ORCID Profile
0000-0001-7632-5491
Current Organisation
University of New South Wales
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Physical Geography and Environmental Geoscience | Hydrogeology | Environmental Science and Management | Inorganic Geochemistry | Quaternary Environments | Ecosystem Function | Environmental Impact Assessment | Environmental Monitoring | Geomorphology and Regolith and Landscape Evolution | Organic Geochemistry |
ANZSRC Socio-Economic Objective (SEO)
Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and Industrial Use) | Land and Water Management of environments not elsewhere classified | Sparseland, Permanent Grassland and Arid Zone Land and Water Management | Ecosystem Assessment and Management of Fresh, Ground and Surface Water Environments | Climate Change Mitigation Strategies | Urban Water Evaluation (incl. Water Quality) | Forest and Woodlands Soils | Expanding Knowledge in the Environmental Sciences | Forest and Woodlands Water Management | Forest and Woodlands Land Management | Rural Water Evaluation (incl. Water Quality) | Farmland, Arable Cropland and Permanent Cropland Water Management
Related Links
Publications
River–groundwater connectivity in a karst system, Wellington, New South Wales, Australia,Connectivité entre rivière et eaux souterraines d’un système karstique, Wellington, New South Wales, Australie,Conectividade rio–água subterrânea em um sistema cárstico, Wellington, Nova Gales do Sul, Austrália,Conectividad agua subterránea–río en un sistema kárstico, Wellington, New South Wales, Australia
Publisher: Springer Science and Business Media LLC
Date: 07-12-2017
A post-wildfire response in cave dripwater chemistry
Publisher: Copernicus GmbH
Date: 21-07-2016
DOI: 10.5194/HESS-20-2745-2016
Abstract: Abstract. Surface disturbances above a cave have the potential to impact cave dripwater discharge, isotopic composition and solute concentrations, which may subsequently be recorded in the stalagmites forming from these dripwaters. One such disturbance is wildfire however, the effects of wildfire on cave chemistry and hydrology remains poorly understood. Using dripwater data monitored at two sites in a shallow cave, beneath a forest, in southwest Australia, we provide one of the first cave monitoring studies conducted in a post-fire regime, which seeks to identify the effects of wildfire and post-fire vegetation dynamics on dripwater δ18O composition and solute concentrations. We compare our post-wildfire δ18O data with predicted dripwater δ18O using a forward model based on measured hydro-climatic influences alone. This helps to delineate hydro-climatic and fire-related influences on δ18O. Further we also compare our data with both data from Golgotha Cave – which is in a similar environment but was not influenced by this particular fire – as well as regional groundwater chemistry, in an attempt to determine the extent to which wildfire affects dripwater chemistry. We find in our forested shallow cave that δ18O is higher after the fire relative to modelled δ18O. We attribute this to increased evaporation due to reduced albedo and canopy cover. The solute response post-fire varied between the two drip sites: at Site 1a, which had a large tree above it that was lost in the fire, we see a response reflecting both a reduction in tree water use and a removal of nutrients (Cl, Mg, Sr, and Ca) from the surface and subsurface. Solutes such as SO4 and K maintain high concentrations, due to the abundance of above-ground ash. At Site 2a, which was covered by lower–middle storey vegetation, we see a solute response reflecting evaporative concentration of all studied ions (Cl, Ca, Mg, Sr, SO4, and K) similar to the trend in δ18O for this drip site. We open a new avenue for speleothem science in fire-prone regions, focusing on the geochemical records of speleothems as potential palaeo-fire archives.
