Chennai's agony

Published : Jun 23, 2001 00:00 IST

CHENNAI, the country's only metropolitan city without a perennial source of drinking water, is in the grip of acute water scarcity. Two of the rain-fed lakes that meet the city's needs - Poondi, and Red Hills - have severely depleted storage owing to the failure of the southwest monsoon (June-September) and the northeast monsoon (October-December) last year, and a third, Sholavaram, is dry. Tanker trucks pressed into service by the Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) and those run by private operators are trying to meet the people's daily needs, at least partially. The people of Chennai get 35 litres of water per capita in the best of times. The poor, the majority of them living in slums, are the worst-affected. They depend almost entirely on the public water supply systems.

Although the city receives rain during both the monsoons, it is the northeast monsoon that replenishes its reservoirs, which also receive the surface run-off from the Araniyar and the Kortalaiyar rivers. These reservoirs are shallow (Poondi is 2.2 metres deep, Sholavaram 3.4 m, and Red Hills 3.8 m) and are spread over a total catchment area of 3,513 sq km. In years of normal rainfall, about 200 million litres a day (mld) can be drawn from them. Poondi's capacity is 76.7 million cubic metres (mcm), Sholavaram's 22.5 mcm and Red Hills' 71 mcm.

The public water distribution system meets 65 per cent of the city's needs, sources such as wells 21 per cent, community facilities (mainly India Mark 2 deep handpumps and open public wells) 10 per cent and private sources 4 per cent. About 92 per cent of the city is piped. Since 1978, water has also been supplied by tankers to the needy areas from one of the three headworks in the city.

The water supply to Chennai during years of normal rainfall is around 313 mld (78 litres per capita a day, or lpcd). But during the drought years availability has been as low as 127 mld (32 lpcd). There is considerable variation in the availability of water across different sections of the people. According to a study undertaken in 1993 by the Centre for Environment Planning and Technology, Ahmedabad, while the average gross availability of water was 69 lpcd, it was 8 lpcd in the slums.

GROUNDWATER is the city's major water source now. It is drawn mainly from the well-fields in the Araniyar-Kortalaiyar basin and the aquifer between Tiruvanmiyur and Muttukadu along the coast south of Chennai. The well-fields yield 148 mld and the southern aquifer supplies 10 mld. There are a number of minor well-fields and individual wells. The other sources of groundwater are 5,759 tubewells, 35 open wells operated by municipal corporations in the suburbs and 4,700 hand pumps. According to the Census of 1991, there are about two lakh private wells in the city.

CMWSSB, or Metrowater, the government agency that is responsible for supplying water to Chennai, supplies 250 mld, including 50 mld for industrial use, every day. Nearly half of this comes from the wells operated by it (70 mld) and those it has hired in Tiruvallur district (30 mld, which is to be increased to 60 mld). Metrowater has added 1,075 storage tanks to the existing 2,525 in order to meet the current water crisis. Water is distributed by over 300 tankers that make over 2,000 trips every day. In order to ensure effective distribution, Metrowater has commissioned filling points at six distribution stations in the past three months.

The Southern Railway runs 'water specials' to Chennai from Chengalpattu and Erode. Each train carries 10 lakh litres in 50 wagons every day.

With a view to tapping the ready market for water, private suppliers have stepped in. They draw water from the southern aquifer and sell it in multiples of 4,000 litres. They charge anywhere between Rs.550 and Rs.750 for a tanker-load of 12,000 litres.

Groundwater extraction is reaching its limits. Accordin to the Central Groundwater Board, 80 per cent of Chennai's groundwater has been depleted and any further exploration could lead to salt water ingression. The assured yield from groundwater sources is estimated at 190 mld; of this, 158 mld has been tapped.

The rapid growth of the city's population has strained the water supply systems. In 1911, when most of these systems were designed, its population was only about five lakhs. The present population is 55 lakhs. Efforts to tap the groundwater resources started in 1965. Six well-fields were commissioned between 1965 and 1987. In early 2000, 17 deep borewells were dug and 13 deepened. This is in addition to the existing 49 deep-borewells. According to C.P. Singh, the outgoing Managing Director of Metrowater, the board has commissioned a study, "The Second Chennai Plan," to explore the possibility of augmenting the sources of groundwater and tapping the run-off water in the Araniyar-Kortalaiyar river basin.

HOWEVER, the city's annual agony during summer is unlikely to end unless other options are explored. Chief Minister Jayalalitha has promised to provide "potable water to all citizens". The new government has also promised to revive the Veeranam Water Supply Scheme that was launched in 1968 to bring water from the Veeranam lake, about 250 km from Chennai, desilt tanks, and construct reservoirs at Ramanjeri and Thirukandalam on the outskirts of Chennai, as part of the second phase of the Krishna River Water Project, which is popularly known as the Telugu Ganga project.

According to an official release, the government, taking into account factors such as the rate of population growth and the sustainability of the Krishna water scheme for 50-60 years, decided in 1996 to spend Rs.1,000 crores during the following five years to strengthen the distribution system. But the plan remains on paper.

The Public Works Department's plan to construct reservoirs at Ramanjeri and Thirukandalam has been delayed because of problems relating to land acquisition. The new government plans to implement the two projects.

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