Groundwater quality is expected to respond to changes in climatic parameters
because of the consequences on the recharge and discharge of groundwater (Green
2016). Changes of intensity and duration of recharge and increase in underground
temperature in the vadose zone affect pore water chemistry, residence time and
volume of water in matrix and fractures, and downward transfer of contaminants,
which together modify the chemical composition of groundwater (Glassley et al.
2003; Panwar and Chakrapani 2013). Increased infiltration mobilizes large
porewater chloride and nitrate reservoirs in the vadose zone of arid and semiarid
regions, resulting in the salinization of groundwater (Gurdak et al. 2007; Green
2016).
Under the climate change scenario, recharge during a dry period may generate a
higher concentration of total dissolved solids (TDS), whereas recharge during wet
periods may produce lower TDS concentrations in groundwater (Sukhija et al. 1998;
Green 2016). In a wet climatic scenario, accelerated infiltration will cause the
dissolution of more carbonate rock, resulting in higher calcium content, which
increases groundwater hardness (Gurdak et al. 2007; Aizebeokhai et al. 2017).
Intrusion of salinity into coastal aquifers will be enhanced by climate changeinduced factors of sea level rise and spatiotemporal changes in precipitation and
evapotranspiration that determine recharge (Sharif and Singh 1999; Ranjan et al.
2006; Green 2016). Shallow aquifers of the low-lying coastal areas will be affected
more because of the rise in sea level and resultant changes in groundwater flow
pattern (Singh and Kumar 2010). Uncontrolled withdrawal and the resultant rapid
drop in groundwater level leads to land subsidence in coastal areas, which accelerates the intrusion of salt seawater into the freshwater aquifer (Kundzewicz et al.
2007; Taniguchi et al. 2008; Konikow 2011; Panwar and Chakrapani 2013).
Future Groundwater Scenario in India with Respect
to Projected Climatic Change Trends
From the previous analysis it is evident that the groundwater resource in India is now
facing crisis from perspectives of both quantity and quality. The northwestern,
western, southern, and some coastal areas are the most vulnerable areas of the
country in respect to sustainability of this precious resource. In spite of adequate
recharge, huge extractions for irrigation purposes is causing overexploitation of
groundwater in the northwestern parts of India including the states of Punjab,
Haryana, Delhi, and Western Uttar Pradesh. The occurrence of scanty rainfall has
resulted in limited recharge of groundwater in the western part of the country,
particularly in parts of Rajasthan and Gujarat, leading to stress on this resource.
The crystalline aquifer system of southern peninsular India retards the recharge
process, limiting availability of the groundwater resource. In several coastal areas
of the country salinization of groundwater is an alarming threat to this precious
freshwater resource.
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S. Mukhopadhyay and A. K. Mandal
because of the consequences on the recharge and discharge of groundwater (Green
2016). Changes of intensity and duration of recharge and increase in underground
temperature in the vadose zone affect pore water chemistry, residence time and
volume of water in matrix and fractures, and downward transfer of contaminants,
which together modify the chemical composition of groundwater (Glassley et al.
2003; Panwar and Chakrapani 2013). Increased infiltration mobilizes large
porewater chloride and nitrate reservoirs in the vadose zone of arid and semiarid
regions, resulting in the salinization of groundwater (Gurdak et al. 2007; Green
2016).
Under the climate change scenario, recharge during a dry period may generate a
higher concentration of total dissolved solids (TDS), whereas recharge during wet
periods may produce lower TDS concentrations in groundwater (Sukhija et al. 1998;
Green 2016). In a wet climatic scenario, accelerated infiltration will cause the
dissolution of more carbonate rock, resulting in higher calcium content, which
increases groundwater hardness (Gurdak et al. 2007; Aizebeokhai et al. 2017).
Intrusion of salinity into coastal aquifers will be enhanced by climate changeinduced factors of sea level rise and spatiotemporal changes in precipitation and
evapotranspiration that determine recharge (Sharif and Singh 1999; Ranjan et al.
2006; Green 2016). Shallow aquifers of the low-lying coastal areas will be affected
more because of the rise in sea level and resultant changes in groundwater flow
pattern (Singh and Kumar 2010). Uncontrolled withdrawal and the resultant rapid
drop in groundwater level leads to land subsidence in coastal areas, which accelerates the intrusion of salt seawater into the freshwater aquifer (Kundzewicz et al.
2007; Taniguchi et al. 2008; Konikow 2011; Panwar and Chakrapani 2013).
Future Groundwater Scenario in India with Respect
to Projected Climatic Change Trends
From the previous analysis it is evident that the groundwater resource in India is now
facing crisis from perspectives of both quantity and quality. The northwestern,
western, southern, and some coastal areas are the most vulnerable areas of the
country in respect to sustainability of this precious resource. In spite of adequate
recharge, huge extractions for irrigation purposes is causing overexploitation of
groundwater in the northwestern parts of India including the states of Punjab,
Haryana, Delhi, and Western Uttar Pradesh. The occurrence of scanty rainfall has
resulted in limited recharge of groundwater in the western part of the country,
particularly in parts of Rajasthan and Gujarat, leading to stress on this resource.
The crystalline aquifer system of southern peninsular India retards the recharge
process, limiting availability of the groundwater resource. In several coastal areas
of the country salinization of groundwater is an alarming threat to this precious
freshwater resource.
148
S. Mukhopadhyay and A. K. Mandal