Chennai, crippled by water crisis, is also a metaphor for what Indian cities are experiencing in sourcing and managing the most precious natural resource: water. An in-depth analysis
Emergency
A cruel summer has been left behind. Pipes are gurgling to life and the surge of water tankers on Chennai's streets is on the ebb. People and leaders are now free to discuss issues non-aqueous. There are even days when Chennai's papers skip the almost mandatory columns devoted to water. It is beguilingly close to good times.
From November 15, the Chennai Metro Water Supply and Sewage Board (cmwssb, popularly called Metro Water) resumed piped water supply for the first time since January 2004. Now, it supplies through pipes on alternate days. "This month we have purchased only three lorries of water," says S Kumuraswamy, president of the residents' association of Kadhir Kasturi Apartments, a block of flats in Adayar. Earlier, the block of flats required 11 tankers per month.
The residents' association owns a water treatment plant, with reverse osmosis technology, that converts brackish water from their borewell to drinking water. The plant now runs twice a week; till a couple of months ago, it used to run everyday. On an average, the total water bill of the apartment block is Rs 13,000 each month, which works out to an average of Rs 1,625 per household every month. And this excludes what they pay for bottled water. For comparison, consider Delhi. Even after the proposed revision in water prices, a luxury apartment will pay Rs 192 per month for water supplied at the rate of 140 litres per capita per day.
Despite resumption of piped water, several residents don't share Kumuraswamy's exuberance. "Metro Water's supply is a trickle of water laced with rust particles from the pipes," says V H Balakrishnan on Dr Radhakrishna Salai. He lives in Shanti Apartments, a block of 16 flats, which still requires six 12,000-litre tankers every month, costing Rs 700-750 each. The average cost of tankers alone to each household is about Rs 260 per month. The complex has a borewell, but its water has high iron content. So the residents had to install a filtering plant at the cost of Rs 50,000. They also pay Rs 20 per kilolitre as cost of filtering the water. In addition, the residents have to spend on bottled water. Two decades ago, the dugwell in the apartment block met the drinking water needs. Chennai relied almost exclusively on dugwells, which have now gone dry. Water from dugwells is available to all, rich and poor. As input costs of obtaining water increase, the divide becomes starker.
While the rich somehow manage, albeit at a high cost, the poor have no option but to bear with Metro Water's vagaries. In the large slum of Srinivasapuram are numerous fixed plastic tanks that Metro Water's tankers fill up daily. Each tank provides drinking water to about 100 people. In October 2004, a fire destroyed several houses in the slum. The road the tankers used was littered with debris and some belongings that could be salvaged from flames.
In desperation
The reason Chennai faces chronic water scarcity: it depends on the rain it captures in its lakes, ponds and groundwater aquifers. It has no perennial rivers. So, if the city has not built reservoirs of water, one or two bad monsoons leave it crippled. If the northeast monsoon (October-December) fails, the city is in deep trouble.
And the rains have failed not for one but two consecutive years -- 2002 and 2003. Last year, the city received 280 millimetres of rain, almost half the normal precipitation of 580 mm. In January 2004, the combined storage in the three major reservoirs of Poondi, Redhills and Cholavaram fell to the lowest in 54 years -- 268 million cubic feet, a mere 3.6 per cent of their total capacity of 7,412 million cubic feet. Is this due to siltation and poor maintenance? A study of siltation of the Poondi reservoir from 1944 to 1983 by the public works department showed the average annual rate of siltation is a mere 0.298 per cent of the reservoir's capacity of almost 80 million cubic metres (MCM). and the annual rate of sedimentation over the drainage area is 0.031 MCM per sq km.
So is Chennai's perennial water crisis a result of nature's vagaries? Or gross mismanagement? Essentially, its politicians and scientific institutions are unwilling to accept that it doesn't have a perennial river. The fantasy that water must be accessed from a river must be realised, over and over again. So it is that over time, and conveniently increasing cost, they have reached ever farther to distant rivers. The desire to be free of monsoon dependence might be justifiable but the history of attempts to fulfil this yearning shows that the exact opposite has been achieved.
