Two of the world’s most densely populated regions, northern India and northern China, are experiencing high levels of groundwater depletion, according to a 2015 study sponsored by Nasa.
For these and many other highly stressed aquifers, natural replenishment through precipitation is unable to offset human-led extraction, threatening water quality and supply sustainability.
Three notable cases are the Ganges River and Indus Basin (both in India), and the North China Aquifer. Given that these areas account for a significant percentage of the national population in the world’s two largest countries, groundwater depletion should be an urgent policy imperative.
In China, significant efforts have been made to address water shortages in scarcity prone regions, including pipeline transfers, desalination, and stronger urban design standards. Nevertheless, depletion of groundwater continues and the impacts are dire, both for individual users and for urban health and safety in general.
In rapidly developing regions, groundwater provides a quick and easy way to satisfy unexpectedly high demand. However, increased usage resulting from population growth, industrial expansion, and lingering agricultural activity is causing water stress where groundwater reserves are already overdrawn.
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Increasingly erratic weather and saltwater intrusion, both associated with climate change, can alter groundwater levels and quality. The impacts of lower levels are dire; not only is there less to consume, but lower quality can worsen public health crises and burden existing purification systems (or require the purchase of expensive new ones).
In China, a population equal to 20% of the world total relies on less than 6% of the world’s groundwater. The overstressed North China Aquifer serves 11% of the country’s population, 13% of its agricultural production, and 70% of its coal production.
China’s solutions have, so far, been inadequate. The massive South-North Water Transfer Project has supplied Beijing with an annual 2 billion cubic meters of Yangtze River water since 2014, but is not a long-term solution.
The project, costly and imposing as it is, could mask the need to address other water management challenges such as leakage, aging infrastructure, and wasteful usage.
As the largest such project in the world, the transfer also brings negative impacts to source regions, including over-withdrawal during dry seasons and displacement of communities (a common problem for China’s dam projects).
Further, a government-led study of groundwater quality, which included source regions for the Yangtze River, found that 80% of the country’s groundwater is contaminated by toxic metals and other pollutants, rendering supply unfit for human consumption.
Desalination is another solution with thus-far unrealized potential. In coastal areas near Beijing, restrictions on extraction of groundwater for industrial use have been adopted to force desalination into the supply portfolio, but desalinated water has not been incorporated systematically into China’s municipal water systems. Additionally, the negative impacts of scaled-up desalination on marine and coastal areas may be overlooked at great peril to sustainability and ecological health.
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The incompleteness of these measures has perpetuated dependence on groundwater, and over-extraction is having severe impacts on Beijing; including that the city is dropping by 11 centimeters per year due to the gaps left after extraction, causing subsidence and damage to infrastructure.
The problem is particularly acute in the Chaoyang district, which encompasses the capital city’s eastern suburbs – areas that are rapidly expanding with dense, high-rise construction.
In the United States, the highly publicized case of a new luxury tower leaning several degrees only years after construction, due to poor foundation standards, illustrates the legal, financial, and social challenges of building in areas with geotechnical instability.
San Francisco’s leaning tower is 57 floors tall, but many in Beijing’s rapidly subsiding districts are far taller. Will it take a disaster to generate calls for robust demand management?
According to the authors of the Nasa study, “It is important to understand where existing socio-economic tensions may collide with water stress to produce stress-driven conflicts.”
In China, the desire for economic growth has long conflicted with environmental protection and public health; crisis-level air pollution is a continuous reminder of this.
California Governor Jerry Brown called for a state-wide reduction in usage of 25% in July 2015, and the state exceeded expectations by reducing usage 31%
As water governance occurs largely at the central level, high-level policies should target continued economic growth and urbanization only within the confines of water resource limits.
Efforts such as the “three red lines” initiative require cities to constrain water consumption to enable more effective regional allocation. Similar restrictions could be imposed for water-intensive industries and other heavy users. Water conservation is also dependent as much on individual decisions as on national policymaking.
One example is California’s 2015 water shortage. Governor Jerry Brown called for a state-wide reduction in usage of 25% in July 2015, and the state exceeded expectations by reducing usage 31%.
Much of this reduction came from changes in personal habits; fewer people watered lawns and washed cars. The state also encouraged municipalities to actively manage demand; in turn, many imposed surcharges on individual users who exceeded stipulated limits. Pricing is a powerful water demand management tool.
China’s demand profile for water does not closely resemble California’s; both markets have high usage for agriculture (64% in China and 80% in California), but China’s manufacturing activity as a share of economic output is larger than California’s.
Furthermore, Chinese citizens are less likely to use water for lawns and washing cars. However, China must adopt a more aggressive volumetric pricing program to manage demand, particularly for industrial users.
On a per cubic meter basis, water tariffs on businesses and individuals are less than 12% of those in Denmark and less than half those in the world’s developed countries. China’s implicit subsidization of water serves little purpose, least of all in prompting conservation and innovation.
China has made some effort to address these challenges. The sponge-cities program, a modified version of low-impact development that focuses on permeable surfaces and water infrastructure, seeks to increase groundwater absorption.
The central government has set a target for 80% of Chinese cities to meet sponge-city standards by 2030. This is a crucial step in aggressively and publicly addressing groundwater depletion under urban areas, including Beijing.
However, there appears to be a tepid appetite for private investment in these projects. More aggressive inducements may be needed to prompt public-private partnerships for sponge-city development.
Addressing the groundwater depletion problem – and in broader measure the growing crisis of water scarcity amid rapid urbanization – will require a multi-pronged approach that includes unequivocal political will, transparency regarding the impacts and costs of depletion, creative policy initiatives to manage demand, and support for technical innovations to improve efficiency in usage.
Both China’s economic and environmental sustainability are at stake.