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

The report and map synthesise groundwater studies made since 1954. Analysis of hydrogeological data defines the distribution of bore yield and groundwater chemistry for the regional aquifers of the ACT and environs. The aquifers are composed of fractured sedimentary, volcanic, and igneous rocks, and limited unconsolidated sediments in several different physiographic settings. Analysis of data, based on a three-way geological, 'broad-physiographic', and 'local-landform' subdivision scheme, shows that for bore yield, only the 'local-landform' parameter shows consistent relationships: in a given geomorphic unit, hill-crest bores always have lower yields than valley-floor or hill-slope bores. The highest mean yields are obtained from valley-floor bores tapping fractured aquifers in Ordovician to Early Silurian sedimentary rocks on the Cullarin Tableland. Groundwater yield is mostly obtained from the top 40 m of bores, and boreholes deeper than 100 m failed to improve yields. Groundwaters are generally dilute - less than 1200 mglL total dissolved salts. The variation in solute concentration is attributable to the geochemistry of the aquifer, the dissolution of soluble salts in the unsaturated zone of recharge areas, and the residence time of water in the aquifer. The better-quality water is found in aquifers that are geochemically stable, under high hydraulic gradients, close to recharge zones.

Final report on activities in the Gawler - Eucla region of South Australia for the Palaeovalley Groundwater Project

Final report on project activities in the Wilkinkarra demonstartion site for the Palaeovalley Groundwater project

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

In 2008, the Ord Irrigation Cooperative commissioned an airborne electromagnetics (AEM) survey of the ORIA Stage 1 and 2 areas to identify, quantify and understand any potential salinity risks in the current Ord irrigation area and the parts of the catchment that have been identified as potential future irrigation sites or potentially impacted by future irrigation. The project has been funded by the Australian and Western Australian governments through the National Action Plan for Salinity and Water Quality. Geoscience Australia and CSIRO were contracted to carry out the analysis and interpretation of the AEM dataset, and produce customised interpretation products. Some of the more specific questions it was hoped to address included: - Are we at risk of salinity in the Ord Catchment? - If so what areas are at the greatest risk? - Where can we target management to reduce this risk? - How can we plan future development to minimise salinity risk and maximise longevity of projects? The areas surveyed include the current Stage 1 Ord Irrigation Area, Stage 2 Irrigation Area (including Weaber and Knox Plains and Carlton Hill - Parry's Lagoon Conservation Area. The inclusion of undeveloped land in this survey is because the technology provides the opportunity to ensure any future irrigation development is guided by the best available information on soil type, aquifer quality and location and salinity risk. The information generated by this project will be publicly available and can be used for such things as: - Identifying leaky areas in the landscape that may require more concentrated management or can be designated for more suitable land use; - Where salt is stored in the landscape and at what depth, and where in the landscape it may influence plant growth; - Provide new constraints on the connectivity of aquifer systems in 3D across the ORIA and enable the construction of more realistic hydrogeological models to improve surface and groundwater management.

In 2008, the Ord Irrigation Cooperative commissioned an airborne electromagnetics (AEM) survey of the ORIA Stage 1 and 2 areas to identify, quantify and understand any potential salinity risks in the current Ord irrigation area and the parts of the catchment that have been identified as potential future irrigation sites or potentially impacted by future irrigation. The project has been funded by the Australian and Western Australian governments through the National Action Plan for Salinity and Water Quality. Geoscience Australia and CSIRO were contracted to carry out the analysis and interpretation of the AEM dataset, and produce customised interpretation products. Some of the more specific questions it was hoped to address included: - Are we at risk of salinity in the Ord Catchment? - If so what areas are at the greatest risk? - Where can we target management to reduce this risk? - How can we plan future development to minimise salinity risk and maximise longevity of projects? The areas surveyed include the current Stage 1 Ord Irrigation Area, Stage 2 Irrigation Area (including Weaber and Knox Plains and Carlton Hill - Parry's Lagoon Conservation Area. The inclusion of undeveloped land in this survey is because the technology provides the opportunity to ensure any future irrigation development is guided by the best available information on soil type, aquifer quality and location and salinity risk. The information generated by this project will be publicly available and can be used for such things as: - Identifying leaky areas in the landscape that may require more concentrated management or can be designated for more suitable land use; - Where salt is stored in the landscape and at what depth, and where in the landscape it may influence plant growth; - Provide new constraints on the connectivity of aquifer systems in 3D across the ORIA and enable the construction of more realistic hydrogeological models to improve surface and groundwater management.

