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.