Electromagnetic ground conductivity surveys (EM surveys)

Electromagnetic ground conductivity surveys (EM surveys) are rapidly becoming an essential part of improving farm performance and future development. The EM-31 can be used to measure soil conductivity to a depth of up to 4 metres, which in turn provides information such as:

• Suitability of area for development
• Detecting soil salinity
• Location of groundwater monitoring devices
• Location of sites for soil sampling
• Suitability of sites for water storages
• Detection of seepage areas in drains, channels and storages
• Survey of embankments to assess compaction properties
• Collection of soil data for property and catchment planning
• Locating buried services, tanks, drums etc.
• Groundwater contamination and landfill studies as well as groundwater resource evaluations

The EM-31 is mounted on a 4-wheel motorbike and is equipped with GPS to enable accurate plotting of the machine position. The data is downloaded onto a computer and is used in conjunction with other data to produce an apparent conductivity map (sub-soil salinity map). Property boundaries and infrastructure details are added and the image can be overlayed onto a topographic map or aerial photograph to allow easier identification of problem areas. Using GPS co-ordinates from the map, particular problem areas or those requiring further investigation can be accurately located and monitored.