'Water hammering’ ruptures Opa pipeline, Tiswadi villages affected

Ponda/Panaji: The rupture of the Opa raw water pipeline on Monday afternoon caused water supply disruption to four assembly constituencies of Panaji, Taleigao, St Cruz and St Andre for over 24 hours.
The public works department (PWD) pressed over 50 water tankers to help mitigate the problems.
PWD engineers said that though resumption in pumping of treated water from the Opa water treatment facility happened around 3pm on Tuesday, the water had reached the Kadamba plateau near Old Goa only by 8pm.
The water was expected to reach Altinho, Panaji, by 9pm. While water supply was restored to the areas of Neura and Mandur late on Tuesday evening, Agacaim, Siridao and neighbouring areas were expected to get water only in the night.
PWD executive engineer Dilip Dhavalikar who looks after the supply of Ponda and Tiswadi talukas revealed that department tankers made about 90 trips of tankers on Tuesday to check the water problem in the state capital and surrounding areas.
More than 15 tanker trips supplied water to the Goa medical college since the Monday mishap.
Engineers worked through the night and managed to replace the pipeline by 6am on Tuesday. Treatment of raw water and re-pumping of treated water could only begin around 3pm on Tuesday.
The water hammer effect caused by loud banging of water inside an empty pipe led to the rupturing of the pipeline, PWD sources said.
This effect is caused by high pressure collision of water inside the empty pipe and it happened three weeks earlier on August 13, when a lead joint of the rising /pumping main pipeline of 750mm diameter was broken. The rupture occurred again on Monday, September 8 in the same pipeline, but, a few meters away from the earlier spot.
PWD assistant engineer Nivruti Parsekar at the Opa water works revealed that the 750 mm diameter rising /pumping main pipeline pumps water to master balancing reservoir (MBR) at 190 mt ht of the Opa hill and then supplied 55 MLD water to another MBR at Altinho, Panaji, through gravity.
Dhavalikar briefed that air is created in the pipe when the pipeline remains empty for a long time or water stops passing through the pipe more frequently.
Later, when the water is passed through the pipeline, the residual water returns and collides with the fresh water entered in the line and both collide with each other with a high pressure resulting in breaking of joints, valves or rupture in pipes.
This phenomenon is called as water hammering.