Burnett, Kolan, Baffle and Burrum Basins Land Degradtion Study

This study set the basis for a Water Quality Improvement Plan for the Burnett, Kolan, Baffle and Burrum River basins. Grazing is the dominant land use in these catchments but baseline information on the current condition of these grazing lands was very sparse.

The project used LANDSAT 5 Thematic Mapper satellite imagery to provide coverage of the catchments during September 2004 and May 2005. A supervised classification process was applied to the May 2005 imagery. This involved visually selecting sample areas (training regions) representing the major types of land cover within the region. The classification process then allocated pixels within the imagery into units representing each training region. Extensive ground-truthing was undertaken to verify training region selection, subsequent regional classification and to correlate land degradation with cover.

Grassland areas were further subdivided into four cover classes that closely reflect the Queensland DPI Pasture Condition Classes.

Rainforest, scrub, open forest, woodlands and shrubby woodlands were not the focus of this study and were combined with regrowth, forestry plantations and orchards into a single mapping unit of standing timber.

Enhanced colour image	Classified image

The difference in land cover between September 2004 and May 2005 was used to highlight cropping areas, enabling crop stubble and pastures to be separated.

Highlighted cropping areas

The land cover classification was considered sufficiently accurate for 1:50 000 subcatchment planning and thus suitable for identifying priority subcatchments. The data was subsequently used within a landscape precincts approach to relate the distribution of land cover and land degradation to various combinations of biophysical and socioeconomic factors and land use controls.

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