Time filter

Source Type

Jex C.N.,University of New South Wales | Jex C.N.,National Center for Groundwater Research and Training | Pate G.H.,University of New South Wales | Blyth A.J.,Curtin University Australia | And 5 more authors.
Quaternary Science Reviews | Year: 2014

Lignin has been analysed as a proxy for vegetation change in the Quaternary science literature since the early 1990s in archives such as peat, lakes, and intertidal and marine sediment cores. Historically, it has been regarded as comparatively resistant to various types of degradation in comparison to other plant components. However, studies of modern biogeochemical processes affecting organic carbon have demonstrated significant degradation and alteration of lignin as it is transported through the terrestrial biosphere, including phase changes from particulate to dissolved organic matter, mineral binding and decay due to biotic and abiotic processes. The literature of such topics is vast, however it is not particularly useful to Quaternary research without a comprehensive review to link our understanding of modern processes involving lignin to Quaternary environments. This review will outline the current state of the art in lignin phenol research that is relevant to the Quaternary scientist, and highlight the potential future applications for this important biomarker for vegetation change and terrestrial organic carbon cycling. © 2014 Elsevier Ltd.


Irvine D.J.,National Center for Groundwater Research and Training | Irvine D.J.,Flinders University | Brunner P.,Center for Hydrogeology and Geothermics | Franssen H.J.H.,Jülich Research Center | And 2 more authors.
Journal of Hydrology | Year: 2012

A common approach in modeling surface water-groundwater interaction is to represent the streambed as a homogeneous geological structure with hydraulic properties obtained by means of model calibration. In reality, streambeds are highly heterogeneous, and there are currently no methodical investigations to justify the simplification of this geologic complexity. Using a physically based numerical model, synthetic surface water-groundwater infiltration flux data were generated using heterogeneous streambeds for losing connected, losing transitional and losing disconnected streams. Homogeneous streambed hydraulic conductivities were calibrated to reproduce these fluxes. The homogeneous equivalents were used for predicting infiltration fluxes between streams and the aquifer under different hydrological conditions (i.e. for different states of connection). Homogeneous equivalents are shown to only accurately reproduce infiltration fluxes if both the calibration and prediction are made for a connected flow regime, or if both the calibration and prediction are made for a disconnected flow regime. The greatest errors in flux (±34%) using homogeneous equivalents occurred when there was a mismatch between the flow regime of the observation data and the prediction. These errors are comparatively small when compared with field measurement errors for hydraulic conductivity, however over long river reaches these errors can amount to significant volumes of water. © 2011 Elsevier B.V.


Mendham E.,National Center for Groundwater Research and Training | Mendham E.,Charles Sturt University | Curtis A.,National Center for Groundwater Research and Training | Curtis A.,Charles Sturt University | Millar J.,Charles Sturt University
Ecology and Society | Year: 2012

One aspect of recent rural change is in-migration, which is challenging the traditional dominance of production values in some areas. We explored the natural resource management implications of property turnover in two Australian regions. Our mixed-methods approach combined analysis of property sales records and spatially referenced landholder survey data with data from key informant interviews. Close to 50% of rural properties are expected to change hands between 2006 and 2016, double the change in the previous decade. This change is linked to the transformation of these rural areas, including the influx of non-farming rural landholders seeking amenity values. Our research suggests that property turnover of this scale has important implications for natural resource management. Newer and longer term owners were very different in terms of their values, attitudes, knowledge, land use, and management practices. A substantial proportion of these new property owners are absentees, which further complicates natural resource management, and our view is that a "business as usual" approach to the engagement of the new cohort of rural land managers is unlikely to be effective. © 2012 by the author(s).


