The Hindu             25.06.2013

Most RWH structures in the city defunct, reveals survey

After realising that most of the city’s rain water harvesting (RWH) structures is ineffective, the Vellore Corporation has gone on a campaign mode to revive the RWH concept to improve the falling ground water table. With the city reeling under a severe drought for the past three months, the borewells have gone dry and with people preferring to dig more borewells depleting the already depleted ground water table, the corporation has decided to revive the RWH structures.

It has already convened several meetings with councillors and has been printing pamphlets for distribution to the residents.

About 10 years ago, most households in the State, including Vellore, had dug RWH pits following a directive from the government that all households must have RWH structures. Building plan approvals were given for new buildings only if they had RWH structures.

But, over the years, the pits got silted up and the house owners virtually neglected the pits.

Survey reveals ineffective structures

A survey carried out by the Vellore Corporation through its field staff from June 13 to 15 has revealed that out of the 6,592 buildings that were inspected, only 3,810 had RWH structures, while 2,782 did not have them. Out of the 3,810 building which had the structures, the structures were not in good condition in 2,286 buildings. The owners of these buildings have been advised to repair and revive the structures.

Steps are also being taken to make the building owners construct the structures in buildings which did not have any structures.

Meanwhile, an independent survey carried out by this correspondent has revealed that the RWH structures were not in good condition in many of the corporation’s own premises such as the erstwhile municipal and town panchayat offices which were now functioning as tax collection centres of the Vellore Corporation.

A visit to the tax collection centre in Thorapadi revealed that the RWH pit has been filled with silt and garbage. When asked about it, E. Devakumar, corporation engineer told TheHindu that the Vellore Corporation would certainly be taking steps to revive all the silted RWH structures in its premises.

Different types

The corporation is recommending different types of RWH structures for different areas: percolation pits and recharge wells for sandy areas, percolation pit with bore and recharge well for clay soil and percolation pit and recharge well for hard rock areas.

In houses which have wells, rain water could be filtered and then let directly into the wells. The corporation has advised the public to clean the terrace of their houses for effective harvesting of rainwater, and ensure that there were no blocks or cracks in the rainwater drain pipes.

Those having RWH filter chambers and percolation pits should clean the pebbles or blue metals in the structures and refill them with new materials. They should ensure that the rainwater reaches the filter chamber and flows into the recharge well. The silt in percolation pits and recharge wells should be removed.

The public have been requested to contact the Vellore Corporation (toll free no.1800-425-4464) for further details. One could also log on to the website, www.vellorecorp.tn.gov.in.

Case study

T. Jacob John, Emeritus Professor of Virology, Christian Medical College, who has constructed a 50,000-litre sump at the backyard of his residence in Kamalakshipuram here in 2004 to store rainwater suggests that people construct such sumps to store water when they construct houses. This way, they could store rainwater throughout the year, he said.

“Digging pits and chambers would only facilitate recharge of groundwater, but real harvesting would be only through such sumps. I am pumping only rainwater from the sump into the two overhead tanks in my house throughout the year”, says Dr. John, who has a sand filtration system too, through which the rainwater enters the sump.