Circa 1772
Chennai's primary water source used to be a network of eris (tanks), ponds, temple tanks and dugwells managed by local communities. Typically, several households shared each well. In 1772, when it was under the control of the English East India Company, the 'first' public water supply works was set up. It was designed to supply 0.635 million litres per day (mld) from a cluster of 10 wells to Fort Saint George (now, the state secretariat in the city). Over the next 100 years, a larger scheme was completed. This brought water from two eris -- Cholavaram and Redhills -- to municipal waterworks, distributing it across the city.
These two tanks met the growing city's demand till the early 1900s. Between then and the 1940s, the city's population doubled to almost one million. To meet the growing demand, a reservoir was constructed at Poondi across the Koratallaiyar river. This raised the total surface storage capacity from 100 MCM to 180 MCM. Till the 1970s, the city's public water supply system depended exclusively on these three reservoirs, located 20-50 km to its northwest.
Chennai's water worries had already begun in the 1950s. R Muthuswamy Pillai was the mayor in 1954. He contacted an American firm to explore the possibility of arranging artificial rain to combat drought. In 1957-58, the then chief minister C N Annadurai invited the United Nations Development Programme (UNDP) to find out the feasibility of setting up a desalination plant. "But the (UNDP) team recommended that instead of seawater, the groundwater in the Araniyar-Koratallaiyar basin (northwest of the city) be utilised to fulfil the drinking water requirements... when UNDP started drilling borewells in the area, the farmers realised the groundwater potential and started doing the same," says R Sakthivadivel, Patancheru-based senior fellow of the International Water Management Institute, a think tank in Colombo, Sri Lanka.
As the city continued to grow, water availability fell from a comfortable 140 litres per capita per day (LPCD) to a low 80 LPCD in 1971. The public system was under additional pressure to extend its distribution network to new areas being developed. This led to installation of public taps, borewells fitted with hand pumps and large tanks to store municipal water. In 1976, the politicians became fixated with the idea of the river as the source of water. The closest was Krishna, 170 km north of the city, and the Telugu Ganga Project was drawn up. But work proceeded at a snail's pace: the first phase of the project was commissioned in 1996. However, the scheme has failed to live up to its promise (see box: The flow and the ebb).
Chennai's water search also took it to the well fields of the Araniyar-Koratallaiyar basins 40 km northwest. More sources were brought under the control of Metro Water when it was formed in 1978. The wells in Tamaraipakkam, Panjatty and Minjur fields were reserved for industry in north Chennai. Over the years, these wells were diverted for domestic use, forcing several industrial units to sink private borewells.
All bottled up
The perpetual water shortage in Chennai prompted the Centre for Science and Environment (cse) to study the different facets of the problem. A Vaidyanathan, eminent irrigation economist, and water researcher J Saravanan conceptualised and supervised the survey, which was carried out by students of the Madras Christian College. The survey covered over 1,510 households throughout the metropolis and collected data on water use. The 155 wards of the city were divided into three broad categories according to the water availability based on the assessment by Metro Water officials. Each of the three categories were sub-divided into upper, middle and low income groups; nine in all. A random sampling procedure was used to identify the households to be included in the survey, conducted from December 2003 to January 2004.
The number of sample households selected in each of the nine groups was in proportion to the total number of households in the respective groups (obtained from the census). Households for the survey were selected from randomly identified streets within each sample ward. Ten households from each selected street should be surveyed. Thus, 1,510 sample households were identified from 151 streets in 31 wards spread over the city. The survey was designed to elicit details of sources of water, water use pattern, storage tanks and sumps, the characteristics of dugwells/borewells, and implementation of rainwater harvesting.
Some years earlier, a large scale survey of water use in the city had been conducted by A M Murugappa Chettiar Research Centre. It showed the per capita water consumption (measured as litres per capita daily or lpcd) was considerably lower than the 135 lpcd taken as the norm for a metropolis and that public sources accounted for less than half of the total consumption. Though it was known that use of groundwater from private wells (including borewells) was rampant and the water table was plummeting, hard data was not available. The cse survey not only filled this gap, but found some striking facts:
• Contribution by Metro Water to the city's water requirement is dismal
Metro Water provides 79.8 million litres per day (mld), which is barely 34 per cent of the water requirement of 235.3 mld. The people have to make up for the deficit on their own: from dugwells/borewells; private tankers and bottled water.
