Lost in transmission
The picture alongside shows what happens when the BMC opens a valve on a water main that it wants to empty before repairing it.mumbai Updated: Apr 08, 2010 13:12 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-year-old, 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 official who was 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: The BMC is 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 1,800 mm 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 a major 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 months have 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, has made slow progress — so far, only 43 km 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 700 MLD is lost due to leakage and theft.
When a pipe bursts, the impact of those numbers is multiplied many times over.
‘Middle Vaitarna dam is behind schedule by almost 10 years’
International water management expert Madhavrao Chitale has said our municipality lacks the foresight needed to run the city’s water system, and that if things continue the way they are, it won’t be long before our water situation gets out of hand.
Chitale stressed the Brihanmumbai Municipal Corporation (BMC) urgently needs a technical team with a research background. “We need the technology to check pressure variations in the pipeline so these ruptures are avoided,” he said on the phone from Pune.
He believes the BMC must quickly begin work on the Gargai and Pinjal dams, and that any further delay in these projects will compound the problem. “The Middle Vaitarna project, which the BMC is banking on, is behind schedule by almost 10 years. Pretty soon, it will not serve its purpose as the city’s population has escalated many times over since it was first proposed,” he pointed out.
Anand Deodhar, a former BMC hydraulic engineer, said the BMC should take expert opinion from engineering institutes such as VJTI or IIT Mumbai instead of going to outside consultants. He also suggested soil samples be taken from chronic leakage spots.
“The BMC is scouting for a new system to monitor pipeline pressure when it already has the SCADA
(Supervisory Control And Data Acquisition) system — which is most likely not even working at this point because of disuse,” he said.
“The city urgently needs a new water management system, and the BMC needs a research team to suggest the changes needed in the current system,” Chitale said, adding that the BMC simply stopped innovating by the end of 1960 — the last major the BMC built its last dam. Upper Vaitarna
“Basically, the water distribution system has too old. It’s like our local train system, which has its limits,” Deodhar said.