Infrastructure Engineering - Research Publications

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    The behavior of stratified pools in the Wimmera River, Australia
    Western, AW ; ONeill, IC ; Hughes, RL ; Nolan, JB (AMER GEOPHYSICAL UNION, 1996-10)
    Numerous inland Australian streams contain density‐stratified or saline pools, which are usually located on channel bends. Saline pools consist of a layer of saline water underlying a layer of fresh water. Saline pools generally form as a result of saline groundwater seeping into the stream and collecting in scour depressions during periods of low flow. Inflows of saline river water can also collect in scour depressions. Field and laboratory investigations of saline pool mixing by overflowing fresh water reveal that mixing depends on a balance between interfacial shear and buoyancy forces acting on a thin dense layer flowing up the downstream slope of the scour depression, and on the bend sharpness. Convection associated with surface cooling also causes mixing. A model for saline pools formed by groundwater inflows and mixed by fresh overflows is proposed and applied to several saline pools in the Wimmera River.
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    Preferred states in spatial soil moisture patterns: Local and nonlocal controls
    Grayson, RB ; Western, AW ; Chiew, FHS ; Bloschl, G (AMER GEOPHYSICAL UNION, 1997-12)
    In this paper we develop a conceptual and observational case in which soil water patterns in temperate regions of Australia switch between two preferred states. The wet state is dominated by lateral water movement through both surface and subsurface paths, with catchment terrain leading to organization of wet areas along drainage lines. We denote this as nonlocal control. The dry state is dominated by vertical fluxes, with soil properties and only local terrain (areas of high convergence) influencing spatial patterns. We denote this as local control. The switch is described in terms of the dominance of lateral over vertical water fluxes and vice versa. When evapotranspiration exceeds rainfall, the soil dries to the point where hydraulic conductivity is low and any rainfall that occurs essentially wets up the soil uniformly and is evapotranspired before any significant lateral redistribution takes place. As evapotranspiration decreases and/or rainfall increases, areas of high local convergence become wet, and runoff that is generated moves downslope, rapidly wetting up the drainage lines. In the wet to dry transitional period a rapid increase in potential evapotranspiration (and possibly a decrease in rainfall) causes drying of the soil and “shutting down” of lateral flow. Vertical fluxes dominate and the “dry” pattern is established. Three data sets from two catchments are presented to support the notion of preferred states in soil moisture, and the results of a modeling exercise on catchments from a range of climatic conditions illustrate that the conclusions from the field studies may apply to other areas. The implications for hydrological modeling are discussed in relation to methods for establishing antecedent moisture conditions for event models, for distribution models, and for spatially distributing bulk estimates of catchment soil moisture using indices.
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    The Tarrawarra data set: Soil moisture patterns, soil characteristics, and hydrological flux measurements
    Western, AW ; Grayson, RB (AMER GEOPHYSICAL UNION, 1998-10)
    Experiments investigating the spatial variability of soil moisture conducted in the 10.5 ha Tarrawarra catchment, southeastern Australia, are described. The resulting data include high‐resolution soil moisture maps (over 10,000 point measurements at up to 2060 sites), information from 125 soil cores, over 1000 soil moisture profiles from 20 sites, 2500 water level measurements from 74 piezometers, surface roughness and vegetation measurements, meteorological and hydrological flux measurements, and topographic survey data. These experiments required a major commitment of resources including 250 person days in the field, with a further 100 person days in the laboratory preparing for field trips and checking and collating data. These data are available on the World Wide Web (http://www.civag.unimelb.edu.au/data/).
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    Observed spatial organization of soil moisture and its relation to terrain indices
    Western, AW ; Grayson, RB ; Blöschl, G ; Willgoose, GR ; McMahon, TA (AMER GEOPHYSICAL UNION, 1999-03)
    We analyze the degree of spatial organization of soil moisture and the ability of terrain attributes to predict that organization. By organization we mean systematic spatial variation or consistent spatial patterns. We use 13 observed spatial patterns of soil moisture, each based on over 500 point measurements, from the 10.5 ha Tarrawarra experimental catchment in Australia. The measured soil moisture patterns exhibit a high degree of organization during wet periods owing to surface and subsurface lateral redistribution of water. During dry periods there is little spatial organization. The shape of the distribution function of soil moisture changes seasonally and is influenced by the presence of spatial organization. Generally, it is quite different from the shape of the distribution functions of various topographic indices. A correlation analysis found that ln(a), where a is the specific upslope area, was the best univariate spatial predictor of soil moisture for wet conditions and that the potential radiation index was best during dry periods. Combinations of ln(a) or ln(a/tan(β)), where β is the surface slope, and the potential solar radiation index explain up to 61% of the spatial variation of soil moisture during wet periods and up to 22% during dry periods. These combinations explained the majority of the topographically organized component of the spatial variability of soil moisture a posteriori. A scale analysis indicated that indices that represent terrain convergence (such as ln(a) or ln(a/tan(β))) explain variability at all scales from 10 m up to the catchment scale and indices that represent the aspect of different hillslopes (such as the potential solar radiation index) explain variability at scales from 80 m to the catchment scale. The implications of these results are discussed in terms of the organizing processes and in terms of the use of terrain attributes in hydrologic modeling and scale studies. A major limitation on the predictive power of terrain indices is the degree of spatial organization present in the soil moisture pattern at the time for which the prediction is made.
