From Effluent to Asset: Supporting Agricultural Reuse through the Wamuran Irrigation Scheme
Services: Agronomy and irrigation advisory services, land capability assessment and environmental planning
Location: Wamuran, Queensland
Date: 2020-2021
Caboolture River (Image Credit: Unsplash)
Our Scope
With the population of the Caboolture River catchment expected to increase by over 100,000 people in the next 20–25 years, Unitywater faced a growing challenge: how to sustainably manage the effluent produced by the South Caboolture Sewage Treatment Plant (STP). Although effluent is A-grade and suitable for a range of non-potable uses, without intervention, the increased nutrient loading could threaten the health of the Caboolture River and downstream waterways.
To address this, Unitywater launched the Wamuran Irrigation Scheme (WIS)—a circular economy initiative to beneficially reuse treated effluent in agriculture. Verterra was appointed to provide deep expertise in agronomy, irrigation, land capability, and environmental planning to help guide the project’s success.
Challenges
Rapid population growth: Forecast wastewater volumes from the Caboolture West expansion required innovative effluent disposal solutions.
Environmental protection: Without intervention, increased nutrient loads from the STP could degrade sensitive aquatic ecosystems.
Regulatory complexity: The project required coordination across multiple stages of design, compliance, and stakeholder engagement.
Technical integration: Ensuring that irrigation, agronomic, and environmental systems aligned with recycled water quality and end-use requirements.
Verterra’s Solution
Verterra supported Unitywater across project stages by acting as a Client-Side Technical Advisor and Representative, with responsibility for ensuring best-practice outcomes in recycled water reuse and agricultural application.
Key contributions included:
Review and input on design and planning documentation
Assessment of land suitability, irrigation system design, crop water use modelling, and nutrient management
Oversight of farm engagement and farm management planning to match scheme outputs with grower needs
Guidance on environmental monitoring, risk management, and Recycled Water Management Plan development
Stakeholder liaison support, aligning agronomic outcomes with regulatory and commercial requirements
Project Highlights
Enabled agronomically viable reuse of effluent for high-value crops
Integrated irrigation and environmental modelling into scheme planning
Supported Unitywater in reviewing water quality investigations and setting a robust environmental baseline
Developed a collaborative framework to connect treated water supply with agricultural demand
Outcomes
Risk turned into value: Effluent previously considered a liability is now being used as a productive irrigation water source.
Informed development: Verterra’s expertise ensured the scheme was grounded in science and aligned with best-practice irrigation and agronomic methods.
Enhanced sustainability: The WIS demonstrates a scalable model for circular water use that benefits both urban growth and rural productivity.
Strategic leadership: Unitywater has positioned itself as a leader in integrated water cycle management and resource recovery.