The supply of as much water as we want has become a widely accepted luxury of life in Europe and North America. Whether it is developed from a river or a well, water has been supplied so effectively, and at such low cost, over the last couple of hundred years that we tend to take it for granted.

This is mainly because, all over the world, centres of habitation have grown up close enough to significant rivers, or above major aquifers, so that the cost of developing, transporting and distributing the water is affordable to the populations concerned.

Now, however, the combination of burgeoning populations, with higher living standards, has created a situation in which potential new water sources are far away, and pumping depths from major aquifers are becoming excessive.

By way of contrast, there are many places, particularly on the African continent, where the water is still right there, only a few metres below the ground. The obvious way to supply water here is to drill a well, but the financing needed to do that is simply not available.

On the whole, though, the statistics on water use and development seem to show that, even where there are still significant resources available, the process of developing them has slowed to a relative trickle. It might even be said that the Age of Water Development is now effectively over, and we must move on into the Age of Water Management.