There's nothing like a new catchword to liven up the real estate industry. In the past, we've had "sprawl," "flip" and "big box."

Now, thanks to the latest U.S. Census, "boomburb" has been introduced to the lexicon.

So what is a boomburb? According to the Fannie Mae Foundation, a boomburb is an area that currently has more than 100,000 residents and has maintained double-digit rates of population growth in each recent decade, but is not the largest city in its metropolitan area. Boomburbs almost never have a dense central business area. And their housing, retail, entertainment, and offices are spread out and loosely configured.

"The boomburbs are elusive and not yet fully part of the public policy debate," said Stacey Davis, president and CEO of the Fannie Mae Foundation. "They are complicated places with potentially big problems that will need attention -- affordable housing, traffic jams, spread-out development, strained public services. But they also present opportunities for cities and suburbs to find regional solutions to their common challenges."

According to a new report by the Foundation -- Boomburbs: The Emergence of Large, Fast-Growing Suburbs & Cities In The U.S. -- the United States now has 53 boomburbs. They're located in 14 metro areas surrounding Phoenix, Los Angeles, San Diego, San Francisco, Denver, Miami, Tampa, Chicago, Las Vegas, Portland, Dallas, Salt Lake City, Norfolk and Seattle. Boomburbs range from Mesa, Ariz., with nearly 400,000 residents, to Westminister, Colo., with just over 100,000.

Four of them have more than 300,000 residents, eight have more than 200,000 and 41 exceed 100,000. These important -- but seldom talked-about -- areas account for 51 percent of growth in cities between 100,000 and 400,000 residents in the last decade.

Since I grew up in one of the boomburbs listed in Fannie Mae's study, I was fascinated by the report's conclusions. My once-small hometown of Arlington, Texas, now counts nearly 330,000 residents, up more than 4,000 percent since 1950. Growing up in this exploding, spreading mass of suburbia, it never occurred to me that Arlington's growth patterns were unusual.

The Fannie Mae report, however, has corrected that notion. Boomburbs are all but foreign to the Northeastern, Southeastern and Midwestern United States. Limited almost entirely to the Southwest, boomburbs are prevalent in California, Arizona and Texas, which also happen to be a few of the states most often accused of suburban sprawl. In the Midwest, one boomburb has been established outside of Chicago. In the Southeast, three have sprung up around Miami, while one has exploded outside Tampa and one near Norfolk, Va.

Since almost half of these cities are in California, the report credits the boomburbs have helped foster master-planned community development and the need to form large water districts.

Because of their large size, boomburbs often have more diverse populations than smaller suburbs. Many are affluent, but virtually all Boomburbs contain lower-income neighborhoods as well. They are not -- myths to the contrary -- suburbs filled exclusively with middle-class, white families. Instead, they tend to attract people of diverse racial and ethnic backgrounds. For example, Hialeah, northwest of Miami, had a 70.4 percent foreign-born population in 1990. In Santa Ana (Orange County), Calif., 50.9 percent of the 1990 population was foreign-born.

Boomburbs generally grow out rather than up. While some have annexed land to expand their populations, others are land-locked and near a "build-out point." Landlocked boomburbs, such as Tempe, Ariz., are at a crossroad: if they want to keep growing, they must change their land use patterns to accommodate higher density development.

Exceptionally fast growth rates can cause extreme developmental problems, such as the traffic congestion of Los Angeles, the strained public services of San Francisco and the sprawl of Phoenix and Dallas.

Yet some see this as an opportunity, rather than a threat. Because of their large size and nearness to other large cities, boomburbs can be a part of regional solutions to big problems.

"Cities of all shapes and sizes have been on the comeback," U.S. Conference of Mayors President and Boise Mayor Brent Coles. "Older cities are coming alive again with new investment and activity. Newer cities are continuing to thrive. We need to grasp this moment in time and forge relationships that will help deliver a better quality of life for everyone."

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