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Author: Robert A. Frosch
American cities have generally been aging at the center and growing at the edges. In the center there are often problems with brownfields (polluted ex-industrial sites), poor housing stock, noise, and serious social problems. The infrastructure of central cities is aging -- already quite old in some places -- and often embodies engineering details that have been lost in history. New York City water is delivered through an underground aqueduct which is leaking 10 percent of the water, and has not been inspected in 40 years (you can’t turn off the city’s water to inspect the aqueduct). During the Boston "big dig," work has sometimes been delayed by the discovery of unsuspected geology, water, and infrastructure underground.
At the edges of the cities there are problems of urban spread into agricultural, forest, and prairie lands with concomitant developing environmental problems and conflicts. Everywhere in urban areas there are traffic congestion problems.
Many of these problems would be familiar to ancient Roman and medieval city residents and governments (although on a smaller, but similarly dense, scale), and like our earlier counterparts, we don’t seem to have good engineering solutions, either. (In ancient Rome they attempted to deal with congestion by forcing delivery and pickup to nighttime hours, with resulting problems caused by noise and irate citizens. We, too, haven’t done very well with this problem.)
Nevertheless, because of their employment, cultural, social, and business advantages, cities and their metropolitan areas remain popular and continue to grow in most parts of the world. As the World War I song has it: "How ya gonna keep ‘em down on the farm after they’ve seen Paree?" Meanwhile, the population of the world is expected to about double in the next 50 years, adding another 5 billion people or so, most of them in the developing world. If recent trends continue, about 80 percent of these people will end up in cities. Approximately 80 million people a year are going into cities -- the equivalent of 8 cities of 10 million people a year. How will these cities, or city extensions, come into being? How will they be designed and built? What will they be like to live in? Can they have a healthy and functioning infrastructure and population?
But be of good cheer: There is engineering work to do!
The NAE’s Annual Technical Symposium, held in conjunction with the Annual Meeting, introduced these problems and examined some aspects of them. After a keynote address by John Porcari, secretary, Maryland Department of Transportation, we had four sessions with speakers on topics including urban growth, industrial ecology, sustainable communities, planning, transportation, information technology, cities of the future, and megacities. Four papers from these sessions are included in this issue of The Bridge. Each session concluded with questions from the floor with answers and some resulting discussions among the speakers. While not all aspects of the subject could be discussed in the one-day session, it was a lively forum.
In my view, this subject, the future development of cities and metropolitan areas, deserves more systematic attention from the engineering profession and could be a lively subject for programmatic attention by the NAE and its members.