chance to infiltrate or evaporate.

Most importantly, this principle means no curbs. Curbs catch polluted run-off, siphon it to pipes, and send it directly to waterways, with no chance at all of percolation.

An urban drainage system based on infiltration returns clean, plentiful water to streams at the rate they need for healthy fish habitat. It brings little pockets of nature within walking distance of every house. And it costs millions of dollars less than piping polluted runoff directly into waterways.

Scenario for East Clayton

Studies of what these principles imply for the quality of daily life offer some remarkable statistics. Based on these principles, East Clayton will be a place where:

Water quality and stream habitats are respected and protected. Average reduction in impact on streams compared to that in conventional subdivisions: 90 percent to 100 percent.

Over the next few years, Patrick Condon and his colleagues intend to continue researching, facilitating, developing, and monitoring East Clayton as a prototype for sustainable urban growth.

 

Along a riparian greenway, an artificial stream provides habitat and biofiltration of surface water. Image: UBC James Taylor Chair Buildings that present a friendly face to the street have porches and trees out front, parking out back. Image: UBC James Taylor Chair Natural drainage systems permit surface runoff to infiltrate back into the soil. Image: UBC James Taylor Chair Providing vehicle and service access via lanes at the backs of houses frees the pedestrian-oriented streetscape of garage-fronts and promotes social interaction. Photo: UBC James Taylor Chair Interconnected street systems ensure that all trips, whether in a car, on a bike, or on foot, are by the shortest possible route. Image: UBC James Taylor Chair Narrower, tree-shaded streets save infrastructure costs while providing a greener, friendlier neighborhood character. Image: UBC James Taylor Chair Section through a riparian arterial. Image: UBC James Taylor Chair   Click on thumbnail images to view full-size pictures.