Monitoring the transition from preferential to matrix flow in cracking clay soil through changes in electrical anisotropy
Publisher: Elsevier BV
Date: 06-2012
Experimental investigation of the thermal dispersivity term and its significance in the heat transport equation for flow in sediments
Publisher: American Geophysical Union (AGU)
Date: 03-2012
DOI: 10.1029/2011WR011038
Investigation of a dynamic seawater intrusion event using strontium isotopes (87Sr/86Sr)
Publisher: Elsevier BV
Date: 2008
The impact of fire on the geochemistry of speleothem-forming drip water in a sub-alpine cave
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.SCITOTENV.2018.05.310
Abstract: Fire dramatically modifies the surface environment by combusting vegetation and changing soil properties. Despite this well-documented impact on the surface environment, there has been limited research into the impact of fire events on karst, caves and speleothems. Here we report the first experiment designed to investigate the short-term impacts of a prescribed fire on speleothem-forming cave drip water geochemistry. Before and after the fire, water was collected on a bi-monthly basis from 18 drip sites in South Glory Cave, New South Wales, Australia. Two months post-fire, there was an increase in B, Si, Na, Fe and Pb concentrations at all drip sites. We conclude that this response is most likely due to the transport of soluble ash-derived elements from the surface to the cave drip water below. A significant deviation in stable water isotopic composition from the local meteoric water line was also observed at six of the sites. We hypothesise that this was due to partial evaporation of soil water resulting in isotopic enrichment of drip waters. Our results demonstrate that even low-severity prescribed fires can have an impact on speleothem-forming cave drip water geochemistry. These findings are significant because firstly, fires need to be considered when interpreting past climate from speleothem δ
Heat as a tracer to quantify water flow in near-surface sediments
Publisher: Elsevier BV
Date: 02-2014
Examining past and projecting future: an 800-year streamflow reconstruction of the Australian Murray river
Publisher: IOP Publishing
Date: 25-09-2023
Stream-aquifer interactions in the Maules Creek catchment, Namoi Valley, New South Wales, Australia
Publisher: Springer Science and Business Media LLC
Date: 12-08-2009
Social tipping points in global groundwater management
Publisher: Springer Science and Business Media LLC
Date: 21-08-2017
DOI: 10.1038/S41562-017-0181-7
Abstract: Groundwater is critical to global food security, environmental flows, and millions of rural livelihoods in the face of climate change
Pyrite Oxidation in Unsaturated Aquifer Sediments. Reaction Stoichiometry and Rate of Oxidation
Publisher: American Chemical Society (ACS)
Date: 08-09-2001
DOI: 10.1021/ES0105919
Abstract: The oxidation of pyrite (FeS2) contained in unsaturated aquifer sediment was studied by sediment incubation in gas impermeable polymer laminate bags. Reaction progress was followed over a period of nearly 2 months by monitoring the gas composition within the laminate bag. The gas phase in the incubation bags became depleted in O2 and enriched in CO2 and N2 and was interpreted as due to pyrite oxidation in combination with calcite dissolution. Sediment incubation provides a new method to estimate low rates of pyrite oxidation in unsaturated zone aquifer sediments. Oxidation rates of up to 9.4 x 10(-10) mol FeS2/g x s are measured, and the rates are only weakly correlated with the sediment pyrite content. The reactivity of pyrite, including the inhibition by FeOOH layers formed on its surface, apparently has a major effect on the rate of oxidation. The code PHREEQC 2.0 was used to calculate the reaction stoichiometry and partitioning of gases between the solution and the gas phase. Pyrite oxidation with concurrent calcite dissolution was found to be consistent with the experimental data while organic carbon oxidation was not. The reaction involves changes in the total volume of the gas phase. The reaction scheme predicts the volume of O2 gas consumed to be larger than of CO2 produced. In addition the solubility of CO2 in water is about 30 times larger than of O2 causing a further decrease in total gas volume. The change in total gas volume therefore also depends on the gas/water volume ratio and the lower the ratio the more pronounced the loss of volume will be. Under field conditions the change in total volume may amount up to 20% in the absence of calcite and over 10% in the presence of calcite. Such changes in gas volume during the oxidation of pyrite are expected to result in pressure gradients causing advective transport of gaseous oxygen.
Drip water isotopes in semi-arid karst: Implications for speleothem paleoclimatology
Publisher: Elsevier BV
Date: 06-2014
Roles of forest bioproductivity, transpiration and fire in a nine-year record of cave dripwater chemistry from southwest Australia
Publisher: Elsevier BV
Date: 07-2016
Discharge of nitrate-containing groundwater into a coastal marine environment
Publisher: Elsevier BV
Date: 03-2007
Unsaturated zone hydrology and cave drip discharge water response: Implications for speleothem paleoclimate record variability
Publisher: Elsevier BV
Date: 10-2015
Dissolved Organic Carbon Mobilisation in a Groundwater System Stressed by Pumping
Publisher: Springer Science and Business Media LLC
Date: 22-12-2015
DOI: 10.1038/SREP18487
Abstract: The concentration and flux of organic carbon in aquifers is influenced by recharge and abstraction and surface and subsurface processing. In this study groundwater was abstracted from a shallow fractured rock aquifer and dissolved organic carbon (DOC) was measured in observation bores at different distances from the abstraction bore. Groundwater abstraction at rates exceeding the aquifers yield resulted in increased DOC concentration up to 3,500 percent of initial concentrations. Potential sources of this increased DOC were determined using optical fluorescence and absorbance analysis. Groundwater fluorescent dissolved organic material (FDOM) were found to be a combination of terrestrial-derived humic material and microbial or protein sourced material. Relative molecular weight of FDOM within four metres of the abstraction well increased during the experiment, while the relative molecular weight of FDOM between four and ten metres from the abstraction well decreased. When the aquifer is not being pumped, DOC mobilisation in the aquifer is low. We hypothesise that the physical shear stress on aquifer materials caused by intense abstraction significantly increases the temporary release of DOC from sloughing of biofilms and release of otherwise bound colloidal and sedimentary organic carbon (SOC).
