Lost in transmission
The Tansa water main — which feeds the western suburbs and parts of the island city — is springing leaks faster than the municipality can fix them. Hindustan Times follows the line from its source near Bhiwandi to the tap in your home, report Bhavika Jain & Sujit Mahamulkar.Updated: Apr 08, 2010, 13:13 IST
The picture alongside shows what happens when the BMC opens a valve on a water main that it wants to empty before repairing it.On Thursday, the opening of this valve coincided with pipeline ruptures at Mulund and Kapurbawdi in Thane. Even after the municipality fixed on Friday six major leaks in the 83-yearold, 120-km Tansa water main, there are more than 25 leaks still left unattended. The Tansa line is part of the city’s 4,000-km water system, which is the eighth largest in the world, and the oldest, most complex water network in the country. And those 25 leaks together account for more than 20 lakh litres wasted every day—enough for around 20,000 people.
To give you an idea of how desperate the situation is, listen to the civic officialwhowas inspecting the site near Kapurbawdi in Thane, around 80 km from the pipe’s source at the Tansa lake: “For any repair on this line, its water supply needs to be shut off,which we can’t do all the time—so if it’s not a major leak, we don’t repair it.” So there you have it: TheBMCis willing to lose — every hour of every day, all year round — millions of litres of water out of at least 25 leaks on the massive 1,800mm Tansa main because they are not major enough.
All of these accidental breaches happen because the pipes, laid by the British, are simply too old. “Age is amajor factor—these pipes cannot withstand even minor pressure or temperature fluctuations,” admitted Additional Municipal Commissioner, Anil Diggikar. An internal BMC report says the Tansa main (east and west) has exceeded its life span of 50 years.
“Even if these leaks are repaired,some other stretch develops cracks and eventually ruptures,” said a civic official requesting anonymity. The last two monthshave seen 18 pipe breaches,wasting roughly 150 million litres —enough for more than 16 lakh Mumbaiites.
The Tansa network alone has seen more than 300 ruptures in the last year. According to civic data, there have been 1,051 pipeline ruptures, across pipelines —that’s an average of three every day.
“The rupturing of water mains is a serious issue. The only permanent solution is replacement of the old lines,” said Municipal Commissioner, Swadheen Kshatriya. The mega project to replace the Tansa line, which begun in 2008, hasmade slowprogress —so far, only 43km of its 120-km length have been replaced.
This year’s BMC budget allocated Rs 380 crore for the replacement of old pipelines. Kshatriya said that given the Tansa main’s condition, there is also the need for a mechanism that can detect pressure imbalance in the water in this main and prevent a rupture.
The Tansa line (east and west) supplies 550 million litres daily (MLD) to the city. After the 15 per cent water cut now in force, the city gets 2,900 MLD, and 700MLD is lost due to leakage and theft.
When a pipe bursts, the impact of those numbers is multiplied many times over.