Groundwater – Making the Invisible Visible

By Debra Tan, Dawn McGregor, Sophie Lam 22 March, 2022

Happy World Water Day! This year we highlight 5 reasons why groundwater may be out of sight but can never be out of mind. CWR's Tan, McGregor & Lam expand

GW accounts for 99% of liquid freshwater reserves, is a major source for food production & can play a critical role in adapting to climate change but is still taken for granted
GW recharge is decreasing but GW demand is increasing; unknown quantity & quality urgently needs unveiling as well as stronger transboundary & trans-state cooperation
China has been taking action & seeing some results (over-extraction & poln); companies are also acting as part of water positive targets & there are things individuals can do

Anything that is invisible, we take for granted. Groundwater is no different. Did you know that it accounts for 99% of our liquid freshwater reserves? If you didn’t know that, we rest our case … groundwater is definitely under-appreciated.

GW = 99% of liquid freshwater reserves

So this World Water Day, we are going to give it some love by highlighting why it’s important.


Below are 5 reasons why groundwater may be out of sight, but never out of mind … and … read to the end for tips on what you can personally do to help save groundwater!

1. The IPCC AR6 WG2 recently warned that climate change has altered groundwater levels

Groundwater feeds springs, rivers, lakes and wetlands, and seeps into oceans and is recharged mainly from rain and snowfall infiltrating the ground. Climate change has profound impacts snow and rainfall affecting recharge in some regions.

The IPCC AR WG2 warned that in higher altitudes mountain regions, groundwater recharge and contribution to streamflow is expected to decrease with ongoing climate change. Groundwater recharge is also projected to decrease in some aquifers in the US and Europe which further exacerbate their ongoing depletion due to high demand or unstainable pumping.

GW recharge is decreasing….

…but GW demand is increasing – 30% increase by 2050 in Asia

At the same time as potentially dwindling groundwater resources, demand for it is going up. In Asia and the Pacific region groundwater use is predicted to increase 30% by 2050 leading to the further depletion of aquifers in already over-extracted regions. Indeed, in many regions farmers and already digging deeper for water as water tables fall, raising costs. Moreover, this requires more energy – often cheap and carbon-intensive – to pump the water up to the surface for irrigation. This will clearly need to be addressed going forward.

Overextraction of groundwater can also lead to land instability and subsidence – for example in China, an area the size of Florida in North China Plain has been sinking by 165.4mm/yr during 2016-2018, whereas over in California, the draining of groundwater for agriculture has resulted in parts of Central Valley sinking as much as 60cm/yr, causing roads to buckle and irrigation canals to crack, and permanently depleting the storage space in key aquifers .

In coastal regions, over-extraction of groundwater can result in seawater intrusion under the land – an example of this in Jakarta where lax regulations allow just about anyone, from landlords to massive shopping mall operators to carry out their own ground water extractions, which has resulted in key coastal aquifers filling up with highly saline and brackish waters making the water from those aquifers no longer safe to use. Clearly subsidence will also accelerate the risks of coastal threats such as sea level rise as well as storm surges, all of which are according to the IPCC AR6 WG2 set to increase in the future.

“… GW can play a critical role in adapting to climate change…”

Regardless, groundwater can play a critical role in adapting to climate change – it is a potential reserve resource especially when surface water flows could become increasingly unreliable in the future. So how much groundwater reserves do we have now? Is what we have adequate for the future? Is it too polluted to use? Simple questions, but they are difficult to answer, which brings us onto the next points…

2. Quantity & quality unknown needs unveiling to ensure water & food security

Groundwater is a finite supply; but in many regions, we have no idea exactly how much there is or how much of it is polluted. Because it is hidden, it’s difficult figure out the amount available let alone monitor its pollution and over-extraction.

NASA & IGRAC using satellites & country overviews to gauge how much & how polluted global GW is…

We cannot manage what we do not measure – so, groundwater should be thoroughly explored, analysed and monitored. We have made some progress here with obtaining direct measurements of global groundwater changes from NASA’s GRACE satellite mission. Since 2002, these satellite images have revealed significant groundwater depletion and soil moisture drought over large regions such as the Middle East, Northwest India, North China Plain for the first time.

Aside from NASA, the International Groundwater Resources Assessment Center (IGRAC) have put together the first country-based global overview of groundwater resources and groundwater-related indicators to encourage countries to better regulate groundwater use.

…need to get on top of as GW is major water source for food production…

It is important we get on top of this because groundwater supports food production. Already, 40% of all the water used for irrigation comes from aquifers according to the FAO. Can groundwater support the projected increase of 60% in food production required to feed a rising global population of 9 billion by 2050?

