Tamil Nadu's temple tanks hold key to water recharge

But authorities cement tank beds and fail to restore water inlet channels

The onset of the north-east winter monsoon over south India heralds the arrival of the the float festival in Tamil Nadu, which is held just after rains cease. Idols of presiding temple deities are floated in the water tanks on rafts decked with flowers and flickering lamps. The tanks are usually attached to temples and occupy an important space in the state's cultural landscape.

But these tanks have another important role. “They are tools for recharging groundwater and absorbing floodwater,” says Madhavi Ganesan, associate professor at the Centre for Water Resources in Anna University in Chennai.

Pammal tank restoration shows the way

	The tank is six hundred years old and the water in it was potable 35 years ago. Over the years, the inlets slowly got clogged; and the tank was also affected by siltation. S Indra Kumar says the depth of the tank decreased to 1.2 metre in 2000. Under ideal conditions, the depth should be about four metres. In 2000, Kumar, a resident of the area, thought of reviving the tank. The tank was in bad shape, there were dead animals floating in it and raw sewage was entering the tank. Kumar approached the adminstration but failed to get funds from them although they promised support. Kumar then tried to revive the tank through the support of Exnora International. Local residents, schools and clubs also supported the programme financially. About Rs 15 lakh was used to clean the tank spread over 2.6 hectare. Kumar explains that before 2000, the groundwater in the neighbourhood of the tank was highly polluted by the outflow from nearby tanneries. After the renovation of the tank, there is improvement in the quality of groundwater within five kilometres radius of the water body. Not only this, Exnora International president Mangalam Balasubramaniam says the non-profit maintains the tank by desilting it every year.