This is the third quarterly report on the progress of the Murray Basin Hydrogeological Project. Participating organisations are the Geological Survey of New South Wales, the Water Resources Commission of New South Wales, the Geological Survey of Victoria, the State Rivers and Water Supply Commission of Victoria, the Department of Mines and Energy of South Australia, and the Bureau of Mineral Resources.

Sonic drilling is a relatively new technology that has been used successfully to obtain relatively uncontaminated and undisturbed continuous core samples with excellent recovery rates to depths of 206m in fluvio-lacustrine sediments of the Darling River floodplain in western NSW. However, there are limitations with the method. Sands, in particular, are disturbed when they are vibrated out of the core barrel into the flexible plastic sampling tube. There can be changes to moisture content, pore fluid chemistry and sediment mineralogy on exposure to the atmosphere, even when the samples are processed and analysed soon after collection. The option exists during drilling to encapsulate the core in rigid polycarbonate lexan tubes. Although this increases costs and reduces drilling rates, atmospheric exposure of the core during drilling is reduced to the ends of the lexan tubes before being capped. In addition, the tubes can be purged with an inert gas such as argon. Lexan coring is best carried out below the watertable as the heat from drilling dry clays can cause the polycarbonate to melt. In this study, lexan-encapsulated core samples were obtained for analysis of pore fluids (salinity, major ions, trace metals, stable isotopes) and mineral phases (XRD, XRF). The major advantage was the recovery of encapsulated and intact sediment intervals for determining hydraulic conductivity by centrifuge or falling head permeameter methods. By painting some tubes black, sand samples were also successfully obtained for optically stimulated luminescence (OSL) dating. Alternatively, opaque black lexan can be made to order by the supplier.

During the period under review, progress with the first phase of the Project continued. Two items of interest, described in more detail in this report, are the start of IGCP Project 184 'Palaeohydrology of low latitude deserts', and Bureau of Mineral Resources field work in the northwest New South Wales part of the Basin with the objective of adding more detail to the surface geology as depicted on existing 1:500 000 scale maps. The Steering Committee met in Melbourne on 10 June.

Traditional aquifer tests are an expensive and time-consuming method for obtaining hydraulic information. Furthermore, in many environments, it is becoming increasingly difficult to obtain environmental clearances to dispose produced waters. In this study, the Nuclear Magnetic Resonance (NMR) method was evaluated to provide data on hydraulic conductivities (K) and transmissivities (T) of sediments within the Darling River Floodplain, Australia. NMR data were acquired every 0.5 m using a slim-hole logging system in 26 sonic cored wells to a depth of ~70 m. KNMR can be estimated from the NMR measurements using the Schlumberger-Doll Research Equation: KNMR = C x ?2 x T2ML2, where is the NMR effective porosity, T2ML is the logarithmic mean of the T2 distributions, and C is a formation factor related to tortuosity. Prior to the calculation of the KNMR, the NMR data were classified into five hydraulic classes ranging from clay to gravely-coarse sand using the core, geophysical, mineralogical, and hyperspectral logs. In selected zones aquifer tests were conducted to provide constraints on the K and T of the formations. Least-squares inversion was used to solve for the optimum C values for each of the hydraulic classes versus the aquifer test obtained T. Comparisons between laboratory permeameter measurements and KNMR indicated correspondence within two orders of magnitude. The borehole NMR method provides a rapid way of estimating the near continuous variations in K through a sedimentary sequence, while also providing useful estimates of K at a scale not achievable using traditional aquifer testing methods.

This GA Professional Opinion report is one of a series of 4 reports being undertaken by the GA Groundwater Group under the National Collaboration Framework Project Agreement with the Office of Water Science (in DSEWPaC). The Maryborough Basin in central-eastern Queensland is a priority coal-bearing sedimentary basin that is not currently slated for Bioregional Assessment.

At the request of the National Capital Development Commission (NCDC) a hydrogeological investigation of the Hume Industrial Estate, ACT, including areas fro future possible development, was undertaken March-April 1983. The location of the Estate is shown in Figure1. The object of the investigation was to provide detailed information on the geological and hydrogeological characteristics of the Estate, particularly in terms of susceptibility to possible groundwater pollution from industires using hazardous or toxic chemicals.

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.

This interim report documents progress against the Project Plan and Project Scope for the Broken Hill Managed Aquifer Recharge Project, Phase 1. Specifically, the report covers: (1) the investigative methodology being used for the Phase 1 Risk Assessment (2) details of key data (assessed/) obtained to meet the project outcomes (3) indicative findings to date. An assessment of pre-existing geospatial, hydrogeological, geophysical and borehole data in the Broken Hill area has identified 6 potential priority areas for further investigation. Initial investigations in these 6 priority areas support the general findings and recommendations of Lewis et al. (2008), and re-affirm the view that there is significant potential to develop options for the Broken Hill Managed Aquifer Recharge (BHMAR) project. In summary, the project is on track to deliver on the Phase 1 Risk Assessment as scheduled (by end February 2009).

Under the Community Stream Sampling and Salinity Mapping Project, the Australian Government through the Department of Agriculture, Fisheries and Forestry and the Department of Environment and Heritage, acting through Bureau of Rural Sciences, funded an airborne electromagnetic (AEM) survey to provide information in relation to land use questions in selected areas along the River Murray Corridor (RMC). The proposed study areas and major land use issues were identified by the RMC Reference Group at its inception meeting on 26th July, 2006. This report has been prepared to facilitate recommendations on the Lindsay-Walppolla study area. The work was developed in consultation with the RMC Technical Working Group (TWG) to provide a basis for the RMC Reference Group and other stake holders to understand the value and application of AEM data to the study area. This understanding, combined with the Reference Group's assessment of the final results and taking in account policy and land management issues, will enable the Reference Group to make recommendations to the Australian Government. The report is based on an assessment the application of AEM to the Reference Group's land management issues as specified by the TWG at its meeting on 16th August 2006 and out of session.

Legacy product - no abstract available