Effect of Transient Wave Forcing on the Behavior of Arsenic in a Nearshore Aquifer
Publisher: American Chemical Society (ACS)
Date: 26-09-2018
Abstract: Groundwater-coastal water interactions influence the fate of inorganic chemicals in nearshore aquifers and their flux to receiving coastal waters. This study evaluates the impact of variable wave conditions on the geochemical changes and distribution of mobile arsenic (As) in a nearshore aquifer. Field measurements in a sandy nearshore aquifer on Lake Erie, Canada, are presented with geochemical changes analyzed over a period of high waves. A numerical model of wave-induced groundwater flow dynamics, validated against field data, is used to provide insight into the physical flow processes underlying the observed geochemical changes. Rapid changes in dissolved As, Fe, Mn, and S demonstrate the importance of reactions as well as dynamic transport in controlling the behavior of reactive species, especially those that are redox sensitive. Field data suggest the presence of sediment traps, which under certain hydrological and geochemical conditions may result in a "hot moment" with episodic release of As. The study provides new insight into factors controlling the fate of reactive species in dynamic coastal environments as required to better predict chemical fluxes to coastal waters. Additionally, it highlights the need to pay particular attention to "hot moments" for reaction and transport caused by storms and waves.
Heat as a tracer to quantify processes and properties in the vadose zone: A review
Publisher: Elsevier BV
Date: 08-2016
Experimental observation of increased apparent dispersion and mixing in a beach aquifer due to wave forcing
Publisher: Elsevier BV
Date: 09-2018
Investigation of the thermal regime and subsurface properties of a tidally affected, variably saturated streambed
Publisher: Wiley
Date: 06-2017
DOI: 10.1002/HYP.11197
Carbon dynamics in a Late Quaternary-age coastal limestone aquifer system undergoing saltwater intrusion
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.SCITOTENV.2017.06.094
Abstract: This study investigates the inorganic and organic aspects of the carbon cycle in groundwaters throughout the freshwater lens and transition zone of a carbonate island aquifer and identifies the transformation of carbon throughout the system. We determined
Effects of wildfire on long-term soil CO2 concentration: implications for karst processes
Publisher: Springer Science and Business Media LLC
Date: 02-2016
Controls on cave drip water temperature and implications for speleothem-based paleoclimate reconstructions
Publisher: Elsevier BV
Date: 11-2015
A post-wildfire response in cave dripwater chemistry
Publisher: Copernicus GmbH
Date: 19-01-2016
DOI: 10.5194/HESS-2016-1
Abstract: Abstract. Cave environments are sensitive because surface environmental changes can affect both the isotopic composition and solute concentration of infiltrating cave dripwaters. These changes subsequently affect the speleothem geochemical record. One such agent of change is wildfire, however its effect on karst processes remains poorly understood. Using dripwater data from a shallow cave, at a forested site in southwest Australia, we provide a unique analysis of the post-wildfire effects on dripwater δ18O and solute concentrations. We analyse how wildfires affect on local controls, i.e. vegetation cover, evapotranspiration and carbonate water-rock interactions, effects cave dripwater hydrology and geochemistry. We compare our post-wildfire data with modelled drip water δ18O, regional groundwater chemistry, and a second cave dripwater dataset, to determine the extent to which wildfire affects cave dripwater composition. We find in our forested, shallow cave site, by effecting surface evaporation and transpiration rates wildfire can have a multi-year impact on subsurface hydrology and dripwater chemistry. Here we open a new avenue for speleothem science in fire-prone regions, focusing on the geochemical records of speleothems as potential paleo-fire archives.
An agent-based platform for simulating complex human-aquifer interactions in managed groundwater systems
Publisher: Elsevier BV
Date: 11-2015
River–aquifer interactions in a semi‐arid environment stressed by groundwater abstraction
Publisher: Wiley
Date: 13-04-2012
DOI: 10.1002/HYP.9229
One Thousand Three Hundred Years of Variability in the Position of the South Pacific Convergence Zone
Publisher: American Geophysical Union (AGU)
Date: 25-08-2020
DOI: 10.1029/2020GL088238
Abstract: The South Pacific Convergence Zone (SPCZ) is the largest rain belt in the Southern Hemisphere and a key driver of precipitation variability, impacting South Pacific island communities. Our millennial‐long reconstruction is based on a trans‐Pacific tree‐ring network, containing chronologies sensitive to changes in the SPCZ because of its pervasive nature, spatial extent, and link to the El Niño‐Southern Oscillation. The reconstruction explains 58% of variance in the instrumental SPCZ index from 1911–1998. El Niño‐Southern Oscillation cycles are identified throughout the reconstruction period. Multidecadal periodicities wax and wane, coinciding with a sustained eastward shift during the Medieval Climate Anomaly (~1,000–1,200 CE). We find large volcanic eruptions increased the tendency for the SPCZ to be displaced eastward. The reconstruction helps improve our understanding of past hydroclimatic behavior in the southwest Pacific and can be used to validate general circulation model projections for Pacific Island communities and the wider region in the 21st century.
