Preliminary interpretation of regolith landforms in the Booberoi to Quandialla Transect area, Central West NSW

Landholders in the Booberoi to Quandialla (B-Q) Transect area, central west NSW (Figure 1), have been concerned about an emerging dryland salinity problem since the late 1990's (Wooldridge pers. comm. 2002, Muller pers. comm. 2002). The presence of salt tolerant indicator species, waterlogging of soils and salinised land are becoming increasingly prevalent. The B-Q Transect lies within the Bland Creek catchment, a broad plain receiving sediments from rises and low hills located to the west, south and east. Stream flow across low angle alluvial fans and alluvial plains is intermittent, with most of the flow diverted into groundwater storage or lost to evaporation. Streams rarely flow into Lake Cowal to the north. As part of an approach to assist with hazard mitigation and land management, a preliminary interpretation of regolith-landforms was completed in the Back Creek and Quandialla areas. Compilation of these observations will result in the production of two detailed regolith-landform maps (1:10,000 scale). A more regional interpretation of regolithlandforms will culminate in the production of a regolith-landform map covering the BQ Transect (1:100,000 scale; Holzapfel & Moore 2002). In this study, the compilation of information from available spatial imagery (aerial photographs, topographic maps, a map illustrating reconstructed palaeotopography, a digital elevation model, a depth to basement map, Landsat imagery) and geophysical data (e.g. gamma-ray spectrometric data) complements a field-based regolith-landform analysis for the B-Q Transect. The preliminary evaluation of this information provides the context for ongoing regolith-landform mapping and geophysical interpretation of subsurface regolith configuration.