Chennai tries to fix its water woes…..Niranjana Ramesh
A river clean-up and desalination plants are part of the plan; critics say better solutions are being ignored
A river clean-up and desalination plants are part of the plan; critics say better solutions are being ignored
Chennai is a neatly sliced-up city.
Cutting through its centre is the noisome Cooum and a little south, the Adyar river. The two waterlines flank the 12km wide Marina beach to drain into the Bay of Bengal that laps at the city. A third river snakes through the city’s north to meet the sea near Ennore port.
And carelessly scattered about are at least two dozen lakes and erys—an ingenious system of water tanks conjured up by the city’s early residents. Yet, Chennai’s water woes have toppled governments.
Last week, after years of deliberation, the Chennai Corporation finally moved to restore the city’s rivers, beginning with a mass cleaning of the Cooum. Corporation workers have a month to scoop out an estimated 871 tonnes of solid waste dumped along the river.
Two months earlier in July, Tamil Nadu inaugurated a desalination plant at Minjur that’s equipped to pump out 100 million litres a day (mld) of potable water. The plant—in Tiruvallur district, neighbouring Chennai—will sell the water to the Chennai Metro Water Supply and Sewerage Board (CMWSSB) for 25 years at Rs.45 for every thousand litres. At Nemmelichery, 15km south of Chennai, along the scenic East Coast Road, a second 150 mld desalination plant is under construction. Chennai’s 4.4 million people need 1,200 mld of drinking water; the water board supplies 660 mld.
Not many are applauding the recent efforts.
“It is just silly for a city receiving 1,200mm of rainfall per year to turn to desalination for its drinking water needs,” says Nityanand Jayaraman, an environmental activist associated with the Coastal Protection Group and Youth for Social Change.
“If Israel and other Middle Eastern countries build desal(ination) plants, it’s because they receive just about 300mm of rainfall,” says S. Janakarajan, a professor at the Madras Institute of Development Studies doing research on water and environment. He’d rather that the public funds spent on buying water from the desalination plant— costing Rs.164 crore a year at Rs.45 per kilolitre—be spent on restoring the erys to augment the city’s water resources. Designed hundreds of years ago by farmers, erys are a speciality of the topography of the Deccan Plateau, at whose edge stands Chennai, on India’s east coast.
T.M. Mukundan, an alumnus of the Indian Institute of Technology, Madras (IIT-M), and a water rights activist, describes erys in his book, The Ery Systems of South India.
These were essentially water bodies meant for irrigation and formed by constructing earthern bunds or embankments along the path of rainwater that runs off from west to east on the plateau. So when it rains in the Western Ghats, the erys would fill up one by one from west to east.
Chennai receives more rainfall than most large cities but has had to rough out several years of drought (there’s less of a scarcity now after the city administration enlisted new sources for drinking water). Between 1981 and 2006, average annual rainfall in Chennai was 1,549.9 mm, far more than Bangalore’s 877.8 mm, Hyderabad’s 821.7 mm and Delhi’s 755.4 mm, according to data compiled by the Centre for Science and Environment. But much of the city’s rainwater is not collected and flows into the sea, wasting efforts by the administration to enforce rainwater harvesting.
Water activists are calling for a restoration of the erys not to draw drinking water from these directly but to use them to harvest rainwater and recharge ground water. Chennai has 29 such water tanks. The city’s expansion zones in Tiruvallur and Kanchipuram districts—fast growing industrial corridors—boast 1,500 erys.
Rainwater harvesting (RWH) structures in the city’s buildings—mandatory since 2003—have helped push up Chennai’s water table to 8.73 ft below ground level, back to 1990 levels, according to data from the Tamil Nadu public works department (PWD). In 2005, the city’s water table was at 16.5 ft below ground level. “If this is possible using RWH in buildings, sustained public water supply should be possible by reviving and maintaining erys, which contribute to ground water replenishment in a big way,” says Sekar Raghavan, a retired physicist and an RWH consultant.
About half of the city’s drinking water needs is met through ground water supplies using private borewells or by transporting water from distant towns in tankers.
As per a Chennai high court order, the state PWD (public works department), responsible for maintaining water bodies with an irrigable area of over 100 acres, has to report to the court the status of Chennai’s 29 water tanks every quarter.
The department’s latest report, released in July, show that seven of these 29 tanks have been completely encroached upon and are irretrievable. The combined size of all the other water tanks has been reduced to a surface area of 605 hectares from 1,267 ha originally.
“Water bodies were occupying 30% of the surface area available for housing and settlement in this city,” says PWD superintendent engineer Vijay Kumar.
The river cleaning project Chennai’s finally got down to is a rather late effort to save whatever is left of its water bodies. Photographs of three decades ago show the Cooum as a clean water host for fishing and boat races. The Chennai Rivers Restoration Trust, set up by the state government some years ago to do what its name suggests, is aiming to restore at least the riverfront by 2020.
The immediate goal is to clear the garbage and encroachments on and by the Cooum’s bank, says Phanindra Reddy, member secretary of the trust. The scores of settlements on the river bank have to be relocated and the 18 sewage pipes draining into the Cooum have to be linked to treatment centres. The city corporation plans to build parks and walkways along the 18km stretch of the river cruising through Chennai.
“All the silt at the depths of the river will have to be dealt with only after that, in order to facilitate any ground water recharge,” says Reddy. “I doubt it will ever be used for drinking water purposes as it’ll now cost Rs.35-40 per kilolitre to treat its water.” The trust was originally established as the Adyar Poonga Trust to beautify the Adyar riverfront but it hasn’t begun work on that yet.
There’s trouble elsewhere.
At Nemmelichery, where the second desalination plant is expected to come up by December 2011, the Soolerikattukuppam fishing village is cloaked in gloom. “We tried protesting a couple of weeks back to prevent them from undertaking surveys in the seabed… They went ahead anyway and construction work has started now,” says S. Kothandan, a 60-year-old fisherman. The fisherfolk fear saline discharge from the plant will affect marine life in the area irreversibly.
Shiv Das Meena, managing director of CMWSSB, says discharge from the plant will comply with environmental standards. He declined to give the actual discharge level. The conversion rate of the plant is quoted at 45% by volume, which means the water it pumps back into the sea will be twice as saline as before. “Fishermen here use catamarans to go just about two-four kilometres into the sea, about the same distance where desal plants discharge their residual concentrate,” says R. Srinivasan, a founding member of the Chennai Fishermen Welfare Board.