Sacred tanks have a hoary origin in India. The concept of a tank as a public space is first seen in the water storage facilities of the ancient Indus-Sarasvati cities of Mohenjo Daro, Harappa and Dholavira. Sage Narada advised Yudhishthira, one of the heroes of the Indian epic Mahabharata, to excavate large lakes to store water, thereby making agriculture independent of rainwater. By 300 BC tanks had come to stay. Kautilya in the Arthashastra mentions officers to supervise and maintain freshwater sources, including tanks and reservoirs.

In a political system that was fairly liberal, it was not possible to enforce laws. Ancient India therefore used religion to protect its freshwater sources, as it did trees, groves, health and agriculture. Nothing was excluded from the ambit of religion. Water, already a precious liquid thanks to frequent droughts and floods, was regarded as sacred, and rivers and lakes were endowed with a sanctity that protected them from pollution and misuse.

Whereas the north had perennial rivers thanks to the glaciers and melting snows of the Himalayas, the South was rain-dependant. This made the harvesting of rainwater essential, and three artificial water bodies were developed: the yeri or large irrigation lake, with a tall bund or side walls above ground level; kuttai or small pond; and kulam or temple tank, a deep pond protected by an enclosure or wall with steps on all four sides leading to the bottom. Each temple generally had two or more tanks. One was used for the ritual abhishekha of the deity and for the maintenance of the nandavanam, the temple garden, which provided the flowers for the temple rituals. The other provided water for the devotee and pilgrim to wash himself before entering the temple. In time, the tanks came to represent the sacred rivers, such as the Shiva Ganga tanks at Chidambaram and Ekambareshwara at Kanchipuram; the Anantasaras tank at the Varadaraja Temple at Kanchipuram; and the Mahamakam Tank at Kumbakonam, described as the southern Prayag, believed to be the confluence of all the sacred rivers of India every twelve years.

Many of the tanks have unique names. For example, each of the tanks in the 108 Vaishnava divyadeshas has a sacred name, sacred tree (sthala vriksha) and so on. The tanks of many Shaiva temples are named after Shaiva devotees, Nandi, etc.

But the temple tank fulfilled another important social role: the maintenance of ground water levels. Seeing its efficacy, it became an essential part of South Indian life and culture. Temple tanks and earthen reservoirs or yeris were dug in villages and towns of ancient Tamilaham. The yeris were interconnected with channels that took the overflow of one to another, and to the temple tanks. It also cooled the hot summer evenings, when people could sit on the tank steps and enjoy the breeze, and the musical concerts that were organised alongside the tanks.

Construction of a tank was an act of great merit, for provision of water is the greatest of all daanams (gifts). It was also one of the saptasantanam or seven kinds of wealth. Thus it was an act of merit for rulers to excavate tanks and endow lands for their maintenance, apart from directly arranging for their maintenance. Regular maintenance and repair was a duty. Manu imposes the death penalty on the destroyer of a dam or tank, while the Padma Purana devotes a whole chapter to its conservation.

Temple tanks are generally square or rectangular and built of brick, although granite was occasionally used. The temple of Pundarikaksha at Thiruvellarai, one of the 108 Vaishnava divyadeshas, is constructed in the form of a swastika. Some are bare earthen tanks. There are inlets for the water and outlets for the overflow. Some tanks had underground springs. The houses surrounding the tank had to slope their roofs towards the tank. To prevent evaporation, water plants like the lotus and lily were grown in the tanks, giving names like Thiru-alli-keni (tank of the sacred white lily) to the tank of the Parthasarathy Temple at Triplicane. The herbs used in the ritual bath (abhishekha) of the deity were mixed with the tank water, making it tirtha or sacred and giving the temple tanks medicinal properties.

Generally, the temple and the tank were constructed simultaneously, the two linked in the term kovil kulam, meaning temple tank. The temple tank also fulfilled one of the three important components of pilgrimage, which were the sthaanam (place), moorthi (deity) and jalam (water), all of which were tirtha or sacred. In North India, the fl owing rivers provided the sacred waters. In Tamilnadu and elsewhere in the South, sacred tanks were excavated to provide this facility. Before entering the temple, the worshipper could bathe in the temple tank to cleanse himself of the dust and grime of travel.

The sacred tank is also the location of the annual teppotsavam (float festival). The bronze image of the deity is taken in procession around the temple tank, on a palanquin by the devotees. Sometimes, a pillared mandapam, or neerali mandapam, may be built in the tank or a wooden mandapam floated in the tank where the deity is placed to the chanting of shlokas and nadaswaram music. Apart from its role in the daily abhishekham and the teppotsavam, the tank plays an important role in the annual brahmotsavam, when the deity would come to the banks of the tank to bless the waters.

As most of the temples belong to the Department of Hindu Religious and Charitable Endowments (HR&CE) of the Government of Tamilnadu, only the department can maintain and renovate tanks. Unfortunately, this has not been done regularly or till recently. No renovation can be taken up by local people or NGOs without the department’s permission and co-operation. Urban tanks are even worse off, becoming a receptacle for the garbage and sewage of surroundings.

Tamilnadu’s Temple Tanks must be repaired and restored. It is essential to combat the ever-increasing water shortages and droughts that plague our land. To this end,

• Tanks must be desilted and maintained properly. The area around the tanks must be regarded as heritage precincts and construction of houses without sloping roofs or cement and tar roads must be banned.
• Those who throw garbage, sewage or other filth into temple tanks, or any other freshwater source must receive strict punishment, including fines and arrests
• Inlet and outlet channels must be repaired and maintained regularly
• Gardens and public recreation spaces may be established around tanks to inspire and force people to keep the tank clean
• Concrete floors for tanks should be banned
• Maintenance of tanks may be handed over to local people’s committees

Temple tanks were a brilliant innovation to harvest and store water voluntarily, a religious duty, whereby people earned merit even as they contributed to society’s welfare. By discarding traditions, we are destroying systems that sustained Tamil society and made life endurable. Water is essential for life: it is not a luxury. Its provision and protection must be the first duty of the government and the people.