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.
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.”
Josh Rosenau posts a thought at “Thoughts from Kansas“:
“Creationists think the world is younger than the water people drink in the Holy Land. There’s something very funny about that.”
Lawrence Livermore scientists are using isotope hydrology to learn about groundwater sources, ages, travel times, and flow paths and to determine the path and extent of contaminant movement in the water. See here for their website.
All waters have “fingerprints” of naturally occurring isotopes that provide information about their origin. Among the most powerful and cost-effective fingerprinting tools are the ratios of stable isotopes of hydrogen–deuterium to hydrogen (D/H)–and of oxygen-18 to oxygen-16 (18O/16O). The concentrations of atmospherically derived noble gases (neon, argon, krypton, and xenon) in groundwater provide another excellent fingerprinting tracer because the noble gases do not react with surrounding materials and because their concentrations are preserved as they are recharged into the aquifer.
Livermore was also asked to study groundwater resources in the Brentwood region of Contra Costa County, California, which is undergoing rapid urbanization after decades of agricultural use. Declining water quality, particularly that caused by high nitrate concentrations, is the result of fertilizer application and extensive agricultural irrigation.