Airborne Geophysics Provides Improved Spatial Information for the Management of Dryland Salinity

Abstract

Biophysical information forms the technical base for farm planning and landscape management. Such information is required at spatial scales which are suited to the application of the user. Within the past five years, two catchments in the South West of Western Australia were studied to assess the contribution that airborne geophysics data (specifically electromagnetics, magnetics and radiometrics) makes, in conjunction with existing datasets, to the understanding and management of land degradation, principally dryland salinity. The Towerrinning (30 000 ha) and Toolibin surveys (70 000 ha) are located in areas of intensely weathered Archaean granitic terrain in a low gradient landscape. At both sites over 80 bores were drilled and extensive ground geophysical surveys were undertaken as a part of a formal process of calibration and landscape investigation.

Our analysis suggests that the airborne systems used have the ability to map: geologic structures critical for the management of land and water salinity at a local scale; farm-scale changes in regolith salt-store and groundwater salinity, and local and regional-scaled patterns of soils. When combined they provide for better salinity hazard assessment and management decision making, not previously available from any other data sources. Finally, when compiled in a simple to use GIS format, a wide array of people may easily access and use the data.