Werribee Irrigation Modernisation

A project with history and purpose

The Werribee Irrigation Modernisation is a staged approach to redeveloping the Werribee Irrigation District (WID)—known as one of Melbourne’s ‘vegetable gardens’, and located on the city’s doorstep by the Werribee River estuary. Since the influx of Australia’s first settlers, the district has remained an important agriculture centre since the early 19th century. The region is one of Victoria’s biggest producers of fresh vegetables, and replacing their ageing irrigation infrastructure has the positive impact of increasing water security and boosting agricultural growth within the region.

The region is known for its cabbage, broccoli and cauliflower

Like Bacchus Marsh and the Macalister Irrigation District in Gippsland, the WID is a gravity irrigation district, and relies on upstream heads of water to move supply through the pipes and channels to the customer.

Southern Rural Water, 2018.

Werribee Irrigation District (WID) depends on three major storages upstream

• Pykes Creek Reservoir, which has a capacity of 22,119 megalitres (ML)
• Melton Reservoir, which has a capacity of 14,340 ML
• Merrimu Reservoir, which has a capacity of 32,215 ML

Currently, none of these sources are designed to manage floods or the storage of water beyond their capacities. With most of the water being used for either irrigation or drinking water—the storages have fixed crest spillways, so that once they are full, any excess water coming into the reservoir will flow over the spillway into the river or creek downstream (Southern Rural Water, 2018). This loss only adds to the water that is lost through the open channel system each year.

Following the extreme drought in the early 2000s onwards, the WID Recycled Water scheme was established in 2004 to help contribute to the diminished water supply. However, while there has been upgrades and pipe lining implemented over the years due to urban development, most of the WID remains an open channel.

The concrete V-shaped notch that currently makes up the district’s open channel is completely uncovered. By the current design, this means that a sizeable portion of water is lost to evaporation and other environmental factors.

Project delivery — stage 1

Clover Pipelines worked with Southern Rural Water, the water authority of the region, to complete Stage 1 of the project in August 2017.
The upgrade aims to replace the current channel system, while providing better service to the customer outlets in the area. Replacing the open channel with pipeline infrastructure allows for greater and more consistent flow for irrigators, while providing better water security and management.

Over three stages, the project will replace 39km of open channel with pipelines, and once complete, has been projected to save up to five billion litres of water that is currently lost each year through evaporation. This will underpin 660 existing jobs, as well as help to create 18 new on-farm positions.

The first stage covered 2.9km of pipeline, from the corner of Duncans and Cliffords Rd, Werribee South. This area spans across the top of the main channel at Harrison’s Lane, through to the junction between Diggers Road and Aviation Road.

The project required the source, supply and delivery of:

• 2.49 km of DN1000 FW GRP Pipe at PN10, SN 10,000 & fittings.

With the provision of bends and various custom outlets, the entire pipeline was constructed in GRP. The use of GRP was specified for the project due a range of reasons, including its cost-efficiency for these lengths of pipe. The smoothness of the internal surface (ColebrookWhite coefficient k=0.029) allows for more consistent flow, and its simple installation requiring only a rubber ring joint made for a quick installation.

Lightweight and easy to handle, GRP is becoming an industry choice for irrigation systems. An example of this is the Central Plains development completed in New Zealand, which set the industry precedent of using GRP within irrigation applications.
The specification of DN1000 was relevant to the first stage of this project as the pipeline needed to cater for the highest flows of water located at the main channel.

The pressure rating of PN10 was specifically chosen due to its ability to cater for the head pressure to push water through an irrigation system. While not particularly high or low, this pressure rating provides the consistency required for the application.
Alongside the supply and delivery of GRP products, Clover was involved in the management of stakeholders and subcontractors, as well as offering expert quality assurance and technical support.

With over five years’ experience in construction and engineering, the project was supported by Jordan Andrews—Project Operations Manager leading the Major Projects team at Clover’s Head Office. His role involved ensuring the customer service Clover is known for—going above and beyond with reliable delivery, engineering support and on-site training for installation and ongoing maintenance.

Part of our role as suppliers is to assure the excellence and performance of our products. This is achieved through the Australian standards we adhere to across our range. All the products we supplied as part of the project are certified to AS3571.2.

This standard is relevant to Plastic Piping Systems—Glass reinforced thermos setting plastics (GRP) systems based on unsaturated polyester (UP) resin in pressure and non-pressure water supply. This standard accredits that Clover’s GRP range adheres to strict guidelines that span sizing, diameters, ratings and the manufacturing process itself.

Innovation in supply and delivery

With a timeframe of only six weeks—the first stage of the project posed equally timely challenges. To achieve the desired outcome, we maintained a balance between meeting deadlines, and satisfying the water requirements of irrigators in the area.

It was a challenging project with critical timelines to be met—requiring the delivery of over 50 semi-trailer loads of pipe in under six weeks.

Jordan Andrews, Project Operations Manager (BEng (Hons) MIEAust.

The winter water supply is distributed during the May-August period. Generally, works can commence prior to 15 May, or following August 30—provided that services are not interrupted. During the distribution period, water is usually delivered to customers every two weeks, and is dependent on the surrounding weather conditions.

As delivery days typically occur 2-3 days per delivery week, this meant a limited window of opportunity to complete the works required. Governed by the shutdown schedule, Clover Pipelines worked alongside contractors to ensure the volume and delivery of pipes were consistent with the construction timeline.
Part of the reason this was successful was our ability to forecast stock levels throughout the duration of the works. Clover Pipeline’s effective project management in the delivery of major pipelines allowed us to schedule priority fittings and craft a tailored product and delivery schedule for our project partners. This enabled delivery of the project on time and on budget.

Looking forward to the future

Since the successful completion of Stage 1 (covering over 2,900 meters), Clover Pipelines has been engaged to undertake the sequential developments of the WID project.
The ongoing relationship between Clover and Southern Rural Water speaks volumes of the collaboration and technical expertise undertaken by both teams involved.
Southern Rural Water is currently in the process of planning for the upcoming development, which will be completed during 2018’s winter period. Stage 2 of the project will continue to replace the old channels with new pipelines to improve the efficiency of the system.
Alongside the improved water efficiencies, comes the benefit of underpinning existing jobs in agriculture, as well as helping to create new on-farm positions through boosting farm production.

Werribee and Bacchus Marsh irrigators have been doing it tough with on-going dry conditions and ageing irrigation infrastructure. These projects will give Victoria’s biggest producers of vegetables a secure water supply for the future.

Lisa Neville, Minister for Environment, Climate Change and Water.

With these improvements, comes additional benefits to the environment surrounding the region.

Two thirds of the water saved from the project’s upcoming stages will be returned to the district’s irrigators to boost their agricultural production.

This additional water will also help support the reliability of their irrigation systems over the years to come.

The remaining third of the saved water will be provided to the general environment in need of irrigation within the district.

Stay tuned for the second instalment of this project—we’re looking forward to joining forces with Southern Rural Water to collaborate on a project that will continue to give back to the irrigators, agriculture and environment of the region.