SELECTION OF THE SOURCE OF WATER
Water is a vital natural resource which forms the basis of all life.
It is the key resource in all economic activity ranging from agriculture to industry.
With ever increasing pressure of human population, there is severe stress on water resources.
About 70% of the carth’s surface is covered by water and most of the animals and plants have 60-65% water in their body.
Water also plays key role in the development of the earth’s surface, moderating climate and diluting pollutants, water is essential for humans as well as for plants, animals and micro-organism for their physiological activities.
The water we use keeps on cycling endlessly through the environment, which we called as “Hydrological Cycle”.
The water from various moist surfaces evaporates and falls again on the earth in the form of rain or snow and passes through living organism and ultimately returns to the oceans.
Every year about 1.4 inch thick layer of water evaporates from the oceans, more than 90% of which returns to the oceans through hydrological cycle.
The following points should be considered while selecting the site for the sources of inter for a water supply scheme :
i) Location :
The sources should be as near as possible to the town or city to minimize the cost of conveyance.
ii) Elevation of intake point :
The Reduced Level (R.L) of the intake point should be higher than that of the supply zones that the water can flow by gravity.
Other wise, pumping unit should be established for the conveyance of water from the intake point to the treatment plant. It will increase the cost of the scheme.
iii) Quantity of water :
The sources should be such that the required quantity of water may be available throughout the year to meet the water demand.
iv) Quality of water :
The cost of the treatment depends on the quality of water.
Bad quality water requires excessive treatment and increases the cost.
But the good quality requires less treatment and decreases the cost of the scheme.