As freshwater resources become increasingly strained, scientists are turning their attention to an overlooked potential solution: brackish groundwater. These saline aquifers, when properly treated through desalination, could become a crucial supplementary water source in drought-prone regions. Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) is leading research efforts to unlock this resource, particularly in water-scarce Western Australia.

Brackish groundwater—water with salinity higher than freshwater but lower than seawater—has long been neglected due to its limited direct usability. However, as freshwater supplies dwindle, its strategic value is becoming apparent. Through desalination, brackish groundwater can be transformed into potable water suitable for drinking, agriculture, and industrial use.

Compared to freshwater sources, brackish groundwater is more widely distributed and abundant, particularly in arid and semi-arid regions. Yet its utilization faces significant challenges, including desalination costs, brine disposal, and environmental impacts.

CSIRO, in collaboration with Australia's National Water Grid Authority, is conducting comprehensive assessments of brackish groundwater resources in Western Australia. The project aims to:

• Compile existing data on brackish groundwater locations, quality, and reserves into a unified database
• Evaluate its potential as an alternative water source to enhance regional water security
• Assess existing and emerging desalination technologies along with brine management solutions
• Explore renewable energy options to power desalination facilities
• Engage stakeholders to align research with practical needs

The CSIRO team has collected extensive groundwater data from various Western Australian agencies. To address inconsistencies in data formats and standards, researchers developed a standardized processing workflow to create a unified, high-quality brackish groundwater database that will support future analysis and modeling.

Desalination remains the critical step in utilizing brackish groundwater. CSIRO is evaluating mainstream technologies including reverse osmosis (RO), electrodialysis (ED), multi-stage flash distillation (MSF), and multi-effect distillation (MED), along with emerging methods like forward osmosis (FO) and membrane distillation (MD). Key evaluation criteria include:

• Desalination efficiency (water output per unit of energy)
• Operational costs (equipment, maintenance, energy)
• Environmental impacts (brine discharge, chemical use)
• Technology maturity and reliability

Brine disposal presents another major challenge. Traditional methods like deep well injection, surface evaporation, or ocean discharge carry environmental risks. CSIRO is examining alternative approaches:

• Zero liquid discharge technologies that recover salts through evaporation or electrodialysis
• Resource recovery methods to extract valuable minerals (e.g., sodium chloride, magnesium chloride)
• Eco-friendly treatment using constructed wetlands or algae-based systems

Given desalination's high energy demands, CSIRO is investigating renewable energy integration to reduce costs and carbon emissions. The team is assessing Western Australia's solar and wind resources to determine their potential for powering desalination plants. Energy storage solutions like batteries or pumped hydro are also being explored to address renewable energy intermittency.

To ensure practical relevance, CSIRO has conducted extensive interviews with government agencies, industries, and community representatives in Western Australia. These discussions have clarified specific information needs regarding water demand, technology preferences, and policy expectations—insights that will guide the research direction.

Scheduled for completion in 2025, the project will deliver several key reports:

• Brackish groundwater resource maps for Western Australia
• Comprehensive evaluations of desalination and brine management technologies
• Feasibility studies on renewable energy-powered desalination
• Strategic recommendations for brackish groundwater development

These findings will provide critical technical support and policy guidance for Australia's water security strategy, potentially offering a sustainable solution to climate change-induced water scarcity.

Despite its promise, brackish groundwater utilization faces ongoing challenges:

• Technological limitations in desalination efficiency and cost
• Significant capital and operational expenses
• Environmental concerns regarding brine disposal
• Need for comprehensive regulatory frameworks

As technology advances, costs decrease, and policies mature, brackish groundwater could emerge as a vital freshwater supplement globally. CSIRO's foundational research positions Australia as a leader in developing this underutilized resource.