CALGARY?The plane slips lower, through the yellow-brown haze of smog that drapes lazily into the river valley, bringing them into sharp view: vast tracts of tightly packed, near-identical houses, spilling into the endless plains at the city's southeast corner and over the green foothills in the northwest, where the prairie buckles on its way to the Rocky Mountains, looming and majestic, to the west.

Calgary proper, a vast unicity with the largest footprint of any city in North America, occupies almost the same amount of land as the five boroughs of New York, which form a tightly packed urban zone with 12 million people. Calgary celebrated the arrival of its one millionth citizen just this summer.

In 1951, Calgary held 127,000 people within the bounds of a mere 40.4 square kilometres. By next year, this roiling centre of commerce and oil-fuelled optimism, the heart of the western boom, will swallow another 102 square kilometres to accommodate, it projects, another 400,000 people over the next 40 years. That swell will expand its current boundaries from 745 square kilometres to 847 ? more than 20 times the 1951 figure.

Toronto, meanwhile, a much-chastised offender in the annals of urban sprawl, spreads its 2.6 million people over about 630 square kilometres of land. But Calgary, like Toronto, Vancouver and virtually every other Canadian city, faces an issue loudly proclaimed at the World Urban Forum in Vancouver in June to be among the most pressing social concerns of the future: Continued and accelerating urbanization.

By next year, for the first time in history, urban dwellers worldwide will outnumber ruralites. In Canada, where 80 per cent of the population already lives in cities, major urban centres will swell rapidly and municipal governments will strain to create and maintain infrastructure to support them.

But most would agree that Calgary's rapid growth is unique. The city expected to hit 1 million some time in 2008; swarmed by job-seekers from across the country, even those generous population projections proved way off. More than 35,000 people came to this city last year, drawn by Alberta's super-heated economy. Calgary's high-speed development is now swallowing about 1.5 hectares a day. And it shows no sign of slowing.

This is the downside of boomtown: With gridlock on its vast networks of freeways that link the core to its ever more distant suburbs, the average commute time increasing more rapidly than anywhere in Canada, mounting pollution and spiralling real estate prices, this fiercely independent heart of the new West faces the real possibility of morphing into its most-loathed nightmare: Toronto.

"Calgary is like a big balloon, growing in all directions," says Noel Keough, bundled in a grey fleece jacket to ward off the summer morning chill. It's a cloudless day, but here in the faraway new developments of the city's northwest, downtown is a distant collection of unidentifiable spires, shrouded in a smoggy haze.

Houses cluster along the city boundary, marked by a small green sign, and seem eager to flow past it into the foothills beyond.

"I guess that's why they need to annex," says Keough, smiling ruefully. "They've pretty much used up all their land."

Keough, soft-spoken and ruddy, came to Calgary in 1982, a recent engineering grad from Newfoundland with a job in the first oil-patch boom. He experienced the subsequent bust. "That job lasted three years," he says. "I was out of the industry for good."

He moved on to urban and community development, and is the director of Sustainable Calgary, a non-profit group that lobbies local leaders for a new era of development meant to humanize this increasingly car-dependent city: More walkable spaces, better transit, increased density in the city's sparsely populated core.

He's not pleased with what he sees.

"One of the problems is that it's all over the place. It's car-oriented development," he says, passing a distended strip mall surrounded by four lanes of fast-moving traffic.

"To get in your SUV and drive two kilometres to get a litre of milk is insane. It's an insane way to design a city in the 21st century."

Mary Axworthy, the city's director of land use, planning and policy, has heard the sprawl label applied all too often. The city has drawn a raft of criticism recently from all over the West for its expansive plans. An article in the Vancouver Sun in August, profiling Calgary city planner Brent Toderain, soon to take over the planning department in Vancouver, offhandedly referred to the city as "the temple of sprawl."

So Axworthy can be forgiven if she's a little sensitive to the term.

"Sure, we feel like it's unfair criticism sometimes, but I think mainly it's misunderstanding," says Axworthy, a friendly, no-nonsense ex-Winnipegger who came to Calgary during the first boom, in the late '70s.

She describes a different kind of Calgary from the one seen from the air: one with an increasing cluster of condominium projects dotting the city core. Most are under construction, or planned, with a few completed and occupied. She speaks of a city centre that will see its population spike from its current 35,000 to 103,000 over the next 20 years.

But in the last two years, a hard reality came to pass. "The city just exploded. Everyone could feel it," she says. "We could tie a noose around the city and say, well, the city isn't going to grow any larger. But we simply can't accommodate all the growth we have into the downtown area. That's just not going to happen. The reality for us is we still need to grow out."

If it's not a crisis, it's near one. The city's vacancy rate for residential properties is 0.6 per cent. For industry, it's 0.95 per cent. A story in the Calgary Herald this week said the price of industrial property had doubled in the past year due to the shortage.

Managing rapidly expanding suburbs is not new here.

In 1995, Calgary introduced citywide guidelines to increase density in suburban areas, to a minimum of 7 units per hectare.

This year, the city has taken another step, this time by removing a cap of 8 units per hectare.

