There has been a flood of complaints about pipe bursts in the Milnerton area in recent weeks, but the City of Cape Town says normal wear and tear is to blame.
In the past few weeks, Milnerton, Tygerhof and Sandrift have been hit with pipe bursts, and every day, there is a resident on the Milnerton Neighbours Facebook page, complaining about having little or no water.
Suzette Little, area north Mayco member, said: “The high burst rate can be linked to normal wear and tear on the pipework combined with a rezoning exercise taking place in the area.”
The rezoning involves dividing the water supply system into pressure management zones to allow the City to manage water pressure which can extend the life of the pipes, minimising leaks and bursts.
Ms Little said the City had taken steps to reduce the pressure in the pipes, which should help to reduce the number of bursts.
“A pressure-reducing valve was installed on the feed-in to the area, and will be commissioned within the next two weeks in order to reduce water pressure, which will reduce the rate of bursts in the short term as well as over the long term, and reduce wear and tear on the pipes.”
She said some critical pipes in the area were due to be replaced.
Water problems are not a new thing in Milnerton. Two months ago, Milnerton residents said that they were fed up with having to endure water interruptions with no warnings or explanation from the City (“Water worries, Tabletalk, August 22).
Retired City of Cape Town chief engineer Brannon Meyer, believes that the problem is electrolytic corrosion.
According to him, devices called sacrificial anodes are fitted at various locations along the bulk pipeline around the city. There are about 60 of them, each weighing between 20kg and 25kg, and they help to stop accelerated corrosion of the steel pipes.
“If you leave a piece of steel exposed to the elements, it will corrode erode; if you put it into the ground containing various minerals, it will corrode faster and if you put it into water with salt and other minerals, it will corrode even faster. The moisture and specific minerals in the ground and the salt in the water form an electrolyte and react with the steel as in a water pipeline, to form a local cell, like a mini motor car battery, causing a circulating current and this accelerates the corrosion process even more,” said Mr Meyer.
He told Off My Trolley’s Brian Joss earlier this year that prior to his retirement he had done essential tests and regular inspections at the 60 sites to check that the anodes and not the pipelines were being corroded. However, he believed that regular testing and inspections had long since stopped (“Warning for City’s piping network,” Tabletalk, May 16).
At the time Xanthea Limberg, Mayco member for informal settlements, water and waste services; and energy, conceded that repair and maintenance of the cathodic corrosion protection systems had taken a back seat.
However she added: “It is highly unlikely that large numbers of catastrophic pipeline failures would occur as there are other corrosion protection measures in place. These include cement sheathings around pipelines and paint coatings on the accessible valves and fittings. During frequent work on our pipelines and other infrastructure, we have not observed areas of extensive steel loss due to corrosion. Any leaks detected are immediately repaired to prevent water loss.”