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| Titel |
Assessing impacts of climate change, sea level rise, and drainage canals on saltwater intrusion to coastal aquifer |
| VerfasserIn |
P. Rasmussen, T. O. Sonnenborg, G. Goncear, K. Hinsby |
| 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 ; 17, no. 1 ; Nr. 17, no. 1 (2013-01-31), S.421-443 |
| Datensatznummer |
250017700
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| Publikation (Nr.) |
 copernicus.org/hess-17-421-2013.pdf |
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| Zusammenfassung |
| Groundwater abstraction from coastal aquifers is vulnerable to climate
change and sea level rise because both may potentially impact saltwater
intrusion and hence groundwater quality depending on the hydrogeological
setting. In the present study the impacts of sea level rise and changes in
groundwater recharge are quantified for an island located in the Western
Baltic Sea. The low-lying central area of the investigated part of the
island was extensively drained and reclaimed during the second half of the
19th century by a system of artificial drainage canals that significantly
affects the flow dynamics of the area. The drinking water, mainly for summer
cottages, is abstracted from 11 wells drilled to a depth of around 20 m into
the upper 5–10 m of a confined chalk aquifer, and the total pumping is only
5–6% of the drainage pumping. Increasing chloride concentrations have
been observed in several abstraction wells and in some cases the WHO
drinking water standard has been exceeded. Using the modeling package
MODFLOW/MT3D/SEAWAT the historical, present and future freshwater-sea water
distribution is simulated. The model is calibrated against hydraulic head
observations and validated against geochemical and geophysical data from new
investigation wells, including borehole logs, and from an airborne transient
electromagnetic survey. The impact of climate changes on saltwater intrusion
is found to be sensitive to the boundary conditions of the investigated
system. For the flux-controlled aquifer to the west of the drained area only
changes in groundwater recharge impacts the freshwater–sea water interface
whereas sea level rise does not result in increasing sea water intrusion.
However, on the barrier islands to the east of the reclaimed area, below
which the sea is hydraulically connected to the drainage canals, and the
boundary of the flow system therefore controlled, the projected changes in
sea level, groundwater recharge and stage of the drainage canals all have
significant impacts on saltwater intrusion and the chloride concentrations
found in abstraction wells. |
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