Groundwater resilience to human development and climate change
in South Asia
Dr. Mohammad Shamsudduha, Institute for Risk and Disaster Reduction,
University College London, UK
Child pumping water, India.
Source: F. Fiondella (IRI/CCAFS).
Globally, groundwater is recognized as an important natural resource with great economic
value. In many developing nations, groundwater abstraction has accelerated resource
development over the past 20 years and led to major social and economic benefits. 1
Estimates show that freshwater represents nearly 2.5 percent of the Earth’s total water
content, of which around 30 percent is groundwater and the rest includes ice and glaciers,
surface water, and soil and atmospheric water.2 Thus groundwater represents a significant
proportion of the Earth’s freshwater content, and in many countries groundwater is the only
reliable source of freshwater.
Approximately one-fifth of the Earth’s total freshwater resources can be found in South Asia
– the home of around 1.7 billion people (Figure 1). During the monsoon surface water is
abundant throughout the region; during the dry season surface water scarcity is common. A
vast amount of freshwater is stored as groundwater beneath the densely populated
floodplains of the Ganges, Brahmaputra and Indus River systems. In the dry season or when
the monsoon is delayed, this storage is critical. It can also be a safer alternative to oftenpolluted surface water year-round. For these reasons, groundwater is the main source of
domestic, industrial and irrigation water supplies throughout South Asia.
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Groundwater resilience to human development and climate change
in South Asia
Figure 1 (enlarge). Spatial distribution of
population in South Asian countries. Data
taken from a global population model of
LandScan 2007
(http://www.ornl.gov/sci/landscan/).
A safe and sustainable water supply is essential for improving public health, and achieving
economic growth and food security in the region. Currently, groundwater resources are
facing degradation due to a range of problems, such as overexploitation, mismanagement,
and natural and anthropogenic contamination. The strategic importance of groundwater for
global water and food security will further intensify under climate change.3
Groundwater-fed irrigation has become the mainstay of irrigated agriculture over much of
India and Bangladesh, Punjab and Sindh provinces of Pakistan, and the Terai plains of
Nepal.4 Traditionally, surface water from ponds and rivers had been used to provide both
drinking and irrigation water supplies in all South Asian countries. However, over the last
few decades groundwater has largely replaced surface water-fed water sources. In
Bangladesh, currently 97 percent of drinking water and nearly 80 percent of irrigation
water come from groundwater (Figure 2). The use of groundwater for irrigation in India and
Pakistan is approximately 60 and 35 percent respectively. By volume, India is the biggest
groundwater user in the world. A recent estimate shows that in India, Bangladesh, Pakistan
and Nepal combined the annual groundwater withdrawal is nearly 250 km3 – approximately
35% of the world’s total groundwater withdrawal. A substantial proportion of this
groundwater is used to produce rice, the staple food of South Asia. Recently, Bangladesh
has made significant progress towards becoming self-sufficient in food grains, primarily
through groundwater-sustained agriculture. It has long been taken for granted that shallow
groundwater used for irrigation and drinking water supplies in Bangladesh is fully
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Groundwater resilience to human development and climate change
in South Asia
recharged during the monsoon season. However, recent studies reveal that the volume of
groundwater storage is rapidly declining in many parts of Bangladesh and India because
groundwater is not being recharged at the same rate as it is used.5,6
Figure 2 (enlarge). Use of freshwater and
groundwater in different sectors in South
Asian countries.
