Ch 3 Water Resources Class 10th Geography
Water
• Water is a renewable resource
• Three-fourth of the earth’s surface is covered with water but only a small
proportion of it accounts for freshwater fit for use.
Some facts and Figures
• 96.5 percent of the total volume of world’s water is estimated to exist as
oceans and only 2.5 per cent as freshwater.
• India receives nearly 4 percent of the global precipitation and ranks 133 in
the world in terms of water availability per person per annum.
• By 2025, it is predicted that large parts of India will join countries or regions
having absolute water scarcity.
Water Scarcity and need for water conservation and management
• The lack sufficient water as compared to its demand in a region is known as
Water Scarcity.
• Causes of Water Scarcity are:
→ over-exploitation
→ excessive use and unequal access to water among different social groups.
→ Large population
Dams
• A dam is a barrier across flowing water that obstructs, directs or retards the
flow, often creating a reservoir, lake or impoundment.
Multi-purpose river projects
• Multi-purpose river projects large dams that serve several purposes in
addition to impounding the water of a river and used later to irrigate
agricultural fields. For example, the Sutluj-Beas river basin, the
Bhakra–Nangal project etc.
Advantages of multi-purpose river projects are:
→ Electricity generation
→ Irrigation
→ Water supply for domestic and industrial uses
→ Flood control
→ Recreation
→ Inland navigation
→ Fish breeding
Disadvantages of Multi-purpose river projects are:
→ It affects the natural flow of river causing poor sediment flow and excessive
sedimentation at the bottom of the reservoir.
→ It destroys the habitats for the rivers’ aquatic life.
→ It submerges the existing vegetation and soil if created on the floodplains.
→ It displaces the local people of the place where it is created.
→ These are unsuccessful in controlling floods at the time of excessive
rainfall.
→ These projects induced earthquakes, caused water- borne diseases and
pests and pollution resulting from excessive use of water.
Movements against Mult-purpose river projects
• These projects cause of many new social movements like the ‘Narmada
Bachao Andolan’ and the ‘Tehri Dam Andolan’ etc.
→ This is due to the large-scale displacement of local communities.
• Inter-state water disputes are also becoming common with regard to sharing
the costs and benefits of the multi-purpose project.
Rainwater Harvesting
• Rainwater Harvesting refers to the practice of storing and using of rainwater
from the surface on which it falls.
• In hill and mountainous regions, people built diversion channels like the
‘guls’ or ‘kuls’ of the Western Himalayas for agriculture.
• In Rajasthan, ‘Rooftop rain water harvesting’ was commonly practised to
store drinking water.
• In the flood plains of Bengal, people developed inundation channels to
irrigate their fields.
In arid and semi-arid regions, agricultural fields were converted into rain fed
storage structures that allowed the water to stand and moisten the soil.
• In the semi-arid and arid regions of Rajasthan, almost all the houses
traditionally had underground tanks or tankas for storing drinking water.
• How Tankas works:
→ Tankas were connected to the sloping roofs of the houses through a pipe.
→ Rain falling on the rooftops would travel down the pipe and was stored in
these underground ‘tankas’.
1. The tankas are part of the well-developed rooftop rainwater harvesting system and are built
inside the main house or the courtyard. This is mainly practised in Rajasthan, particularly in
Bikaner, Phalodi and Barmer areas for saving rainwater. Many houses have constructed
underground rooms adjoining the ‘tanka’ to beat the summer heat as it would keep the room
cool.
Tamil Nadu is the first state in India which has made rooftop rainwater harvesting structures
compulsory for all houses across the state. There are legal provisions to punish defaulters.
The JJM envisages the supply of safe drinking water through tap connections
to all rural households by the end of 2024, and has set a target to supply 55
liters of water per person, per day, to every household in villages where the
people have been facing water scarcity.