"We've done a lot with our suburbs," Axworthy says. Sprawl, to her, is an inappropriate term. "It has the connotation of being unplanned ? leapfrogging development, unplanned, uncontrolled. We don't think we fit that description."

`To get in your SUV and drive two kilometres to get a litre of milk is insane'

Noel Keough, director of Sustainable Calgary

`For the first time, Calgary has the political will and the right fit to make it happen'

Jeremy Sturgess, architect

But Axworthy's contention is a flashpoint of debate here, where explosive growth, and how to manage it, is a divisive urban issue.

"The city, all the way down from the mayor, will tell you there's no sprawl," says Beverly Sandalack, the co-ordinator of the University of Calgary's Urban Design program.

"But that's absolutely not true. You fly into Calgary, and what do you see? A city overwhelmed by its suburbs."

In Sandalack's downtown office, the university's urban design lab, a map of the city from 1924 hangs on the wall. It is almost comic in its proportions: A small cluster around the Bow and Elbow rivers, extending not more than six kilometres in any direction. It seems an unlikely forebear, only 80 years previous, of the distended urbanity that exists now.

Sandalack calls the city's minimum density requirements "pathetically low." She looks to the culture for the root of the problem. "People move to the West, and always have, for 100 years or more, so they can have a house of their own," she says.

Annexation ? the city's ever-expanding outward growth ? is the issue: If vast lands are swallowed for growth, then low-density suburbs are inevitable. "The horse is already out of the barn, so to speak," she says.

"We need to do something to make a better quality of city inside."

For Keough, the issue lies at the heart of an Albertan political reality. "Governments think they'll be pilloried if they suggest interventionist planning," with the result of letting the developers decide how the city grows, he says. "It goes all the way to the provincial level ? `the oil companies are going to provide for everyone and all we have to do is sit back and stay out of their way.'"

Increasingly, though, that's proving to not be the case. The vast wealth generated here by the oil boom has also brought just as dramatic inequities. Once a minor issue, homelessness in Calgary has exploded. In the past year alone, the homeless population in Calgary has ballooned by more than 30 per cent, to 3,400.

It is the pain of growth, most here will allow. But a brighter future is a managed one, says Druh Farrell, a Calgary alderman. A native Calgarian, Farrell remembers the unchecked sprawl of the '80s boom, and the bullying ways of developers.

"They ruled this city," she says. "If things were made too difficult, there was this threat that they would simply go elsewhere."

When she first took office in 2001, she heard the same threats. "My answer was `Don't let the door hit you on the way out,'" she says. "You're building a city here, and every development is part of that."

Farrell is quick to acknowledge that Calgary, while growing rapidly, still has some growing up to do. She describes, with a laugh, the guideline of 7 units per hectare as "enough to be annoying, but not enough to accomplish anything, really."

But Farrell's vision is of a Calgary with a bustling downtown, day and night, where people eat, sleep, play, and above all, walk ? still rare in all but a scant few districts, like Kensington, just north of downtown, or the busy social strips of 17th Ave. and 4th St. to the south.

"There's a realization that downtown can be so much more," she says. "There is an opportunity to do something better here. It's our choice, and it's one we have to make now."

In recent years, Farrell has been active in recruiting architects to the city's Urban Planning Commission, previously a domain of developers, councillors and the general public. There are now three. "In the past, you'd be lucky to have one," says Jeremy Sturgess, a celebrated local architect on the commission.

Looking at the handful of condo towers either planned or poking up in major redevelopment areas around downtown, Sturgess says he's pleased with what it implies. "I'm not worried about the inner city any more. If even half of them get built, it's going to do very well for itself."

But the city needs densifying suburban models ? "sustainable villages" where people can live, walk, play and work, and scrap the growing commute ? to turn the tide of its rapid land consumption.

A shift at city council offers hope that, finally, it might be possible, Sturgess says. "Their hearts are in the right place. For the first time, Calgary has the political will and the right fit to make it happen."

But that future vision of Calgary is very different from its current form. Of the 75 communities recently built, or being built, only two ? Garrison Woods in the near southwest and McKenzie Towne in the distant southeast ? are built on the "sustainable village" principles.

"The city says all the right things, and you look at it, but it's always business as usual," Sandalack says. "This is a drop-dead beautiful landscape, built on ranching.

"It's going to take some real visionary politicians to say `Let's make a different city.'"

On the fringe of that landscape in the city's northwest, the mountains tower serenely in the late morning sun. Keough steps out of the car on to a dusty gravel track where construction vehicles rumble back and forth on the rough, cleared lots, rapidly assembling Sherwood, a distant suburb lined with single-family homes with big garages in front.

"Legendary Living," the sign reads in an Arthurian font, complete with cartoon castle.

"I liken this to clear-cut logging," Keough says. "You clear the land, you throw down a bunch of cookie-cutter houses ? it's easy. That's what we're geared to do here."

The city's talk of density leaves him wondering if it's too late. Meanwhile, thousands of hectares of rolling countryside wait for the bulldozer blades