Source: AQUASTAT
Intensive and unsustainable use of groundwater in South Asia, particularly in northern India
and central and northwestern Bangladesh, has led to rapid depletion of aquifers in recent
years. NASA’s GRACE (Gravity Recovery and Climate Experiment) satellite observations
have been used to show that northern India has lost approximately 109 km3 of groundwater
between 2002 and 2008 (Figure 3).6,7 Over the same period, India’s neighbor Bangladesh,
which has 4.5% of India’s landmass, has lost nearly 3 km3 of its groundwater due to overabstraction. 8 It is reported that sustained groundwater depletion has contributed
substantially to global sea-level rise3; groundwater depletion in Asia is estimated to have
contributed to a global rise of 2.2 millimeters over the period 2001 to 2008. Recent sea-level
rise in the Bay of Bengal has been attributed, at least in part, to over-abstraction of local
groundwater to supply irrigation and municipal water over the last few decades.5
Another concern is the deterioration of groundwater quality due to both natural processes
and anthropogenic activities. In large parts of Bangladesh and several northeastern states of
India, shallow groundwater is contaminated with high concentrations of naturally occurring
arsenic. Nearly 100 million people in the Indian sub-continent are currently exposed to
dangerous levels of arsenic in their drinking water supply.9 High concentrations of naturallyoccurring fluoride is another threat to public health affecting nearly 66 million people in
southern and northwestern India.10,11 Although, arsenic and fluoride contamination is not as
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Groundwater resilience to human development and climate change
in South Asia
big a problem in coastal Bangladesh, highly saline groundwater is a major public-health
concern, particularly for maternal health.12 Similar concerns exist in other deltaic areas of
South Asia. Although sources of high salinity in coastal groundwater are difficult to identify,
it has been shown that the reduction of flow through the lower Ganges and rising sea levels
are partly responsible.13
Figure 3 (enlarge). Trends in GRACEderived terrestrial water mass (period
August 2002 to December 2011) shows
mass loss over northern India associated
with recent decline in groundwater
storage.7
How will climate change affect South Asia’s groundwater resources in future? Unlike
surface water, groundwater is more resilient to climate change and slow to respond to any
change.14 However, some specific aspects of climate change can greatly influence the timing
and magnitude of groundwater recharge and quality, such as a shift in monsoon season,
heavy rainfall events, increased evaporation, increased runoff and rising sea levels.3,15
Elsewhere, it has been shown that episodic heavy rainfall events favor more rapid
groundwater recharge in central Tanzania.15 Heavier rainfall events are also projected to
occur in South Asia but the potential impact on groundwater recharge remains unanswered.
As mentioned above, sea level rise can cause coastal fresh groundwater at shallow depths to
be gradually replaced by saltwater. This process can accelerate through over abstraction of
groundwater in many of the growing coastal cities of South Asia.
The degradation of groundwater resources by human development and climate change is
increasingly disturbing drinking and irrigation water supplies globally. The problem is not
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Groundwater resilience to human development and climate change
in South Asia
exclusive to South Asia, but it is perhaps most critical in what is the world’s most densely
populated region. Public health, food security, industrial growth, and ecosystems all are
currently at greater risk than ever before. More public investment will be needed to manage
the growing demand for drinking, industrial and irrigation water supplies. Alternatives are
needed and improved efficiency of use is required. Many past development projects in South
Asia did not take into consideration the declining state of groundwater. Governments need
to recognize the social and economic importance of protecting aquifers from further
deterioration. Public awareness and education are also essential. Lastly, more scientific
research is necessary, particularly in complex coastal environments. Continually improving
our knowledge of groundwater systems in South Asia, and the threats they face, is a key
step in protecting this precious natural resource.
References:
1. Foster, S.S.D. and P.J. Chilton (2003), ‘Groundwater: the processes and global
significance of aquifer degradation’, Philosophical Transactions of the Royal Society B,
358(1440): 1957-1972.
2. Shiklomanov, I.A. (1993), ‘World fresh water resources’, in P.H. Gleick (ed.) Water in
Crisis: A Guide to the World’s Fresh Water Resources, Oxford University Press: New York.
3. Taylor, R.G., et al. (2013), ‘Ground water and climate change’, Nature Climate Change, 3:
322-329.
