2. • Water is an renewable resources.
• The water amount in world is renewed by
the Hydrological Cycle.
• About 97% of the total earth surface is
covered by water. Nearly 60% of water is
present in animals and plants body.
• Every year 4 to 5cm(appx.) thick layer of
water get evaporated from oceans
surface; 90% of which returns back to
oceans through hydrological cycle.
3. Water Quality Problems- In India
People and environment in India is now getting affected
by the shortage of water.
Due to the excess use of the ground water for various
purposes have resulted in lowering of water table in
large parts of India. In some parts water table has
gone such low that in summers there is no water
available.
Most of the rural areas doe not have the access to
the clear and safe drinking water.
Ingress of sea water into coastal aquifers has
resulted in saline water.
Pollution of ground and surface water from
agricultural chemicals has imposed major
environmental health hazard.
5. • Pond- natural small size depression
formed within the surface of earth when it
is filled with water is known as pond.
• Lake- natural large sized depression
formed within surface of earth and filled by
the water is called lake.
• Streams- on mountain peaks small
amount of water starts to flow towards
down slope which is called as streams.
• Rivers- when number of streams meets
together they form river.
6. • Perennial rivers- those in which water is
available for 365days.
• Non-perennial rivers- those in which
water is available during certain months.
• Storage reservoir- form by construction
of dams across river.
• Stored rain waster
9. Sub-surface water
• Springs- natural out flow of ground water at earth’s
surface.
• Infiltration galleries- horizontal tunnels constructed at
shallow depth along banks of river.
• Wells
– Dug well- open well with masonary wells with large
diameter. Diameter varies from 2 to 9 m.
– Tube well- it is a long tube. It is bored or drilled deep into
ground,
– Artesian well- constructed in pervious layer which is bound
between two impervious layer.
– French well- special type of a well in which surface water
is collected from river bed. Radial perforated pipes are laid
with slope towards the center below the bed level of river.
12. Problem due to excess use of water
• Problems related with overuse of surface water-
– Decrease in flow of water in stream and rivers
– Wet land surface reduction
– Water logging
– Migration of people
• Problems related with overuse of sub-surface water-
– Pumping of wells results in lowering of the ground water
table
– Heavy pumping at large scale can dry up the whole water
table.
– Excess pumping causes collapsing of porous formation
resulting in subsidence of surface.
– Heavy pumping along coastline allow salt water to introduce
in aquifers.
