PARIS, Jan 30 — The level of groundwater in aquifers has been declining dramatically worldwide since the 1980s, as one of the most extensive studies on the subject has shown. But the good news is that it is possible to reverse the trend.
With the water crisis intensifying in many areas around the world, there are numerous conservation methods being adopted to avoid shortages. Some, however, are controversial, such as the use of giant reservoirs in France designed primarily for the agricultural sector, but which many environmental associations consider to be a “false solution,” insofar as “they increase pressure on water resources, harm biodiversity and continue to feed a devastating and ill-adapted agro-industrial model,” stresses the French branch of NGO Greenpeace on its website. A team of researchers from the University of California at Santa Barbara (USA) have come to the same conclusion with their analysis. In a major international study published in the journal Nature, they recommend the use of underground reserves, known as aquifers, to optimise water resources. The research examined data from nearly 1,700 such sites with underground water reserves.
According to the study, the level of groundwater resources has fallen in 71 per cent of the aquifers since the 1980s, with a clear acceleration from the 2000s onwards, particularly in heavily cultivated arid zones (this is the case, for example, in Afghanistan, Chile, China, Mexico, Morocco, Spain and the south-western United States). “Groundwater is a renewable resource, but it can take decades or even centuries for some aquifers to recover after they are depleted,” explain the researchers in an article published by The Conversation. This is a major problem given that, in addition to having a real impact on agricultural land (these wells provide almost half the water used for irrigation worldwide).
Restricting groundwater pumping: A successful strategy
But some community-led initiatives can help reverse the trend, and depleted aquifer systems can be replenished, say the researchers. They cite the case of a valley in the USA near Tucson, Arizona, where the water table has fallen by 30 meters since the 1940s. To replenish the valley’s underground reserves, basins called leaky ponds were created and filled with water from the Colorado River transported hundreds of kilometres via canals. This intervention, which sees the water seeping from the ponds into the aquifer, raised the water level by up to 60 meters in some areas.
Taking certain types of political actions can also reduce demand for groundwater. The study cites the example of Bangkok (Thailand) where, “so many private wells were drilled for domestic, industrial or commercial purposes between 1980-2000 that groundwater pumping doubled and groundwater levels fell.” The authorities then decided to quadruple the fees that had to be paid to extract groundwater. As a result, users were pushed to turn to other water sources, and groundwater levels gradually rose. — ETX Studio