The problem is acute in India where 90% of groundwater is used to irrigate crops. If it continues to run dry by 2040, it is highly likely that 60% of India’s districts will reach critical levels of groundwater depletion. Of course, climate change does not make this easier as the Ganges is facing increased droughts and extreme high temperatures. Also in many areas, groundwater is the only source of water available.

Also in many areas, groundwater is the only source of water available. This is evident in Saudi Arabia, Tunisia and Morocco, where conditions are arid, and precipitation is scarce and so groundwater accounts for 75%-95% of these countries’ water use.

… plus, already seeing loss of GW forcing communities to migrate

Loss of this underground resource will leave these communities with no choice but to migrate. For example, the overexploitation of groundwater used for agriculture has made it challenging for rural communities in Northeast Nigeria to find suitable water for household purposes, causing hundreds and thousands of them to migrate to the South.

Agriculture is not just the largest user of groundwater but also its biggest polluter. Excessive use of fertilizers and pesticides is a serious threat to groundwater quality – nitrate is the most common contaminant of groundwater resources worldwide.

But it’s not just in Asia, nitrates and pesticides are also a big threat to groundwater quality in North America and Europe where 20% of the EU’s groundwater bodies exceed EU standards on good water quality no thanks to agricultural pollution.

Clearly, we need to get a better handle on our aquifers globally if we are to draw up adaptation plans for the future. But it’s not just about risk, we could be missing out on an opportunity to harness a potentially vital but hidden water resource. Regardless, in the meantime, we can still protect this resource by limiting its over-extraction and pollution.

3. Preventing over-extraction & controlling pollution of groundwater

Groundwater supports our drinking water supplies, sanitation systems, farming, industry, and ecosystems, yet we seldom fuss over its protection and use; rivers and lakes receive much more attention. It’s time to accord groundwater the attention it is due. Avoiding the problems of groundwater depletion and pollution requires coherent policies on energy, land use and irrigation and takes time.

In China, where groundwater over-extraction and pollution have been rampant, efforts are being made – Grade V+ groundwater at which is not fit for both agricultural and industrial use has gone from 18.8% in 2015 to 17.6% in 2020.

China – where GW over-extraction & pollution has been rampant – is making big efforts to improve

There have also been efforts to prevent its overextraction – from higher tariffs to using alternate water sources such as reuse. Specifically, Northern China (where groundwater is over-extracted), groundwater levels in some areas have stopped falling and rebounded through “一减一增”综合措,  “Reduction & Increase” Comprehensive Measures. These interventions include water saving and agricultural reform as well as increasing water supplies from alternate water sources and recharging groundwater from rivers and lakes.

Cities like Beijing have also adopted water reuse to help alleviate groundwater reliance with the mix of water supply in the municipality changing from 36% GW in 2019 to 33% GW in 2020 while water reuse increased from 28% to 30% in the same period.

Groundwater is a top priority for China, with a dedicated section on “Promoting Comprehensive Treatment of Groundwater Overexploitation”. This includes amongst others:

  • preventing groundwater over-extraction and irrational development of groundwater with water permits, differentiated tariffs and water resources tax reform;
  • agricultural reform – improving agricultural irrigation to alleviate groundwater use; lowering excessive fertiliser use etc.;
  • accelerating groundwater recharge from rivers and lakes;
  • seeking alternate sources of water to replace groundwater use; and
  • improving monitoring network system for groundwater to rein in pollution and illegal extraction of groundwater.

14FYP for Water Security has harsher measures for areas with GW over-extraction

Moreover, the 14FYP for Water Security has harsher measures for areas with “weak ecology” and “severe water and groundwater over-extraction”. In these areas, new projects that will require water and put stress on the existing resources will be “strictly controlled”. Although China still has a long way to go to remediate its polluted groundwater, its measures to protect groundwater appear to be delivering results and could be adopted by other developing countries.

FYI – we will be reviewing the 14FYP for Water Security in our next newsletter – so sign up now.

4. Restoration of groundwater & the rising trend of water neutrality

As groundwater is also critically important to the healthy functioning of ecosystems, such as wetlands and rivers, it is important to replenish groundwater and restore damaged watersheds. Clearly, China is replenishing its groundwater … but it is also planting trees which can help watershed replenishment if done properly. The recently released IPCC AR6 WG2 noted that nature-based solution or green infrastructure (e.g. rain gardens, wetlands) to replace traditional stormwater management techniques can promote groundwater recharge.

