Canberra, Australia
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Mosley L.M.,University of Adelaide | Mosley L.M.,CSIRO | Biswas T.K.,Murray Darling Basin Authority | Biswas T.K.,Australian National University | And 9 more authors.
Geoderma | Year: 2017

Pyrite in acid sulfate soils can get oxidised during drought resulting in severe soil and water acidification (pH<4). The frequency and severity of drought and flooding is increasing in many regions of the world due to climate change but there has been limited research on the ability of acid sulfate soils to recover from these events. We studied the recovery of heavy clay soils in the Lower Murray River (South Australia) irrigated agricultural areas over a 5year period (2011-2015). The heavy clay acid sulfate soils in this region dried, cracked and acidified due to river and groundwater levels falling by nearly 200cm during the 2007-2010 severe "Millennium" drought followed by reflooding events between 2011 and 2015. Approximately 300cm deep soil cores were collected from three locations along a transect in 2011, 2012, 2013, and 2015. The soil properties measured were pH, reduced inorganic sulfur (RIS, pyrite), titratable actual acidity (TAA), retained acidity, and acid neutralising capacity. Soil pH showed very little change over the post-drought period with a very acidic (pH3.5-4.5) layer at approximately 100-225cm depth in all three soil profiles. In this acidic layer there also were substantial amounts of TAA (up to 200molH+ tonne-1 dry weight) and retained acidity (up to 70molH+ tonne-1 dry weight) in the form of the Fe oxyhydroxy sulfate mineral jarosite. There was limited reformation of RIS. To assess why the sulfuric material in the acid sulfate soils has not recovered post-drought we conducted (i) laboratory incubation experiments with and without organic matter amendment, and (ii) modelling of the flushing of acidity from the soil due to irrigation, rainfall and drainage. Based on the field and laboratory results the causes of slow recovery appear to be: (i) lack of available organic carbon and too low a pH to enable microbial reduction reactions that generate alkalinity, ii) slow flushing of acidity due to the low hydraulic conductivity in the heavy clay layers with the main zone of below the drain depth, and (iii) slow dissolution of the sparingly soluble jarosite mineral, which is likely buffering the sub-surface soil layers at approximately pH4. The implications are that acid sulfate soils with sulfuric materials have long recovery times following droughts and impacts are likely to increase in the future. © 2017 Elsevier B.V.


Bethune M.,Murray Darling Basin Authority | Korn A.,Murray Darling Basin Authority | Bishop A.,Murray Darling Basin Authority | Adams G.,eWater Solutions | Carr R.,eWater Solutions
The Art and Science of Water - 36th Hydrology and Water Resources Symposium, HWRS 2015 | Year: 2015

The National Hydrologic Modelling Platform, Source, has been under development since 2006. Originally developed by the eWater Cooperative Research Centre (CRC) in cooperation with the CRC partners, development and maintenance is continuing under the stewardship of eWater Solutions. eWater Solutions is a not-for-profit organisation owned by Australian federal and state governments. Source is an integrated modelling environment designed for a range of purposes including water resource planning, development of water sharing plans, analysis and management of groundwatersurface water interactions, analysis and management of in-stream water quality, management of environmental water entitlements, analysis of catchment management issues, and river operations. This paper reports on progress made by the Murray-Darling Basin Authority (MDBA) in building a Source model to support operations and planning on the Murray and Lower Darling River System. © 2015, Engineers Australia. All rights reserved.


Forghani A.,Murray Darling Basin Authority | Kazemi S.,Murray Darling Basin Authority | Darmawan A.,Murray Darling Basin Authority | Thalari J.,Murray Darling Basin Authority | And 2 more authors.
34th International Symposium on Remote Sensing of Environment - The GEOSS Era: Towards Operational Environmental Monitoring | Year: 2011

The Murray-Darling Basin Authority (MDBA) is a Commonwealth agency responsible for the sustainable management of water resources in the Murray-Darling Basin. The Authority has identified the need for web mapping infrastructure to provide online access to the Authority's spatial information via discovery, access and publishing tools. In line with the requirement to harmonise the Authority's online information strategies with those of other Commonwealth agencies, it is imperative that any web based information services are provided on robust open standards. With this in mind, standardisation of systems that implement Open Geospatial Consortium (OGC) standards is a high priority task. We are undertaking a staged approach to these implementations, initially adopting ArcGIS Server at the back end to provide integrated and scalable web services that support WMS and KML. This paper describes the process of building an OGC compliant infrastructure for the Murray-Darling Basin's web mapping requirements.


