INTRODUCTION
The subject of hydrology deals with the entire domain of water and is a
multidisciplinary subject. It studies the occurrence of water, both at surface and
groundwater, its circulation, its movement affecting the human lives, plants,
fishes, its depletion and replenishment, etc. Quality of water, both surface and
groundwater, affects the environment. With the advancement of civilization,
water utilization in various fields have progressed rapidly like in the field of
agriculture, industries, energies (hydel projects), housing compendium, etc. In
fact there is no area where water use is not involved. Multiplicity of water use
has developed into various sciences and technologies like Irrigation
Engineering, Public Health Engineering , Industrial Engineering with various facets
of water supply.
Notwithstanding such importance of this scarce natural resource, water has
been very badly managed throughout the world so much so that with the
advancement of science and increase in population, there will be acute
shortage of water within the next few decades. This may lead to international
dispute on sharing of water and ultimately lead to devastating war. Arid and
semi-arid regions of the earth are already suffering but the measures taken with
the help of modern technologies are not adequate to mitigate the hardship. Even
an advanced country like Israel will face the water crisis beyond 2020. While
many advanced countries having adequate resources have resorted to
desalinization of sea water, but such technology may be beyond the reach of
poor nations. Coupled with the problem of water shortage, contamination of
water is emerging as a major problem and water borne diseases have become
a major health hazard. Awareness regarding water conservation, prevention of
pollution and contamination measures to keep our rivers clean is very poor. The
need for recycling of water for further use is generally overlooked. Water is a
visible resource, no doubt, but many people may not know how do they occur in
nature and how water can be used beneficially for the human kind, how they get
contaminated.
Storage of water on earth is 1387.71 x 10
15
m
3
out of which 97.2%
occurs in ocean. Fresh water resources on the earth is 37.526 x 1010
15
m
3
including groundwater (Gilbert M Masters, 1995).
Hydrologic cycle is an important process fixing the water resources on the earth.
Precipitation is a major source of fresh water. A brief outline has been
given in the book about precipitation, its measurement, surface and
sub-surface run off base flow and stream flow on earth.
Rivers and stream which are visible throughout the earth, its origin and how
river water can be beneficially used for mankind by its storage are also
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