Island groundwater resources, impacts of abstraction and a drying climate: Rottnest Island, Western Australia
Publisher: Elsevier BV
Date: 11-2016
Unprecedented High Northern Australian Streamflow Linked to an Intensification of the Indo‐Australian Monsoon
Publisher: American Geophysical Union (AGU)
Date: 03-2022
DOI: 10.1029/2021WR030881
Abstract: Streamflow in Australia’s northern rivers has been steadily increasing since the 1970s, most likely due to increased intensity in the Indo‐Australian monsoon. However, because of limited data availability, it is hard to assess this recent trend and therefore contextualize potential future climatic changes. In this study, we used a network of 63 precipitation‐sensitive tree‐ring chronologies from the Indo‐Australian and Asian monsoon regions to reconstruct streamflow in the Daly catchment in the Northern Territory of Australia from 1413 to 2005 CE. We used a novel wavelet‐based method to transform the variance structure of the tree‐ring chronologies to better match the hydroclimate prior to reconstruction with a hierarchical Bayesian regression model. Our streamflow reconstruction accounts for 72%–78% of the variance in the instrumental period and closely matches both historical flood events and independent proxy records, increasing confidence in its validity. We find that while streamflow has been increasing since the 1800s, the most recent 40‐year period is unprecedented in the last ∼600 years. Comparison to an independent coral‐based streamflow record shows regional coherency in this trend. Extreme high flows were found to be linked to La Niña events, but we found no significant relationship between streamflow and El Niño events, or streamflow and other regional climatic drivers. More work is therefore needed to understand the drivers of the recent streamflow increase, but, regardless of the cause, water managers should be aware of the paleoclimatic context before making decisions on water allocations.
Field Measurement of Fluorescent Dissolved Organic Material as a Means of Early Detection of Leachate Plumes
Publisher: Springer Science and Business Media LLC
Date: 17-06-2015
A 1-D analytical method for estimating surface water-groundwater interactions and effective thermal diffusivity using temperature time series
Publisher: American Geophysical Union (AGU)
Date: 11-2012
DOI: 10.1029/2012WR012007
Dating stalagmites in mediterranean climates using annual trace element cycles
Publisher: Springer Science and Business Media LLC
Date: 04-04-2017
DOI: 10.1038/S41598-017-00474-4
Abstract: Speleothems may preserve geochemical information at annual resolution, preserving information about past hydrology, environment and climate. In this study, we advance information-extraction from speleothems in two ways. First, the limitations in dating modern stalagmites are overcome by refining a dating method that uses annual trace element cycles. It is shown that high-frequency variations in elements affected by prior calcite precipitation (PCP) can be used to date speleothems and yield an age within 2–4% chronological uncertainty of the actual age of the stalagmite. This is of particular relevance to mediterranean regions that display strong seasonal controls on PCP, due to seasonal variability in water availability and cave-air p CO 2 . Second, using the chronology for one stalagmite s le, trace elements and growth-rate are compared with a record of climate and local environmental change i.e. land-use and fire, over the 20 th century. Well-defined peaks in soil-derived trace elements and simultaneous decreases in growth-rate coincide with extreme annual rainfall totals in 1934 and 1974. One of which, 1934, was due to a recorded cyclone. We also find that bedrock-derived elements that are dominated by PCP processes, reflect a well-known period of drying in southwest Australia which began in the 1970’s.
Semi-arid zone caves: Evaporation and hydrological controls on δ18O drip water composition and implications for speleothem paleoclimate reconstructions
Publisher: Elsevier BV
Date: 2016
What determines the calcium concentration of speleothem-forming drip waters?