In 2008, the Ord Irrigation Cooperative commissioned an airborne electromagnetics (AEM) survey of the ORIA Stage 1 and 2 areas to identify, quantify and understand any potential salinity risks in the current Ord irrigation area and the parts of the catchment that have been identified as potential future irrigation sites or potentially impacted by future irrigation. The project has been funded by the Australian and Western Australian governments through the National Action Plan for Salinity and Water Quality. Geoscience Australia and CSIRO were contracted to carry out the analysis and interpretation of the AEM dataset, and produce customised interpretation products. Some of the more specific questions it was hoped to address included: - Are we at risk of salinity in the Ord Catchment? - If so what areas are at the greatest risk? - Where can we target management to reduce this risk? - How can we plan future development to minimise salinity risk and maximise longevity of projects? The areas surveyed include the current Stage 1 Ord Irrigation Area, Stage 2 Irrigation Area (including Weaber and Knox Plains and Carlton Hill - Parry's Lagoon Conservation Area. The inclusion of undeveloped land in this survey is because the technology provides the opportunity to ensure any future irrigation development is guided by the best available information on soil type, aquifer quality and location and salinity risk. The information generated by this project will be publicly available and can be used for such things as: - Identifying leaky areas in the landscape that may require more concentrated management or can be designated for more suitable land use; - Where salt is stored in the landscape and at what depth, and where in the landscape it may influence plant growth; - Provide new constraints on the connectivity of aquifer systems in 3D across the ORIA and enable the construction of more realistic hydrogeological models to improve surface and groundwater management.

This GA Record report is one of a series of 4 reports undertaken by the GA Groundwater Group under the National Collaboration Framework Project Agreement with the Office of Water Science (in the Department of the Environment). The report was originally submitted to the OWS in July 2013, and subsequently reviewed by the Victorian and South Australian governments. The Otway Basin is a priority coal-bearing sedimentary basin that is not currently slated for Bioregional Assessment programme research in the initial tranche of work.

Poster prepared for International Association of Hydrogeologists Congress 2013 Surface-groundwater interactions are often poorly understood. This is particularly true of many floodplain landscapes in Australia, where there is limited mapping of recharge and discharge zones along the major river systems, and only generalised quantification of hydrological fluxes based on widely spaced surface gauging stations. This is compounded by a lack of temporal data, with poor understanding of how surface-groundwater interactions change under different rainfall, river flow and flood regimes. In this study, high resolution LiDAR, in-river sonar, and airborne electromagnetic (AEM) datasets (validated by drilling) have been integrated to produce detailed 3-dimensional mapping that combines surface geomorphology and hydrogeology. This mapping enables potential recharge zones in the river and adjacent landscape to be identified and assessed under different flow regimes. These potential recharge zones and groundwater flow pathways were then compared against the spatial distribution of discontinuities in near-surface and deeper aquitard layers derived from the AEM interpretation. These 3D mapping constructs provide a framework for considering groundwater processes. Hydrochemistry data, allied with hydraulic data from a bore monitoring network, demonstrate the importance of recharge during significant flood events. In many places, the AEM data also affirm the spatial association between fresher groundwater resources and sites of river and floodplain leakage. At a more localised scale, hydrogeochemical data allows discrimination of lateral and vertical fluxes. Overall, this integrated approach provides an important conceptual framework to constrain hydrogeological modelling, and assessments of sustainable yield. The constructs are also invaluable in targeting and assessing managed aquifer recharge (MAR) options.