With much of the media space being occupied by flying froth and flaming suds, the teeth gnashing around the revival of tanks has once again occupied centrestage in the city. While much needs to be done and should be done to revive our water bodies, taking a step back and getting a perspective would be of help.
For one, none of our water bodies in the cities are lakes, they are not natural water bodies but artificial ones formed by throwing an earthen bund across a valley and holding water on the ground.
They were built by an agrarian community principally to serve as irrigation structures and secondarily as drinking water for cattle. Most of them were non-perennial. Therefore the nomenclature ‘tanks’ which applies to these water bodies.
An interesting take was that the silt was as much priced as the water, for it could be collected and spread on farms to increase yield. The Ganesha festival is a celebration of the silt in our tanks with a fervent wish to re-emerge the following year when the idol is immersed in the tank from where the original clay came for the idol itself.
The potter community around the city and the villages harvested the clay and stocked it up for a year, especially when the tank was about to dry up but yet the clay was wet enough to be dug and collected.
Silt trapsCut to modern times when the silt is an enemy and silt traps are built in all the tanks as a way to manage it. Plaster of Paris Ganeshas coated with lead paint threaten to enter the water bodies as volunteers and the urban local body heroically try to limit the damage by creating separate ponds for immersion. A culture uprooted from its connect sees also rowdy drunk youth creating loud noise as part of a celebration of immersion.
The tank in the city now has to decide whether it has to be removed because it harbours mosquito-carrying dengue, Chikungunya or malaria. In the 1970s and 1980s, public health specialists called for the draining of these tanks and their removal because of the widespread nature of malaria.
The tank has also to decide whether it is a water body, a wetland, a place for storing waste-water, a percolation pond, a recreation zone, an ecological spot, a flood control storage pond, a place for livelihoods such as fishing and clothes washing and all or some of the above.
The city itself has not needed these tanks once it made a choice to go far away to a river as its primary water source. Once urbanisation drove out agriculture, the need for the tanks became even less.
As vast sums of waste-water, up to 1400 million litres per day, sloshed around they tended to accumulate in these tanks and become breeding ground for disease. Then came the garbage and the construction debris as the city entered a rapid growth phase. Finally real estate prices, spawned by the booming economy, made it impossible for the tank to survive in its original role.
The water channel links between the tanks, called the ‘rajakaluves’, are crucial for the health of the water ecosystem. The connectivity ideally, should be maintained as natural wetland-based channels rather than drains.
One more thing to remember is that it is in the nature of urban water bodies to become land. The progression from water to land is through a wetland. If we want to spend minimum energy and money to maintain our lakes then we must re-imagine them as wetlands. That would be water wisdom.
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