Skurray J.H.,University of Western Australia | Skurray J.H.,National Center for Groundwater Research and Training | Roberts E.J.,GHD Pty. Ltd. | Roberts E.J.,Edith Cowan University | And 2 more authors.
Journal of Hydrology | Year: 2012

Perth, Western Australia (pop. 1.6m) derives 60% of its public water supply from the Gnangara groundwater system (GGS). Horticulture, domestic self-supply, and municipal parks are other major consumers of GGS groundwater. The system supports important wetlands and groundwater-dependent ecosystems. Underlying approximately 2200km 2 of the Swan Coastal Plain, the GGS comprises several aquifer levels with partial interconnectivity. Supplies of GGS groundwater are under unprecedented stress, due to reduced recharge and increases in extraction. Stored reserves in the superficial aquifer fell by 700GL between 1979 and 2008. Over a similar period, annual extraction for public supply increased by more than 350% from the system overall. Some management areas are over-allocated by as much as 69%.One potential policy response is a trading scheme for groundwater use. There has been only limited trading between GGS irrigators. Design and implementation of a robust groundwater trading scheme faces hydrological and/or hydro-economic challenges, among others. Groundwater trading involves transfers of the right to extract water. The resulting potential for spatial (and temporal) redistribution of the impacts of extraction requires management. Impacts at the respective selling and buying locations may differ in scale and nature. Negative externalities from groundwater trading may be uncertain as well as not monetarily compensable.An ideal groundwater trading scheme would ensure that marginal costs from trades do not exceed marginal benefits, incorporating future effects and impacts on third-parties. If this condition could be met, all transactions would result in constant or improved overall welfare. This paper examines issues that could reduce public welfare if groundwater trading is not subject to well-designed governance arrangements that are appropriate to meeting the above condition. It also outlines some opportunities to address key risks within the design of a groundwater trading scheme. We present a number of challenges, focusing on those with hydrological bases and/or information requirements. These include the appropriate hydrological definition of the boundaries of a trading area, the establishment and defining of sustainable yield and consumptive pool, and the estimation of effects of extractions on ecosystems and human users. We suggest several possible design tools. A combination of sustainable extraction limits, trading rules, management areas, and/or exchange rates may enable a trading scheme to address the above goals. © 2011 Elsevier B.V.


Cox M.E.,Queensland University of Technology | Cox M.E.,National Center for Groundwater Research and Training | James A.,Queensland University of Technology | Hawke A.,Queensland University of Technology | And 2 more authors.
Journal of Hydrology | Year: 2013

Management of groundwater systems requires realistic conceptual hydrogeological models as a framework for numerical simulation modelling, but also for system understanding and communicating this to stakeholders and the broader community. To help overcome these challenges we developed GVS (Groundwater Visualisation System), a stand-alone desktop software package that uses interactive 3D visualisation and animation techniques. The goal was a user-friendly groundwater management tool that could support a range of existing real-world and pre-processed data, both surface and subsurface, including geology and various types of temporal hydrological information. GVS allows these data to be integrated into a single conceptual hydrogeological model. In addition, 3D geological models produced externally using other software packages, can readily be imported into GVS models, as can outputs of simulations (e.g. piezometric surfaces) produced by software such as MODFLOW or FEFLOW. Boreholes can be integrated, showing any down-hole data and properties, including screen information, intersected geology, water level data and water chemistry. Animation is used to display spatial and temporal changes, with time-series data such as rainfall, standing water levels and electrical conductivity, displaying dynamic processes. Time and space variations can be presented using a range of contouring and colour mapping techniques, in addition to interactive plots of time-series parameters. Other types of data, for example, demographics and cultural information, can also be readily incorporated. The GVS software can execute on a standard Windows or Linux-based PC with a minimum of 2. GB RAM, and the model output is easy and inexpensive to distribute, by download or via USB/DVD/CD.Example models are described here for three groundwater systems in Queensland, northeastern Australia: two unconfined alluvial groundwater systems with intensive irrigation, the Lockyer Valley and the upper Condamine Valley, and the Surat Basin, a large sedimentary basin of confined artesian aquifers. This latter example required more detail in the hydrostratigraphy, correlation of formations with drillholes and visualisation of simulation piezometric surfaces. Both alluvial system GVS models were developed during drought conditions to support government strategies to implement groundwater management. The Surat Basin model was industry sponsored research, for coal seam gas groundwater management and community information and consultation. The "virtual" groundwater systems in these 3D GVS models can be interactively interrogated by standard functions, plus production of 2D cross-sections, data selection from the 3D scene, rear end database and plot displays. A unique feature is that GVS allows investigation of time-series data across different display modes, both 2D and 3D. GVS has been used successfully as a tool to enhance community/stakeholder understanding and knowledge of groundwater systems and is of value for training and educational purposes. Projects completed confirm that GVS provides a powerful support to management and decision making, and as a tool for interpretation of groundwater system hydrological processes. A highly effective visualisation output is the production of short videos (e.g. 2-5. min) based on sequences of camera 'fly-throughs' and screen images. Further work involves developing support for multi-screen displays and touch-screen technologies, distributed rendering, gestural interaction systems. To highlight the visualisation and animation capability of the GVS software, links to related multimedia hosted online sites are included in the references. © 2013 Elsevier B.V.