Chen Y.,CSIRO | Rana T.,Murray Darling Basin Authority | Abbas A.,Murray Darling Basin Authority | Buettikofer H.,CSIRO
Water Resources Management | Year: 2012

Australian irrigated agriculture utilises about 70% of all water used in the country, 21% of which is derived from groundwater. Sustainability for irrigated agriculture also depends on keeping the watertables at a safe level below the rootzone to avoid salinisation and reduction in crop yields. There is a vital need to understand groundwater and aquifer systems and their roles in the sustainability of irrigated agriculture in order to manage groundwater properly. This study builds on the previous hydrogeological and groundwater investigations of the Coleambally Irrigation Area (CIA) in New South Wales of Australia. It presents a new approach which systematically characterises regional hydrogeological environment using a three-dimensional (3-D) conceptual framework developed in ArcGIS. The 3-D hydrological conceptualisation of the CIA has integrated disparate sources of data into a coherent knowledge base for a better visualisation of hydrogeological characteristics and a comprehensive analysis of groundwater flow and aquifers. As an application example, the model was used to develop cross-sectional models of the area and to estimate regional-scale net recharge. The results have provided a basis for the numerical modelling and added values to procedures which underpin irrigation system management investment decisions through improving the understanding of hydrogeology underlying the area and creating an action-oriented dialogue among stakeholders. © 2012 Springer Science+Business Media B.V.


Dutta D.,CSIRO | Chen J.,CSIRO | Penton D.,CSIRO | Bethune M.,Murray Darling Basin Authority | And 4 more authors.
Water Resources Management | Year: 2014

Different water agencies use different modeling tools for water resources planning and management. For example, different jurisdictions in Australia use a variety of river system models and these models vary considerably in approach and assumptions, including different time steps (monthly and daily), flow routing (different types of routing and no routing), ordering solution (optimization and heuristic) and representation of management and operational rules. These fundamental differences in approach make it difficult to integrate existing models of connected river systems at a basin scale. A collaborative joint venture (the eWater CRC) between research, industry and government partners has recently developed an integrated river system modelling tool called "eWater Source" to improve on the existing river system models in Australia. One of the major advances in Source is the implementation of two decision algorithms, heuristic and NetLP approaches, for water distribution modelling in the same modelling platform. This paper describes the implementation of heuristic and NetLP approaches for water delivery under management and operations rules in Source, and compares the performance of the two approaches through a case study in the Goulburn-Broken-Campaspe-Loddon (GBCL) river system in south-eastern Australia. The key performance measures used to compare the approaches include the efficiency and equity of water delivery to water users, impacts on the reliability of supply, agreement with storage operating targets, and model application run time. The results demonstrate that the heuristic approach implemented in Source can replicate the performance of the NetLP approach for a model of reasonable complexity. This is important because the run times of models with heuristic approaches are shorter than models with NetLP approaches, so this will allow more complexity to be represented than was previously practical in equivalent NetLP applications. Agreement between jurisdictions to move to the single river system modelling platform will contribute to overcoming the problems faced by river managers in Australia in transboundary river basins. © 2014 Springer Science+Business Media Dordrecht.


Aziz K.,University of Western Sydney | Rai S.,Murray Darling Basin Authority | Rahman A.,University of Western Sydney
Natural Hazards | Year: 2015

This paper focuses on the development and testing of the genetic algorithm (GA)-based regional flood frequency analysis (RFFA) models for eastern parts of Australia. The GA-based techniques do not impose a fixed model structure on the data and can better deal with nonlinearity of the input and output relationship. These nonlinear techniques have been applied successfully in many hydrologic problems; however, there have been only limited applications of these techniques in RFFA problems, particularly in Australia. A data set comprising of 452 stations is used to test the GA for artificial neural networks (ANN) optimization known as GAANN. The results from GAANN were compared with the results from back-propagation for ANN optimization known as BPANN. An independent testing shows that both the GAANN and BPANN methods are quite successful in RFFA and can be used as alternative methods to check the validity of the traditional linear models such as quantile regression technique. © 2015, Springer Science+Business Media Dordrecht.


Luo Y.,Hohai University | Khan S.,UNESCO | Peng S.,Hohai University | Rana T.,Murray Darling Basin Authority | And 2 more authors.
Mathematical and Computer Modelling | Year: 2012

The estimation of groundwater evapotranspiration (ET) helps evaluate the risk of soil salinisation and the capacity of regional water resources. This paper focused on the effect of discretisation cell size on the output uncertainty of regional groundwater evapotranspiration modelling. The study area, the Liuyuankou Irrigation System (LIS), was discretised into cell sizes of 100×100m, 200×200m, 500×500m, 1000×1000m, and 2000×2000m. Digital elevation models (DEM) at the lower resolutions were obtained by resampling the 90m Shuttle Radar Topography Mission (SRTM) DEM using an averaging algorithm. The krigged groundwater table was subtracted from the ground surface elevation to generate the groundwater depth maps for various cell sizes. For each resolution, the groundwater ET was calculated using two ET functions (linear and exponential) for each cell. Lastly, the effects of the cell size on the output of the regional groundwater ET modelling were evaluated. The results showed that lower ET rates were obtained when a coarser cell size was used due to the smothering of the surface elevations and the groundwater depths, regardless of the employed ET functions. From comparisons of the delineated area, the cell numbers, the groundwater depth maps and the simulated groundwater ET rates, a discretisation cell size of 500 m was recommended for the LIS to balance the model's accuracy and computation efficiency in groundwater ET modelling. © 2012 Elsevier Ltd.


