Sewer team's work nearing end

01:38, Aug 29 2012
Mark Bell,
Men at work: Adcock and Donaldson contractors from left Lyndon Denton, Mark Bell, Wayne Russ and Brian Cargill have almost completed the sewage pipes upgrade but they are promising to be back

Although digging up and replacing old sewage pipes all winter doesn't sound like everyone's cup of tea, the team of Nelson contractors from Adcock and Donaldson have managed to have fun every step of the way.

And they are still smiling now, nearing completion of the project which began in July last year.

Of course they have not been laying pipes all that time - the obliging workmen kindly agreed to halt proceedings for the Rugby World Cup at the behest of West End business owners concerned about the impact on visitors.

Contracts manager Wayne Russ said a month of work was completed before the World Cup, and they returned on May 1 this year to continue.

A total 570 metres of pipe has been replaced, plus an extra section of Kiwi St/Ludstone Rd, of 430 metres, making the total pipe length around 1km.

The technology makes it pretty simple - a camera is sent down the pipes first in order to find the existing connections.


Using an American-made machine - the first of its kind in New Zealand - 50m sections of pipe are replaced easily and efficiently. Steel rods are pushed into the existing pipe, then drawn back with a cutter on them to break up the old pipe, then the new pipe is pulled in from behind.

Up to 100m can be replaced at a time in this way, although in this case the contractors were trying to keep disruption to a minimum.

The 1km of pipework replaced ranges in depth from 1.8 to four metres. The replacement pipe is larger in diameter and made from polyethylene (PE) which has a design life of 100 years.

Mr Russ said the old pipes were about 50 years old. Made from concrete which is susceptible to degradation, the works were vital and in some places the pipes were in a very bad way, causing a lot of water infiltration.

Kaikoura District Council asset manager Marlene Roberts said the works to date had been quite successful. Council had been pleased with the performance of the contractor and the outcome - between 300 and 350 cubic metres of stormwater each day has been stopped from entering the system since the repair work. This equates to a reduction in the pumping rates at the nearest pumping station, from seven hours a day to four, she said.

Further work could be implemented if tests results return sufficient evidence to warrant it - a section of the line between Brighton St and West End was identified in the CCTV footage three years ago. If analysis showed it needed renewing, it would be done within the next two years.

Kaikoura Star