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    [Review of the book Fermat's last theorem]
    Lewin, E. ; Park, M. M. (The Victorian Bar, 1997)
    Two recent books celebrate the long sought solution of a venerable maths problem.
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    [Review of the books Skunk works: a personal memoir of my years at Lockheed and The story of Webster's Third: Philip Gove's controversial dictionary and its critics]
    Park, Malcolm McKenzie (The Victorian Bar, 1995)
    Description of two creative men and their work products – innovative top secret US military aircraft and the current edition of Webster’s Third New International Dictionary.
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    Groundwater Quality Hydrogeological Assessments
    Lane, Mr Anthony ; Leonard, Mr John ; Weaver, Dr Tamie R ( 1999)
    Groundwater is a vital resource in Victoria. The Environment Protection Authority (EPA) and other authorities recognise the need to protect the quality of groundwater as a resource and as part of the natural environment. Hydrogeological Assessments (HAs) is one of the tools used to provide the information necessary to determine the status of groundwater quality or the effects of a proposal on the beneficial uses of groundwater. For example, a proponent of a new landfill or industrial development with potential to impact groundwater is likely to be required to perform a HA. The HA guidelines that have been published by EPA (EPA publication 668) provide an overview of HA methodologies, and the reasons for using different investigative techniques. The document presented here is a background document. It was commissioned and funded by the EPA; however it was never published by EPA. Instead, this document formed the basis for development of the guidelines, Hydrogeological Assessments (Groundwater Quality) Guidelines, published by EPA in August 2006.
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    Considerations is assessing the potential success of a cadastral or land information management project in developing countries: a case study of the Thailand Land Titling Project
    Williamson, Ian P. ( 1990)
    The Thailand Land Titling Project is undoubtedly a successful project combining technical, institutional, management, legal, training and educational components. It is a joint project by the Royal Thai Government, the World Bank and the Australian International Development Assistance Bureau. It is primarily concerned with the issuing of land titles to all freehold parcels in the Kingdom of Thailand, in addition to undertaking land administration reform, establishing a national valuation system, carrying out urban cadastral mapping for all urban areas in the country and developing a national land information strategy. The paper briefly overviews the project, outlines some of the lessons from the project and the significant socio-economic benefits of the project. However the paper concentrates on attempting to evaluate the reasons for the success of the project. In particular it argues that the institutional, economic, social, legal and political environment at the time of project preparation and implementation was conducive to its success. Such an evaluation is necessary to place the lessons, achievements and benefits of the Land Titling Project in perspective for others who may wish to translate these experiences to their own countries or jurisdictions. By drawing on the experiences of the Land Titling Project and other projects with which the author has been involved, an attempt is made to generalize the considerations and necessary environment for success of similar projects.
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    Why cadastral reform?
    Williamson, Ian P. ( 1990)
    Why has it been necessary to have a conference on cadastral reform? In fact what is cadastral reform in the Australasian context? The paper addresses these issues from an historical perspective and looks at present issues and pressures on Australasian cadastral systems. Present cadastral reforms are reviewed and some issues which need to be addressed in the future are highlighted. In particular the paper emphasises that an holistic approach is necessary in reforming cadastral systems while recognising that cadastral systems are fast becoming information systems as we move into the era of an information society. The paper recognises that our present cadastral systems had their genesis in the 19th Century and that many of our practices, laws and regulations and institutional arrangements are not applicable to today's society. Present day changes to our cadastral systems however must recognise that it is only during the last decade that cadastral principles have been accepted within our land administration systems.
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    Teaching and research programs in land and geographic information systems at the University of Melbourne, Australia
    Williamson, Ian P. ; Hunter, Gary J. ( 1990)
    As in many other parts of the world, Australia is experiencing a severe shortage of Land and Geographic Information System (LIS/GIS) specialists who possess appropriate tertiary education backgrounds. This shortage of qualified personnel is causing difficulties for public agencies trying to establish LIS/GIS which, having fought for approval of staff increases, are often in the embarrassing position of not being able to fill positions when finally allowed to do so. This shortage applies just as equally to the private and academic sectors.In an effort to address this imbalance, The University of Melbourne has designed new LIS/GIS courses and subjects, at both the undergraduate and postgraduate levels, with the aim of catering for young professionals about to enter the LIS/GIS community, and current administrators, academics and practitioners who find they now need a stronger background in the science, technology and management issues surrounding LIS/GIS.The paper outlines a multi-disciplinary strategy at The University of Melbourne for teaching and research in LIS/GIS. The paper, however, concentrates on the programs within the Department of Surveying and Land Information (A Centre of Excellence in Land Information Studies designated by the Institute of Land Information based in Washington, DC), and a new Graduate Diploma in Geographic Information Systems being introduced jointly by the above department and the School of Environmental Planning within the University.