Publisher: Elsevier BV
Date: 08-2016
Mechanisms of water adsorption into partially saturated fractured shales: An experimental study
Publisher: Elsevier BV
Date: 11-2015
Use of heat as tracer to quantify vertical streambed flow in a two-dimensional flow field
Publisher: American Geophysical Union (AGU)
Date: 10-2012
DOI: 10.1029/2012WR011918
Abstract: Analytical solutions to the heat transport equation in porous media have been developed in the past to estimate surface water‐groundwater interactions. These solutions, however, are based upon simplifying assumptions that are frequently violated in natural systems. A nonvertical flow field, inherent to most field settings, can violate the one‐dimensional (1‐D) flow assumption and lead to erroneous velocity estimates. In this study, we have developed a 2‐D heat and mass transport finite element‐based numerical model for a stream aquifer cross section experiencing flow‐through. Synthetic multilevel streambed temperature time series were generated with the model using a sinusoidal temperature boundary. The temperature data was used to quantify the vertical flow velocity with a 1‐D analytical solution based on the litude decay and phase shift of temperature with depth. Results demonstrate that erroneous vertical components of fluid velocity can be obtained by the 1‐D analytical solution when the true vertical velocity approaches zero and the flow regime becomes almost horizontal. The results also illustrate that the litude ratio method performs quite poorly on the gaining side of the stream where the only reliable method is phase shift. On the losing side of the stream, both methods can be employed but a better estimation is obtained from the litude ratio method. In general, litude ratio and phase shift data should be used in conjunction to maximize the information of the system.
Investigations of soil cracking and preferential flow in a weighing lysimeter filled with cracking clay soil
Publisher: Elsevier BV
Date: 10-2010
Dripwater organic matter and trace element geochemistry in a semi-arid karst environment: Implications for speleothem paleoclimatology
Publisher: Elsevier BV
Date: 06-2014
Organic characterisation of cave drip water by LC-OCD and fluorescence analysis
Publisher: Elsevier BV
Date: 10-2015
To what extent do long-duration high-volume dam releases influence river–aquifer interactions? A case study in New South Wales, Australia,长期大容量水坝放水对河流-含水层相互作用的影响能到什么程度?澳大利亚新南威尔士州的一个研究实例,Dans quelle mesure les lâchers de barrages de longue durée et gros volume influencent-ils les interactions nappe–rivière? Une étude de cas en Nouvelle-Galles du Sud, Australie,Até que ponto as descargas de longa duração e grande volume de barragens influenciam as interações rio–aquífero? Um estudo de caso na Nova Gales do Sul, Austrália,En qué medida los vertidos de larga duración y alto volumen de los diques influyen en la interacción río–acuífero? Un estudio de caso en Nueva Gales del Sur, Australia
Publisher: Springer Science and Business Media LLC
Date: 20-11-2015
Groundwater fluxes and flow paths within coastal barriers: Observations from a large-scale laboratory experiment (BARDEX II)
Publisher: Elsevier BV
Date: 07-2014
Geochemical processes and solute transport at the seawater/freshwater interface of a sandy aquifer
Publisher: Elsevier BV
Date: 08-2005
Calculating water saturation from passive temperature measurements in near-surface sediments: Development of a semi-analytical model
Publisher: Elsevier BV
Date: 03-2016
Stochastic reconstruction of paleovalley bedrock morphology from sparse datasets
Publisher: Elsevier BV
Date: 03-2014
Local thermal non-equilibrium in sediments: Implications for temperature dynamics and the use of heat as a tracer
Publisher: Elsevier BV
Date: 11-2014
Association of Arsenic and Phosphorus with Iron Nanoparticles between Streams and Aquifers: Implications for Arsenic Mobility
Publisher: American Chemical Society (ACS)
Date: 23-11-2015
Abstract: The microbial oxidation of organic matter coupled to reductive iron oxide dissolution is widely recognized as the dominant mechanism driving elevated arsenic (As) concentrations in aquifers. This paper considers the potential of nanoparticles to increase the mobility of As in aquifers, thereby accounting for discrepancies between predicted and observed As transport reported elsewhere. Arsenic, phosphorus, and iron size distributions and natural organic matter association were examined along a flow path from surface water via the hyporheic zone to shallow groundwater. Our analysis demonstrates that the colloidal Fe concentration (>1 kDa) correlates with both colloidal P and colloidal As concentrations. Importantly, increases in the concentration of colloidal P (>1 kDa) were positively correlated with increases in the concentration of nominally dissolved As (<1 kDa), but no correlation was observed between colloidal As and nominally dissolved P. This suggests that P actively competes for adsorption sites on Fe nanoparticles, displacing adsorbed As, thus mirroring their interaction with Fe oxides in the aquifer matrix. Dynamic redox fronts at the interface between streams and aquifers may therefore provide globally widespread conditions for the generation of Fe nanoparticles, a mobile phase for As adsorption currently not a part of reactive transport models.
