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As part of the controlled release experiments at the Ginninderra test site, geophysical surveys have been acquired using electromagnetic techniques at a range of frequencies. The primary objective was to assess whether these could provide insight into the soil structure at the site, give guidance as to where to monitor for leakage, and provide additional information that may explain the observed sub-surface and surface CO2 migration behavior. A secondary objective was to assess whether CO2 leaks could be located based on secondary impacts such as drying of the soil profile. Ground penetrating radar surveys were taken during the second release experiment (October - December 2012). Different frequency shielded antennas were trialled in order to optimize the signal. Two surveys were conducted: one baseline survey prior to CO2 release and another during the release experiment. The GPR results show a reduction in range and clear reflections to the west indicating that clay was present. To the east we see clearer reflections from sand layers and the water table. These observations corresponded with larger scale sub-surface soil features determined from EM31 and EM38 electromagnetic surveys. Application of these geophysical surveys for CO2 leak detection and monitoring design are discussed. Paper for CO2CRC Research Symposium 2013
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Wind multipliers are factors that transform regional wind speeds into local wind speeds, accounting for the local effects which include topographical, terrain and shielding influences. Wind multipliers have been successfully utilized in various wind related activities such as wind hazard assessment (engineering building code applications), event-based wind impact assessments (tropical cyclones), and also national scale wind risk assessment. The work of McArthur in developing the Forest Fire Danger Index (FFDI: Luke and McArthur, 1978) indicates that the contribution of wind speed to the FFDI is about 45% of the magnitude, indicating the importance of determining an accurate local wind speed in bushfire hazard and spread calculations. For bushfire spread modeling, local site variation (@ 100 metre and also 25 metre horizontal resolution) have been considered through the use of wind multipliers, and this has resulted in a significant difference to the currently utilized regional '10 metre height' wind speed (and further to the impact analysis). A series of wind multipliers have been developed for three historic bushfire case study areas; the 2009 Victorian fires (Kilmore fire), the 2005 Wangary fire (Eyre Peninsula), and the 2001 Warragamba - Mt. Hall fire (Western Sydney). This paper describes the development of wind multiplier computation methodology and the application of wind multipliers to bushfire hazard and impact analysis. The efficacy of using wind multipliers within a bushfire spread hazard model is evaluated by considering case study comparisons of fire extent, shape and impact against post-disaster impact assessments. The analysis has determined that it is important to consider wind multipliers for local wind speed determination in order to achieve reliable fire spread and impact results. From AMSA 2013 conference
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Imagine you are an incident controller viewing a computer screen which depicts the likely spread of a bushfire that's just started. The display shows houses and other structures in the fire's path, and even the demographics of the people living in the area, such as the number of people, their age spread, whether households have independent transport, and whether English is their second language. In addition, imagine that you can quantify and display the uncertainty in both the fire weather and also the type and state of the vegetation, visualising the sensitivity of the expected fire spread and impact to these uncertainties. It will be possible to consider 'what if' scenarios as the event unfolds, and reject those scenarios that are no longer plausible. The advantages of such a simulation system in making speedy, well-informed decisions has been considered by a group of Bushfire CRC researchers who have collaborated to produce a 'proof of concept' for such a system, demonstrated initially on three case studies. The 'proof of concept' system has the working name FireDST (Fire Impact and Risk Evaluation Decision Support Tool). FireDST links various databases and models, including the Phoenix RapidFire fire prediction model and building vulnerability assessment models, as well as infrastructure and demographic databases. The information is assembled into an integrated simulation framework through a geographical information system (GIS) interface. Pre-processed information, such as factors that determine the local and regional wind, and also the typical response of buildings to fire, are linked through a database, along with census-derived social and economic information. This presentation provides an overview of the FireDST simulation 'proof of concept' tool and walks through a sample probabilistic simulation constructed using the tool. Handbook MODSIM2013 Conference
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The dry-tropics of central Queensland has an annual bushfire threat season that generally extends from September to November. Fire weather hazard is quantified using either the Forest Fire Danger Index (FFDI) or the Grassland Fire Danger Index (GFDI) (Luke and McArthur, 1978). Weather observations (temperature, relative humidity and wind speed) are combined with an estimate of the fuel state to predict likely fire behaviour if an ignition eventuates. A high resolution numerical weather model (dynamic downscaling) was utilised to provide spatial texture over the Rockhampton region for a range of historical days where bushfire hazard (as measured at the Rockhampton Airport meteorological station) was known to be severe to extreme. From the temperature, relative humidity and wind speeds generated by the model, the maximum FFDI for each simulated day was calculated using a maximum drought factor. Each of these FFDI maps was then normalised to the value of the FFDI at the grid point corresponding to Rockhampton Airport (ensemble produced). The annual recurrance interval (ARI) of FFDI at Rockhampton Airport for the current climate was calculated from observations by fitting Generalised Extreme Value (GEV) distributions. For future climate, we considered three downscaled General Circulation Models (GCM's) forced by the A2 emission scenario for atmospheric greenhouse gas emissions. The spatial pattern of the 50 and 100 year ARI fire danger rating for the Rockhampton region (current and future climate) was determined. In general, a small spatial increase in the fire danger rating is reflected in the ensemble model average for the 2090 climate. This is reflected throughout the Rockhampton region in both magnitude and extent through 2050 to 2090. Cluster areas of higher (future climate) bushfire hazard were mapped for planning applications. Handbook MODSIM2013 Conference
