Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Final demonstration site report for the Murchison region completed as part of the Palaeovalley Groundwater Project

Legacy product - no abstract available

The final technical report for the Ti-Tree Basin Demonstration site for work undertaken as part of the Palaeovalley Groundwater Project

Final report on project activities for the Paterson demonstration site for the Palaeovalley Groundwater Project

Introduction Developing predictive numerical models of hydrogeochemical systems requires an understanding of the physical and chemical processes affecting the composition of the water. Physical processes like mixing and evaporation can be reasonably well defined using the chemical data but redox sensitive chemical processes are more difficult to quantify. Applying the isotope chemistry of dissolved sulfate to characterise and even quantify these redox processes enhances the capabilities of numerical modelling, in particular those associated with acid mine drainage, acid sulfate soils and sulfide mineral exploration. This work describes how the stable isotopes of sulfur and oxygen in sulfate can be used to better characterise geochemical processees and thereby improve reactive transport models. Discussion Groundwater, pore water and surface water from a number of areas in Australia have been used to determine the sources of sulfur in acid sulfate susceptable systems. Several trends become apparent, sulfate reduction, and sulfide oxidation commonly dominate the chemical processes controlling sulfur in a groundwater system. Bacterial sulfate reduction (BSR) can be recognised by the affect on the 34S and 18O of sulfate. Both ratios increase as the lighter isotope is removed through dissimilatory bacterial reduction, leaving behind the heavier isotopes. Oxidation of sulfides occurs through 2 processes, one involving molecular oxygen (O2) and the other involving oxidised iron (Fe3+). The different pathways result in considerable differences in the oxygen isotopic composition of the product sulfate. Surface water and some groundwater from the Loveday basin in SA show evidence of evaporation and BSR while the near surface pore waters, although similarly evaporated, contain sulfate that predominantly originates from sulfide oxidation. Sulfate in groundwater from several other regions has stable isotopic compositions that indicate sulfide oxidation involving either the O2 or the Fe3+ pathways. The implications of are that the sulfate history can be understood through isotopic analysis and that this can be used in geochemical models to trace

The Sustainable Management of Coastal Groundwater Resources (SMCGR) project aims to improve the management of groundwater in coastal dune aquifers, which is used to supply water for coastal communities in the Mid North Coast region. There is increasing pressure on groundwater resources from expanding urbanisation and tourism in this region, which has made sustainable management of existing groundwater supplies an important issue for coastal communities and councils. Over extraction from groundwater systems can affect the water available for ecosystems, which may be dependent on shallow groundwater resources. Withdrawal of groundwater resources in excess of the sustainable yield may also result in fresh water resources being degraded by seawater intrusion or by upcoming from underlying saline water bodies.

Technical report on operational activities, including data, analysis and interpretation, for the Paterson demonstration study site conducted for the Palaeovalley Groundwater Project. This work was funded by the National Water Commission and managed by Geoscience Australia.