Tanker economics
The water tanker has come to symbolise Chennai's water crisis. From January to October this year, Chennai Metro Water hired private agricultural wells and engaged lorries to supply water as its sources ran dry. "We were supplying water only through lorries (not pipes)," says S Ranganathan, engineering director of Metro Water. The lorries were discontinued only after water arrived through the New Veeranam project in November.
Metro Water paid the farmers Rs 40 for every 10,000 litres and transport and delivery costs came to Rs 80 per kilolitre. The farmers are not amused. V Samantham, a farmer in Kannigaiperu village in the well field area, calculates his costs: "Selling water to Chennai doesn't earn me as much as cultivation. If I sell 15 tankers of water per day for three months, I get Rs 72,000. If I grow paddy on my 2.6 hectares, I earn Rs 1,30,000." So why does he sell the water? Because Metro Water officials came to him and begged to quench Chennai's thirst -- the utility's borewells had gone dry. But a majority of farmers have smaller landholdings with lower incomes, and it actually makes better sense for them to sell the water.
In turn, Metro Water charged Rs 650 for a 9,000 litre tanker. Payments had to made only through demand drafts, which most customers found bothersome. For piped water supply, Metro Water charges a flat rate of Rs 50 per month -- meters don't work given the lack of pressure in the pipelines. This is regardless of availability.
Metro Water used around 1,200 lorries of 9,000 litres and 6,000 litres. Each made 10-13 trips daily. In addition, about 2,000 lorries with a 10,000 litre or 20,000 litre capacity ferried water from distant sources. "We incurred an additional cost every day of Rs 1 crore during the peak of the drought this year," Ranganathan informed.
With absolutely no water being supplied by Metro Water through the pipeline for nine months, private tanker operators became big players. At the peak of the crisis, about one-fifth of Chennai's demands were met by private operators, who have become an influential lot. Even the Chennai Metropolitan Area Groundwater (Regulation) Act was relaxed for them this year. "We approached the revenue minister in July 2004. The matter went up to the chief minister. We pointed out that as there's a demand, we have to provide water," says G Raja, secretary of the Tamil Nadu Drinking Water Lorry Owners' Association, which owns 600 lorries.
One of the worst affected areas was the Anna University, whose Centre for Water Resources (cwr) is in the forefront of research on water related issues. cwr director K Karunakaran says, "This summer most of the borewells on the campus dried up. For a period of six months, the university was completely dependent on water tankers -- the university purchased 22 tankers per day." This worked out to an astronomical monthly cost of Rs 4,95,000. Residents realised that a quick payment to the driver was essential to get a tanker in time. Says Rekkha S of Radhakrishna Salai: "I live in an independent house a little away from the main road. I had to pay Rs 200 extra for each tanker." Being a tanker driver is an enviable job. Ashirvatham B hails from Poondamalee. Eight months ago, he quit being a taxi driver and jumped on to the tanker bandwagon: "It is a seasonal job. But we make good money during the season. This summer, a lot of us have switched to tankers. At least 50 of us are from my area." He ferried as many as 10 loads a day from Poondamalee when the water shortage was at its worst.
Tanker operators built contacts in areas such as Poonnamallee, Kundrathur, Medavakam and paid the farmers Rs 100 for every 12,000 litres (Metro Water paid Rs 60 for the same). "There were nearly 1,000 private lorry operators on Chennai's roads during the peak of the crisis. Now there are around 200. Many had come from outside Chennai and were outside our control," informs Raja. The average number of daily trips of tankers have come down from five to three.
Bottled water
Besides water tankers, another common sight in the city is tempos carrying cans of drinking water. Wayside stores stock small pouches of water that people sip while on the move. The 200 millilitre pouches cost Re 1 each.
