Heavily irrigated regions in drier climates face the greatest threat
In the upcoming decades, important underground resources could be depleted as a result of excessive pumping of groundwater for drinking and agriculture. According to a new research, parts of India, southern Europe and the U.S. will probably be the most affected areas, while this would affect around 1.8 billion people. The results of the research - conducted by the Colorado School of Mines in Golden, Colorado and Utrecht University in the Netherlands- were presented at the American Geophysical Union (AGU) Fall Meeting.
New modeling of the worldâ€™s groundwater levels allowed the research team to forecast when and where aquifers around the world may reach their limits, or when water levels drop below the reach of modern pumps (limits were considered â€œexceededâ€ when groundwater levels dropped below the pumping threshold for two consecutive years). As expected, the findings showed that heavily irrigated regions in drier climates face the greatest threat of depletion with the large aquifers in the US being the first to deplete, as Californiaâ€™s Central Valley, Tulare Basin and southern San Joaquin Valley could be depleted even within the 2030s. Aquifers in the Upper Ganges Basin area of India, southern Spain and Italy could be depleted between 2040 and 2060 and those in the southern High Plains, which supply groundwater to parts of Texas, Oklahoma and New Mexico, could reach their limits between the 2050s and 2070s. â€œWhile many aquifers remain productive, economically exploitable groundwater is already unattainable or will become so in the near future, especially in intensively irrigated areas in the drier regions of the world,â€ said Inge de Graaf, hydrologist at Colorado School of Mines and head of the research. She added that "when water tables decline, pumping costs will increase and also it will cost more money to maintain the wells. The decline will also reduce discharge into rivers, which could result in rivers running dry".
While previous studies used satellite data to show that several of the worldâ€™s largest aquifers were nearing depletion, aquifer depletion on a smaller, regional scale could not be measured. But the new research used new data on aquifer structure, water withdrawals, and interactions between groundwater and surrounding water to simulate groundwater depletion and recovery on a regional scale. However, scientists still lack complete data about aquifer structure and storage capacity to say exactly how much groundwater remains in individual aquifers. â€œWe donâ€™t know how much water there is, how fast weâ€™re depleting aquifers, or how long we can use this resource before devastating effects take place, like drying up of wells or rivers,â€ says de Graaf.
As expected, the new study found that heavily irrigated regions in drier climates, such as the U.S. High Plains, the Indus and Ganges basins, and portions of Argentina and Australia, face the greatest threat of depletion.