Perez C.,University of Chile | Mariethoz G.,University of New South Wales | Mariethoz G.,National Center for Groundwater Research and Training | Ortiz J.M.,University of Chile
Computers and Geosciences | Year: 2014

Parameter inference is a key aspect of spatial modeling. A major appeal of variograms is that they allow inferring the spatial structure solely based on conditioning data. This is very convenient when the modeler does not have a ready-made geological interpretation. To date, such an easy and automated interpretation is not available in the context of most multiple-point geostatistics applications. Because training images are generally conceptual models, their preparation is often based on subjective criteria of the modeling expert. As a consequence, selection of an appropriate training image is one of the main issues one must face when using multiple-point simulation. This paper addresses the development of a geostatistical tool that addresses two separate problems. It allows (1) ranking training images according to their relative compatibility to the data, and (2) obtaining an absolute measure quantifying the consistency between training image and data in terms of spatial structure. For both, two alternative implementations are developed. The first one computes the frequency of each pattern in each training image. This method is statistically sound but computationally demanding. The second implementation obtains similar results at a lesser computational cost using a direct sampling approach. The applicability of the methodologies is successfully evaluated in two synthetic 2D examples and one real 3D mining example at the Escondida Norte deposit. © 2014 Elsevier Ltd.


Yang Y.,Tsinghua University | Shang S.,Tsinghua University | Guan H.,Flinders University | Guan H.,National Center for Groundwater Research and Training | Jiang L.,Tsinghua University
Journal of Geophysical Research: Biogeosciences | Year: 2013

Quantifying carbon fluxes at large spatial scales has attracted considerable scientific attentions. In this study, a novel approach was proposed to estimate the terrestrial ecosystem gross primary production (GPP) using imagery from the satellite-borne Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. The new model (named Temperature and Greenness Rectangle, TGR) uses a combination of MODIS Enhanced Vegetation Index and Land Surface Temperature products as well as in situ measurement of photosynthetically active radiation to estimate GPP at a 16 day interval. Three major advantages are included in the model: (1) the model follows strictly the logic of the light use efficiency model and each parameter has physical meaning; (2) the model reduces the dependency on ground-based meteorological measurements; and (3) the overlap of information in correlated explanatory variables is avoided. The model was calibrated with data from 17 sites within the Ameriflux network and validated at another 13 sites, covering a wide range of climates and eight major vegetation types. Results show that the TGR model explains reasonably well the tower-based measurements of GPP for all vegetation types, except for the evergreen broadleaf forest, with the coefficient of determination in a range from 0.67 to 0.91 and the root mean square error from 9.0 to 31.9 g C/m2/16 days. Comparisons with other two models (the TG and GR model) show that the TGR model generally gives better GPP estimates in nearly all vegetation types, especially under dry climate conditions. These results indicate that the TGR model can be potentially used to estimate GPP at regional scale. © 2013. American Geophysical Union. All Rights Reserved.


