Around the world, as water from underground aquifers gets pumped out at ever alarming rates, towns are sinking, whole communities are being uprooted, agricultural landscapes are getting transformed and instances of water-related conflicts are increasing.
Last year, as California experienced its fifth consecutive year of drought, excessive groundwater pumping resulted in parts of the San Joaquin Valley in Central California sinking by as much as 5 centimeters per month. This unprecedented rate of ground sinking put at risk some of the valley's main infrastructure, including its roads, bridges and aqueducts.
Land sinking, or subsidence of soil as it collapses into space created by depletion of groundwater in aquifers, is increasingly becoming common around the world. In some neighborhoods of the Chinese capital Beijing, ground is sinking at a rate of over 10 centimeters a year, as water in the giant aquifer below the city gets depleted through over-pumping. With a population of over 20 million, Beijing is among the most water-stressed cities in the world, and, with groundwater getting depleted at increasing rates, there are serious concerns for the city’s high-rise buildings and infrastructure such as rail system and roadways.
In India, which is the world’s largest consumer of groundwater, more than 30,000 people living in Noida, a city located 25 kilometers south-east of the Indian capital New Delhi, recently protested before the city’s water authority after receiving muddy water from their taps.
The Noida Water Authority, which supplies water to the city and surrounding areas, says underground aquifer levels are sinking as water is depleted at unsustainable rates by illegal pumps and increased construction activity. The city currently receives around 300 million liters per day (MLD) of water from two sources – the Ganga Canal located in Ghaziabad, about 22 km away, and from 200 tube-wells and half-a-dozen Ranney wells located around the city.
But increasing population, currently around 700,000, and the large number of residential and office blocks coming up in the area, have led to groundwater depletion rates of over one meter per year. With the city projected to need over 550 MLD of water by 2020, city planners are warning that unless new water replenishment techniques and policies are introduced, the city could face severe shortages in future.
Falling groundwater levels have not only led to decrease in water supply but also in the quality of water available. In some areas of Noida, the Total Dissolved Solids (TDS) in water have increased to as high as 2,200mg per liter; the World Health Organization (WHO) recommends a TDS rate of 500mg per liter for safe drinking water.
Of even greater concern for public safety is the risk to lives of people lining in high-rise apartment blocks that were constructed on land reclaimed from the nearby Yamuna River. With falling groundwater levels, the risk of ground below these high-rises sinking is a distinct possibility. Already, there have been reports of damages to the city's Metro Station with large cracks appearing on platforms and elsewhere.
Other cities around the world that made the news recently on account of land subsidence and the appearance of huge sinkholes that swallowed up homes and infrastructure are Bangkok, Mexico City, parts of Shanghai in China, New Orleans in the US and Christchurch in New Zealand.
Groundwater has for long served as a backup in cases of severe drought and warm winters when there is insufficient snow to feed rivers around the world; but more and more it is being used as the primary source of water, especially by agriculture. More than two-thirds of the groundwater pumped up worldwide is now used to irrigate agriculture, while the rest goes to supplying drinking water to cities and towns.
The inefficient practice of flood- irrigation, which is the prevalent form of irrigation in many parts of the world, and distorted use of subsidies to grow water-intensive crops in areas naturally ill-suited for the purpose, are among the reasons behind the humongous use of water by agriculture. For instance, in parts of India that have in recent years been enduring severe drought, millions of farmers have been forced to rely on groundwater to irrigate their fields.
This has led to groundwater in many areas being pumped out more rapidly than is naturally replenished. Also, the government's subsidies on electricity have allowed many farmers to keep pumps running to irrigate water-intensive crops such as rice and sugarcane in previously arid areas.
Similarly, in more affluent Saudi Arabia, engineers have drilled into underground water reserves in the Wadi Al-Sirhan Basin to allow farmers in one of the driest places on earth to grow grain, fruits and vegetables. Meanwhile, in the developed world, farm subsidies enable many giant multinational companies to use large amounts of water to grow corn in the naturally unfavorable High Plains of North America. Farm subsidies also allow large fish farms to use cold groundwater to breed cold water fish such as trout and sturgeon in hot arid regions.
Continued periods of drought, bad water management policies, poorly maintained water storage and transport systems, inadequate technology, population growth, and the demand for more food production, have all placed increasing demand on groundwater reserves. A recent report by the United Nations warned that continued irresponsible depletion of groundwater could lead to a global shortfall in availability of fresh water by 2030.
Citing scientific studies on the subject, the UN report notes that the world’s largest underground water reserves in Africa, Eurasia and the Americas, which account for around 30 percent of the world’s available freshwater reserves, are under severe stress. Scientists involved in the 2015 study, which recorded changes in the world’s 37 largest aquifers using satellite images from NASA, says that the ones under the greatest threat are those in the most heavily populated areas of the world.
According to the report, the world’s top over-stressed underground water sources are, in first place, the Arabian Aquifer System that supplies water to over 60 million people in Saudi Arabia and Yemen. This is followed by the Indus Basin Aquifer that provides water to Pakistan and northeast India, and, in third spot, the Murzuk-Djado Aquifer in northern Africa.
Scientists warn that as dry parts get drier, people around the world will begin to rely increasingly on groundwater and this could have staggering implications for world security and stability. Calling for discussions on the international level, scientists are cautioning that without proper oversight and sustainable management of groundwater, global security and the lives of billions of people could be at risk.
Recent events around the world bear witness to these grim predictions. The ongoing conflict in Yemen, which depends extensively on fast drying-up groundwater reserves for its traditional agricultural and animal husbandry, as well as the regionally destabilizing Syrian civil war, which began with high food prices and shortages due to failed crops, can both be traced back to a scarcity of available water.
According to a study conducted by the global, non-governmental World Resources Institute, 14 of the 33 likely most water-stressed countries in the world by 2040 will be in the Middle-East. These include Bahrain, Israel, Kuwait, Lebanon, Oman, Palestine, Qatar, Saudi Arabia and the United Arab Emirates, all of which are considered as extremely water stressed areas. Similarly, Jordan, which relies on aquifers as its only source of water, has now become even more water-stressed as a result of the arrival of more than half-million Syrian refugees.
It is worth noting that countries in the region, already arguably the least water-secure in the world, draw heavily upon groundwater and desalinated sea water to quench the needs of their growing population and to sustain rapid development. Unless regulatory measures are introduced immediately or alternate water resources are found, these countries could face exceptional water-related challenges in the near future.