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| Titel |
Modelling the effects of climate and land cover change on groundwater recharge in south-west Western Australia |
| VerfasserIn |
W. Dawes, R. Ali, S. Varma, I. Emelyanova, G. Hodgson, D. McFarlane |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 8 ; Nr. 16, no. 8 (2012-08-14), S.2709-2722 |
| Datensatznummer |
250013422
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| Publikation (Nr.) |
 copernicus.org/hess-16-2709-2012.pdf |
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| Zusammenfassung |
The groundwater resource contained within the sandy aquifers of the Swan
Coastal Plain, south-west Western Australia, provides approximately 60 percent
of the drinking water for the metropolitan population of Perth.
Rainfall decline over the past three decades coupled with increasing water
demand from a growing population has resulted in falling dam storage and
groundwater levels. Projected future changes in climate across south-west
Western Australia consistently show a decline in annual rainfall of between
5 and 15 percent. There is expected to be a reduction of diffuse recharge
across the Swan Coastal Plain. This study aims to quantify the change in
groundwater recharge in response to a range of future climate and land cover
patterns across south-west Western Australia.
Modelling the impact on the groundwater resource of potential climate change
was achieved with a dynamically linked unsaturated/saturated groundwater
model. A vertical flux manager was used in the unsaturated zone to estimate
groundwater recharge using a variety of simple and complex models based on
climate, land cover type (e.g. native trees, plantation, cropping, urban,
wetland), soil type, and taking into account the groundwater depth.
In the area centred on the city of Perth, Western Australia, the patterns of
recharge change and groundwater level change are not consistent spatially,
or consistently downward. In areas with land-use change, recharge rates have
increased. Where rainfall has declined sufficiently, recharge rates are
decreasing, and where compensating factors combine, there is little change to
recharge. In the southwestern part of the study area, the patterns of
groundwater recharge are dictated primarily by soil, geology and land cover.
In the sand-dominated areas, there is little response to future
climate change, because groundwater levels are shallow and much rainfall is rejected
recharge. Where the combination of native vegetation and clayey surface
soils restricts possible infiltration, recharge rates are very sensitive to
reductions in rainfall. In the northern part of the study area, both climate
and land cover strongly influence recharge rates. Recharge under native
vegetation is minimal and is relatively higher where grazing and pasture
systems have been introduced after clearing of native vegetation. In some
areas, the recharge values can be reduced to almost zero, even under dryland
agriculture, if the future climate becomes very dry. |
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