Interactions between a saline lagoon and a semi‐confined aquifer on a salinized floodplain of the lower River Murray, southeastern Australia

Banks, E.; Simmons, Craig T.; Jolly, Ian; Doble, Rebecca; McEwan, Kerryn; Herczeg, Andrew L.

doi:10.1002/hyp.7453

Cited by 5 publications

(2 citation statements)

References 20 publications

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“…These extraordinarily elevated isotopic compositions may represent evaporation under very low humidity conditions (I. Cartwright, pers comm;Banks et al, 2009;Cartwright, Hall, Tweed, & Leblanc, 2009;Tweed, Leblanc, Cartwright, Favreau, & Leduc, 2011). We test this hypothesis by modelling the evaporation process as described below.…”

Section: Isotope Geochemistrymentioning

confidence: 99%

Groundwater geochemistry, hydrogeology and potash mineral potential of the Lake Woods region, Northern Territory, Australia

Caritat

Bastrakov

Jaireth

et al. 2019

Australian Journal of Earth Sciences

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We collected 38 groundwater and two surface-water samples in the semi-arid Lake Woods region of the Northern Territory to better understand the hydrogeochemistry of this system, which straddles the Wiso, Tennant Creek and Georgina geological regions. Lake Woods is presently a losing waterbody feeding the underlying groundwater system. The main aquifers comprise mainly carbonate (limestone and dolostone), siliciclastic (sandstone and siltstone) and evaporitic units. The water composition was determined in terms of bulk properties (pH, electrical conductivity, temperature, dissolved oxygen, redox potential), 40 major, minor and trace elements, and six isotopes (18 O water , d 2 H water , d 13 C DIC , d 34 S SO 4 2-, d 18 O SO 4 2-, 87 Sr/ 86 Sr).The groundwater is recharged through infiltration in the catchment from monsoonal rainfall (annual average rainfall $600 mm) and runoff. It evolves geochemically mainly through evapotranspiration and water-mineral interaction (dissolution of carbonates, silicates and to a lesser extent sulfates). The two surface waters (one from the main creek feeding the lake, the other from the lake itself) are extraordinarily enriched in 18 O and 2 H isotopes (d 18 O of þ10.9 and þ16.4‰ VSMOW, and d 2 H of þ41 and þ93‰ VSMOW, respectively), which is interpreted to reflect evaporation during the dry season (annual average evaporation $3000 mm) under low humidity conditions (annual average relative humidity $40%). This interpretation is supported by modelling results. The potassium (K) relative enrichment (K/ Clmass ratio over 50 times that of sea water) is similar to that observed in salt-lake systems worldwide that are prospective for potash resources. Potassium enrichment is believed to derive partly from dust during atmospheric transport/deposition, but mostly from weathering of K-silicates in the aquifer materials (and possibly underlying formations). Further studies of Australian salt-lake systems are required to reach evidence-based conclusions on their mineral potential for potash, lithium, boron and other low-temperature mineral system commodities such as uranium.

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Section: Isotope Geochemistrymentioning

confidence: 99%

Groundwater geochemistry, hydrogeology and potash mineral potential of the Lake Woods region, Northern Territory, Australia

Caritat

Bastrakov

Jaireth

et al. 2019

Australian Journal of Earth Sciences

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“…Banks et al (2009) studied the role of a floodplain wetland in modifying groundwater-surface water interactions between a floodplain aquifer and the River Murray. They found that the wetland intercepted groundwater discharge from a nearby irrigated upland area, concentrated it by evaporation and then recharged more saline water to the floodplain aquifer.…”

mentioning

confidence: 99%

Hydrology and ecohydrology of Australian semi‐arid wetlands

Lamontagne

Herczeg

2009

Hydrological Processes

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Terrestrial freshwater lenses in stable riverine settings: Occurrence and controlling factors

Werner

Laattoe

2016

Water Resources Research

106

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Rivers in arid and semiarid regions often traverse saline aquifers, creating buoyant freshwater lenses in the adjoining riparian and floodplain zones. The occurrence of freshwater lenses where the river is otherwise gaining saline groundwater appears counterintuitive, given that both hydraulic and density forces act toward the river. In this paper, an analytical solution is presented that defines the extent of a stable, sharpinterface terrestrial freshwater lens (in cross section) in a riverine environment that otherwise contains saline groundwater moving toward the river. The method is analogous to the situation of an island freshwater lens, except in the riverine setting, the saltwater is mobile and the lens is assumed to be stagnant. The solution characterizes the primary controlling factors of riverine freshwater lenses, which are larger for situations involving lower hydraulic conductivities and rates of saltwater discharge to the river. Deeper aquifers, more transmissive riverbeds, and larger freshwater-saltwater density differences produce more extensive lenses. The analytical solution predicts the parameter combinations that preclude the occurrence of freshwater lenses. The utility of the solution as a screening method to predict the occurrence of terrestrial freshwater lenses is demonstrated by application to parameter ranges typical of the South Australian portion of the River Murray, where freshwater lenses occur in only a portion of the neighboring floodplains. Despite assumptions of equilibrium conditions and a sharp freshwater-saltwater interface, the solution for predicting the occurrence of riverine freshwater lenses presented in this study has immediate relevance to the management of floodplains in which freshwater lenses are integral to biophysical conditions.

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Interactions between a saline lagoon and a semi‐confined aquifer on a salinized floodplain of the lower River Murray, southeastern Australia

Cited by 5 publications

References 20 publications

Groundwater geochemistry, hydrogeology and potash mineral potential of the Lake Woods region, Northern Territory, Australia

Groundwater geochemistry, hydrogeology and potash mineral potential of the Lake Woods region, Northern Territory, Australia

Hydrology and ecohydrology of Australian semi‐arid wetlands

Terrestrial freshwater lenses in stable riverine settings: Occurrence and controlling factors

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