Water is one of the most important natural resources on earth for sustaining the human life. It is available to us from rivers, springs, ponds, underground sources for our daily needs from drinking to cleaning. Some of these sources are replenished by annual rains while some are fast depleting which is giving an alarming call for water conservation. Water is available on earth in many forms ranging from ice-capped mountains to mighty seas. Though it appears in abundance a limited portion of it is potable, the rest is to be processed through costly methods to remove the undesired salts and materials.
The sources of water
The natural sources of water for human consumption are taken from rivers, ponds, springs and groundwater. These waters generally contain a low amount of salt (less than 1 gram of salt in one litre of water) and are potable. Though 2/3rd of earth surface is covered with sea water it contains a high amount of salt (about 30-35 grams of salt in one liter of water ) and it is not suitable for drinking purposes. Salt is available in sea water in such a large proportion that commercial extraction of salt is done by evaporating sea water under the sun in big flat fields and collecting the residues. Conversion of sea water to potable water using reverse osmosis process is feasible but due to its high cost, it has not been commercialized in a big way.
The nature is doing this job for us by evaporation of sea water in summers to form the water vapors which form the clouds and these clouds are taken to other places on earth by the winds and they precipitate in form of rains on the land masses and rejuvenate the springs, rivers, and ponds with fresh and drinkable water.
In the hilly terrain there are ups and downs and in between big valleys and plateau are enclosed. These valleys and plateau comprise of the large catchment area. During the rainy season a lot of water is attained by these catchment areas and interestingly a small portion of that water (less than 5 % of the total rain) is absorbed by the outcropping parts of porous rocks and penetrates deep in these rocks due to gravity and slowly moves along the rock layers. In forest or tree rich areas the amount of water absorbed may be slightly more due to retention of rain water in the shades for a longer time. This absorbed water is the one which ejects itself from the rocks at a lower height and we see that in form of springs. This travel of water from absorption to ejection takes time and it is due to this fact that we see small waterfalls and streams falling from different heights in hills even after the end of rainy season and these falls sometimes survive the whole year when next year rains again freshen them up. This is a very interesting observation which one can make during rainy season if one gets an opportunity to visit a hilly place during that time. The small springs, small falls, and small streams are short-lived and survive a few days after the rains while big ones can survive for a few months to a whole year.
Unfortunately, most of the rainwater ( about 95 % of the total rain) is spilled on the earth surface and accumulates to form seasonal streams and rivers and flows down and meets the regular rivers before commencing its journey to seas. This is the water which is accumulated in ponds and dams for storage and sent to the towns and cities by pipes for annual human consumption. In villages, it is accumulated in local ponds and suffice for some months or sometimes even a full year depending on a number of ponds and their sizes.
Some rivers like the Ganges originate from ice-capped mountains by melting of ice bodies and these are the regular rivers remaining vibrant throughout the year and are swollen in the rainy season due to the addition of rain water.
In hills, the absorbed water in porous rocks comes out in form of spring at a lower height but in plains, the absorbed water is retained in the rocks deep below the earth surface and remains there till we dig an artificial water well to take it out with the help of pumps. This is the groundwater which is immensely used by the villages, cities, and towns. Unfortunately, the replenishment of this ground water by above-mentioned absorption process is very very slow. The groundwater we have used till today and still are using was accumulated in the earth below the surface during last thousands of years and now with continuous exploitation, its level has gone very low and in many areas, it is almost depleted. There are many remote places in the world which fall in arid and desert climate, they are acutely facing this problem of ground water depletion and are dependent on an external supply of water or fetching water from far flung places for daily needs. Even in normal places because of a large population, water rationing is a routine thing.This is an alarming condition and lot of initiatives at Government as well as NGO level are being taken up for management and conservation of water.
Importance and usage of water
Water is used everywhere - from human consumption to various industries usage. We can see its use in a variety of ways. It is the lifeline for various crops, it is a great solvent, it can be used for dilution of innumerable substances, it is used as a coolant, when frozen it becomes ice, on heating it forms steam which is used for various industrial mixing and injection processes, water falling from height is producing electricity in dams and like that we can list many more.
It is such an important material provided by nature to us that without this all the flora and fauna will not be there. We can not imagine life without water.
Today all the research for extraterrestrial life ( life beyond Earth) is focused on a finding of water on distant planets in the universe so that chances of them being habitable can be bright.
Respecting the nature - respecting water
Once we have understood the sources of water and its importance, it becomes our moral duty to honor and respect this valuable commodity. Such a precious item gifted by nature to mankind definitely deserves our care. We must not waste this precious commodity and use it sparingly and try to preserve it right from its supply storage to the water tap.
As a good citizen, it is also our duty to make other people also conscious for its judicious use so that the society as a whole takes interest in conserving this lifeline of humans on our planet - Earth.
Mr. Umesh, a very well written article.
As told by you, reverse osmosis of seawater is very costly. I have done many trials using RO plant for potable water. My observation is just 5 liters of potable water is available from 100 L, that too after 3 cycles. Hence I have given up. Recently I heard that a process has been developed for seawater treatment but details are not available. Definitely I feel our scientists will come out with a process for this. Let us hope for the best.
Mr Rao, I came to know that one big project for sea water conversion to drinkable one is undertaken by Govt near nuclear plant in Tamilnadu. You can find more details in net if interested. The nuclear power department is also associated in that.
Thanks for reviewing my article.
Thoughtful article on water and its importance. Surely the importance of water is known to those who face the scarcity of the same. Every drop counts. We should not waste water. I have seen people simply keeping the tap open while brushing and thus waste water. Please for God's sake save water for tomorrow.