Interpretation of geophysics for land management planning, Broomehill, Western Australia

Abstract

In 1995, the SALTMAP airborne electromagnetic (AEM) system was used to survey an area of around 50 000 hectares west of Broomehill in the southwest of Australia. It was the first practical application of a new AEM system developed specifically for mapping salinity. The project was a cooperative study between farmers in the area, World Geoscience Corporation, Western Australian Department of Agriculture, Water and Rivers Corporation, and the Cooperative Research Centre for Australian Mineral Exploration Technology (CRC-AMET). Previous AEM surveys in the southwest were carried out using INPUT and QUESTEM, but the results had not been incorporated into land management decisions. The aim of the Broomehill study was to develop the information products to enable farm plans to be created using information from the SALTMAP data. Inherent in the approach was the collection of a large range of complementary geospatial data using geophysical surveys, remote sensing, and other techniques, and incorporation of the data obtained into a geographic database. Various techniques were explored to ensure that as much information as possible from the geophysical surveys flowed through to the eventual land management plans. These techniques included manual interpretation of magnetic and radiometric data and the development of new smart data interpretation in GIS. Intermediate information sets such as ?Salt Hazard?and regolith maps guided the development of new farm plans to address land degradation in the area. Ten years later the Broomehill study remains as one of the few cases where farm plans were created based on a full range of geospatial data. This paper reports on the interpretation process which enabled an effective information transfer from geophysicist to farm planner and discusses how new interpretation techniques to define a new set of information could be used to guide land management decisions today.