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| Titel |
Impacts of groundwater extraction on salinization risk in a semi-arid floodplain |
| VerfasserIn |
S. Alaghmand, S. Beecham, A. Hassanli |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 13, no. 12 ; Nr. 13, no. 12 (2013-12-23), S.3405-3418 |
| Datensatznummer |
250085594
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| Publikation (Nr.) |
 copernicus.org/nhess-13-3405-2013.pdf |
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| Zusammenfassung |
| In the lower River Murray in Australia, a combination of a reduction in the
frequency, duration and magnitude of natural floods, rising saline
water tables in floodplains, and excessive evapotranspiration have led to an
irrigation-induced groundwater mound forcing the naturally saline
groundwater onto the floodplain. It is during the attenuation phase of
floods that these large salt accumulations are likely to be mobilised and
discharged into the river. This has been highlighted as the most
significant risk in the Murray–Darling Basin and the South Australian
Government and catchment management authorities have subsequently developed
salt interception schemes (SIS). The aim of these schemes is to reduce the hydraulic
gradient that drives the regional saline groundwater towards the River
Murray. This paper investigates the interactions between a river (River
Murray in South Australia) and a saline semi-arid floodplain (Clark's
floodplain) that is significantly influenced by groundwater lowering due to
a particular SIS. The results confirm that groundwater extraction maintains
a lower water table and a higher amount of fresh river water flux to the saline
floodplain aquifer. In terms of salinity, this may lead to less solute
stored in the floodplain aquifer. This occurs through three mechanisms,
namely extraction of the solute mass from the system, reducing the saline
groundwater flux from the highland to the floodplain and changing the
floodplain groundwater regime from a losing to a gaining one. It is shown
that groundwater extraction is able to remove some of the solute stored in
the unsaturated zone and this can mitigate the floodplain salinity risk. A
conceptual model of the impact of groundwater extraction on floodplain
salinization has been developed. |
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