Finding new groundwater supplies - western NSW
This project is part of the NSW Government’s response to drought. The Future Ready Regions strategy was released in June 2021, outlining the NSW Government’s commitment to building strong communities and diversified regional economies.
The NSW Government has outlined several key commitments to develop sustainable, secure and healthy water resources including fast-tracking investigations into new groundwater supplies.
The Geological Survey of NSW is investigating alternative groundwater resources to help ‘drought proof’ western NSW. Such supplies could be used in times of drought, for agriculture and industry to reduce dependence on current potable water supplies. Newly discovered groundwater resources are likely to be deeper than those currently being used and may require treatment for some uses.
Two areas have been chosen to investigate new groundwater resources:
- the Yathong–Ivanhoe Trough
- the Bancannia Trough
The Yathong–Ivanhoe Trough is south of Cobar, where the local economy is based on agriculture (mainly grazing) and mining (gold, silver, copper, lead and zinc). The domestic water supply is being upgraded, with new pump stations to be added to existing infrastructure. Water is currently piped over 125 km from Nyngan.
The Bancannia Trough is northeast of Broken Hill, which is well supplied with water using a 270 km pipeline from near Wentworth on the Murray River. The Menindee Lakes and other water infrastructure lie to the southeast of Broken Hill.
Finding additional groundwater resources in the northwest corner of the state will help to ensure consistent supply during times of drought, providing water security for isolated communities, pastoralists and businesses there. This will reduce the usage of potable water for activities that don’t require a high water quality.
Water exploration activities
Groundwater resources will be identified by creating 3D geological models of the Yathong–Ivanhoe Trough and Bancannia Trough.
Field mapping
To inform the 3D models, geological field mapping is being done to improve understanding of the surface geology. This is a low impact activity, with descriptions of outcrops recorded and some hand specimens taken for microscopic examination. Much of the two targeted areas has not been mapped in detail. Various outcrops visible on satellite imagery have been chosen for investigation, provided access is granted.
Observations and measurements will be available online through MinView in the Geological field observations layer. Once surface mapping is completed, a summary report will be added to the digital repository of geological information, DIGS. This is a publicly available and searchable library of geological information about NSW.
Seismic surveys
A seismic survey has been planned to further understand the Yathong–Ivanhoe Trough. This is a type of ground-based geophysical survey that is low impact. Seismic surveys help to build an image of the geology under the ground. Vehicles move along a route and generate energy vibrations that penetrate the ground and bounce off buried rocks. The reflected energy is recorded by a series of sensors.
Following roads, fire trails and existing farm tracks, no clearing will be necessary for the survey. Disturbance to traffic, residents, livestock and wildlife will be minimal. Two or 3 small trucks will transfer sound energy to the ground and will be supported by small vehicles for equipment, communication and personnel. Once the survey is complete, all equipment is removed from the site.
The survey of 3 lines is planned for the northern part of the Yathong–Ivanhoe Trough and eastwards to the Cobar Basin, and will take about 6 weeks to complete, weather permitting. Data over the Cobar Basin will be used for mineral mapping as part of another project.
Planned possible seismic routes are in blue and follow roads or established tracks.
Drilling for groundwater
Five drillholes for water monitoring and sampling will be installed in the Bancannia Trough. Analysis of the water will determine its salinity, the abundance of naturally occurring elements and the age of the water. Results will be used to determine if the water can be used and for what purposes (for example livestock or road maintenance).
Another drilling project in central NSW, near the proposed seismic lines above, will assess the area for carbon storage and geothermal energy potential. Data from the carbon storage drilling project will be used in the groundwater project and help geoscientists generate geological models.
Airborne surveys
Two airborne surveys are planned for the Yathong area: an airborne electromagnetic survey (AEM) and an airborne magnetic and radiometric survey (AMR). Both surveys will be done in collaboration with Geoscience Australia. The surveys are proposed for the second quarter of 2023.
Map showing proposed airborne survey areas:
An interactive map of the survey areas is available on MinView.
Weekly updates on survey progress will be available on Minview.
A comprehensive community engagement plan will inform the community and stakeholders about the surveys.
The AMR and AEM data will be made publicly available after they are processed. If you wish to receive the data please contact geophysics.products@regional.nsw.gov.au
Yathong airborne elecromagnetic (AEM) survey
The AEM survey will measure the natural electrical properties of rocks and soil up to 400 m deep. These properties vary depending on the type of rocks and soil, and the water content, and salinity. The data collected will help us to understand the geology and groundwater resources of the area, assisting the government and farmers to make informed decisions.
A specialist and experienced contractor will undertake the survey. An aircraft will fly at a height of between 60 and 120 m, along east-west lines. The lines will be about 30 to 60 km long and up to 2.5 km apart. The plane will fly higher over towns and buildings and try to avoid groups of stock.
For more information on AEM surveys see our fact sheet and videos.
Yathong airborne magnetic and radiometric (AMR) survey
An AMR survey measures small variations in Earth's magnetic field caused by different rock types and the naturally occurring radiation coming from the ground. AMR surveys use passive sensors, are non-invasive and do not disturb the ground. For more information on AMR surveys see our fact sheet.
This survey will increase the resolution of our existing AMR coverage, and will improve our knowledge of the rocks, faults, soils and groundwater of the area.
A specialised and experienced contractor will undertake the survey. A plane will fly 60 m above the ground along east‒west-oriented lines, that are 60 to 90 km long and 200 m apart. Some lines will be flown north-south to 'tie' the data together. The plane will fly higher over towns and buildings and try to avoid groups of stock.