Slick idea proposed to stretch water supplies

摘要

In the southwestern United States, where years of drought are leading water managers to consider drastic water-provision measures such as desalination and cloud seeding, entrepreneurs have suggested reviving a technique that was tried and abandoned half a century ago. They propose to stretch dwindling water supplies by slowing down evaporation from reservoirs by means of a surface barrier of cheap, non-toxic, biodegradable chemicals just one molecule thick - two-millionths of a millimetre. The technology is far from proven, but it showed some potential in field tests in Texas last year.