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| Titel |
From days to decades: numerical modelling of freshwater lens response to climate change stressors on small low-lying islands |
| VerfasserIn |
S. Holding, D. M. Allen |
| 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 ; 19, no. 2 ; Nr. 19, no. 2 (2015-02-16), S.933-949 |
| Datensatznummer |
250120631
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| Publikation (Nr.) |
 copernicus.org/hess-19-933-2015.pdf |
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| Zusammenfassung |
| Freshwater lenses on small islands are vulnerable to many climate
change-related stressors, which can act over relatively long time periods, on
the order of decades (e.g., sea level rise, changes in recharge), or short
time periods, such as days (storm surge overwash). This study evaluates the
response of the freshwater lens on a small low-lying island to various
stressors. To account for the varying temporal and spatial scales of the
stressors, two different density-dependent flow and solute transport codes
are used: SEAWAT (saturated) and HydroGeoSphere (unsaturated/saturated). The
study site is Andros Island in the Bahamas, which is characteristic of other
low-lying carbonate islands in the Caribbean and Pacific regions. In addition
to projected sea level rise and reduced recharge under future climate change,
Andros Island experienced a storm surge overwash event during Hurricane
Francis in 2004, which contaminated the main wellfield. Simulations of
reduced recharge result in a greater loss of freshwater lens volume (up to
19%), while sea level rise contributes a lower volume loss (up to 5%)
due to the flux-controlled conceptualization of Andros Island, which limits
the impact of sea level rise. Reduced recharge and sea level rise were
simulated as incremental instantaneous shifts. The lens responds relatively
quickly to these stressors, within 0.5 to 3 years, with response time
increasing as the magnitude of the stressor increases. Simulations of the
storm surge overwash indicate that the freshwater lens recovers over time;
however, prompt remedial action can restore the lens to potable
concentrations up to 1 month sooner. |
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