The Millennium drought and increased demand for water throughout Australia placed the water supply infrastructure of the day under considerable stress. In response the Bureau of Meteorology (BoM) was given the role of compiling and delivering Australia’s water information under the conditions set out in the Federal Water Act 2007.
To achieve this the BoM developed the Australian Water Resource Information System (AWRIS) and the National Groundwater Information System (NGIS) to support AWRIS. Functionality of the NGIS relied on updating and compiling state and territory groundwater databases. Completeness of the data contained in these databases was critical in facilitation data migration to the NGIS and groundwater bores in the Galilee Basin were identified as a priority target for addressing data gaps.
To achieve this a stratigraphic framework was created using published wireline log interpretation information to map structure surfaces for the Galilee Basin. Assessment of these structure surfaces and wireline log interpretations identified numerous inconsistencies with the established basin stratigraphy, particularly for some recent exploration wells. This is partially attributed to the large number of interpretation sources, exploration relevance and an incomplete understanding of facies variability.
Systematic reinterpretation of the published wireline log data has been undertaken to validate and reassign inconsistent interpretations in the eastern Galilee Basin. Reinterpretation has resulted in shifting formation top picks vertically by up to 300m in some instances, leading to significant modification of some structure contour surfaces.
Uncertainty over the internal architecture of the Galilee Basin has significant implications for understanding the hydrogeology of aquifer systems and springs in the basin. Reinterpretation by a single operator has assisted in removing some of this uncertainty and provided a consistent dataset of interpretations. This is significant with regard to assessing potential impacts that proposed coal mining activities will have on these aquifer systems and springs.