drainage
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This project involved two phases, the first of which compiled reviews of recharge and discharge studies that have been undertaken in Australia (Crosbie et al., 2010a; O'Grady et al., 2010). It also involved preliminary identification of the parameters (climate, soils, regolith, near-surface geology, landforms, vegetation etc.) that determine recharge and discharge rates along with a review of the appropriate scale mapping approaches available for these parameters (Pain et al., 2011). The second phase of the project utilised empirical relationships derived from data collected in Phase 1 of the project in a decision tree methodology that guides the user to the most appropriate estimate for recharge/discharge given the data availability. This report provides detailed instruction in the use of both recharge and discharge spreadsheets and the associated GIS datasets previously made available via Geoscience Australia's MapConnect website.
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The Lapstone Structural Complex (LSC) comprises a series of north-trending faults and monoclinal flexures forming the eastern margin of the Blue Mountains Plateau, ~50 km west of the Sydney CBD. The LSC is considered a potential source of large earthquakes, however its evolution, and in particular its tectonic history is not well constrained. The LSC is bounded to the west by the Kurrajong Fault System (KFS), a series of <i>en echelon </i>reverse faults downthrown to the west. Streams crossing the LSC oversteepen by about 2-5 times over these faults. This study aims, through longitudinal profile analysis of 18 streams crossing the LSC coupled with field observation, to determine whether the oversteepening can be attributed to a lithological change at the faults, or tectonically-induced disequilibrium. Two approaches are used. Firstly, plots of log slope versus log distance (DS plots) are produced for each of the streams. As a result of noise in the topographic data, these results are inconclusive in demonstrating either situation. Secondly, an area-slope relationship, defined by <i>A<sup>0.4</sup>S</i> (where A = area and S = slope), is plotted against downstream distance. This factor is derived from the stream incision law, <i>dz/dt </i>= <i>KA<sup>m</sup>S<sup>n</sup></i>, where <i>K</i> is assumed to be constant, and <i>m</i> and<i> n</i> are positive constants relating to erosional processes, and basin hydrologic and geometric factors. The analysis shows that in all but two streams, values for <i>A<sup>0.4</sup>S</i> are at a maximum over the LSC. Peak <i>A<sup>0.4</sup>S</i> values of about 0.2 are estimated to be equivalent to vertical incision rates of about 70 m/Ma. <i>A<sup>0.4</sup>S</i> varies with lithology; however the lithological effect is demonstrated to be of similar magnitude or smaller than the apparent structural control exerted by the LSC. All streams with catchment areas less than 100 km<sup>2</sup> have developed swamps upstream of faults on the LSC. Sediment accumulated in these swamps is generally 0.5-4 m thick, but reaches 14 m in Burralow Swamp. In Blue Gum Creek and Burralow Swamps, the sedimentary sequence includes an organic clay layer indicative of low-energy depositional conditions. Previous radiocarbon dating and pollen analysis suggests the sediment is of Pleistocene age. The elevation of the clay layer is similar to that of bedrock downstream of the faults, consistent with damming related to from tectonically induced uplift.
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The combined analysis of airborne electromagnetics (AEM), airborne gamma-ray spectrometry (AGRS), magnetics and a digital elevation model with ground-based calibration, has enable construction of a 3D architectural and landscape evolution model of valley fill deposits around the township of Jamestown in South Australia. The valley fill sediments consist of traction, suspension and debris-flow deposits that range in age (optically stimulated luminescence OSL dating) from 102 ka (±12) to the present day. A sediment isopach map generated from the AEM dataset reveals the 3D structure of the valley-fill deposits. The sediments are up to 40 m thick within asymmetrical valleys and are the result of colluvial fan, floodplain and sheet-wash processes. The sediments fine upwards with a higher proportion of coarser bed load deposits toward the base and fine sand, silt and clay towards the top of the sequence. A strong linear correlation between airborne K response and soil texture allowed the percentage of surface silt to be modelled over the depositional landforms. The sediments are thought to have been derived by a combination of aeolian dust accessions, and weathering and erosion of bedrock materials within the catchment. Older drainage lines reflected in the distribution of relatively closely spaced and well connected 'magnetic channels' differ markedly from present day streams that are largely ephemeral and interrupted. This is thought to reflect a change in local hydrology and associated geomorphic processes from relatively high to lower energy conditions as the valley alluviated. These hydrological changes are likely to be associated with a drying climate, lower recharge and runoff.
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Four data formats are available for download, three vector (e00, mif, shp) and one raster (ecw).
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Drainage network containing perennial/non-perennial waterbodies and linear features such as streams, coastlines and inland shores (dataset derived from the Digital Chart of the World (DCW)). Generic information on DCW data sets The primary source for DCW is the US Defense Mapping Agency (DMA) Operational Navigation Chart (ONC) series produced by the United States, Australia, Canada, and the United Kingdom. The ONCs have a scale of 1:1,000,000, where 1 inch equals approximately 16 miles.The charts were designed to meet the needs of pilots and air crews in medium and low altitude en route navigation and to support military operational planning, intelligence briefings, and other needs. Therefore, the selection of ground features is based on the requirement for rapid visual recognition of significant details seen from a low perspective angle. The DCW database was originally published in 1992. Data currency varies from place to place depending on the currency of the ONC charts. Chart currency ranges from the mid 1960s to the early 1990s. Compilation dates for every ONC chart are included in the database. For more information on the Digital Chart of the world please browse the DCW website where you can download these data in VPF format. GA has converted these VPF format files to common GIS formats Arcview and Mapinfo. Available datasets include drainage, roads and railway networks, political areas and boundaries and population centres. Available for free download.
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This service has been created specifically for display in the National Map and the symbology displayed may not suit other mapping applications. Information included within the service includes the polygon/area locations for surface hydrology, including natural and man-made features such as water courses (including directional flow paths), lakes, dams and other water bodies and marine themes. The data is sourced from Geoscience Australia 250K Topographic data and Surface Hydrology data. The service contains layer scale dependencies.
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This service has been created specifically for display in the National Map and the symbology displayed may not suit other mapping applications. Information included within the service includes the point locations for surface hydrology, including natural and man-made features such as water courses (including directional flow paths), lakes, dams and other water bodies and marine themes. The data is sourced from Geoscience Australia 250K Topographic data and Surface Hydrology data. The service contains layer scale dependencies.
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This service has been created specifically for display in the National Map and the symbology displayed may not suit other mapping applications. Information included within the service includes the linear locations for surface hydrology, including natural and man-made features such as water courses (including directional flow paths), lakes, dams and other water bodies and marine themes. The data is sourced from Geoscience Australia 250K Topographic data and Surface Hydrology data. The service contains layer scale dependencies.
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This service has been created specifically for display in the National Map and the symbology displayed may not suit other mapping applications. The service includes natural and man-made surface hydrology features, such as water courses (including directional flow paths), lakes, dams and other water bodies and marine themes. The data is sourced from Geoscience Australia 250K Topographic data and Surface Hydrology data. The service contains layer scale dependencies.
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This project involved two phases, the first of which compiled reviews of recharge and discharge studies that have been undertaken in Australia. It also involved preliminary identification of the parameters (climate, soils, regolith, near-surface geology, landforms, vegetation etc.) that determine recharge and discharge rates along with a review of the appropriate scale mapping approaches available for these parameters. The second phase of the project utilised empirical relationships derived from data collected in Phase 1 of the project in a decision tree methodology that guides the user to the most appropriate estimate for recharge/discharge given the data availability. This report documents the various methods of estimating recharge and/or discharge using specifically developed Excel spreadsheets and associated input GIS data.