In the era of intense pressures on water resources, the loss of groundwater by increased seawater intrusion (SWI), driven by climate, sea level and landscape changes, may be critical for many people living in commonly populous coastal regions. Analytical solutions have been derived here for interface flow in coastal aquifers, which allow for simple quantification of SWI under extended conditions from previously available such solutions and are suitable for first-order regional vulnerability assessment and mapping of the implications of climate- and landscape-driven change scenarios and related comparisons across various coastal world regions. Specifically, the derived solutions can account for the hydraulically significant aquifer bed slope in quantifying the toe location of a fresh-seawater sharp interface in the present assessments of vulnerability and safe exploitation of regional coastal groundwater. Results show high nonlinearity of SWI responses to hydro-climatic and groundwater pumping changes on the landside and sea level rise on the marine side, implying thresholds, or tipping points, which, if crossed, may lead abruptly to major SWI of the aquifer. Critical limits of coastal groundwater change and exploitation have been identified and quantified in direct relation to prevailing local-regional conditions and stresses, defining a safe operating space for the human use of coastal groundwater. Generally, to control SWI, coastal aquifer management should focus on adequate fresh groundwater discharge to the sea, rather than on maintaining a certain hydraulic head at some aquifer location. First-order vulnerability assessments for regional Mediterranean aquifers of the Nile Delta Aquifer, the Israel Coastal Aquifer and the Cyprus Akrotiri Aquifer show that in particular the first is seriously threatened by advancing seawater. Safe operating spaces determined for the latter two show that the current pumping schemes are not sustainable under declining recharge. / <p>The thesis was founded by two research programmes: NEO private-academic sector partnership and Ekoklim, a strategic governmental funding through Stockholm University</p><p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.</p><p> </p>
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:su-103137 |
| Date | January 2014 |
| Creators | Mazi, Aikaterini |
| Publisher | Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), National Observatory of Athens, Greece, Stockholm : Department of Physical Geography and Quaternary Geology, Stockholm University |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Doctoral thesis, comprehensive summary, info:eu-repo/semantics/doctoralThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | Dissertations from the Department of Physical Geography and Quaternary Geology, 1653-7211 ; 42 |
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