Saravana and Selvarathinam Stores in T Nagar is the neighbourhood store for milk and packaged water. A litre of milk sells for Rs 12.50, a 12-litre can of water costs Rs 50. Water sales are higher. The can is also delivered to the doorstep. "It is a growing market and only 10 per cent of it has been captured so far," says M Suresh Kumar of Sabols, a packaged drinking water chain. What needs to be built up, he insists, "is the awareness of water quality." He claims his manufacturing units in Sriperumbadur and Coimbatore -- their raw material is groundwater -- are the first in the country to be accredited by the South Asian Drinking Water Association. He sells 3,000 bottles of 20 litres every day. "During the peak of summer, it crossed 5,000. Groundwater is treated through reverse osmosis."
Waterman Water Products has found a good location. The small factory is on the Koratallaiyar riverbed. It claims to sell ozonised water. During high season, it was selling 1,000 cans of 25 litres each. Bottled water units are sprinkled across the neighbourhood promising purified, treated water. But almost all draw groundwater and package it without treatment. Vinayak Murthy, general secretary of the Tamil Nadu Packaged Drinking Water Association, says there are 340 packaged water operators in Tamil Nadu, 270 of them in Chennai. Production average in these plants is said to be 34,000 litres per hour.
The
long haul
Production cost of water from various sources as compared to the selling price |
| Source |
Cost (Rs Per kilolitre) |
| Red hills |
4 |
| Telugu Ganga ( Krishna
water project ) |
6 |
| Veeranam
|
22 |
| Reverse Osmosis |
45 |
| Domestic Borewell |
3 |
| Private tanker |
70 |
| Metro Water’s
selling price |
2.5 |
| Source:
Chennai Metro Water |
|
Raintapping
The reality of Chennai's dependence on rain is not fully appreciated. If it were, then rainwater harvesting (rwh) would have been looked upon as a social obligation. Considering the annual average rainfall of 1,280 millimetre in the city area of 174 sq km, the annual rainwater harvesting potential is about 222 billion litres, which means 608 mld. The city's water demand is 880 MLD. There are two aspects of RWH: lakes in the open areas and rooftops in built up areas.
Rooftop-spin
After the severe drought of 1992 and 1993, Metro Water began a actively promote RWH. It worked out a 'statutory understanding' with the Madras Metropolitan Development Authority and the Chennai Municipal Corporation: they would accept building applications only if they included a proposal of RWH. But this was totally ineffective. Several approved buildings either lacked RWH systems or the structures were inadequate. A sample survey, conducted by the Madras Institute of Development Studies in 2002 at the behest of the Centre for Science and Environment (CSE), shows that of the 75 buildings approved for construction in 1997 and 1998, two-thirds had not installed any RWH system despite showing it in the map. In 1994, the state government made RWH compulsory for multi-storey buildings. In 2001, it became mandatory for all buildings. But people made RWH structures more to meet the building criteria than to solve their water crisis.
The state government then issued an ordinance in 2002, imposing a strict deadline for implementing RWH in all buildings. With chief minister Jayalalithaa embracing RWH with zeal, it has become a buzzword in Chennai, showing other cities the benefits of this time-tested system. This ordinance, claims Metro Water, has had such an impact that all the houses in Chennai have RWH.
A CSE survey in January 2004 found 86 per cent of the households had implemented RWH. (The survey also found that Chennai residents opted for a small percolation pit with a shallow borewell merely to meet the legal requirements.)
Shekhar Raghavan of Akashganga Trust, an NGO in Chennai, conducted a household survey on the effectiveness of RWH in Gandhinagar area from June to October 2003. It covered 309 independent houses and found that only 50 per cent had implemented RWH properly. The parameters he looked at included system implementation, apportioning of water, design and maintenance of water to ensure silt removal.
"In many homes, RWH is not done scientifically, the surface runoff is not harvested," he points out. The CSE survey had also found that 65-70 per cent of the households implemented RWH with designs obtained from either a plumber or developed on their own, indicating lack of technical guidance.
While the government effort to promote RWH is commendable, it is clear that legislation by itself will not make any difference. It needs stricter enforcement. Civic/community groups have to take up its monitoring and implementation. The RWH imperative has not got woven into the social fabric. But not all people have to be goaded into RWG.