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In May 2013, Geoscience Australia (GA) and the Australian Institute of Marine Science (AIMS) undertook a collaborative seabed mapping survey (GA0340/ SOL5754) on the Leveque Shelf, a distinct geological province within the Browse Basin, offshore Western Australia. The purpose of the survey was to acquire geophysical and biophysical data on seabed environments over a previously identified potential CO2 injection site to better understand the overlying seabed habitats and to assess potential for fluid migration to the seabed. Mapping and sampling was undertaken across six areas using multibeam and single beam echosounders, sub-bottom profilers, sidescan sonar, underwater towed-video, gas sensors, water column profiler, grab samplers, and vibrocorer. Over 1070 km2 of seabed and water column was mapped using the multibeam and single beam echosounder, in water depths ranging between 40 and 120 m. The sub-surface was investigated using the multichannel and the parametric sub-bottom profilers along lines totalling 730 km and 1547 km in length respectively. Specific seabed features were investigated over 44 line km using the sidescan sonar and physically and sampled at 58 stations. Integration of this newly acquired data with existing seismic data will provide new insights into the geology of the Leveque Shelf. This work will contribute to the Australian Government's National CO2 Infrastructure Plan (NCIP) by providing key seabed environmental and geological data to better inform the assessment of the CO2 storage potential in this area of the Browse Basin. This dataset contains identifications of Polychaetes collected from 64 Smith-McIntyre grabs deployed during GA0340/SOL5754.
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Geoscience Australia defines a borehole as the generalized term for any narrow shaft drilled in the ground, either vertically or horizontally, and would include Mineral Drillholes, Petroleum Wells and Water Bores along with a variety of others types, but does not include Costean, Trench or Pit. For the purposes of a Water Well as defined by Groundwater ML v1.0, the dataset has been restricted to onshore Australian boreholes only, and bores that have the potential to support assessment of groundwater resources, within a Bioregional Assessment.
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The Clarence-Moreton and the Surat basins in Queensland and northern New South Wales contain the coal-bearing sedimentary sequences of the Jurassic Walloon Coal Measures, composed of up to approximately 600 m of mudstone, siltstone, sandstone and coal. In recent years, the intensification of exploration for coal seam gas (CSG) resources within both basins has led to concerns that the depressurisation associated with future resource development may cause adverse impacts on water resources in adjacent aquifers. In order to identify the most suitable tracers to study groundwater recharge and flow patterns within the Walloon Coal Measures and their degree of connectivity with over- or underlying formations, samples were collected from the Walloon Coal Measures and adjacent aquifers in the northern Clarence-Moreton Basin and eastern Surat Basin, and analysed for a wide range of hydrochemical and isotopic parameters. Parameters that were analysed include major ion chemistry, -13C-DIC, -18O, 87Sr/86Sr, Rare Earth Elements (REE), 14C, -2H and -13C of CH4 as well as concentrations of dissolved gases (including methane). Dissolved methane concentrations range from below the reporting limit (10 µg/L) to approximately 50 mg/L in groundwaters of the Walloon Coal Measures. However, the high degree of spatial variability of methane concentrations highlights the general complexity of recharge and groundwater flow processes, especially in the Laidley Sub-Basin of the Clarence-Moreton Basin, where numerous volcanic cones penetrate the Walloon Coal Measures and may form pathways for preferential recharge to the Walloon Coal Measures. Interestingly, dissolved methane was also measured in other sedimentary bedrock units and in alluvial aquifers in areas where no previous CSG exploration or development has occurred, highlighting the natural presence of methane in different aquifers. Radiocarbon ages of Walloon Coal Measure groundwaters are also highly variable, ranging from approximately 2000 yrs BP to >40000 yrs BP. While groundwaters sampled in close proximity to the east and west of the Great Dividing Range are mostly young, suggesting that recharge to the Walloon Coal Measures through the basalts of the Great Dividing Range occurs here, there are otherwise no clearly discernable spatial patterns and no strong correlations with depth or distance along inferred flow paths in the Clarence-Moreton Basin. In contrast to this strong spatial variability of methane concentrations and groundwater ages, REE and 87Sr/86Sr isotope ratios of Walloon Coal Measures groundwaters appear to be very uniform and clearly distinct from groundwaters contained in other bedrock units. This difference is attributed to the different source material of the Walloon Coal Measures (mostly basalts in comparison to other bedrock units which are mostly composed of mineralogical more variable Paleozoic basement rocks of the New England Orogen). This study suggests that REE and 87Sr/86Sr ratios may be a suitable tracer to study hydraulic connectivity of the Walloon Coal Measures with over- or underlying aquifers. In addition, this study also highlights the need to conduct detailed water chemistry and isotope baseline studies prior to the development of coal seam gas resources in order to differentiate between natural background values of methane and potential impacts of coal seam gas development.