Analytical methods that use natural heat as a tracer to quantify surface water-groundwater exchange, evaluated using field temperature records
Publisher: Springer Science and Business Media LLC
Date: 11-03-2010
River-aquifer interactions in a semiarid environment investigated using point and reach measurements
Publisher: American Geophysical Union (AGU)
Date: 04-2014
DOI: 10.1002/2012WR012922
In-situ estimation of subsurface hydro-geomechanical properties using the groundwater response to Earth and atmospheric tides
Publisher: Wiley
Date: 15-12-2020
Aquifer heterogeneity and response time: The challenge for groundwater management
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/CP13084
Abstract: Groundwater is an important contributor to irrigation water supplies. The time lag between withdrawal and the subsequent impacts on the river corridor presents a challenge for water management. We highlight aspects of this challenge by examining trends in the groundwater levels and changes in groundwater management goals for the Namoi Catchment, which is within the Murray–Darling Basin, Australia. The first high-volume irrigation bore was installed in the cotton-growing districts in the Namoi Catchment in 1966. The development of high-yielding bores made accessible a vast new water supply, enabling cotton growers to buffer the droughts. Prior to the development of a groundwater resource it is difficult to accurately predict how the water at the point of withdrawal is hydraulically connected to recharge zones and nearby surface-water features. This is due to the heterogeneity of the sediments from which the water is withdrawn. It can take years or decades for the impact of groundwater withdrawal to be transmitted kilometres through the aquifer system. We present the analysis of both historical and new groundwater level and streamflow data to quantify the impacts of extensive groundwater withdrawals on the watertable, hydraulic gradients within the semi-confined aquifers, and the movement of water between rivers and aquifers. The results highlight the need to monitor the impacts of irrigated agriculture at both the regional and local scales, and the need for additional research on how to optimise the conjunctive use of both surface-water and groundwater to sustain irrigated agriculture while minimising the impact on groundwater-dependent ecosystems.
Groundwater supports intermittent-stream food webs
Publisher: University of Chicago Press
Date: 03-2018
DOI: 10.1086/696533
Assessing the accuracy of 1‐D analytical heat tracing for estimating near‐surface sediment thermal diffusivity and water flux under transient conditions
Publisher: American Geophysical Union (AGU)
Date: 08-2015
DOI: 10.1002/2015JF003466
Characterising the dynamics of surface water-groundwater interactions in intermittent and ephemeral streams using streambed thermal signatures
Publisher: Elsevier BV
Date: 09-2017
A New Method for Estimating Recharge to Unconfined Aquifers Using Differential River Gauging
Publisher: Wiley
Date: 02-04-2013
DOI: 10.1111/GWAT.12046
Abstract: In semiarid and arid environments, leakage from rivers is a major source of recharge to underlying unconfined aquifers. Differential river gauging is widely used to estimate the recharge. However, the methods commonly applied are limited in that the temporal resolution is event-scale or longer. In this paper, a novel method is presented for quantifying both the total recharge volume for an event, and variation in recharge rate during an event from hydrographs recorded at the upstream and downstream ends of a river reach. The proposed method is applied to river hydrographs to illustrate the method steps and investigate recharge processes occurring in a sub-catchment of the Murray Darling Basin (Australia). Interestingly, although it is the large flood events which are commonly assumed to be the main source of recharge to an aquifer, our analysis revealed that the smaller flow events were more important in providing recharge.
Experimental investigation of the thermal time-series method for surface water-groundwater interactions
Publisher: American Geophysical Union (AGU)
Date: 03-2012
DOI: 10.1029/2011WR011560
Effect of solid–fluid thermal expansion on thermo-osmotic tests: An experimental and analytical study
Publisher: Elsevier BV
Date: 02-2015
Investigation of the kinetics of water uptake into partially saturated shales
Publisher: American Geophysical Union (AGU)
Date: 04-2016
DOI: 10.1002/2015WR017786
A reassessment of the Lower Namoi Catchment aquifer architecture and hydraulic connectivity with reference to climate drivers
Publisher: Informa UK Limited
Date: 03-04-2014
High rates of organic carbon processing in the hyporheic zone of intermittent streams
Publisher: Springer Science and Business Media LLC
Date: 16-10-2017
DOI: 10.1038/S41598-017-12957-5
Abstract: Organic carbon cycling is a fundamental process that underpins energy transfer through the biosphere. However, little is known about the rates of particulate organic carbon processing in the hyporheic zone of intermittent streams, which is often the only wetted environment remaining when surface flows cease. We used leaf litter and cotton decomposition assays, as well as rates of microbial respiration, to quantify rates of organic carbon processing in surface and hyporheic environments of intermittent and perennial streams under a range of substrate saturation conditions. Leaf litter processing was 48% greater, and cotton processing 124% greater, in the hyporheic zone compared to surface environments when calculated over multiple substrate saturation conditions. Processing was also greater in more saturated surface environments (i.e. pools). Further, rates of microbial respiration on incubated substrates in the hyporheic zone were similar to, or greater than, rates in surface environments. Our results highlight that intermittent streams are important locations for particulate organic carbon processing and that the hyporheic zone sustains this fundamental process even without surface flow. Not accounting for carbon processing in the hyporheic zone of intermittent streams may lead to an underestimation of its local ecological significance and collective contribution to landscape carbon processes.
