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Ground water recharging in Chennai, TN : Presence of percolation space around buildings
ShareIn cities like Chennai , increase in apartments & the incidence of concrete aprons restrict the percolastion of rain water in to the ground. Also the conversion of roads in cities & villages to water proof structures also restrict the percolation opportunities of rain water. Thus creating a break in the water cycle. To ensure that Rain Water Harvestin is beneficial is it not ncecessary to have open places that are permeable to the percolation of water to ensure the uninterrupted nature of the water cycle ?
Is it possible for the government to enact a rule / legislation to ensure the presence of adequate percolation space around residential buildings & other structures as appropriate? I humbly request the experts to enlighten me on the same.
Your views please
- hrkchennai
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Dear HRK,
The apartment builders are right in making the entire basement impervious and thereby prevent any surface water, which is normally in a contaminated state, to percolate or infiltrate into the underground. The best way to recharge groundwater is by resorting to rooftop rainwater harvesting (RWH) to collect rainwater, treat it properly, and store it in a large sump for productive use.
The best example of rainwater harvesting in India comes from the house at Porbandar in Gujarat where Mahatma Gandhi, the Father of the Nation, was born. The terrace on the top floor of that house, thoroughly washed before the first monsoon showers, served as the rainwater catchment. An underground reservoir with a capacity of around 91 cubic metres served to store water for drinking and other domestic purposes throughout the year, while a pipe having a heap of lime at its mouth served to convey filtered water from the terrace into the reservoir.
If construction of a large sump is not feasible, the treated water can be injected into the underground through a specially constructed recharge well under expert supervision to ensure that large quantity of treated rainwater enters the aquifer.
It must be noted that use of improper methods of groundwater recharging often lead to groundwater contamination and does not allow for percolation of adequate water into the underground. RWH can give good results if only the people are genuinely interested to carry it as a mission. When they are forced to take up RWH through legislation, they carry it out only as a ritual.
Our studies in Sri Venkateswara University have indicated that many RWH structures constructed even under expert supervision have done more harm than good, indicating on the need to educate the so-called experts for taking up effective groundwater recharging.
Instead of recharging groundwater in an improper way, it is better not to recharge groundwater at all.
Best wishes,
Dr. R. Jagadiswara Rao
Professor of Geology Retired
Sri Venkateswara University
Tirupati, AP 517502
rjagadiswara@gmail.com
R. Jagadiswara Rao, Professor of Geology Retired, Sri Venkateswara University, Tirupati, AP 517502, India rjagadiswara@gmail.com