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<p>A new finite volume algorithm to solve the two dimensional shallow water equations on an unstructured triangular mesh has been implemented in the open source ANUGA software, which is jointly developed by the Australian National University and Geoscience Australia. The algorithm supports discontinuouselevation, or `jumps in the bed profile between neighbouring cells. This has a number of benefits compared with previously implemented continuous-elevation approaches. Firstly it can preserve stationary states at wetdry fronts without using any mesh porosity type treatment. It can also simulate very shallow frictionally dominated flow down sloping topography, as typically occurs in direct-rainfall flood models. In the latter situation, mesh porosity type treatments lead to artificial storage of mass in cells and associated mass conservation issues, whereas continuous-elevation approaches with good performance on shallow frictionally dominated flows tend to have difficulties preserving stationary states near wet-dry fronts. The discontinuous-elevation approach shows good performance in both situations, and mass is conserved to a very high degree, consistent with floating point error. <p>A further benefit of the discontinuous-elevation approach, when combined with an unstructured mesh, is that the model can sharply resolve rapid changes in the topography associated with e.g. narrow prismatic drainage channels, or buildings, without the computational expense of a very fine mesh. The boundaries between such features can be embedded in the mesh using break-lines, and the user can optionally specify that different elevation datasets are used to set the elevation within different parts of the mesh (e.g. often it is convenient to use a raster DEM in terrestrial areas, and surveyed channel bed points in rivers). <p>The discontinuous elevation approach also supports a simple and computationally efficient treatment of river walls. These are arbitrarily narrow walls between cells, higher than the topography on either side, where the flow is controlled by a weir equation and optionally transitions back to the shallow water solution for sufficiently submerged flows. This allows modelling of levees or lateral weirs much finer than the mesh size. A number of benchmark tests are presented illustrating these features of the algorithm. All these features of the model can be run in serial or parallel, on clusters or shared memory machines, with good efficiency improvements on 10s-100s of cores depending on the number of mesh triangles and other case-specific details
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The Evidence Based Decision Making (EBDM) paradigm encourages managers to base their decisions on the strongest available evidence, but it has been criticized for placing too much emphasis on the choice of study design method without considering the types of questions that are being addressed as well as other relevant factors such as how well a study is implemented. Here we review the objectives of Australia’s Marine Park network, and identify the types of questions and data analysis that would address these objectives. Critically, we consider how the design of a monitoring program influences our ability to adequately answer these questions, using the strength of evidence hierarchy from the EBDM paradigm to assess the adequacy of different design strategies and other sources of information. It is important for conservation managers to recognize that the types of questions monitoring programs are able to answer depends on how they are designed and how the collected data are analyzed. The socio-political process that dictates where protected areas are placed typically excludes the strongest types of evidence, Random Controlled Trials (RCTs), for certain questions. Evidence bases that are stronger than ones commonly employed to date, however, could be used to provide a causal inference, including for those questions where RCTs are excluded, but only if appropriate designs such as cohort or case-control studies are used, and supported where relevant by appropriate sample frames. Randomized, spatially balanced sampling, together with careful selection of control sites, and more extensive use of propensity scores and structured elicitation of expert judgment, are also practical ways to improve the evidence base for answering the questions that underlie marine park objectives and motivate long-term monitoring programs. <b>Citation:</b> Hayes KR, Hosack GR, Lawrence E, Hedge P, Barrett NS, Przeslawski R, Caley MJ and Foster SD (2019) Designing Monitoring Programs for Marine Protected Areas Within an Evidence Based Decision Making Paradigm.<i> Front. Mar. Sci</i>. 6:746. doi: 10.3389/fmars.2019.00746
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The DMCii Mosaic presents a sample of imagery acquired by Geoscience Australia under CC-BY Creative Commons Attribution 3.0 Australia licence. This imagery was captured by UK2-DMC satellite between December 2011 to April 2012 and has spatial resolution of 22 metres. Spectral bands are: Band 1 NIR; Band 2 Red; Band 3 Green. The DMCii Mosaic is displayed as a Pseudo Natural Colour Image.