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Groundwater is an essential part of life, especially in Australia. Whether it’s for urban planning, agriculture, mining, industrial or even recreational use, the success of many projects depends on securing a suitable, reliable and cost- effective source of water.

Finding that source of water is where SGC can help! SGC has experience in all aspects of geophysics including magnetics, gravity, radiometrics, satellite spectrometry, electrical, electromagnetic, nuclear magnetic resonance, and seismic survey methods.

SGC can design and manage your survey, process and interpret the data, and identify and prioritise targets for drilling. SGC’s team of professional geoscientists will work closely with you to ensure the optimal result to maximise the benefit to your project.

The SGC group has considerable experience working on groundwater projects all over the world, including Australia, Tanzania, Mozambique, Madagascar and Sri Lanka.

GEOPHYSICS FOR GROUNDWATER EXPLORATION

Where should we drill?Groundwater resources that are necessary for industrial or agricultural operations typically come from a nearby borefield. Our solutions are aimed at improving the drillhole targeting success rate and thereby reducing overall drilling costs.

Airborne surveys can quickly cover large areas to map entire regions or groundwater prospects of interest. AIRBORNE MAGNETIC surveys are an excellent starting point (many datasets are free). With correct processing and skillful interpretation, subtle features in the data can be identified as geological structures with potential for groundwater presence. AIRBORNE ELECTROMAGNETIC surveys can efficiently map the paths of paleochannels, depth to groundwater and the freshwater-saltwater interface.

To target groundwater resources on smaller scales, ground-based methods can provide the detailed information needed to inform decision making. GRAVITY, PASSIVE SEISMIC, and ELECTROMAGNETIC surveys are efficient and cost-effective at mapping paleochannel depth and depth to basement. ELECTRICAL RESISTIVITY and ELECTROMAGNETIC surveys are used to find fresh water and depth to groundwater. NUCLEAR MAGNETIC RESONANCE is used when information on formation porosity and bore yield is critical.

Examples of mapping and characterising paleochannels using A) airborne EM plan view and section views B) ground-based EM C) ground-based gravity and D) passive seismics

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B

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FOR FURTHER INFORMATION PLEASE VISIT OUR WEBSITE Southern Geoscience Consultants - HEAD OFFICE39 Richardson Street, West Perth, WA 6005 AustraliaT: +61 (8) 6254 5000 E: geophysics@sgc.com.au

Southern Geoscience Consultants - AMERICASSuite 401, 15 Toronto Street, Toronto, Ontario, M5C 2E3, CanadaT: +1 (416) 407 6355 E: geophysics@sgc.com.au

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COASTAL AQUIFERS• Airborne or ground-based ELECTROMAGNETIC or ELECTRICAL

RESISTIVITY surveys are highly effective in mapping the saline water interface and zones of fresh water.

• In the adjacent example from Exmouth, WA, the fresh-to-saltwater transition has been effectively mapped using AIRBORNE ELECTROMAGNETICS, where previously very little was known about the extent of the saline water interface.

• Excellent targets for increased extraction have been identified and include zones where freshwater is thicker than was known, and existing bores located further west of the saltwater interface than was realised.

• A source of good quality water is important to local communities, farmers, and industrial operations. However, over-extraction and contamination can affect water quality.

• Targeted surveys using ELECTROMAGNETICS or ELECTRICAL RESISTIVITY can often identify the source of salinity or pollution and can map zones of better quality groundwater.

• In the example right from southeast Western Australia, ground-based TIME-DOMAIN ELECTROMAGNETICS was used to identify better quality groundwater adjacent to existing bores where saline intrusion had developed.

FRACTURED ROCK AQUIFERS• In the crystalline basement rock, groundwater can be stored in faults, fractures and joints.

Their yield is extremely variable, and is dependent on the distribution of major fractures and rock types, as well as recharge potential.

• AIRBORNE MAGNETIC surveys can be used to identify faults and fractures in the basement, thus greatly improving the success rate of groundwater exploration.

• AIRBORNE RADIOMETRIC surveys can aid in identification of rock types or soils, which, when combined with knowledge of their competencies and porosities, can further refine groundwater targets.

• Interpretation of these detailed airborne datasets, in conjunction with elevation data, geological mapping and existing water bore information, can lead to improved targeting for water-bearing structures and assessing their prospectivity.

Airborne magnetics: 2nd vertical derivative (grey scale) with structural interpretation

WATER QUALITY / BOREFIELD SALINISATION