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| Titel |
Effects of climate variability on saltwater intrusions in coastal aquifers in Southern Denmark |
| VerfasserIn |
Rena Meyer, Torben Sonnenborg, Peter Engesgaard, Anne-Sophie Høyer, Flemming Jørgensen, Klaus Hisnby, Birgitte Hansen, Jørn Bo Jensen, Jan A. Piotrowski |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121661
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| Publikation (Nr.) |
 EGU/EGU2016-458.pdf |
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| Zusammenfassung |
| As in many other regions of the world fresh water supply in Denmark is based on
groundwater resources. Aquifers in the low-lying areas in the south-west of Jutland are
particularly vulnerable to saltwater intrusions which are likely to intensify due to relative sea
level rise. To understand the dynamics and development of this complex flow system, the
initial hydrodynamic conditions imposed by the last Scandinavian Ice Sheet (SIS) must be
taken into account.
The whole region has undergone changes in climatic and hydraulic conditions within the
last 15000 years that may show influence on the present flow conditions. It is likely that the
groundwater-flow dynamics, driven by the postglacial hydraulic head drop and the
relative sea level rise are not yet equilibrated. Enhanced by the potential future
sea level rise due to climate change, contamination of fresh-water aquifers will
continue.
The 2800-km2 - large coast-to-coast study area located in the southern part of Jutland
was partly overridden by the Weichselian ice sheet. Geophysical and geological
mapping shows salt water intrusions up to 20 km inland from the present coast.
Based on a geological voxel model spanning Miocene through Quaternary deposits a
large-scale 3D numerical groundwater flow and salt water transport model has been
developed. It includes density-driven flow and simulates the distribution of the current
saltwater intrusions and their evolution during the last 15000 years. Particle tracking
and direct age simulations are performed to identify recharge areas and constrain
groundwater ages. The simulated ages are compared to ages derived from isotope analysis
of groundwater samples both from Miocene and Quaternary aquifers. The origin
of the groundwater is determined based on isotopic and chemical composition.
Additionally, heavy noble gas analysis is carried out to estimate recharge temperatures and
mechanisms at locations where groundwater recharge during the last glaciation is
indicated.
This study shows how hydrogeological, geophysical and geochemical data can be
complementarily used together with groundwater flow and transport simulations to
understand the history of the groundwater systems and thus help adapting water resources to
future changes. |
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