Reuse, recycle

Or relocate

Published: Sunday 28 June 2015

Reuse, recycle

-- "Shift Chennai to the vicinity of the Cauvery river," says K Karunakaran, director of the Centre for Water Resources (CWR) of the Anna University, which advises the government on water issues. This preoccupation with a perennial river -- that can supply water round the year and carry off the city's sewage -- is at the heart of Chennai's incomparable water crisis. The political leaders of Tamil Nadu have desperately searched for that elusive river. They have tried to tap into the Cauvery and the Krishna. These efforts have failed because there are several uses for the limited water available, irrigation most notably. In purely environmental terms, irrigation is a better use of water as it plays a role in recharge of groundwater.

Tamil politicians will just have to accept the fact that peninsular India doesn't have snow-fed Himalayan rivers. And even the metropolitan cities of northern India, spoiled for choice by large rivers and high annual rainfall, are desperate for more water and are doing what Chennai is doing -- tapping sources far and away. Large rivers like the Ganga and the Yamuna have been reduced to sewers. While Chennai's desperation is far greater than theirs, they are fast getting there by managing their water and sewage mindlessly.

Chennai is an example -- a warning for other cities as well as symbol of tenacity. The city takes rainwater harvesting (RWH) more seriously than any other, though there are several problems in implementation. RWH from rooftops can be successful only if it is part of a social movement rather than a government diktat. But rooftop RWH, even if implemented properly, is a small part of the bigger solution. The centrepiece of RWH in Chennai should be its 200 tanks and lakes. These are essential to maintain the health of the city's groundwater that is fast declining and turning brackish. But instead of keeping these clean and ready to store water for around the year, the government treats these waterbodies as garbage sites. The government's housing board is using their beds and catchment to construct housing colonies. People will live where water once was. Obviously, they will not get water.

As for the three major reservoirs that have sustained the city for decades, 40 per cent of their water is lost due to evaporation. Aegis Chemical Industries Ltd, a company in Jalgaon, Maharashtra, spreads a blend of saturated fatty alcohols on a waterbody to prevent evaporation losses. Karunakaran of CWR will do well if he can direct his institute to find solutions to cut these losses, instead of talking about quixotic ideas like shifting the city.

Chennai needs to re-focus. For example, water from desalination plants will cost Rs 50 per kilolitre. If the city instead invests in effective sewage treatment, the water will cost only Rs 3 per kilolitre. This can be used for non-drinking uses or groundwater recharge. The Union government has allocated Rs 1,000 crore for desalination. Chennai needs to recalculate its costs and prioritise investments. "Desalination should be the hundredth option," says S Janakarajan, professor at the Madras Institute of Development Studies.

Chennai's water strategy will be realistic only if it accepts its location and ecology. Hydrologically, it is a city at the tail end -- beyond it is the sea. At some point, it will have to end its search for a perennial river or water sources hundreds of km away or expensive desalination plants. It will have to look at its waterbodies, its sewage. It is possible, given the city's desperation. If it does, it will show other Indian cities the way to the future, because every city is a tail end for water and the source of sewers. If Chennai can't do that, then it can begin its relocation plans.

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