Chennai: water supply
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Dropping crystals in clouds to induce rain, transporting water from other states by trains, covering a reservoir with thermocol to check loss of water to evaporation -there was no dearth of suggestions in Tamil Nadu's corridors of power as the state witnessed its worst drought in 142 years. It is one such idea, criticised as expensive and unviable, that now accounts for 40% of the water supply in capital Chennai: Tapping sea water.
Desalination plants in Nemmeli and Minjur -with a capacity to produce 100 million litres of water per day (mld) each -are now the city's lifelines with traditional sources drying up. Chennai is almost entirely dependent on the monsoon for its water supply, the failure of which puts the city in a tight spot.
Combined storage level in the four reservoirs that cater to Chennai stands at 3% against their total capacity. The supply of Krishna river water from neighbouring Andhra Pradesh under the Telugu Ganga project has been suspended for more than two months now. Chennai's nodal agency for water distribution, CMWSSB, has been coercing farmers in neighbouring districts to sell Chennai their water.Officials are also trying to sourcing water from stone quarries 23km from the city .
In all this, it is the treated seawater -that normally is an option in regions with no rains or other water sources -that meet the city's demand for water. But senior officials doubt the sustainability of the desalination projects.Apart from environmental concerns, sourcing water thus is expensive. At present, CMWSSB pays Rs 60 per kilo litre for the water from Minjur, up from Rs 48 per kilolitre that it paid when the facility began operating in 2010. This works out to Rs 60 lakh for 100 mld of water. Water from the Nemmeli plant costs around Rs 30 per kilolitre. “We're able to do this because the state is rich. I don't know if it's feasible in other states,“ a senior official said. Voltage fluctuations and adverse weather are a serious challenge too in operating the plants and hike the costs. But this has not deterred the state from proposing two new plants, of 150 mld and 400 mld capacity in Perur, close to Nemmeli.
At present, TN accounts for 24% of the total desalinated water capacity in India, second only to Gujarat. Experts meanwhile describe desalination as a “last option“.S Janakarajan, professor at Madras Institute of Development Studies, says that seawater desalination was conceived for rich, rain-starved countries like those in West Asia. “Chennai's average annual rainfall is well over 1,200 mm. It should ideally be the last resort which, in this case, is not,“ Janakarajan said. With scant supply , water distribution is charted out daily by the CMWSSB.“Our planning [daily distribution] hinges on how much water the desalination plants supply ,“ Arun Roy , managing director of CMWSSB, said.
On average, the two plants churn out around 180 mld of the 470 mld CMWSSB now supplies, against Chennai's demand of 1,300-1,400 mld.The plant in Minjur caters to industries and a few localities in north Chennai, while the Nemmeli plant caters to nearly 13-15 lakh residents in south Chennai, which is also house to the city's IT hub.
The causes, and some solutions
Let’s learn from past floods to deal with present scarcity
Chennai suffers from a scarcity of ideas, not rain or water. A classic example is the 2015 floods and the water paucity a year-and-a-half later. Flood water from Adyar river entered homes, caused extensive damage, and a large quantum of it drained into the sea under the watchful eyes of the city planners.
Chennai has been banking on three water reservoirs for the past 100 years, with the government not setting up a new reservoir that could at least store Krishna water from Andhra Pradesh or collect rainwater in the city suburbs. In the past 30 years no proper step has been taken to increase the city’s water capacity despite its growing population.
At one point of time, the DMK government considered establishing two reservoirs to store Krishna water but dropped the plan. Instead, Krishna water was taken to the existing Poondi reservoir. The AIADMK government too failed to create an additional reservoir though Rs500 crore was sanctioned in 2012. Had these plans been implemented, the city probably would not have suffered massive damage due to the floods in 2015, and saved part of the water too.
In 2017, the Comptroller and Auditor General (CAG) in the Performance Audit of Flood Management and Response in Chennai and its Suburban Area highlighted several failures on the part of the Tamil Nadu government which led to the "manmade disaster". The CAG report noted, "Considering the catastrophic floods in 1976, TN constituted a nucleus cell to suggest flood mitigation measures." Creation of two reservoirs in the upstream of Chembarambakkam tank on Adyar river to capture 1.57 thousand million cubic feet (tmcft) of water was recommended in 1980. "We noticed that after a delay of seven years, water resources department (WRD) in 1987 proposed a reservoir at Thiruneermalai, by which time the site had become populated and requisite land was not available. Thus, the WRD failed to construct the reservoir which could have accommodated the surplus water in Adyar river in 2015. Instead of creating new reservoirs upstream Chembarambakkam tank, TN envisaged three tanks across the Kosasthalayar river to augment storage by 4.2tmcft."