A citizen's effort
K Venkatraman retired from the army and came back to his house in Padmanabhanagar in Adayar. His found the public supply inadequate, the groundwater brackish. As president of the residents' welfare association, Venkatraman initiated rwh in 1999, much before Jayalalithaa made it mandatory across the state in 2003. He began by installing a simple PVC pipe to divert rainwater. Several others in the 110-house colony followed his example. "Even during the worst crisis, water was available in borewells in our houses at 10 metres," he beams. The groundwater level in the neighbourhood has increased to a comfortable level and only a few households had to purchase water during the drought this year, while adjacent areas depended heavily on private tankers during the summer. "The annual potential of harvesting water in these 110 homes is to the tune of 14 million litres," says Venkatraman.
But the fuss over rooftops has taken attention away from the traditional way of recharging aquifers: maintaining lakes and tanks. Chennai has about 200 lakes, including about 35 temple tanks. Constant depletion of groundwater, encroachment of the lakes' catchment, and diversion of inlets has rendered most of these waterbodies dry. Tanks like Pallikaranai and Ambattur are endangered. The main threats: the housing board and the municipality.
In the city's rush to grab water from waterbodies far and away -- the Veeranam lake, Krishna river -- Chennai's waterbodies have been forgotten. The Citizen Consumer and Civic Action Group (CAG),an NGO, holds the Tamil Nadu Housing Board responsible for destroying several lakes. CAG filed a public interest petition against the board, but by the time the case was heard, the lakes had been filled up. About 58 hectares (ha) of a lake in Ambattur were taken over by the board for a housing project. Three-fourths of the Chittilipakam lake has been taken over. Around 18 ha at Kakallur lake have also been eaten up, says Bharath Jairaj of CAG. At Velachery, eight ha of Lakeland have been filled up by the slum clearance board and the housing board, he adds. The Pallikarani marsh, once a large nesting ground for birds, is now a 120-ha dump yard. The government might be keen on rainwater harvesting, but it has destroyed Chennai's waterbodies.
Desecrated temple tanks
The A M Murugappa Chettiar Research Centre, an NGO, surveyed 36 temple tanks in Chennai. Their aggregate storage capacity of 0.5 million cubic metres is sizeable, and can make a significant difference to groundwater recharge in the city. But most are dry or get only limited inflows; several are in a state of disrepair -- broken sidewalls, water hyacinth infestation, silted tank beds. Most tanks are used as public conveniences for garbage disposal. The ngo suggests the following:
• desiltation
• reconstruction of the boundary wells and, where possible, increasing their height
•identification and removal of impediments to inflow of runoff; and
• measures to increase the rate of percolation into the ground.
But it is an uphill task to ensure that even as storm water drains are desilted and kept clear, sewage does not contaminate the water inflow. Along with these measures, local communities need to be mobilised. There are some good examples.
Pammal tank
After successfully implementing RWH in their houses, about 1,000 residents of the Pammal locality have now moved on to restore their temple tank. "Once we began the desilting and cleaning operations, lots of people came forward to help in different ways like technical advice, monetary help or voluntary labour," says Indra Kumar, a Pammal resident.
The first to draw attention to the pathetic state of the lakes was Mangalam Balasubramanian, head of the Pammal Ladies Club. This led to the club holding a fund-raising campaign. Its members went from door to door. About Rs 13 lakh were raised. More than half of the fund went to strengthen the banks of the tank by constructing a wall around it. Residents are happy with the results. "In May 2004, we had 3.5 metres of water as compared to 1.2 metres in 2003," says Indra Kumar. Both the quality and quantity of water in the region has improved after the tank's restoration.
There are several tanks that can be transformed in a similar manner. "Desilt the 600 lakes in Chennai, Chengalpattu and Thiruvallur districts or construct check-dams along the Adyar and Cooum rivers to solve the water crisis," reckons V Subramanian, president of Water Bodies Protection, an NGO.
