This Record describes the scope of the Great Artesian Basin (GAB) Automatic Data Processing System and outlines Stage 1(Data Transcription), and describes Stage 2, the checking of coded data. The subject of this record is the permanent storage, updating, and retrieval for processing of the data passed through Stages 1 and 2. The system described was developed for application to drill stem test (DST; Formation Test) data by G.E. Seidel (BMR) and then extended to suit the general GAB data by G. Krebs (BRGM).

The Steering Committee met on 3rd June in Canberra, and one of the matters agreed upon was that a field inspection of parts of the Basin should be held for geologists and hydrogeologists working on the Project, mainly to discuss stratigraphic correlation problems and, as well, hydrogeological aspects. Detailed planning for the field inspection, scheduled to begin early in October, and preceded by a one-day seminar, was completed. Work on a preliminary groundwater model of the whole Basin at the Geological Survey of Victoria has resulted in the development of a model to the operational stage. At BMR the compilation of available geological and geophysical data has continued steadily, and by the end of the year it is expected that all bores from which stratigraphic information has been obtained will have been plotted, and preparation of structure contour maps can begin.

Hydrogeological investigations in two pediplain basins at Lanyon, in the southern Tuggeranong Valley of the ACT, have identified areas which require remedial drainage for urban development. The rocks of the central Lanyon area consist of faulted Silurian dectic to rhyolitic ash-flow tuffs and interbedded sediments. Significant storage and transmission of groundwater occurs in well developed sets of open tensile fractures which formed in response to at least two reversals in regional principal stress directions during epeirogenic uplift and erosional unloading. Hydrogeological parameters measured in the field and laboratory included infiltration capacities, effective proosities, and hydraulic conductivities. From these data a predictive model for drain spacings is developed for all hydrogeological populations and for any given rainfall event. Constraints on locations of drains are also identified. It is recommended that a sufficient number of bores and piezometers be preserved after urban development to adequately assess changes to the groundwater regime.

Steady progress with the first phase of the Projectcontinued. Two highlights during the period described in this report are first, the design and implementation of a preliminary groundwater model of the whole Basin, and second, the field inspection of parts of the Basin in South Australia, Victoria and New South Wales undertaken by Project workers during October 1981 mainly to discuss stratigraphic correlation problems. The Steering Committee met in Sydney on 5th November, 1981.

In this study, 3D mapping using airborne electromagnetics (AEM) was used to site a monitoring bore network in the Darling River floodplain corridor. Pressure loggers were installed in over 40 bores to monitor groundwater levels primarily in the shallow unconfined Coonambidgal Formation aquifer, deeper (semi)confined Calivil Formation and confined Renmark Group aquifers. In 2010-11, the network provided the opportunity to monitor the groundwater response to flooding of the Darling River and the replenishment of the Menindee Lakes storages, following a period of prolonged drought. In this event, the Darling River at Menindee (Weir 32) rose from 1.59m in October 2010 and peaked at 7.16m in March 2011. A synchronous rise in groundwater levels varying between 0.5-3.4m was observed in the shallow unconfined aquifer near the river. Shallow groundwater levels also declined following the flood peak. Near-river groundwater levels in the Calivil aquifer rose between 0.2-1.3m and also by 4.0 m at a site near Lake Menindee. The latter confirms lake leakage into the aquifer at this particular site, as previously inferred by the AEM data. There was also a pressure response of 0.1-0.9m evident in certain Renmark aquifer bores near the river. The monitoring confirms the importance of episodic flood events to the recharge of the alluvial aquifers, as supported by groundwater chemistry and stable isotope data. Although some of the confined aquifer response may relate to transient hydraulic loading associated with the flood, the inference is that in places there is a degree of hydraulic connectivity between the aquifers.

This report covers the period during which a joint BMR-BRGM team prepared and started the computer based simulation of the Great Artesian Basin. Geological and hydrologic data were first collected from Federal and State authorities and then processed either manually or automatically. Processed data were then used to prepare input and calibration documents, including geological documents (geometry of system) and hydrologic documents (potentiometry). The first run of the mathematical model was obtained for the initial steady-state, and results appeared very encouraging.

Legacy product - no abstract available

Legacy product - no abstract available

Report on operational activities with data, analysis and interpretation for the Gawler - Eucla demonstration study site in South Australia

Geomorphic landscape features and associated surface materials are fundamental to groundwater recharge processes as they form the first layer through which surface water passes before it becomes groundwater. Different surface materials exhibit different water-holding capacity and hence permeability characteristics. In the Broken Hill Managed Aquifer Recharge project, surface-materials mapping in conjunction with geomorphic mapping, has assisted hydrogeological investigations, including recharge predictions, salinity hazard and the identification of potential infiltration basins. Prior to landform identification, LiDAR DEM data was levelled using trend surfaces to eliminate regional slope (~20m). As a consequence of this, an ArcGIS interactive contour tool could be used to identify specific breaks in elevation associated with landform features. Multivariate image analysis of elevation, high resolution SPOT and Landsat-derived wetness further enhanced the contrast between geomorphic elements to confirm mapping boundaries. While specific landforms can be characterised by particular surface materials, these sediments can vary within a single geomorphic feature. Consequently, SPOT multispectral satellite imagery was used to identify surface materials using principal component analysis and unsupervised classification. This approach generated 20 classes; each assigned a preliminary cover/landform attribute using SPOT imagery. Field data (surface and borehole sample, and observations at shallow pits) were used to refine the classification approach. Interactive mapping using a de-trended DEM provided a rapid, effective and accurate alternative to time consuming manual landform digitisation. The combination of these two new products - surface-materials and geomorphic maps - has assisted in the identification of potential recharge sites and naturally occurring infiltration sites.