Utilizing the Impact of Earth and Atmospheric Tides on Groundwater Systems: A Review Reveals the Future Potential
Publisher: American Geophysical Union (AGU)
Date: 28-05-2019
DOI: 10.1029/2018RG000630
Abstract: Groundwater extraction is increasing rapidly in many areas of the world, causing serious impacts such as falling water tables, ground surface subsidence, water quality degradation, and reduction of stream baseflow on which many ecosystems depend. Methods for understanding and predicting the impacts of groundwater extraction generally lack detailed spatial and temporal knowledge of the subsurface hydrogeomechanical properties. This review provides a comprehensive understanding of Earth and atmospheric tides and their impact on subsurface pore pressure. First, we evaluate the global occurrence of Earth and atmospheric tides. Then, we illustrate their impact on the groundwater response and connect this with the theory of poroelasticity, which underpins quantitative analyses. Finally, we review methods that utilize these impacts to characterize groundwater systems and to quantify their hydrogeomechanical properties. We conclude by highlighting their potential as passive and low‐cost investigation techniques and by outlining the research and developments required to progress and make analyses readily available. Thus, hydrogeomechanical properties of subsurface systems could be obtained at unprecedented spatial and temporal resolution, adding additional value to commonly acquired groundwater and atmospheric pressure data.
Modelling the 14C bomb-pulse in young speleothems using a soil carbon continuum model
Publisher: Elsevier BV
Date: 09-2019
Phosphorus and arsenic distributions in a seasonally stratified, iron-and manganese-rich lake: Microbiological and geochemical controls
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/EN14094
Abstract: Environmental context Despite being present at trace concentrations, arsenic and phosphorus are among the most important of freshwater contaminants. This research highlights the biogeochemical coupling of both elements in a New Zealand lake. We find that the mineralisation of organic residues coupled to the dissolution of colloidal iron and manganese hydroxides may be an important driver of the bioavailability of phosphorus and arsenic. Abstract Seasonal stratification in temperate lakes greater than a few metres deep provides conditions amenable to pronounced vertical zonation of redox chemistry. Such changes are particularly evident in eutrophic systems where high phytoplankton biomass often leads to seasonally established anaerobic hypolimnia and profound changes in geochemical conditions. In this study, we investigated the behaviour of trace elements in the water column of a seasonally stratified, eutrophic lake. Two consecutive years of data from Lake Ngapouri, North Island, New Zealand, demonstrate the occurrence of highly correlated profiles of phosphorus, arsenic, iron and manganese, all of which increased in concentration by 1–2 orders of magnitude within the anaerobic hypolimnion. Stoichiometric and mass-balance considerations demonstrate that increases in alkalinity in hypolimnetic waters were consistent with observed changes in sulfate, Fe and Mn concentrations with depth, corresponding to dissimilatory reduction of sulfate, FeIII and MnIV hydroxides. Thermodynamic constraints on Fe, Mn and Al solubility indicate that amorphous FeIII, MnIV hydroxides most probably controlled Fe and Mn in the surface mixed layer (~0 to 8m) whereas AlIII hydroxides were supersaturated throughout the entire system. Surface complexation modelling indicated that iron hydroxides (HFO) potentially dominated As speciation in the lake. It is likely that other colloidal phases such as allophanic clays also limited HPO42– activity, reducing competition for HAsO42– adsorption to iron hydroxides. This research highlights the coupling of P, As, Fe and Mn in Lake Ngapouri, and the apparent role of multiple colloidal phases in affecting P and As activity within overarching microbiological and geochemical processes.
Understanding and quantifying focused, indirect groundwater recharge from ephemeral streams using water table fluctuations
Publisher: American Geophysical Union (AGU)
Date: 02-2016
DOI: 10.1002/2015WR017503
Improved spatial delineation of streambed properties and water fluxes using distributed temperature sensing
Publisher: Wiley
Date: 09-03-2016
DOI: 10.1002/HYP.10806
Evaporative cooling of speleothem drip water
Publisher: Springer Science and Business Media LLC
Date: 04-06-2014
DOI: 10.1038/SREP05162
Abstract: This study describes the first use of concurrent high-precision temperature and drip rate monitoring to explore what controls the temperature of speleothem forming drip water. Two contrasting sites, one with fast transient and one with slow constant dripping, in a temperate semi-arid location (Wellington, NSW, Australia), exhibit drip water temperatures which deviate significantly from the cave air temperature. We confirm the hypothesis that evaporative cooling is the dominant, but so far unattributed, control causing significant disequilibrium between drip water and host rock/air temperatures. The amount of cooling is dependent on the drip rate, relative humidity and ventilation. Our results have implications for the interpretation of temperature-sensitive, speleothem climate proxies such as δ 18 O, cave microecology and the use of heat as a tracer in karst. Understanding the processes controlling the temperature of speleothem-forming cave drip waters is vital for assessing the reliability of such deposits as archives of climate change.
