Melbourne’s century-old water infrastructure up for renewal

Written by  06 June 2015
Published in Major Projects & Water Reform
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Melbourne Water has kicked off its major infrastructure renewal program in earnest, with several key projects just started or set to begin.

Melbourne Water’s General Manager of Major Program Delivery, David Morse, says that where previous projects had focused on significant infrastructure investment to ensure that Melbourne was well prepared against population growth and extreme events, such as drought and bushfire, the approach over the next few years will concentrate on maintaining an expanded asset base and upgrading ageing infrastructure.

‘A high-quality water supply, safe sewage transfer and treatment, better flood protection, and healthy waterways with good amenity play a vital role in maintaining Melbourne’s status as one of the world’s most livable cities,’ says Morse.

‘As an essential service provider, we have been providing safe and reliable water and sewage services to Melbourne for more than 125 years.

‘The city’s water and sewerage infrastructure has held up well, but it’s time to renew our pipes to ensure that they can continue to serve the community for the next 150 years.’

The shift from large-scale projects to asset maintenance and renewal is reflected in a $1.5-billion reduction in capital expenditure. Key capital projects proposed for the next five years include:

  • renewal of several ageing water supply pipelines
  • growth-related works in Melbourne’s west, including stage two of the St Albans–Werribee pipeline
  • Western Treatment Plant capacity upgrades
  • rehabilitation of the Hobsons Bay Main Sewer and North Yarra Main Sewer replacement works
  • flood protection works.

The biggest infrastructure renewal projects that Melbourne Water is currently undertaking are to replace century-old infrastructure in Melbourne’s inner suburbs – the Alphington Sewer Replacement Project, the Carlton Main Sewer Improvement Project, and the South Yarra to St Kilda Water Main Replacement Project.

Alphington Sewer Replacement Project

Melbourne Water has partnered with Lend Lease to replace the century-old brick sewer between Coate Park and the Latrobe Golf Club in Alphington. The old sewers have deteriorated significantly, and they must be replaced in order to continue to provide essential services to Melbourne’s northern suburbs.

Once complete, the project will improve the network and protect public health and the environment by reducing the likelihood of sewage spills during extreme wet weather, and reducing maintenance issues such as blockages.

Constructing the new sewer will involve trenching and tunnelling under roads, some homes, businesses and public open spaces. It also involves a challenging element of engineering – replacing a pipeline under the Yarra River, which has seen large steel sheet piles used to make a dam for works in the river.

The project team has been careful to ensure that access along the river for recreational boating activities is maintained at all times during the construction period.

Carlton Main Sewer Improvement

Melbourne Water and John Holland are renewing a 1.35-kilometre section of the 114-year-old Carlton main sewer in Carlton North.

The project also involves building a new 510-metre section of sewer line to cater for future population growth, and to ease pressure on the existing system.

The Carlton Main Sewer Improvement presents a range of difficult engineering challenges – the shaft needs to be drilled 25 metres down through basalt rock before any tunnelling can start, and all works are being conducted in a highly urbanised area.

The project team has engaged specialised techniques and equipment to minimise impacts on local residents as much as possible, while still delivering the essential project.

South Yarra to St Kilda water main renewal

The South Yarra to St Kilda water main (M39) was originally constructed in the 1890s, making it one of Melbourne’s oldest operational mains.

It transfers water to around 97,000 homes and businesses in the inner south-east suburbs, from South Yarra to St Kilda and Port Melbourne.

Today, the existing water main is at risk of failing, and must be replaced to ensure that Melbourne’s water supply continues to run efficiently while serving our current and future demand requirements.

Melbourne Water and construction partner Thiess Black & Veatch Joint Venture are replacing three kilometres of water supply main using mostly open trenching. The pipes will be 740 millimetre and 600 millimetre diameter, in six- and 12-metre lengths, with one length of pipe laid per day.

The project is expected to be completed in late 2015, and will navigate through major residential roads and a large park.

Water for a Growing West  The three major renewal projects in Melbourne’s CBD fringe, inner north and inner south-east are being complemented by a key growth project for Melbourne’s expanding outer western suburbs.  Melbourne Water is constructing a new main that will supply water to the Cowies Hill reservoir in Tarneit from the St Albans reservoir.

Called the Water for a Growing West project, the new 17-kilometre water main will service an additional 40,000 homes. It is designed to transfer a maximum of 200 megalitres of water per day – the equivalent of 80 Olympic-sized swimming pools.

To reduce disruption to the community, the water main will be located within an existing power line easement, and current and future road reserves. Construction will include the installation of pipework and valves, and connections to the existing main at each end of the project.

While some vegetation removal has been necessary for the project to proceed, logs that had been removed were provided to a local primary school to be used as seats for the students in their vegetable garden.

Construction commenced in late 2014, and the project is expected to be completed by November 2015.

Morse says that the projects all contributed to building on the legacy of strong water and sewer networks to support the rapidly growing city and surrounds.

‘We recognise the key role we play in Melbourne’s livability, and it’s our responsibility to ensure that we’re not only providing safe and reliable public health services now, but are always preparing for the future.’

A Snapshot

Melbourne Water is responsible for an extensive water supply that includes:

  • 10 storages reservoirs
  • 14 water treatment plants
  • 1062 kilometres of pipes.

We supply the water retailer companies with 400,000 million litres of high-quality drinking water each year – enough to fill the Melbourne Cricket Ground (MCG) 236 times.

Melbourne Water removes and treats most of Melbourne’s sewage. We manage:

  • more than 400 kilometres of sewers
  • nine pumping stations
  • two sewage treatment plants.

Each year, we treat more than 320,000 million litres of sewage, including trade waste.

Read 2113 times Last modified on Tuesday, 22 September 2015 11:48
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