Taste for waste
Chennai Metro Water claims that no less than 98.6 per cent of the city is connected to the sewerage. If the rainfall (and consequently the water supply) is normal in Chennai, it generates 300 million litres per day (MLD) of sewage. It has a treatment capacity of 262 MLD, but the treatment is only up to the secondary level. Of this 27 MLD is sold to industrial units in Manali, where it is further treated and processed for use. 262 MLD of sewage is treated in four major and one small treatment plant. The major plants are: Koyembedu (treats 34 MLD, Nesapakkam (23 MLD), Perungudi (45 MLD) and Kodungaiyur (160 MLD). Four waterways traverse the city. They are: Buckingham canal, Otteri Nallah, and Adayar and Cooum rivers. These are all eyesores at present. They have been reduced to conduits of sewage and industrial effluents.
The flat rate of Rs 50 that Metro Water charges domestic consumers includes water supply and sewage disposal charges. "In addition, a water supply and sewerage tax is collected once in two years. It comes to about 7 per cent of the rental value of the property," says Madhavan Murthy, the utility's chief engineer.
Metro Water claims only 17 per cent of the city's sewage is untreated. One visit to the waterways nails their lie. Even the Central Pollution Control Board points out the level of biological oxygen demand (and indicator of pollution) in the Cooum river is 480 milligramme per litre (mg/l) as against the maximum permissible limit of 3 mg/l. Why does Metro Water lie? Well, it doesn't know for sure the amount of water Chennai uses. How will it calculate the amount of sewage?
Chennai has 4.46 million people. If it is assumed that the water consumption is 200 litres per capita daily, the amount of sewage can be estimated at 700 MLD. The amount of untreated sewage, hence, is 448 MLD, which is 63 per cent of the total sewage -- and this assumes that all the treatment plants are operating at full capacity. No wonder Chennai's waterways are repulsive to the eyes and the nose.
If Chennai collects and treats its sewage and reuses it (for non-potable and industrial uses), a sizeable chunk of its demand can be met. The treatment plant at Kodungaiyur sells 27 MLD of treated sewage at the rate of Rs 8 per kilolitre -- a competitive cost. The daily demand for water is 880 MLD. The 700 MLD of sewage can help meet this. The state government has recently shown an inclination to this. Two major industrial units, Chennai Fertilisers Ltd (CFL) and Petroleum Corporation Limited (CPCL), have installed a tertiary sewage treatment plant each. These will use sewage supplied by the Kodungaiyur sewage treatment plant, which treats it up to the secondary level. The capacity of these plants is 11 MLD and 22 MLD respectively.
An industrious effort
Industry in Chennai has little, if any, dependence on Metro Water. Most industrial units rely on their own borewells or buy water from private operators. But some large units, such as Ford India Limited, Hyundai Motors Limited and Ennore Thermal Units, consume large quantities of groundwater and surface water. Partly treated sewage can provide for several industrial uses, should willingly switch to using such water.
Chennai's water scarcity is an impermeable problem for industry. Most units have effluent treatment plants to reuse wastewater for gardening or cooling. Some units are more daring. CPCL and CFL have started buying partly treated sewage from Metro Water, which they further treat for use as raw water.
CPCL buys 9.45 MLD of partly treated sewage from Metro Water at the rate of Rs 8 per kilolitre. CPCL uses a zero-discharge plant that not only helps convert sewage water into process water but also treats the effluent. "Earlier, we used to discharge our industrial waste into the Buckingham canal. Now, we do not add to the pollution of the city. We reuse every litre of sewage," says a CPCL official.
The company is a pioneer at sewage treatment -- its efforts began in 1991. At its treatment plant, the sewage is settled in huge ponds, aerated to reduce organic pollutants and pumped through filters to remove chemicals. The water is finally pumped under high pressure through imported membranes in a reverse osmosis unit. CPCL's zero-discharge water treatment plant was inaugurated in March 2004. Its capacity is one million litres a day, and it uses membranes developed by CPCL in collaboration with the Central Salt and Marine Chemicals Laboratory in Bhavnagar, Gujarat.
"We undertook the project to develop commercial size membranes matching the performance of imported membranes," says a CPCL official. The Rs 60 lakh project was funded by the Indian Oil Corporation. The zero-discharge plant recovers 75 per cent of the water from the sewage. The technologies adopted by the CPCL can be of use to other water-intensive industries as well as public water supply units for recovering potable water from brackish water, the official added.
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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