> What we do?
The ongoing renewal of water and sewer mains across our region is an integral part of our operations to ensure we maintain and deliver services to customers.
Around 6.6 kilometres of mains which no longer meet the required levels of service are renewed or replaced every year.
> Why do mains need replacing?
Some water mains in our region date back to 1890s and some sewer mains to the 1920s. The majority of mains being replaced are from the 1950s.
We carry out routine testing to assess ageing mains so we are able to identify those which need to be renewed or replaced.
This helps prevent potential bursts and impact to customer services, as well as reducing maintenance and repair costs.
> Main renewal techniques
We utilise the latest mains replacement and renewal techniques to reduce the impact works have on customers and the environment.
In the past, if a water main needed to be replaced the road would be closed and an open-cut trench dug.
Trenchless methods of main renewal reduce the need for excavation work and are environmentally friendly compared to open-cut methods.
Less excavation prevents damage to trees and root systems, waterways, nature strips, gardens and driveways and means substantially less reinstatement work and less carbon emissions from construction machinery.
On average 90 per cent fewer greenhouse gas emissions than open cut excavations and overall cost savings of 25 to 50 per cent.
Road closures and disruption to residents and businesses close to work sites are also reduced.
The pipe bursting replacement technique for water and sewer mains involves bursting the existing main by pulling a cone through followed by the new polyethylene pipe.
Compared to open-cut trenching, pipe bursting can reduce the time it takes to replace a main by more than 50 per cent.
Another advantage of pipe bursting is its capability to increase flow capacity through the upsizing of the pipe.
To see pipe bursting renewal in action view the video on this page.
Cured In Place Pipe relining
Cured In Place Pipe (CIPP) technology is used for sewer renewal and based on the principle of a liner inserted into the old pipe and then thermally cured.
It can be carried out from access chambers, which saves the excavation of footpaths and nature strips.
The liner can handle high loads under pressure even without the old pipe in place.
Rib-Loc relining technique is used for sewer renewals and involves spiral winding a continuous plastic strip directly into a deteriorated sewer pipe.
The edges of the strip interlock as it is spirally wound to form a continuous watertight liner inside the pipe restoring the structural integrity of an aging main.
> Sewer System Testing
We use a number of methods to inspect sewer mains and identify leaks and ‘hotspots’ in our systems where, for instance, storm water is entering the sewer system and overflowing following heavy rainfall.
Leaks and illegal storm water connections can be identified by smoke testing, which works by isolating lengths of main and pumping in smoke to see where it escapes.
Once the gaps or connections have been located they can be repaired or removed.
Another method used to identify leaks and hotspots is CCTV pipeline inspection, where a camera is fed through mains to take video footage.