TAMIL NADU

Some government buildings are yet to have RWH structures

On track: PWD officials say the RWH systems in government buildings are checked periodically for repair and cleaned every three months. Some RWH structures in the PWD office in Chepauk are in the picture.

On track: PWD officials say the RWH systems in government buildings are checked periodically for repair and cleaned every three months. Some RWH structures in the PWD office in Chepauk are in the picture.   | Photo Credit: — Photo: R. Ragu

K Lakshmi

Allotment of more funds suggested for maintaining them

CHENNAI: Nearly 15 per cent of the government buildings in Chennai and its suburbs are yet to be provided with rainwater harvesting (RWH) structures.

Officials of the Public Works Department said that of the 1,750 buildings belonging to various government departments in Chennai, Tiruvallur and Kancheepuram districts, RWH structures have been installed in nearly 1,500 buildings since 2003.

“It is an ongoing process. We are installing such structures in as many buildings as possible with the available funds. We expect to cover the remaining buildings without RWH structures by this year-end,” an official said. Some of the government buildings that have such facilities include those of the Departments of Health, Revenue, Education, Law and hostels for backward and most backward class students.

The PWD adopted two RWH techniques according to the built-up area. While rainwater collected from rooftop is harvested into a recharge well in most of the buildings, those with a large plinth area is provided with percolation trench constructed around the building, said an official.

About 0.5 per cent of the total project cost of a new building is allotted towards setting up of RWH structures. Most of the building projects sanctioned around the city recently were of Education Department. At present, nearly 30 projects have been taken up to upgrade government school infrastructure in and around the city, including in Velachery, Maduravoyal, Kunrathur and Tiruvottiyur at a cost of Rs.45 crore.

However, rainwater harvesting experts complain that only 25-30 per cent of the RWH structures installed in government buildings are being maintained properly. The State government must allot more funds to maintain them and monitor the impact of the system, they said.

R.Ramani, a RWH resource person, said that the filtration media provided in the RWH structure determined the recharge level. Coarse sand and pebbles must be provided as filter materials instead of gravel, as it is of irregular shape and therefore likely to prevent percolation.

But, PWD officials said that the RWH systems are checked periodically for repair and cleaned every three months. Of the annual grant of Rs.30 crore given for the building maintenance, nearly three per cent is spent towards RWH structures.

However, not all recharge structures in the government buildings are monitored for the impact of RWH system. Officials of State Ground and Surface Water Resources Data Centre, PWD, said of the 34 monitoring wells in the city, eight were in public buildings. “We check the water level and quality every month in a few wells located in a radius of 8 sq.km, which represent the area.” an official said.

On an average, the water level across the city has gone up between three to six metres in the past five years, the official added.

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