Canning Basin
The Canning Basin located in north-west WA has an onshore extent of about 530,000 km2 and is Australia’s second-largest sedimentary basin (after the Great Artesian Basin). It hosts significantly thick and regionally extensive stacked sandstone, shale and mudstone strata, offering highly prospective groundwater, minerals, oil and gas resources. Groundwater resources across the basin have been progressively developed to support irrigated agriculture, town and community water supplies, mineral and energy operations, and the basin’s road network. These resources are one of the primary pillars of the basin’s economy and also support a thriving tourism industry and a diverse range of ecologically and culturally significant water-dependent assets. Groundwater resources of the basin are managed within numerous groundwater management areas (GMAs) and sub areas (GMsAs).
Major groundwater resources of the Canning Basin that are reasonably well characterised occur in extensive and productive aquifers hosted in several hydrogeological units that outcrop and subcrop along the north and west of the basin. These include the interconnected Grant Group and Poole Sandstone, Devonian reef complex, and the Wallal, Erskine and Broome sandstones.
Minor or partial aquifers also occur in a variety of hydrogeological units, including the Liveringa Group, the Fitzroy, Margaret, May and Meda alluvium, several palaeovalleys (Cudalgarra, Mandora, Oakover, Paraku, Percival–Canning and Wallal), and various fractured rock aquifers.
Brackish groundwater in the Canning Basin
Brackish groundwater is a promising source of water for consumptive use and was defined in the project by salinity levels ranging from 1,000 to 15,000 mg/L of total dissolved solids (TDS). The project classified Western Australia’s brackish groundwater resources into different categories based on their salinity levels:
- Brackish: aquifers or their section within a Groundwater Management Area (GMA) where 100% of bores produce brackish groundwater.
- Mainly brackish: aquifers or their section within a Groundwater Management Area (GMA) where over 50% of bores produce brackish groundwater.
- Some brackish: aquifers or their section within GMA where 25% to 50% of the bores produce brackish groundwater.
Groundwater resources of the Canning Basin have been characterised across the north and west of the basin, though the central, eastern and southern parts of the basin are data sparse and poorly characterised. Currently, its estimated that about 350 GL of groundwater resources have been characterised across the north and west of the basin. Most of these groundwater resources are hosted in the regional-scale aquifers of the interconnected Grant Group and Poole Sandstone, and the Broome and Wallal sandstones, and some hosted in the intermediate and local-scale aquifers of Devonian reef complex and Liveringa Group respectively.
The majority of groundwater hosted in the extensive and productive regional aquifers is either fresh to marginal away from the freshwater – saltwater interface along the coast, though there is some brackish groundwater in places.
Aquifers hosting either mainly brackish groundwater, or some brackish groundwater and with potential water available for consumptive use, includes the southern part of the Broome Sandstone Aquifer, and the Liveringa Group aquifers.
Currently, it is estimated that there is about 19 GL/year of brackish groundwater, or about 5% of the basin’s charactersied groundwater resources, potentially available for consumptive use. This includes 9.9. GL/year from the Broome Sandstone Aquifer in the West Canning GMsA, and 9.3 GL/year from the minor or partial aquifers hosted in the Liveringa Group across the Canning–Kimberley GMsA in the north of the Canning Basin. However, any future allocation of brackish groundwater resources is likely to depend on community and government acceptance of changes in groundwater resource availability and the approval of groundwater licences.
Explore these aquifers here:
Desalintion and brine management
The Broome Sandstone Aquifer in the West Canning GMsA and the Liveringa Group aquifers in the Canning–Kimberley GMsA offer the most promising opportunities for brackish groundwater desalination. However, elevated concentrations of (Si) in the Broome Sandstone Aquifer are likely to require consideration in terms of pre-treatment prior to desalination. While for the Liveringa Group aquifers, elevated concentrations of alkalinity (HCO3–) and sulfate (SO42-) will require consideration in terms of pre-treatment prior to desalination.
Brine management options associated with brackish groundwater development of the Broome Sandstone Aquifer and Liveringa Group aquifers differ based on the different nature of the aquifers and their potential suitability for a variety of different uses. Use of evaporation ponds and encapsulation infrastructure are likely to be suitable for any potential development of both aquifers subject to approval. Other brine management options such as aquaculture, algal horticulture, energy storage and production will depend upon the nature of any development by a potential proponent, the amount and composition of the brine and the approval of certain practices.
Renewable energy
The hybrid renewable energy cost for desalination of brackish groundwater is lower than the WA average in the West Canning Basin compared to the other analysed regions. This indicates that renewable energy resources are higher in this region. Depending on the operation of the desalination plant, the least-cost site is 33-38% of the cost of the mean sites and the most expensive site is 23-28% more expensive than the mean sites. Geographically, the cost of energy is slightly lower along the coast where there are greater wind resources but variable elsewhere.