Spatially dense drip hydrological monitoring and infiltration behaviour at the Wellington Caves, South East Australia
Publisher: University of South Florida Libraries
Date: 07-2012
A multi-tracer approach to constraining artesian groundwater discharge into an alluvial aquifer
Publisher: Copernicus GmbH
Date: 28-11-2017
DOI: 10.5194/HESS-21-5953-2017
Abstract: Abstract. Understanding pathways of recharge to alluvial aquifers is important for maintaining sustainable access to groundwater resources. Water balance modelling is often used to proportion recharge components and guide sustainable groundwater allocations. However, it is not common practice to use hydrochemical evidence to inform and constrain these models. Here we compare geochemical versus water balance model estimates of artesian discharge into an alluvial aquifer, and demonstrate why multi-tracer geochemical analyses should be used as a critical component of water budget assessments. We selected a site in Australia where the Great Artesian Basin (GAB), the largest artesian basin in the world, discharges into the Lower Namoi Alluvium (LNA), an extensively modelled aquifer, to convey the utility of our approach. Water stable isotopes (δ18O and δ2H) and the concentrations of Na+ and HCO3− suggest a continuum of mixing in the alluvial aquifer between the GAB (artesian component) and surface recharge, whilst isotopic tracers (3H, 14C, and 36Cl) indicate that the alluvial groundwater is a mixture of groundwaters with residence times of 70 years and groundwater that is potentially hundreds of thousands of years old, which is consistent with that of the GAB. In addition, Cl− concentrations provide a means to calculate a percentage estimate of the artesian contribution to the alluvial groundwater. In some locations, an artesian contribution of up to 70 % is evident from the geochemical analyses, a finding that contrasts with previous regional-scale water balance modelling estimates that attributed 22 % of all inflow for the corresponding zone within the LNA to GAB discharge. Our results show that hydrochemical investigations need to be undertaken as part of developing the conceptual framework of a catchment water balance model, as they can improve our understanding of recharge pathways and better constrain artesian discharge to an alluvial aquifer.
对每日和更短周期水头波动进行傅里叶分析来了解相互连接的地表水/地下水系统
Publisher: Springer Science and Business Media LLC
Date: 05-09-2014
Comprensión de los procesos de agua subterránea mediante la representación de la heterogeneidad del acuífero en la cuenca del arroyo Maules, Namoi Valley (Nueva Gales del Sur, Australia)
Publisher: Springer Science and Business Media LLC
Date: 26-05-2012
Investigating the spatio-temporal variability in groundwater and surface water interactions: A multi-technique approach
Publisher: Copernicus GmbH
Date: 06-09-2013
DOI: 10.5194/HESS-17-3437-2013
Abstract: Abstract. The interaction between groundwater and surface water along the Tambo and Nicholson rivers, southeast Australia, was investigated using 222Rn, Cl, differential flow gauging, head gradients, electrical conductivity (EC) and temperature profiles. Head gradients, temperature profiles, Cl concentrations and 222Rn activities all indicate higher groundwater fluxes to the Tambo River in areas of increased topographic variation where the potential to form large groundwater–surface water gradients is greater. Groundwater discharge to the Tambo River calculated by Cl mass balance was significantly lower (1.48 × 104 to 1.41 × 103 m3 day−1) than discharge estimated by 222Rn mass balance (5.35 × 105 to 9.56 × 103 m3 day−1) and differential flow gauging (5.41 × 105 to 6.30 × 103 m3 day−1) due to bank return waters. While groundwater s ling from the bank of the Tambo River was intended to account for changes in groundwater chemistry associated with bank infiltration, variations in bank infiltration between s le sites remain unaccounted for, limiting the use of Cl as an effective tracer. Groundwater discharge to both the Tambo and Nicholson rivers was the highest under high-flow conditions in the days to weeks following significant rainfall, indicating that the rivers are well connected to a groundwater system that is responsive to rainfall. Groundwater constituted the lowest proportion of river discharge during times of increased rainfall that followed dry periods, while groundwater constituted the highest proportion of river discharge under baseflow conditions (21.4% of the Tambo in April 2010 and 18.9% of the Nicholson in September 2010).
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