Water- depletion and pollution
Neil Armstrong saw the Earth from the Moon, it appeared blue! This
is because water covers more than two-thirds of the Earth's surface.
But fresh water represents less than 0.5% of the total water on Earth.
The rest is either in the form of seawater or locked up in icecaps
or the soil, which is why one often hears of water scarcity in many
Water is continuously
moving around the earth and constantly changing its form. It evaporates
from land and water bodies and is also produced by all forms of life
on Earth. This water vapour moves through the atmosphere, condenses
to form clouds and precipitates as rain and snow. In time, the water
returns to where it came from, and the process begins all over again.
Although water is constantly moving, its total quantity on Earth's
surface is constant.
Water is found in three different forms - liquid, solid or gas, depending
on the temperature but it constantly changes from one form to another.
Changes in temperature will determine which of these forms predominates
in a particular area.
Water is usually encountered in the liquid state, because this is
its natural state when temperatures are between 0° C and 100°
C. 'Fresh' or drinking water is found as groundwater in underground
aquifers, and on the surface in ponds, lakes, and rivers. Seas and
oceans account for 97% of all water on Earth; but their waters contain
dissolved salts and are therefore unfit to drink. In regions of young
volcanic activity, hot water emerges from the earth in hot springs
(examples are Garampani in Assam and Badrinath in Uttaranchal). How
does this phenomenon occur? Surface water percolates downward through
the rocks below the Earth's surface to high-temperature regions surrounding
a magma reservoir, either active, or recently solidified but still
hot. There the water is heated, becomes less dense, and rises back
to the surface through fissures and cracks.
Ice is the frozen form of water. It occurs when temperatures are below
0°C (32°F). For a given mass, ice occupies 9% more volume
than water, which is why when water enters cracks in rocks and freezes
it causes the rocks to crack and split. Being less dense than water,
ice floats. This property of ice is vital to aquatic life in cold
regions. As the temperature drops, ice forms a protective, insulating
layer on the surfaces of streams, pools and other water bodies, allowing
water to remain liquid in the layers beneath and life to survive.
Glaciers, icebergs, and ice caps are all frozen water.
Water is found in the atmosphere in its gaseous form, water vapour.
Steam is nothing but vapourized water. In certain hot water springs
called geysers, jets of steam and hot water rise one hundred feet
or more from the ground. Geysers are found in Iceland, the North Island
of New Zealand and in USA's Yellowstone National Park.
Worldwide, the consumption
of water is doubling every 20 years - more than twice the rate of
increase in population.
A large amount of water
is wasted in agriculture, industry, and urban areas. It has been estimated
that with available technologies and better operational practices,
agricultural water demand could be cut by about 50%, and that in urban
areas by about 33% without affecting the quality or economics of life.
But most governments do not have adequate laws or regulations to protect
their water systems.
Due to the increase in population there has been a rise in the demand
for food, space for housing, consumer products, etc., which has in
turn resulted in increased industrialization, urbanization, and demands
in agriculture thereby leading to both river and groundwater contamination.
|The 'small and
big' of water
The Pacific ocean is
the biggest ocean covering approximately 32.6% of the Earth's
The Arctic ocean is
the smallest ocean
Some interesting facts
75% of the earth's surface
is covered with water
More than 97% of the earth's
water is in its oceans
About 2% of the available
drinking water is frozen leaving only 1% for drinking
The world's average rainfall
is about 850 mm
Water regulates the Earth's
temperature. It also regulates the temperature of the human body,
carries nutrients and oxygen to cells, cushions joints, protects organs
and tissues, and removes waste
60% - 75% of the adult
human body is water - 82% of blood is water; 70% of the brain and
90% of the lungs are made up of water
Blood in animals and sap
in plants is composed mainly of water
To cook 1 cup of rice you
need 2 cups of water but to wash the pan in which it has been cooked
you need 4-5 litres of water
A dripping tap can waste
up to 6 litres of water in a day
More than half the creatures
on the Earth are found under water
Life on earth probably
originated in water
In the summer our bodies
require about 2 litres of water daily. Here is the water content of
some foods (approximate) - 95% in tomato, 91% in spinach, 91% in milk,
85% in apples and 80% in potatoes
10% of the earth's surface
is covered with ice
There are more than one
billion people particularly in North Africa and Western and South
Asia, who lack access to a steady supply of clean water.
Access to water and sanitation,
so crucial to human well-being and development, has now become a priority
for the international community. To underscore the need for immediate
action, the United Nations has designated 2003 as the International
Year of Freshwater.
The importance given
to water in ancient India is reflected in several hymns of the Vedas
and epics and narratives from other valuable works such as the Arthasastra
of Freshwater 2003
"No single measure would do more to reduce disease and save lives
in the developing world than bringing safe water and adequate sanitation
- UN Secretary General Kofi Annan
2003 is the International Year of Freshwater
"Water is probably
the only natural resource to touch all aspects of human civilization
- from agricultural and industrial development to the cultural and
religious values embedded in society."
- Koichiro Matsuura, Director General, UNESCO