water tables are falling, lakes are shrinking, wetlands are disappearing ... Perhaps the clearest signs of water scarcity is the increasing number of countries in which population has surpassed the level that can be sustained comfortably by the water available. As cl rule of thumb, hydrologists designate water-scarce countries as those with annual supplies of less than 1000 cubic meters per person. Today, 26 countries, collectively home to 232 million people, fall into that category. (Postel. 1992a: 2332)