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However, while much more water is needed in flood irrigation, the excess ultimately returns into the basin as runoff, wending its way back into the original flow to be shared among other users.
"One user's water inefficiency often serves as the source of another user's water supply," the researchers wrote.
But with the apparently more efficient drip irrigation technique, water no longer leaks back into the system, which means users downstream need to take water they might otherwise siphon.
Furthermore, much more water is irretrievably lost through 'evapotranspiration' (the process of plants using water to grow).
Ward and Pulido-Velazquez conclude that while "drip irrigation is important for many reasons, including water productivity and food security, [it] does not necessarily save water when considered from a basin scale."
Murray-Darling connection
Peter Smith, an irrigation officer from the NSW Department of Primary Industries, believes these findings may hold some relevance to water conservation efforts in Australia's own Murray-Darling Basin.
"Improvements in irrigation systems and management do not necessarily lead to water savings," he said.
"The real issue is that improvements in efficiency result in [farmers] being able to grow more with their water, so the savings don't automatically revert to environmental or other uses."
So rather than growing one field inefficiently, a farmer may instead use every drop available more efficiently in order to grow two successful fields.
Along with this greater water use, there may be other "hidden dangers" of improving water efficient irrigation, adds Smith's NSW-based colleague Kelvin Montagu, from the national oraganisation, Cooperative Research Centre for Irrigation Futures.
"The build up of salt as well is becoming a major problem, particularly in the very light soils of South Australia," he said.
"When we become more water-efficient, like with drip irrigation, we end up with not enough water running through the soil to take away the natural salt that builds around the root zone of plants."
This can wreak havoc with the soil and crops, he said, and is already making some of our wines overly salty.
But Montagu suggests water management in the Murray-Darling Basin is heading in the right direction.
The Federal Government has committed funds to buy back water entitlements from willing farmers, limiting additional water use, he said. The initiative will assist farmers to employ more water efficient techniques, with the proviso that half of the water saved is returned to the environment.
