It may not be as densely populated as Bermuda, Bangladesh or Bahrain, but the Netherlands packs over 16 million people into an area only a little smaller than Bhutan, with 470 Dutch per square kilometre.

Another 2 million people will have to fit into the same space by 2030 and, to help house them, some planners are proposing to combine four of the country's major cities and an area known as the Randstad into a single megacity. Enter Deltametropolis.

Roughly bounded by Amsterdam, Utrecht, Rotterdam and The Hague, the Randstad is now home to more than 6 million people, scattered amongst a loose collection of urban centres, satellite towns, small villages and farms encircling a 'green heart' of lakes, meadows and marshes. Individually, all four cities face increasingly strained resources and congestion as their populations rise. Yet re-conceptualized as a single cohesive unit they do not seem so crowded. In fact, Deltametropolis's projected population density of 890 people per square kilometre pales compared to those of London (4,500) or Shanghai (8,265).

It would, of course, take more than a name change and image overhaul to turn the Randstad into a thriving megacity. It would not be easy to integrate the municipal services of four cities into one enormous, well-oiled system, or to connect and expand existing water and transport infrastructures. Planners propose a network of canals and reservoirs to provide both water and recreation. And they are devising ways of merging roads, railways and bus lines to provide fast and efficient connections both within the new megacity and with the rest of Europe.

Not everyone is enthusiastic at the prospect, however. Some think the whole idea unnecessary. Many favour restricting future development in the Randstad and encouraging people to migrate elsewhere. Others worry that, despite zoning, urban sprawl will encroach into the green heart of the city at the expense of fields, woods, wildlife and dairy farmers.

As the debate gathers steam, city planners, architects and engineers around the world will watch to see whether the Dutch - who long ago plucked their land from the sea - have found a way of coping with the rising tide of the world's city dwellers.

?Map: Topografische Dienst Kadaster