Using the tools of isotope hydrology, scientists can discover the age, origins, size, flow and fate of a water source. And that information, in turn, can guide sound water-use policy, letting water engineers better map underground aquifers, conserve supplies and control pollution.Creationists think the world is younger than the water people drink in the Holy Land. There's something very funny about that.
For instance, if the method reveals that the water in a well is young and recently derived from rain, villagers can pump away vigorously. But if it turns out to be very old - what scientists call fossil water - they need to move gingerly, taking care not to exhaust the water supply.
"You take it out once, like oil," Werner Burkart, head of the nuclear science programs of the International Atomic Energy Agency, said in an interview.
"If you look at the Middle East, everywhere you are using old water," said Pradeep Aggarwal, the head of the agency's isotope hydrology unit. "It was laid down 10,000, maybe 100,000 years ago. So you have to understand there's a limit to how long this will go."
There's also a lesson here about the interconnectedness of science. The same techniques that tell us how old fossils are also help prevent Bangaldeshi peasants from being poisoned by arsenic. The water supply for the capital of Ethiopia is being reconsidered in light of the same kind of evidence that tells us the age of Australopithecus fossils found in Ethiopia.
And the same techniques are used to help control the spread of nuclear weapons.