These three projects proved to be disappointments, the report said, pointing out that against an outlay of Rs500.36 crore to increase the storage capacity by 1.83tmcft, an expenditure of Rs289.63 crore was incurred until the end of March 2016 to achieve an increase of only 0.17tmcft.
The state has now announced that a new reservoir would be built, combining the Orathur, Arambakkam tanks and Orathur check dam in Sriperumbudur taluk, with a capacity of 1.3tmcft at a cost of Rs60 crore by 2021, even while the proposed new reservoir at Thervaikandigai (Rs330 crore) is under construction. The Thervaikandigai proposal has suffered due to faulty land acquisition resulting in enormous delay, according to the CAG report.
In 2011-12, TN also envisaged construction of a reservoir at Thirukandalam in Tiruvallur district across Kosasthalayar river to store 1tmcft of water downstream of Poondi reservoir and Thamaraipakkam Anicut. As the proposal required acquisition of private land across 1,376.52 hectare, on government orders, WRD downsized the project to construct a check dam to store 0.16tmcft. The structure was designed to withstand a maximum flood discharge of 65,000 cusec, but the WRD failed to take into account the discharge of 92,260 cusec at Poondi reservoir in 1966. The work was completed in September 2014 at a cost of Rs28.65 crore. During the floods in 2015, the retaining wall of the check dam breached due to inflow of 79,564 cusec. The CAG report observed that the imprudent decision of TN to reduce the storage capacity to avoid land acquisition resulted in failure to harness excess water. "Incorrect adoption of flood discharge capacity for construction of the check dam resulted in its breach during 2015 floods thereby causing inundation of nearby areas," the report stated.
Further, TN did not consider construction of check dams at Varadharajapuram and Anakaputhur villages to harness surplus floodwater of Adyar river despite it being recommended by the expert committee on northeast monsoon. On the contrary, it allowed the Airports Authority of India to demolish a check dam across the Adyar. Construction of the suggested check dams, could, to an extent, have reduced the flow of flood water.
Encroachment of tanks, lakes and river beds also played a major role in causing the massive floods in Chennai and the present scarcity. Large-scale illegal constructions and lack of implementation of rainwater harvesting systems contributed to the present crisis. Thousands of waterbodies in Greater Chennai region are crying for attention, which are cost-effective water sources for the parched city. The solution lies within. The question is will there be an end to the dearth of ideas.
The crisis, as in 2019
Why Chennai’s water crisis should worry you
IT COULD BE YOUR CITY NEXT: Reckless Destruction Of Water Bodies, Poor Planning — Today, Citizens Are Paying A Very Heavy Price
Having gone without a single drop of rain for about 200 days at a stretch, Chennai finally got some rain on Thursday. But this is way too little, and way too late for a city experiencing its worst water crisis in 30 years, and headed to becoming a Zero City.
School bags have grown bigger as children carry more water bottles, and Tamil Nadu’s apple of the eye – the famed Information Technology Corridor – has been pushed to the brink. Companies have started asking employees to work from home and bring their own water. Water is rationed in residential apartments and malls are asking their water-intensive outlets to either take a break or use the blue gold frugally. Pipe water supply to homes is not even 10% of what it used to be, and wait for a Metrowater tanker is as much as three to four weeks now. One does not know where the next pot of water will come from. It is that bad.
It is not the usual water-shortage whine anymore. Few outside Chennai could comprehend the mammoth efforts that have to be put in to fill a few pots in every household, every day.
Reservoirs running on empty
Taste this: All the four major reservoirs that supply drinking water to Chennai have dipped far below the zero level and today hold not even 1% of their capacity. Chennai is now critically dependent on its three mega water desalination plants with a combined capacity of 180 mld, and the units are working overtime to remain at least 80-90% efficient. The New Veeranam pipeline brings 90 mld water from a 1,100-yearold Chola-era 235 km away. Water stagnating for months in huge abandoned stone quarries is being pumped out to fill tanks and tankers for about 5% of the city’s 8.5 lakh households that have Metrowater connections.
Even during ‘normal’ times, as against the city’s requirement of 1,300 mld, Metrowater was able to supply only 830 mld. Now, they ‘officially’ maintain that the supply is in the region of 500-525 mld, but there is no way a neutral source can verify the claim as residents complain about an 80% drop in frequency as well as quantity of water supplied to households.
