In a bid to achieve the goal of ensuring water security in the city,
the Chennai Metropolitan Development Authority (CMDA) is planning to
conduct a detailed audit of rainwater harvesting system across Chennai
by involving NGOs.

 A CMDA source told City Express that a tender
had been floated in this regard and the process would be finalised in
the next 15 days.

Sources said that as per the development regulations of CMDA,  rainwater harvesting was mandatory on every premises.

 “We
are likely to engage two NGOs, who will be carrying out the audit
across the Chennai Metropolitan Authority Area,” the sources added.

The plan was to carry out RWH audit though a network of NGOs pioneered in this field, sources added.

The
rainwater harvesting structures installed during the AIADMK regime in
2003 had helped increase the ground water level in the city. According
to a recent report, the ground water level and quality before July 2003
and after June 2011 had increased in the sandy, clay and rocky areas of
the city.

Sources also said that after implementation of the RWH
scheme, not only has the quality of water improved but also a large part
of the fluoride content was diluted. Sources said the audit was
expected to strengthen and streamline the system.

Rainwater
harvesting is the process of augmenting the natural filtration of
rainwater in to the underground formation by some artificial methods.

CMDA
sources said that  rainwater harvesting was a prerequisite for
obtaining plan approvals when new buildings are constructed. Even older
existing structures have been mandated to build the structures.

There
are various ways of rainwater harvesting, including collecting it from
the roof of the house or building. It can either be stored in a tank or
diverted to artificial recharge system. This method is less expensive
and very effective.