Co’s also taking action at basins due to recent water neutral/ positive targets incl. GW recharge projects

But it’s not just governments, corporates must also take responsibility and lead the stewardship of the basin in which they operate. Indeed, corporates have been taking action especially with the recent trend of companies announcing water neutral or water positive targets – including big names like BP, Facebook, Gap Inc., Google, Heineken, Microsoft and PepsiCo. In essence, these targets mean that the companies are replenishing the water they use or more than the water they use.

This replenishment happens at the basin level as that is the source of the water and given water’s multidimensional aspects, is where it needs to be returned in order to maintain the ecosystem and thus the water supply that the company depends on. There are multiple ways to replenish the water that can be accounted for, one of which is groundwater recharge and so some companies, depending on the risks of the basins are contributing in groundwater are charge projects.

We cannot afford get policies on groundwater

Meanwhile, as part of corporate water stewardship activities, some companies have been contributing to WASH projects that improve access to water and sanitation. It all sounds good but recently there have been some findings that by providing access to water from groundwater sources, it is actually causing faster depletion of the aquifers and there is little to no recharge. So, while meaning well, the full impact and lifecycle of such projects need to be analysed too.

Maladaptation warnings were a plenty in the IPCC AR6 WG2 – let’s heed them – with climate change, we cannot afford to get policies on groundwater or anything that affects/ is linked to groundwater wrong as so many rely on it.

5. Transboundary groundwater

There are some 468 transboundary aquifers identified worldwide and many countries share groundwater resources. According to the Earth Security Group, six of the eight largest aquifers under stress globally are transboundary – these are the Arabian Aquifer System, Indus Basin, Ganges-Brahmaputra Basin, Nubian Aquifer System, Murzuk-Djado Basin, and Northwest Saharan Aquifer System. However, the Nubian and North-Western Sahara Aquifer Systems are non-renewable – ‘fossil waters’, due to their negligible rate of recharge.

6/8 largest aquifers under stress globally are transboundary…

…only a handful of transboundary aquifers are governed by an international agreement.

Although we have made substantial progress with assessing transboundary aquifers over the last two decades, “structural and formalized cooperation among aquifer-sharing countries are rare” according to UN Water. According to Water Policy, only a few of the 200+ analyzed agreements on internationally-shared rivers and lakes had specific provisions on groundwater and only a handful of transboundary aquifers are governed by an international agreement.

Given that the AR6 WG2 has warned to expect increasing uncertainty in water availability due to intensifying hydrological cycles and cryosphere changes, it will become increasingly important to strengthen international cooperation on groundwater as well as surface waters.

Trans-state water bodies, particularly in America, also have issues

But it is not just international aquifers; there could be issues with trans-state water bodies, particularly in America. According to the Atlantic, if US key aquifers vanished – California’s Central Valley aquifer and Ogallala aquifer -, 40% of nation’s beef production, and 40% of vegetables, nuts and fruits consumed would be lost. Last year, Mississippi made claims that Tennessee was stealing its groundwater, which was taken to the US Supreme Court. It was unanimously rejected because the high court ruled that sharing groundwater was caring. However, it’s only a matter of time before groundwater depletes in some states and things get messy.

In the US, there is also the issue of water rights which grant access to water beneath your property. Many have bought land, not to build a home to access the water beneath which is then sold. If left unchecked such actors could be using more than their equitable share and worst still empty out the common aquifer for the community. Recently, the investment company Greenstone bought 485 acres of farmland to send its water to the suburbs in Arizona, where develops a plan to build thousands of houses. As climate change depletes key reservoirs, investors have stepped in to try profit by offering water to the highest bidders.

Messy water rights and who owns what underground could further exacerbate the proper allocation of an increasingly scarce resource. Private water rights could drive up the price of water and trigger all out water wars that would unfairly punish the poor.

With the increasing use of groundwater resources worldwide, the need for stronger specific cooperation on domestic and transboundary groundwaters has become ever more evident and urgent.

Yes, you can do something too!

The above may sound like they are beyond your means to solve but every effort counts – even you can do something!

It may sounds beyond you to take action but it isn’t…

…cutting food waste & selecting less water intensive foods are some ways to help

Because groundwater is mainly used for food production, reducing food waste can also play an important role in lowering water consumption plus it reduces emissions – for an idea of how much, check out Action 6: Cut Food Waste of our report Together We Can: Habit Changes for 2ºC.

