Water Resources
Intended
Learning Outcomes
At the end of this session, students will be able to
• Explain Water Resources
• Discuss use and over-utilisation of surface and ground
water
• Explain the benefits and problems associated with floods,
drought, conflicts over water and dams
Contents
• Introduction to Water Resources
• Use and over-utilisation of surface and ground water
• Floods, drought, conflicts over water, dams, their
benefits and problems
Water
resources
• Water cycle, through evaporation and precipitation,
maintains hydrological systems which form rivers and lakes and support in a
variety of aquatic ecosystems
• Wetlands are intermediate forms between terrestrial and
aquatic ecosystems and contain species of plants and animals that are highly
moisture dependent
• All aquatic ecosystems are used by a large number of
people for their daily needs such as drinking water, washing, cooking, watering
animals and irrigating fields
• Water covers 70% of the earth’s surface but only 3% of
this is fresh water
• Of this, 2% is in polar ice caps and only 1% is usable
water in rivers, lakes and subsoil aquifers
• At a global level 70% of water is used for agriculture
about 25% for industry and only 5% for domestic use
• India is expected to face critical levels of water stress
by 2025
• UN has estimated that by the year 2050, 4 billion people
will be seriously affected by water shortages
Overutilization and
pollution of surface and groundwater
• With the growth of human population there is an increasing
need for larger amounts of water to fulfil a variety of basic needs
• Most people use more water than they really need
• There are many ways in which farmers can use less water
without reducing yields such as the use of drip irrigation systems
• Agriculture also pollutes surface water and underground
water stores by the excessive use of chemical fertilizers and pesticides
• Methods like use of biomass as fertilizer, non-toxic
pesticides (neem products) reduces the agricultural pollution of surface and
ground water
• Industry not bothering about its liquid waste and
releasing it into streams, rivers and the sea
• Public awareness may increasingly put pressures on
industry to produce only eco-friendly products which are already gaining in
popularity
• As people begin
to learn about
the serious health
hazards caused by pesticides in their food, public awareness
can begin putting pressures on farmers to reduce the use of chemicals that are
injurious to health
Global climate change
• Changes in climate at a global level caused by increasing
air pollution have now begun to affect our climate
• Everywhere the ‘greenhouse effect’ due to atmospheric
pollution is leading to increasingly erratic and unpredictable climatic effects
• This has seriously affected regional hydrological
conditions.
Floods
• Floods have been a serious environmental hazard for
centuries
• Havoc raised by rivers overflowing their banks has become
progressively more damaging as people have deforested
• Wetlands in flood plains are nature’s flood control
systems into which overfilled rivers could spill and act like a temporary
sponge holding the water and preventing fast flowing water from damaging
surrounding land
• Deforestation
in the Himalayas
causes floods that
year after year
kill people, damage crops and destroy homes in the Ganges and its
tributaries and the Bramhaputra
Drought
• Serious scarcity of water to drink, use in farms or
provide for urban and industrial use
• Drought prone areas are thus faced with irregular periods
of famine
• Agriculturists have no income in these bad years and as
they have no steady income
• India has ‘Drought Prone Areas Development Programs’ which
are used in such areas to buffer the effects of droughts
• Drought is an unpredictable climatic condition and occurs
due to the failure of one or more monsoons
• The scarcity of water during drought years affects homes,
agriculture and industry
• Several measures can be taken to minimise the serious
impacts of a drought
• One of the factors that worsens the effect of drought is
deforestation
Water for Agriculture
and Power Generation
• India’s increasing demand for water for intensive
irrigated agriculture, for generating electricity and for consumption in urban
and industrial centres has been met by creating large dams
• But they have several serious environmental problems- they
alter river flows, change nature’s flood control mechanisms such as wetlands
and flood plains and destroy the lives of local people and the habitats of wild
plant and animal species
Sustainable water
management:
• ‘Save water’ campaigns are essential to make people
everywhere aware of the dangers of water scarcity
• These include measures such as:
1. Building several small reservoirs instead of few mega
projects
2. Develop small catchment dams and protect wetlands
3. Soil management, micro catchment development and
afforestation permits recharging of underground aquifers thus reducing the need
for large dams
4. Treating and recycling municipal waste water for
agricultural use
5. Preventing leakages from dams and canals
6. Preventing loss in Municipal pipes
7. Effective rain water harvesting in urban environments
8. Water conservation measures in agriculture such as using
drip irrigation
9. Pricing water at its real value makes people use it more
responsibly and efficiently and reduces water wasting
10. In deforested areas where land has been degraded, soil
management by bunding along the hill slopes and making ‘nala’ plugs, can help
retain moisture and make it possible to re-vegetate degraded areas
Dams
• Today there are more than 45,000 large dams around the
world, which play an important role in communities and economies that harness
these water resources for their economic development
• Irrigated land worldwide relies on dams
• Hydropower use of stored water to supply electric power
• World’s two most populous countries – China and India –
have built around 57% of the world’s large dams
Dams problems
1. Fragmentation and physical transformation of rivers
2. Serious impacts on riverine ecosystems
3. Social consequences of large dams due to displacement of
people
4. Water logging and salinisation of surrounding lands
5. Dislodging animal populations, damaging their habitat and
cutting off their migration routes
6. Fishing and travel by boat disrupted
7. The emission of greenhouse gases from reservoirs due to
rotting vegetation and carbon inflows
• Large dams have had serious impacts on the lives,
livelihoods, cultures and spiritual existence of indigenous and tribal peoples
• Conflicts over dams have heightened in the last two
decades because of their social and environmental impacts and failure to
achieve targets for sticking to their costs as well as achieving promised
benefits
• The loss of traditional, local controls over equitable
distribution remains a major source of conflict
Summary
• Water covers 70% of the earth’s surface but only 3% of
this is fresh water
• With the growth of human population there is an increasing
need for larger amounts of water to fulfil a variety of basic needs
• Changes in climate at a global level caused by increasing
air pollution have now begun to affect our climate
• Floods have been a serious environmental hazard for
centuries
• ‘Save water’ campaigns are essential to make people
everywhere aware of the dangers of water scarcity