From the magazine

Harcourt’s modern backbone

The $A40 million Harcourt Rural Modernisation Project is underway which, once completed, will completely upgrade the region’s century-old irrigation infrastructure – providing a year-round pressurised supply of water to irrigators in the region. The new system replaces the concrete and earthen gravity channels that have served the region for more than 100 years.

Coliban Water funded approximately $A23 million of the project with a plan to recover approximately $A17 million from Harcourt rural customers via rural modernised tariffs in the future.

Not only will the pipeline provide greater water security for rural residents, but an improved level of business certainty as well, underpinning the sustainability of agriculture within the area.

The Honourable Peter Walsh said when announcing the works in 2013 that the upgrades to infrastructure in rural areas such as Harcourt were crucial for the future of farming production in Australia.

“The Victorian Coalition Government has set a target for Victorian farmers to double production by 2030, and providing a reliable, efficient water supply will help them to achieve that goal,” he said.

Pentair were awarded the contract to supply the 19 km of ductile iron pipes to be used to construct the backbone of the new modernised rural pipeline system.

A trenchless affair to remember

At the time of going to print, the project has already completed roughly 95 per cent of the 19 km backbone pipeline construction works, installed via application of thrust boring. Approximately 55 per cent of the new network pipeline has been installed.

The construction of the pump stations in Faraday and Barkers Creek Reservoir is 30 per cent completed.

Coliban Water Manager of Infrastructure Delivery Ken Laing said the technology was ideally suited for the Harcourt project.

“Trenchless techniques were selected as they were required to lay sections of the pipeline that passed under roads, a cattle pen and a dam.

“There were also sections with significant native vegetation and areas of cultural heritage that couldn’t be trenched,” he said.

The Harcourt project is includes thrust boring, a method selected as the most suitable trenchless technique for the ductile iron (DICL) pipe used for the backline pipeline. Where using thrust boring wasn’t possible, horizontal directional drilling (HDD) was utilised and installed polyethylene (PE) pipe instead of using DICL pipe.

Materials used during the projects included:

  • The backbone pipeline is 19 km with a diameter of 500 mm DICL
  • The reticulation pipeline is 44 km and made up of either PE or DICL
  • The diameter of the reticulation pipeline varies from 225 mm to 63 mm depending on the required flow.

It’s how you use it

During the early planning process Coliban Water was met with various design considerations in order to successfully plan the Harcourt works, and it was these considerations that lead to the use of a various trenchless applications in differing conditions.

“During these ongoing works we have had to pass so close to a dam that we needed a 4 m deep entry pit for the thrust boring application to commence.

“This was a necessary requirement to avoid impacting the dam in any which way, and it has been very effective,”
Mr Laing said.

The benefits of applying HDD technology during these works was considered by the crew from Coliban Water and Mr Laing as an effective plan for when the project would encounter a reticulation pipeline underneath urban transport areas.

“HDD was chosen for when the reticulation pipeline passes under the railway line and the freeway to ensure construction doesn’t cause any disruption to transport,” he said.

Looking ahead

It was announced in October that for the moment, all pipeline and pump station works have been temporarily suspended on the Harcourt Rural Modernisation Project in order to resolve issues with the continued delivery of the project.

Mr Laing said the suspension of works was only a temporary measure to ensure the success of the project.

“We are fully committed to resolving the issues and to the completion of the project.

“All other contracts outside of the main contract are complete, including backbone pipe supply, pump delivery, balancing storage tank and Barkers Creek Reservoir new inlet works,” Mr Laing said.

Coliban Water said they remain in constant communication with land owners and customers in the region.

The Harcourt Rural Modernisation Project was initially set to be completed by the 2014-2015 rural season, which has now been delayed due to the suspension of works and wet weather causing impractical ground conditions.

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