Another way to up savings is by selecting less water-intensive foods – see Action 5: Rethink Diets, plus there is upside on emission cuts as well. Skeptical of the power of one? If enough of us just did these two actions, we could save emissions of 235 million tonnes of GHG emissions, which is equivalent to the combined 2015 emissions of 2x Hong Kong, Denmark, Singapore and Croatia.

And even more, as the report shows, if enough of us made simple habit tweaks across eight areas of our daily life from food (covered above), online shopping to internet surfing plus more, we could save more than two billion tonnes of greenhouse gas emissions – the equivalent to the combined 2015 GHG emissions of Japan and South Korea!

So don’t wait, start on this World Water Day: think groundwater = less food waste & better food choices = water & emission cuts = stay within 1.5-2ºC … and together we can take tangible actions to make the invisible, visible!


Further Reading

  • Valuing Water – Looking At It Differently – Happy World Water Day! With this year’s theme of valuing water, China Water Risk’s Dawn McGregor & Debra Tan look at 3 different ways to value water
  • 3 Takeaways From CEWP’s 2019 Groundwater Policy Dialogue – With China and Europe joining forces to tackle groundwater over-exploitation, China Water Risk’s Yuanchao Xu was on hand to bring us the latest policy and tech ideas from the Jinan forum
  • Water: Leave No One Behind – Happy World Water Day! This year the theme is ‘Leaving no one behind’ so why do we still not have ‘water for all’? Climate change will only make it more difficult – let’s get our act together & start with this update from China Water Risk’s Dawn McGregor
  • Nature For Water In China & HK – Happy World Water Day! Given this year’s “Nature for Water” theme, we sat down with experts on nature-based solutions in China & Hong Kong from sponge cities to rivers and wetlands
  • Wastewater: Good To The Last Drop – Happy World Water Day! In the year of wastewater, we look at China’s management of the ‘waste’. Plus, what does the 13FYP hold? Action; given rising wastewater discharge & low re-use rates
Debra Tan
Author: Debra Tan
Debra heads the CWR team and has steered the CWR brand from idea to a leader in the water risk conversation globally. Reports she has written for and with financial institutions analyzing the impact of water risks on the Power, Mining, Agricultural and Textiles industries have been considered groundbreaking and instrumental in understanding not just China’s but future global water challenges. One of these led the fashion industry to nominate CWR as a finalist for the Global Leadership Awards in Sustainable Apparel; another is helping to build consensus toward water risk valuation. Debra is a prolific speaker on water risk delivering keynotes, participating in panel discussions at water prize seminars, numerous investor & industry conferences as well as G2G and academic forums. Before venturing into “water”, she worked in finance, spending over a decade as a chartered accountant and investment banker specializing in M&A and strategic advisory. Debra left banking to pursue her interest in photography and also ran and organized philanthropic and luxury holidays for a small but global private members travel network She has lived and worked in Beijing, HK, KL, London, New York and Singapore and spends her spare time exploring glaciers in Asia.
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Dawn McGregor
Author: Dawn McGregor
Dawn leads CWR’s work to help corporates navigate increasingly disruptive & material risks from water & climate threats, as well as transitional risks in the supply chain arising from new regulations in China. Here, Dawn engages extensively with the global fashion industry delivering on-ground workshops in China to keynotes and strategic input at European HQs. She has written at length on the end of dirty and thirsty fast fashion and her report to overcome gaps between brands and manufacturers for a clean and circular future inspired the industry to create a new wastewater tool. Dawn also works closely with the property and tourism sectors where she not only conducts strategic assessments of their exposure but builds collective action toward resilience via closed door working groups and invite-only events. Having helped build CWR, Dawn is a frequent keynote, panellist & moderator at events, including being twice selected as the lead-rapporteur at World Water Week. Her articles are cited in various industry publications including the UN’s ‘World Without Water’. Dawn previously worked in a global investment bank assessing geo-political risk, crisis management and business resiliency. She was born and bred in Hong Kong and has lived in France, England, Singapore and Beijing.
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Sophie Lam
Author: Sophie Lam
Sophie has recently graduated from the University of Exeter in the UK with a BA Honours Geography degree. Her final year modules focused on sustainability and environmental issues which she is keen to explore further as commences her journey into the workforce. Through joining CWR, Sophie has had an opportunity to apply her GIS knowledge on a project examining the impact of rising sea levels and extreme weather events on the critical infrastructure in the Asia Pacific region. Sophie hopes her participation in this project will facilitate better resilience planning and the management of risks presented by the challenges of climate change.
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