The dataset was derived by the Bioregional Assessment Programme from multiple source datasets. The source datasets are identified in the Lineage field in this metadata statement. The processes undertaken to produce this derived dataset are described in the History field in this metadata statement.
This dataset contains the aquifer assignment results for the Queensland part of the Clarence-Moreton Basin. The data were organized by hydrostratigraphic units. Assigning a bore to a specific aquifer is underpinned by the screened interval data and the aquifer boundaries. In many cases, it is impossible to assign the screened interval of a bore to a single aquifer as bores are either screened across different aquifers or there is insufficient information on stratigraphy and screened intervals. Bores were assigned to aquifers by comparing their screen intervals and depth with aquifer boundary data. The required information was extracted from the "Casing", "Aquifer", and "Stratigraphy" tables of the DNRM database.
The following steps were followed during the aquifer assignment:
Determine the screen interval of bores. Refer to theThe 'Casing' table contains the screen information for most bores in the database. The codes 'PERF', 'SCRN' and 'ENDD' in the column 'MATERIAL' indicate water entry locations. The code 'OPEN' indicates that a bore is uncased at some depths; if bores intersect an aquifer, then they are considered as water supply points. These codes were used to find the screen interval of a bore. When multiple screens exist, the bore is assumed to be screened across the entire length of the individual screens.
Determine the screen code. A bore may tap into an aquifer in four ways depending on its screen location in aquifers. Four codes (I, T, B and E) were used to indicate the different spatial relationship of a bore with its targeted aquifer. When screen information is lacking, bores with their lower ends located in an aquifer are assumed to be tapped to that aquifer and were assigned a screen code 'BOI'.
Filter bores for a specific area using a shape file or coordinates. If only a part of the aquifer is of interest, then the output bores can be filtered based on their locations.
Cross-check the final datasets against expert knowledge and spatial context of aquifers. As errors are common in such databases, some errors will still persist despite extensive data quality checks. However, such errors are often highlighted during data interpretation and visual representation and can subsequently be corrected through an iterative process.
Bioregional Assessment Programme (2014) CLM - Bore assignments QLD. Bioregional Assessment Derived Dataset. Viewed 28 September 2017, http://data.bioregionalassessments.gov.au/dataset/f8937dd8-b3a0-490e-a452-9dc56fe03914.
Derived From National Groundwater Information System (NGIS) v1.1