In desperation

Chennai must incessantly seek water

Last Updated: Sunday 28 June 2015

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.

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