Capon S.J.,Griffith University | Lynch A.J.J.,University of Canberra | Chessman B.C.,University of Canberra | Chessman B.C.,Center for Ecosystem Science | And 12 more authors.
Science of the Total Environment | Year: 2015

The concepts of ecosystem regime shifts, thresholds and alternative or multiple stable states are used extensively in the ecological and environmental management literature. When applied to aquatic ecosystems, these terms are used inconsistently reflecting differing levels of supporting evidence among ecosystem types. Although many aquatic ecosystems around the world have become degraded, the magnitude and causes of changes, relative to the range of historical variability, are poorly known. A working group supported by the Australian Centre for Ecological Analysis and Synthesis (ACEAS) reviewed 135 papers on freshwater ecosystems to assess the evidence for pressure-induced non-linear changes in freshwater ecosystems; these papers used terms indicating sudden and non-linear change in their titles and key words, and so was a positively biased sample. We scrutinized papers for study context and methods, ecosystem characteristics and focus, types of pressures and ecological responses considered, and the type of change reported (i.e., gradual, non-linear, hysteretic or irreversible change). There was little empirical evidence for regime shifts and changes between multiple or alternative stable states in these studies although some shifts between turbid phytoplankton-dominated states and clear-water, macrophyte-dominated states were reported in shallow lakes in temperate climates. We found limited understanding of the subtleties of the relevant theoretical concepts and encountered few mechanistic studies that investigated or identified cause-and-effect relationships between ecological responses and nominal pressures. Our results mirror those of reviews for estuarine, nearshore and marine aquatic ecosystems, demonstrating that although the concepts of regime shifts and alternative stable states have become prominent in the scientific and management literature, their empirical underpinning is weak outside of a specific environmental setting. The application of these concepts in future research and management applications should include evidence on the mechanistic links between pressures and consequent ecological change. Explicit consideration should also be given to whether observed temporal dynamics represent variation along a continuum rather than categorically different states. © 2015 Elsevier B.V.


Verheijen F.G.A.,University of Aveiro | Jones R.J.A.,Cranfield University | Rickson R.J.,Cranfield University | Smith C.J.,Murray Darling Basin Authority | And 3 more authors.
Acta Agriculturae Scandinavica Section B: Soil and Plant Science | Year: 2012

Soil loss by erosion is a major threat to European soil resources. It is linked to most other threats to soils and is estimated to incur substantial costs to society. To monitor and evaluate soil erosion comprehensively, measurements and modelled estimates of soil loss by erosion need to integrate water, wind and tillage erosion, as these are common throughout Europe. Tolerable rates of soil erosion (thresholds) in Europe can be set equal to estimated soil formation rates, that is, ~1 t ha-1 yr-1, but defining this threshold will require further research in the context of soil functions. There is a strong need for improving the knowledge base of current erosion rates, especially to develop and validate reliable erosion prediction models. This should include depositional environments (e.g. flood plains) where greater erosion rates than those on hill slopes may be tolerable, depending on the consequent effects on all relevant ecosystem goods and services provided by soil. Moreover, in considering erosion at catchment (watershed) level, the distance between erosion sites and areas of deposition should be taken into account. © 2012 Copyright Taylor and Francis Group, LLC.


PubMed | University of New South Wales, Charles Sturt University, Goulburn Broken Catchment Management Authority, Murray Darling Basin Authority and 5 more.
Type: | Journal: The Science of the total environment | Year: 2015

The concepts of ecosystem regime shifts, thresholds and alternative or multiple stable states are used extensively in the ecological and environmental management literature. When applied to aquatic ecosystems, these terms are used inconsistently reflecting differing levels of supporting evidence among ecosystem types. Although many aquatic ecosystems around the world have become degraded, the magnitude and causes of changes, relative to the range of historical variability, are poorly known. A working group supported by the Australian Centre for Ecological Analysis and Synthesis (ACEAS) reviewed 135 papers on freshwater ecosystems to assess the evidence for pressure-induced non-linear changes in freshwater ecosystems; these papers used terms indicating sudden and non-linear change in their titles and key words, and so was a positively biased sample. We scrutinized papers for study context and methods, ecosystem characteristics and focus, types of pressures and ecological responses considered, and the type of change reported (i.e., gradual, non-linear, hysteretic or irreversible change). There was little empirical evidence for regime shifts and changes between multiple or alternative stable states in these studies although some shifts between turbid phytoplankton-dominated states and clear-water, macrophyte-dominated states were reported in shallow lakes in temperate climates. We found limited understanding of the subtleties of the relevant theoretical concepts and encountered few mechanistic studies that investigated or identified cause-and-effect relationships between ecological responses and nominal pressures. Our results mirror those of reviews for estuarine, nearshore and marine aquatic ecosystems, demonstrating that although the concepts of regime shifts and alternative stable states have become prominent in the scientific and management literature, their empirical underpinning is weak outside of a specific environmental setting. The application of these concepts in future research and management applications should include evidence on the mechanistic links between pressures and consequent ecological change. Explicit consideration should also be given to whether observed temporal dynamics represent variation along a continuum rather than categorically different states.

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