This context report is for the Upper Darling River Floodplain module, which represents the easternmost ‘arm’ of the Exploring for the Future Darling-Curnamona-Delamerian project area within New South Wales. The document provides a summarised state of knowledge regarding the geography, geology, hydrology, hydrogeology and water management of the Upper Darling region. It provides baseline information relevant to understanding the regional context of water resources, with relevance to forward planning and prioritisation of further investigations. As such, this report largely represents a collation of existing information (literature review) for the Upper Darling region, with limited new information (e.g., airborne electromagnetic survey results, preliminary review of existing bore data) being presented.

Subtitle: Behind the Scenes of Geofabric Version 3 Pilot & the Future of Geospatial Surface Water Information The Bureau of Meteorology's Australian Hydrological Geospatial Fabric (Geofabric) was established in 2008 as the spatial information database to support water accounting and resource assessment mandated under the Water Act 2007. Foundation layers for Geofabric versions 1 and 2 were developed from 1:250K streamline data and the 9 second resolution national DEM. The uses of the Geofabric data have expanded to new disciplines and have resulted in increased demand for finer national resolution. Version 3 of the Geofabric is now under development in a collaborative project between Geoscience Australia, CSIRO, Australian National University (ANU) and the Bureau of Meteorology. The foundation inputs for Geofabric version 3 are based on the integrated national surface hydrology dataset which uses the best available scale data from the jurisdictions and the 1 second resolution SRTM DEM. This significant enhancement presents both challenges and opportunities. This presentation at the Surveying & Spatial Sciences Institute (SSSI) ACT Region conference on 16 August 2013 aims to show the work being undertaken in the pilot areas of the Namoi and Murrumbidgee River Regions.

Completion of a pilot study over the Namoi and Murrumbidgee catchments was part of the 2012-13 project schedule between Bureau of Meteorology (Bureau) and Geoscience Australia. The purpose of the pilot was to consolidate four years of research and development of the 1 second SRTM DEM, ANUDEM Streams, and National Catchment Boundaries to enable GA operational capacity to recreate the foundation datasets for Geofabric Phase 3 deliverables. This report is aimed to highlight how successfully the process has worked, issues that have arisen and identify and develop future modifications of the methodology to enable the production of Phase 3 Geofabric products. This professional opinion has been created for the Bureau and the Geofabric Steering Committees for review of Phase 3 of the Geofabric.

Wetlands around the world provide crucial ecosystem services and are under increasing pressure from multiple sources including climate change, changing flow and flooding regimes, and encroaching human populations. The Landsat satellite imagery archive provides a unique observational record of how wetlands have responded to these impacts during the last three decades. Information stored within this archive has historically been difficult to access due to its petabyte-scale and the challenges in converting Earth observation data into biophysical measurements that can be interpreted by wetland ecologists and catchment managers. This paper introduces the Wetlands Insight Tool (WIT), a workflow that generates WIT plots that present a multidecadal view of the biophysical cover types contained within individual Australian wetlands. The WIT workflow summarises Earth observation data over 35 years at 30 m resolution within a user-defined wetland boundary to produce a time-series plot (WIT plot) of the percentage of the wetland covered by open water, areas of water mixed with vegetation (‘wet’), green vegetation, dry vegetation, and bare soil. We compare these WIT plots with documented changes that have occurred in floodplain shrublands, alpine peat wetlands, and lacustrine and palustrine wetlands, demonstrating the power of satellite observations to supplement ground-based data collection in a diverse range of wetland types. The use of WIT plots to observe and manage wetlands enables improved evidence-based decision making. <b>Citation:</b> Dunn, B., Ai, E., Alger, M.J. et al. Wetlands Insight Tool: Characterising the Surface Water and Vegetation Cover Dynamics of Individual Wetlands Using Multidecadal Landsat Satellite Data. <i>Wetlands</i><b> 43</b>, 37 (2023). https://doi.org/10.1007/s13157-023-01682-7

<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

The Environmental Attributes Database is a set of lookup tables supplying attributes describing the natural and anthropogenic characteristics of the stream and catchment environment that was developed by the Australian National University (ANU) in 2011 and updated in 2012. The data is supplied as part of the supplementary Geofabric products which is associated with the 9 second DEM derived streams and the National Catchment Boundaries based on 250k scale stream network. Please consult the spreadsheet below for details of the attributes and their source data. Version 1.1.5 corrects an error in the connectivity.lut table where the field ARTFBARIER for a subset of records did not correctly flag the presence of an artificial barrier up or downstream of the stream segment.

Up to date information about the extent and location of surface water provides all Australians with a common understanding of this valuable and increasingly scarce resource. Digital Earth Australia Waterbodies shows the wet surface area of waterbodies as estimated from satellites. It does not show depth, volume, purpose of the waterbody, nor the source of the water. Digital Earth Australia Waterbodies uses Geoscience Australia’s archive of over 30 years of Landsat satellite imagery to identify where over 300,000 waterbodies are in the Australian landscape and tells us the wet surface area within those waterbodies. It supports users to understand and manage water across Australia. For example, users can gain insights into the severity and spatial distribution of drought, or identify potential water sources for aerial firefighting during bushfires. The tool uses a water classification for every available Landsat satellite image and maps the locations of waterbodies across Australia. It provides a timeseries of wet surface area for waterbodies that are present more than 10% of the time and are larger than 2700m2 (3 Landsat pixels). The tool indicates changes in the wet surface area of waterbodies. This can be used to identify when waterbodies are increasing or decreasing in wet surface area. Refer to Krause et al. 2021 for full details of this dataset. https://doi.org/10.3390/rs13081437

Geometric representations of major surface water features of Australia, such as rivers, lakes, reservoirs, dams, canals and catchments. Also includes hydrologic features such as catchment boundaries and drainage basins. <b>Value:</b> This data is not authoritative, but represent a valuable resource for visualisation, decision support and planning activities. <b>Scope:</b> This is a National dataset at resolution relevant for presentation of regional spatial data such as digital maps.