This large, recycled water scheme is modelled on HydroPlan’s irrigation experience from designing other recycled water schemes which have continued to grow and flourish for decades.
The population of the Caboolture River catchment is forecast to grow by more than 100,000 people in the next 20 – 25 years, increasing inflows to the Caboolture South Sewage Treatment Plant by 150%. To cater for the predicted rapid growth in the region, Unitywater has chosen a reuse scheme over the alternatives such as an ocean outfall to reduce the nutrient loading in the river, helping to reach their zero-discharge target by 2050.
The Wamuran Irrigation Scheme (WIS) will supply recycled water to intensive horticulture in and around the Wamuran agricultural district, and it will be constructed by the Wamuran Irrigation Scheme Joint Venture (WIS JV) – a fully integrated joint venture between Pensar, Pinata Farms and Twin View Turf.
HydroPlan played a key role in bringing the delivery team together ahead of the long tendering period, and developing the overall concept and masterplan based on experience with other recycled water schemes. As the Solution Architect for WIS, John Gransbury demonstrated the importance of water users being ‘in the tent’ and for the off-farm scheme to effectively be an extension of the on-farm schemes.
This is a win-win-win-win project:
• A win for the marine environment,
• A win for Unitywater’s customers by keeping water bills as low as possible,
• A win for growers in Wamuran, and
• A win for the local economy from increased employment by the Scheme Participants receiving water from the WIS.
The first stage of the Scheme will deliver 2.6 gigalitres of recycled water per year via a 10 km pipeline to Moodlu Quarry which can store 1.44 gigalitres to buffer variations in seasonal crop demands. Water will then be pumped through a 12 km pipeline with sufficient pressure to safely irrigate crops when scheme participants open their valves. This delivery concept avoids storing the water in on-farm dams to avoid introducing food safety and environmental risks.
HydroPlan assessed the on-farm irrigation systems to optimise and integrate the new water supply and developed Farm Management Plans as part of the scheme compliance requirements. Scheme Participant Liaison Manager for WIS, Scott Johnstone and HydroPlan’s team designed the physical and operational interfaces, and worked closely with AECOM who developed the engineering design to meet Unitywater’s requirements for the scheme.
Pensar’s construction period will be followed by verification and validation of the scheme to deliver Class A water in 2024. The five foundation customers will take water from 10 outlets to grow raspberries, strawberries, pineapples, avocados and turf primarily. The masterplan for the scheme predicts it will grow three-fold by 2050.