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Suggested Citation: Shamsudduha, M. (2013), ‘Groundwater resilience to human development and climate change in South Asia’, GWF Discussion Paper 1332, Global Water Forum, Canberra, Australia. Available online at: http://www.globalwaterforum.org/2013/08/19/groundwater-‐resilience-‐to-‐human-‐development-‐and-‐climate-‐change-‐in-‐south-‐asia/
Groundwater resilience to human development and climate change in South Asia
Mohammad Shamsudduha University College London, UK
Discussion Paper 1332 August 2013
This article highlights the critical issues surrounding groundwater storage and quality in South Asia. These issues include development, irrigation, public health, and climate change. The author concludes that more scientific research is essential for addressing the complex problem of deteriorating groundwater resources.
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Keywords: groundwater, South Asia, climate change, water quality, food security, development, irrigation
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
Groundwater resilience to human development and climate change in South Asia
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
often-polluted surface water year-round. For
these reasons, groundwater is the main source
of domestic, industrial and irrigation water
supplies throughout South Asia.
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.4Traditionally, 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 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
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)
Groundwater resilience to human development and climate change in South Asia
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 over-abstraction.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 naturally-
occurring 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 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
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
Groundwater resilience to human development and climate change in South Asia
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
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.
Figure 1. Spatial distribution of population in South Asian countries. Data taken from a global population model of LandScan 2007 (http://www.ornl.gov/sci/landscan/).
Groundwater resilience to human development and climate change in South Asia
Figure 2. Use of freshwater and groundwater in different sectors in South Asian countries. Source: AQUASTAT
Figure 3. Trends in GRACE-derived terrestrial water mass (period August 2002 to December 2011) shows mass loss over northern India associated with recent decline in groundwater storage.7
Groundwater resilience to human development and climate change in South Asia
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-Brahmaputra-Meghna 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 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.
About the author(s)
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 water-groundwater 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].
Groundwater resilience to human development and climate change in South Asia
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