4. Shah, T., C. Scott, A. Kishore, and A. Sharma (2004), ‘Energy-irrigation nexus in South
Asia: Improving groundwater conservation and power sector viability’, IWMI Research
Reports H033885, International Water Management Institute.
5. Shamsudduha, M., R.E. Chandler, R.G. Taylor, and K.M. Ahmed (2009) ‘Recent trends in
groundwater levels in a highly seasonal hydrological system: the Ganges-BrahmaputraMeghna Delta’, Hydrology and Earth System Sciences, 13(12): 2373-2385.
6. Rodell, M., I. Velicogna, and J.S. Famiglietti (2009), ‘Satellite-based estimates of
groundwater depletion in India’. Nature, 460: 999-1003.
7. Jin, S. (2013), ‘Satellite Gravimetry: Mass Transport and Redistribution in the Earth
System’, in J. Shuanggen (ed.) Geodetic Sciences – Observations, Modeling and
Applications: InTech.
8. Shamsudduha, M., R.G. Taylor, and L. Longuevergne (2012), ‘Monitoring groundwater
storage changes in the highly seasonal humid tropics: validation of GRACE measurements in
the Bengal Basin’, Water Resources Research, 2012: W02508.
9. Ravenscroft, P., H. Brammer, and K.S. Richards (2009), Arsenic pollution: a global
synthesis, Wiley-Blackwell: U. K.
10. Amini, M., et al. (2008), ‘Statistical modeling of global geogenic fluoride contamination
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Groundwater resilience to human development and climate change
in South Asia
in groundwaters’, Environmental Science & Technology, 42(10): 3662-3668.
11. Jacks, G., P. Bhattacharya, V. Chaudhary, and K.P. Singh (2005), ‘Controls on the
genesis of some high-fluoride groundwaters in India’, Applied Geochemistry, 20: 221-228.
12. Khan, A.E., et al. (2011), ‘Drinking water salinity and maternal health in coastal
Bangladesh: implications of climate change’. Environmental Health Perspectives, 119(9):
1328-1332.
13. CEGIS (2006), ‘Impact of sea level rise on landuse suitability and adaptation options’, in
Coastal Land Use Zoning in the Southwest, Center for Environmental and Geographic
Information Services: Dhaka.
14. MacDonald, A.M., H.C. Bonsor, B.E.O. Dochartaigh, and R.G. Taylor (2012),
‘Quantitative maps of groundwater resources in Africa’. Environmental Research Letters, 7:
doi:10.1088/1748-9326/7/2/024009.
15. Taylor, R.G., et al. (2013), ‘Evidence of the dependence of groundwater resources on
extreme rainfall in East Africa’, Nature Climate Change, 3: 374-378.
Dr. Mohammad Shamsudduha (“Shams”) is a Research Fellow at the Institute for Risk and
Disaster Reduction at University College London, UK. Shams did his PhD in Hydrogeology
with a research topic “Groundwater dynamics and arsenic mobilization in Bangladesh” at
University College London. His research interests include groundwater arsenic
contamination, spatial and temporal dynamics in groundwater recharge, surface watergroundwater interactions in the highly dynamic Bengal Basin, and impacts of climate
change and rising sea levels on freshwater storage in Asian Mega-Deltas. His current
research includes an EPSRC of the United Kingdom funded research “Security of deep
groundwater against the ingress of arsenic and salinity is Bangladesh”, and a UKAID-funded
research “Groundwater resilience to climate change and abstraction in the Indo-Gangetic
basin
(http://www.bgs.ac.uk/research/groundwater/international/SEAsiaGroundwater/home.html). Shams is currently serving as an Associate Editor for the
journal Climate Risk Management. He can be contacted at: [email protected].
The views expressed in this article belong to the individual authors and do not represent the
views of the Global Water Forum, the UNESCO Chair in Water Economics and
Transboundary Water Governance, UNESCO, the Australian National University, or any of
the institutions to which the authors are associated. Please see the Global Water Forum
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