Groundwater levels fall at alarming rate around world
▶ Declines recorded in more than two thirds of aquifers, study shows
Groundwater is declining around the world, often at accelerating rates, a study involving about 1,700 aquifers shows.
Researchers at the University of California, Santa Barbara, in the US found that groundwater was being reduced in 71 per cent of aquifers.
This depletion is accelerating in many places. Having declined in the 1980s and 1990s, it has since sped up over the past two decades.
The three-year study, the largest so far, included 300 million water level measurements from 1.5 million wells over the past 100 years.
It found that groundwater deepening was more common in drier climates, with an “accelerated decline” most common in arid and semi-arid lands under cultivation.
In some countries, including Iran, the decline in groundwater is widespread.
Scott Jasechko, an associate professor with the university’s Bren School of Environmental Science and Management and one of the study’s lead authors, told The National that irrigation was probably to blame for the decline.
“Rapid and accelerating groundwater declines are widespread in many valleys across Iran, likely due in large part to intensive groundwater pumping for irrigation,” he said.
“The accelerating pace of groundwater declines in Iran raises questions about the viability of Iranian irrigated agriculture in the near future.”
Most aquifers where declines were worsening are in places where conditions have become drier over the past 40 years, the study said.
It is not all bad news, however. In some regions – including parts of Saudi Arabia – groundwater levels have stabilised, or even recovered.
“In central Saudi Arabia, groundwater levels have declined for decades as groundwater was pumped for irrigation, but there is emerging evidence that these declines may be slowing down in central Saudi Arabia following policy changes,” Mr Jasechko said.
“The study shows that humans can turn things around with deliberate, concentrated efforts.”
The study found the declines of the 1980s and 1990s had reversed in 16 per cent of the aquifer systems for which the authors had data.
The problem can be halted or even reversed by reducing demand and using regulations, permits and fees for groundwater use, the study’s authors said. In Bangkok, the declines of the 1980s and 1990s were reversed by regulations designed to reduce groundwater pumping, they said.
Spain has reported some success, with groundwater levels in several of the country’s aquifers having improved.
Progress has also been made in Australia, where water levels in some aquifers have rebounded and are beginning to rise in some cases.
In South Africa, the levels of some aquifers have recovered but in others groundwater depletion is accelerating.
The data also creates a mixed picture across the US, where groundwater has depleted in some areas but is increasing again in others.
The study highlights a depleted aquifer near Tucson, Arizona, which is being refilled by water diverted from the Colorado River.
The UAE’s aquifers were not included in the study.
But the government has been working to reverse the decline in groundwater resources. In 2019, it was reported that levels in the Liwa Crescent dropped by 14 metres in 12 years.
Abu Dhabi introduced a policy last year that aims to decrease extraction by up to 650 million cubic metres by 2030.
Groundwater constitutes 60 per cent of the water used in the emirate.
No visit to the Emirati city of Al Ain is complete without a trip to its oases, where farmers tend to thousands of date palms, fruit trees and fodder crops that are made possible by a system of aflaj – Iron Age irrigation networks. This ingenious collection of complex underground and surface channels is an engineering marvel recognised by Unesco, but it also reveals how the importance of fresh water is imprinted not just on the landscape but in the hearts of the people.
The persistence of the aflaj networks shows what many in the Middle East have understood for centuries: that the struggle for clean water is a life-or-death one. That is why many in this region will be alert to the conclusions of a new global study of 1,700 aquifers, which say that groundwater is rapidly declining around the world. The three-year survey by researchers at the University of California Santa Barbara found that groundwater levels are dropping in more than two thirds of the aquifers examined.
In some arid countries, such as Iran, groundwater declines are already widespread. The strain put on groundwater resources by agriculture and growing human populations adds to the water scarcity facing many states in the Middle East. But if the region is where the struggle for water is most acute, it is also the place where more innovative ways of managing water resources are emerging.
The report’s authors highlight how in some parts of Saudi Arabia, groundwater levels that had been lowered by agricultural irrigation had stabilised, or even recovered.
The UAE has always been aware of the precarious nature of water security. In 2017, the country launched its Water Security Strategy 2036. Since then, approaches to conservation have been refined, leading to some impressive wins. Earlier this month, for example, the Abu Dhabi Agriculture and Food Safety Authority said it was to supply recycled water to more than 1,600 farms, reducing pressure on groundwater sources.
UAE campaigns to conserve water have also appealed to individual households. In 2020, the Abu Dhabi Department of Energy developed the Use It Wisely app to help users minimise water and energy consumption at home. In Dubai, Dewa’s Smart Living programme lets customers receive alerts when their water use is high.
Another reason for optimism are the many solutions to groundwater management issues. Managed aquifer recharge, for example, involves applying treated wastewater or floodwater to the land and allowing it to refill the aquifer below.
As the UN General Assembly heard last year “there is historically more co-operation than conflict over international waters”. Nevertheless, climate change and growing human demands for water risk increasing disputes “unless shared water resources are managed through science-based water diplomacy”.
Sadly, the Middle East will be at the cutting edge of these coming tensions but it is already demonstrating what can be achieved. The region has been managing this precious resource for thousands of years – it can do so long into the future.