Nowadays, Artificial Recharge to Ground Water is a hot topic of discussion among scientists, technicians and intellectuals. They think it is the ultimate solution to meet up the water crisis and should be implemented pan- India immediately. Why immediately - when it is an age old practice?
The artificial recharge to ground water is in vogue from time immemorial. As soon as people learned agriculture, the process of artificial recharge was initiated. Ploughing of land for sowing of seeds heralded the initiation of artificial recharge in the very early days of human civilization. The process of artificial recharge increased with the expansion of the agricultural activities. Subsequently the artificial recharge was geared up when the agricultural land ownership was admitted. The present day fragmented land holding has led to small agricultural plots having low rising bunds all around. Apart from this, the field are having step like disposition particularly in undulating / sloppy terrain. These bunds and step like features helps to arrest rain water and also spilling over the excess water to the next field which facilitates the process of artificial recharge since a long time.
It is said that expansion of towns and cities reduces open areas resulting in lower scope for ground water recharge through rainfall. The question that immediately follows this is that whether there has been any scientific proof or work carried out particularly in this regard for any of the cities / towns, any where in India or globally or it is just a mere guess work of the scientific fraternity. On the contrary, the expansion of cities may also help in increasing the scope of artificial recharge instead of reducing it. The land developed for dwelling purpose normally reduces surface run off rate of rain water which other wise would have flowed unabated to the drainage channels. The boundary walls constructed around the large number of dwelling units and thousands of vacant small plots hold the rain water for considerable time and this increase in residence time actually should recharge the ground water to a greater extent than it would have earlier.
The artificial recharge to ground water is in vogue from time immemorial. As soon as people learned agriculture, the process of artificial recharge was initiated. Ploughing of land for sowing of seeds heralded the initiation of artificial recharge in the very early days of human civilization. The process of artificial recharge increased with the expansion of the agricultural activities. Subsequently the artificial recharge was geared up when the agricultural land ownership was admitted. The present day fragmented land holding has led to small agricultural plots having low rising bunds all around. Apart from this, the field are having step like disposition particularly in undulating / sloppy terrain. These bunds and step like features helps to arrest rain water and also spilling over the excess water to the next field which facilitates the process of artificial recharge since a long time.
It is said that expansion of towns and cities reduces open areas resulting in lower scope for ground water recharge through rainfall. The question that immediately follows this is that whether there has been any scientific proof or work carried out particularly in this regard for any of the cities / towns, any where in India or globally or it is just a mere guess work of the scientific fraternity. On the contrary, the expansion of cities may also help in increasing the scope of artificial recharge instead of reducing it. The land developed for dwelling purpose normally reduces surface run off rate of rain water which other wise would have flowed unabated to the drainage channels. The boundary walls constructed around the large number of dwelling units and thousands of vacant small plots hold the rain water for considerable time and this increase in residence time actually should recharge the ground water to a greater extent than it would have earlier.
A majority of the present day scientists, intellectuals and surprisingly lot of our law makers opine that roof top rain water harvesting must be made mandatory for every building in urban and rural areas including individual dwelling units with a view to recharge ground water zones artificially. But the rain water is normally acidic and in big cities / towns it contains a large number of harmful / unavoidable elements resulting from the widespread urbanization / industrialization phenomenon. When the rain water percolates through the soil zone through its natural course of movement, it gets modified chemically before reaching the ground water zones and becomes fit for consumption. But if the same rain water is injected to the ground water zones through recharge pits / shafts, the scope of modification becomes less and in the long term may have some adverse effect on the ground water quality. More over, every caution has to be taken for selecting the site of recharge pit / shaft etc to avoid mixing of sewerage water etc with the recharge water. This needs proper guidance and constant vigil through a large number of technically competent persons. Apart from these, the entire system of harvesting and recharge structures needs periodic maintenance, which involves huge cost. More over, roof top rain water harvesting and artificial recharge in a large scale is a definite violation of the natural system. The future impact of this is also unknown. Though encouraging results have been achieved in isolated cases or in small areas, till date no proper documentation is available for project of large scale. Hence every caution has to be taken before implementation of any such large scale scheme.
DISCLAIMER : This is a compilation of the discussion and feedback received from common people, mostly from the non-hydrogeological background and I have merely contributed as a compiler. This article does not in any way reflect my personal opinion or the organization I work for.
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