The Mt Cole project involved the rehabilitation of 1.4km length of a raw water pipeline that services the township of Ararat in regional Victoria. The pipeline is a critical asset that needed to be future-proofed, thus securing the availability and longevity of drinking water for Grampians Wimmera Mallee Water and its customers.

The location of the project was remote and rugged. This led to Interflow choosing a Primus Line solution over traditional methods, which provided a practical way to extend the asset’s design life while concurrently protecting the pristine and sensitive environment.

The Primus Liner was installed using a winch and a pulling head from the top of the site (approx. 200m elevation), working its way down a hill over a 1.4km distance. This set a new single pull record for Interflow.

To access key areas between the ends of the project, Interflow used a helicopter to air-lift heavy materials, strategically placing pre-packaged bundles of new pipes and fittings along the alignment. The helicopter was also used to transport pipework sections offsite that needed to be removed.

The overall Primus Line solution allowed an innovative approach, future-proofing a failing raw water pipeline, whilst overcoming a remote and rugged landscape.

The challenge

GWMWater had been looking for a feasible and cost effective option for renewing this asset for many decades.

The challenging environment and the relatively small storage at the head of the pipeline presented GWMWater with the prospect of abandoning the storage and sourcing all water from Lake Fyans to the west of Ararat. The millennium drought and the impact of climate change, however, reinforced the critical role that Mt Cole played and a decision was made to replace or rehabilitate the pipeline that connected the storage to the town.

Environmental constraints challenged traditional methods, like lift and replace and HDD. Further, the line could only be accessed at the top and bottom of the alignment via walking tracks – access to mid-sections of the line would be challenging and opportunities for laydown areas were few and far between.

GWMWater needed a solution that maximised the amount of water that could be delivered, minimised the impact on the environment and potential cultural disturbance, was resilient to site conditions, and could be installed over long lengths in difficult terrain.

The solution

Interflow proposed using Primus Line, a strong, high pressure flexible liner that is specifically designed for pressure pipelines.

The key to the successful installation was being able to do it in a single pull. Being able to install a liner in one shot – through bends – and containing work sites to the two ends was key not only to the success of the project, but to it proceeding at all.

The single-pull installation eliminated any impact on the natural environment by taking away the need to build access roads or clear vegetation for work areas.

Conclusion

By challenging conventions and working collaboratively, GWMWater and Interflow delivered a landmark rehabilitation project and returned a core water asset to optimum condition.

The success of the project provided GWMWater a cost-effective solution to a decades-old problem and a renewed asset that will serve their community for generations to come.