Hydrochemical processes in a shallow coal seam gas aquifer and its overlying stream–alluvial system: implications for recharge and inter-aquifer connectivity

Duvert, Clément; Raiber, Matthias; Owen, Daniel D.R.; Cendón, Dioni I.; Batiot‐Guilhe, Christelle; Cox, Malcolm

doi:10.1016/j.apgeochem.2015.05.021

Cited by 15 publications

(17 citation statements)

References 55 publications

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“…2c), as has been reported in other parts of eastern Australia (Hughes and Crawford, 2013;King et al, 2015). In streamwater, isotopic ratios were generally lower for S1 and S2 than for rainfall, which most likely reflects the predominant contribution of depleted rainfall to recharge (Duvert et al, 2015b). Also, the position of S1 and S2 samples relative to the meteoric line ( Fig.…”

Section: Discussionsupporting

confidence: 74%

“…2c). The local meteoric water line derived from rainfall samples had an intercept of 15.8 and a slope of 8.4 (Duvert et al, 2015b), similar to that of Brisbane (Fig. 4a).…”

Section: Descriptionmentioning

confidence: 53%

“…Hydraulic gradient analysis indicates that the alluvium mostly drains into the stream; hydrochemical and isotopic data also revealed a close connection between the alluvium and surface water in the Teviot Brook catchment (Duvert et al, 2015b). Borehole G1 is 13.9 m deep and it is screened from 12.3 m to its bottom, i.e.…”

Section: Physical Settingmentioning

confidence: 97%

“…3). The first end-member represents the contribution of younger waters from rapid recharge through the highly fractured igneous rocks forming the mountain front, as outlined in previous studies (Duvert et al, 2015b, a). This younger component was further divided into (i) quick flow and (ii) relatively delayed contribution of waters seeping from the rock fractures (Fig.…”

Section: Conceptual Frameworkmentioning

confidence: 98%

“…Underlying the alluvial deposits is a sedimentary bedrock formation (Walloon Coal Measures) consisting of irregular beds of sandstone, siltstone, shale and coal, some of which contain significant volumes of groundwater. Duvert et al (2015b, a) reported high Fe concentrations and low 3 H activities for some groundwaters of the sedimentary bedrock.…”

Section: Physical Settingmentioning

confidence: 99%

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Time series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream

Duvert

Stewart

Cendón

et al. 2016

Hydrol. Earth Syst. Sci.

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Abstract.A major limitation to the assessment of catchment transit time (TT) stems from the use of stable isotopes or chloride as hydrological tracers, because these tracers are blind to older contributions. Yet, accurately capturing the TT of the old water fraction is essential, as is the assessment of its temporal variations under non-stationary catchment dynamics. In this study we used lumped convolution models to examine time series of tritium, stable isotopes and chloride in rainfall, streamwater and groundwater of a catchment located in subtropical Australia. Our objectives were to determine the different contributions to streamflow and their variations over time, and to understand the relationship between catchment TT and groundwater residence time. Stable isotopes and chloride provided consistent estimates of TT in the upstream part of the catchment. A young component to streamflow was identified that was partitioned into quickflow (mean TT ≈ 2 weeks) and discharge from the fractured igneous rocks forming the headwaters (mean TT ≈ 0.3 years). The use of tritium was beneficial for determining an older contribution to streamflow in the downstream area. The best fits between measured and modelled tritium activities were obtained for a mean TT of 16-25 years for this older groundwater component. This was significantly lower than the residence time calculated for groundwater in the alluvial aquifer feeding the stream downstream (≈ 76-102 years), emphasising the fact that water exiting the catchment and water stored in it had distinctive age distributions. When simulations were run separately on each tritium streamwater sample, the TT of old water fraction varied substantially over time, with values averaging 17 ± 6 years at low flow and 38 ± 15 years after major recharge events. This counterintuitive result was interpreted as the flushing out of deeper, older waters shortly after recharge by the resulting pressure wave propagation. Overall, this study shows the usefulness of collecting tritium data in streamwater to document short-term variations in the older component of the TT distribution. Our results also shed light on the complex relationships between stored water and water in transit, which are highly non-linear and remain poorly understood.

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Section: Discussionsupporting

confidence: 74%

“…2c). The local meteoric water line derived from rainfall samples had an intercept of 15.8 and a slope of 8.4 (Duvert et al, 2015b), similar to that of Brisbane (Fig. 4a).…”

Section: Descriptionmentioning

confidence: 53%

Section: Physical Settingmentioning

confidence: 97%

Section: Conceptual Frameworkmentioning

confidence: 98%

Section: Physical Settingmentioning

confidence: 99%

See 3 more Smart Citations

Time series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream

Duvert

Stewart

Cendón

et al. 2016

Hydrol. Earth Syst. Sci.

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Compositional data analysis as a robust tool to delineate hydrochemical facies within and between gas‐bearing aquifers

Owen

Pawlowsky‐Glahn

Egozcue

et al. 2016

Water Resources Research

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Isometric log ratios of proportions of major ions, derived from intuitive sequential binary partitions, are used to characterize hydrochemical variability within and between coal seam gas (CSG) and surrounding aquifers in a number of sedimentary basins in the USA and Australia. These isometric log ratios are the coordinates corresponding to an orthonormal basis in the sample space (the simplex). The characteristic proportions of ions, as described by linear models of isometric log ratios, can be used for a mathematical-descriptive classification of water types. This is a more informative and robust method of describing water types than simply classifying a water type based on the dominant ions. The approach allows (a) compositional distinctions between very similar water types to be made and (b) large data sets with a high degree of variability to be rapidly assessed with respect to particular relationships/compositions that are of interest. A major advantage of these techniques is that major and minor ion components can be comprehensively assessed and subtle processes-which may be masked by conventional techniques such as Stiff diagrams, Piper plots, and classic ion ratios-can be highlighted. Results show that while all CSG groundwaters are dominated by Na, HCO 3 , and Cl ions, the proportions of other ions indicate they can evolve via different means and the particular proportions of ions within total or subcompositions can be unique to particular basins. Using isometric log ratios, subtle differences in the behavior of Na, K, and Cl between CSG water types and very similar Na-HCO 3 water types in adjacent aquifers are also described. A complementary pair of isometric log ratios, derived from a geochemically-intuitive sequential binary partition that is designed to reflect compositional variability within and between CSG groundwater, is proposed. These isometric log ratios can be used to model a hydrochemical pathway associated with methanogenesis and/or to delineate groundwater associated with high gas concentrations.

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Mecanismos hidrogeoquímicos y conexión hidráulica de las aguas subterráneas en la mina de carbón a cielo abierto de Dongming, Hailar, Mongolia Interior

Zhong,

Wu,

Tang

et al. 2024

Mine Water Environ

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Hydrochemical processes in a shallow coal seam gas aquifer and its overlying stream–alluvial system: implications for recharge and inter-aquifer connectivity

Cited by 15 publications

References 55 publications

Time series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream

Time series of tritium, stable isotopes and chloride reveal short-term variations in groundwater contribution to a stream

Compositional data analysis as a robust tool to delineate hydrochemical facies within and between gas‐bearing aquifers

Mecanismos hidrogeoquímicos y conexión hidráulica de las aguas subterráneas en la mina de carbón a cielo abierto de Dongming, Hailar, Mongolia Interior

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