And barring the famed fresh water aquifer abutting East Coast Road (ECR), underground water level has plummeted to a level few experienced in the recent decades. Even the Pallikaranai marshland, which used to be spread over nearly 7,000 hectares, but has now shrunk to 684.73 hectares, has gone dry.
With no sign of good rains for at least another 100 days, it is not the question of surviving a week or two ‘somehow’. It needs enormous perseverance and a long-haul strategy to survive in Chennai. Already there are plans to bring water by train wagons from Vellore, which is about 143 km away.
How the ‘lake districts’ dried up
Chennai is today paying the price for its downright disrespect for waterbodies and water sources. Chennai and its two neighbouring districts – Kancheepuram and Tiruvallur – together used to be called ‘Yeri (lake) districts’. They had more than 6,000 lakes, ponds and reservoirs that minimised run-off loss of rainwater and kept replenishing the groundwater table throughout the year. At present, authorities say only 3,896 have survived and Chennai city alone has lost nearly 150 such water bodies. Further, whatever survived is nowhere near its actual size. Canals and supply routes have all disappeared while successive governments promoted housing projects called ‘Yeri schemes’ to convert water bodies into residential plots and apartments to house the city’s burgeoning population. From about 39 lakh according to the 1991 census, the extended areas of Chennai today hold nearly 70 lakh people.
Three ‘rivers’ crisscross the metropolis, but they have all been dead for years. Cooum was killed by filth and untreated sewer being let into it for decades. Buckingham Canal and Adyar too are no better. Today, they are glorified gutters as their feeder lines and banks have been ceded to encroachers small and big. Governments have sunk several thousand crores of rupees in ‘river restoration projects’ but little has been achieved.
Nature too has not been very kind to the metropolis. The rain-shadow city gets about 80-85% of its water in two months – October and November. Chennai being a coastal city, run-off rate is very high and it is almost impossible to build big dams to save the water for dry months ahead.
Chennai’s topography, therefore, needed such unusual solutions as rainwater harvesting and desalination plants. During the 2011-16 Jayalalithaa regime, having rainwater structures in every building was made mandatory and that coercive policy is now credited with having helped the city in a big way. Today Chennai has three desalination plants – two of 45 mld each and the other of 90 mld. The present dispensation is now set to lay the foundation for a mega desalination plant of 150 mld capacity.
Policy choices deepened problem
Policy paralysis for decades on the water front is to blame. For instance, the government opened the IT Corridor and showered builders and IT companies with floor space benefits, but no thought was given to the source of water for drinking and regular use. Today, the IT Corridor has at least 150 mega structures owned by 650 big companies that employ 3.2 lakh people. Besides, there are more than 12.5 lakh residents, too. But they have no piped water supply and borewells are of no use as the clayey soil yields highly saline and soapy water. Their sole source of water is private tankers that used to recklessly plunder farm wells located a short distance away.
The IT Corridor alone needs 3 crore litres of water daily, and the 700-odd private water tankers, most opf them of 24,000-litre capacity, fill this critical civic gap. There are even about a dozen 48,000-litre 14-wheeled monster-trucks catering to office needs. They loot farm wells by paying a pittance to farmers and make a killing by selling water to IT companies and gated communities at fancy prices. When the Madras high court tried to curb this unfettered exploitation of groundwater, and pointed to the total absence of regulations governing the trade, the tanker lobby responded with a strike. After bringing the government to its knees and the entire IT Corridor to the brink of closure, tanker operators won a concession: the authorities would turn a blind eye to the plunder.
But, then, which other Indian city is as unenviable as Chennai, on the water front? It does not have a perennial river. Its underground water is too deep and too ‘coloured’ or contaminated for use. Most localities do not have piped water. Water supplied through Metrowater or private tankers takes about a month to reach homes.
Water, or rather its scarcity, has started impacting the law and order situation too as the city has started seeing a spurt in cases of ‘water rage’. Only last week, a retired DSP had to face a criminal case after he assaulted a neighbour who wanted the ex-cop to use water judiciously. Local gangs taking control of public water taps and dominating supply from street-corner tanks is too common. On board buses, trains and share autorickshaws, and even in airports, the compelling theme of discussion is water.
The Chennai water calamity is a leveller, indeed: It has hit everyone, without any rich-poor bias.