The Ord Valley Airborne Electromagnetics (AEM) Interpretation Project was co-funded by the Australian Government and the Western Australian Government to provide information in relation to salinity and groundwater management in the Ord River Irrigation Area (ORIA). The project area covers the existing ORIA Stage 1, and the ORIA Stage 2 areas earmarked for irrigation extension. The project included the acquisition of 5,936 line km of AEM data acquired using the SKYTEM time domain system.
The Ord Valley Airborne Electromagnetics (AEM) Interpretation Project was co-funded by the Australian Government and the Western Australian Government to provide information in relation to salinity and groundwater management in the Ord River Irrigation Area (ORIA). The project area covers the existing ORIA Stage 1, and the ORIA Stage 2 areas earmarked for irrigation extension. The project included the acquisition of 5,936 line km of AEM data acquired using the SKYTEM time domain system.The SkyTEM AEM system successfully mapped key elements of the hydrogeological system over most of the project area. In general terms, the modelled conductivity structure defined from the SkyTEM smooth model Layered Constrained Inversion (LCI) matches that defined from available bore data exceptionally well, with an adjusted R2 = 0.843 determined.Overall, the AEM survey has provided enhanced spatial delineation of key elements of the hydrostratigraphy in 3D, including sand- and gravel-filled palaeochannels, and clay and silt distribution, as well as salt stores and groundwater quality. The study found significant areas of high salinity hazard in several of the Stage 2 areas earmarked for irrigation development, with salt stores and groundwater salinity often higher than in the Stage 1 areas.This study has demonstrated the effective role that AEM methods can play as part of a ‘hydrogeological systems’ approach to the management of groundwater in existing and future irrigation developments in Northern Australia. The study has also demonstrated the potential for ‘calibrated’ AEM systems and Fast Approximate Inversion software to significantly shorten AEM project timelines.Engineering and Community• Geophysics role in increasing innovative engineering opportunities• Better delineating groundwater resources• Case histories in environmental geophysics37C11LUI7
Abstract Celtic interest in groundwater has continued to the modern era in much of Scotland and Ireland, despite abundant good quality surface waters. Groundwater investigation in the 19th and 20th centuries was prompted by the need to remove water from mine workings in Scotland and to provide water for industry in the Midland Valley of Scotland and the Lagan Valley in the north of Ireland. Little development took place in the south of Ireland until relatively recently. Champions of groundwater investigation include the venerable Scottish geologists Ben Peach and John Horne, as well as lesser known advocates of hydrogeology such as John Jerome Hartley in Ireland. These workers were supported by numerous people directly and indirectly involved with developing the understanding of the groundwater resources of Scotland and Ireland.
To improve on earlier hydrogeological models and to better manage the River Murray floodplain environment and water resources from salinity and irrigation impacts, stakeholders in the New South Wales and Victorian Mallee worked with project scientists to identify hydrogeological parameters that might be collected from existing data sets to help resolve land and water management issues (Lawrie at al., 2008). Several areas where improved information were identified, including the extent and thickness of the river flush zone, salt stores in both the unsaturated and saturated zones, and the thickness, extent and depth to the top of the Blanchetown Clay and other clay units across the floodplain and its adjacent uplands. Previous AEM-based studies have demonstrated the potential for these data to provide high geospatial resolution of key elements of the hydrogeological system (Walker et al., 2004). An airborne electromagnetic (AEM) survey was flown in early 2007 along a 450 km stretch of the Murray River and its floodplains in Victoria from the South Australian-Victorian border to Gunbower. The data were acquired under the auspices of the Australian Government?s Community Stream Sampling and Salinity Mapping Project, and were managed by the Bureau of Rural Sciences. This survey utilised a Fugro RESOLVE frequency domain system, with flight lines at 200m line spacing, and oriented at a high angle to the river corridor. RESOLVE is a six frequency EM system mounted in a bird towed beneath a helicopter at a nominal altitude of 30 m. The bird contains horizontal coplanar coils and measure EM responses at 390 Hz, 1798 Hz, 8177 Hz, 39470 Hz and 132700 Hz. It also has one coaxial coil pair which measured a response at 3242 Hz. This paper presents methods for mapping the thickness of Blanchetown Clay in the highlands of the areas surveyed during the course of this work, and the distribution of near surface clay across the floodplains, specifically at Lindsay-Wallpolla, Lake Victoria, Darling River and its anabranch.
In 2007 the Australian Government funded an AEM survey (acquired with the RESOLVE frequency domain system) to provide information in relation to salinity management i
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