Dausman A.M.,U.S. Geological Survey | Doherty J.,National Center for Groundwater Research and Training | Langevin C.D.,U.S. Geological Survey | Sukop M.C.,Florida International University
Ground Water | Year: 2010

The present study demonstrates a methodology for optimization of environmental data acquisition. Based on the premise that the worth of data increases in proportion to its ability to reduce the uncertainty of key model predictions, the methodology can be used to compare the worth of different data types, gathered at different locations within study areas of arbitrary complexity. The method is applied to a hypothetical nonlinear, variable density numerical model of salt and heat transport. The relative utilities of temperature and concentration measurements at different locations within the model domain are assessed in terms of their ability to reduce the uncertainty associated with predictions of movement of the salt water interface in response to a decrease in fresh water recharge. In order to test the sensitivity of the method to nonlinear model behavior, analyses were repeated for multiple realizations of system properties. Rankings of observation worth were similar for all realizations, indicating robust performance of the methodology when employed in conjunction with a highly nonlinear model. The analysis showed that while concentration and temperature measurements can both aid in the prediction of interface movement, concentration measurements, especially when taken in proximity to the interface at locations where the interface is expected to move, are of greater worth than temperature measurements. Nevertheless, it was also demonstrated that pairs of temperature measurements, taken in strategic locations with respect to the interface, can also lead to more precise predictions of interface movement. Journal compilation © 2010 National Ground Water Association.


Skurray J.H.,University of Western Australia | Skurray J.H.,National Center for Groundwater Research and Training
Ecological Economics | Year: 2015

The Gnangara groundwater system in Western Australia supports multiple ecological systems and human uses, and is under unprecedented stress. This paper examines some of Ostrom's 'situational variables' for the analysis of institutional choice in common-pool resources, as they relate to the Gnangara case. The institutional analysis identifies elements of the current governance institutions that could be altered to facilitate collective action. We use data from a set of water licensing documents obtained from the state's Department of Water. A number of factors are identified as inhibiting the potential for collective action. Current arrangements are top-down in nature, with all rules, monitoring, and any enforcement supplied by the state-level management agency. Norms and expectations among appropriators appear to be competitive rather than co-operative, and discount rates appear to be high. Monitoring and enforcement are under-supplied, and opportunistic behaviour affects compliance. The interactions between user and regulator influence the appropriation of flows, and have resulting impacts on the resource stock. We conclude that several factors in this case prejudice the development of collective action institutions by appropriator efforts alone. The study highlights important aspects of the institutional arrangements in place, and their likely effects upon the attitudes and behaviours of appropriators who, along with wildlife and ecosystems, depend on the common-pool resource. © 2015.


Park S.E.,CSIRO | Marshall N.A.,CSIRO | Jakku E.,CSIRO | Dowd A.M.,CSIRO | And 3 more authors.
Global Environmental Change | Year: 2012

Transformative actions are increasingly being required to address changes in climate. As an aid to understanding and supporting informed decision-making regarding transformative change, we draw on theories from both the resilience and vulnerability literature to produce the Adaptation Action Cycles concept and applied framework. The resulting Adaptation Action Cycles provides a novel conceptualisation of incremental and transformative adaptation as a continuous process depicted by two concentric and distinct, yet linked, action learning cycles. Each cycle represents four stages in the decision-making process, which are considered to be undertaken over relatively short timeframes. The concept is translated into an applied framework by adopting a contextual, actor-focused suite of questions at each of the four stages. This approach compliments existing theories of transition and transformation by operationalising assessments at the individual and enterprise level. Empirical validation of the concept was conducted by collaborating with members of the Australian wine industry to assess their decisions and actions taken in response to climate change. The contiguous stages represented in the Adaptation Action Cycles aptly reflected the diverse range of decision-making and action pathways taken in recent years by those interviewed. Results suggest that incremental adaptation decision-making processes have distinct characteristics, compared with those used in transformative adaptation. We provide empirical data to support past propositions suggesting dependent relationships operate between incremental and transformative scales of adaptation. © 2011 Elsevier Ltd.

Loading National Center for Groundwater Research and Training collaborators
Loading National Center for Groundwater Research and Training collaborators