LIAG / Research / Topics / Coastal aquifers 

Coastal aquifers

This research topic specifically investigates the dynamics of systems where both freshwater and saltwater are present, e.g. at coastal regions or in areas of inland salinization. Electric and electromagnetic methods are specifically suited, as the electrical conductictivity is a perfect proxy for salinity.

Only 2.5% of the global water volume is freshwater. And 0.4 percent of this is in motion within the water cycle (evaporation, precipitation, subsurface/surface runoff). The remaining 99.6% are tied: 30.1% in deep seated aquifers, 69.5% in icecaps, glaciers, permanent snow or permafrost.

We need the fresh water to be alive. Salinisation of groundwater endangers our most important good. Main reasons for groundwater salinisation are:


  • Saltwater intrusion in coastal environments
  • Salt domes
  • increased mineralisation in arid areas

Additionally there may be anthropogenic reasons due to overfertilization and brownfields.

Due to the fact that the electrical conductivity depends strongly on mineralisation or salt concentration saltwater-freshwater systems are classical targets of geoelectrical or electromagnetic surveys. These resistivity methods respond to the electrical conductivity of the pore fluid that is increased by salt minerals. Water with chloride concentration higher than 250 mg/l is too salty. The drinking water standard needs an electrical conductivity of maximal 2500 μS/cm

Targets of geophysical surveying are, e.g., transition zone of freshwater-saltwater in coastal areas, submarine groundwater discharges, saltwater intrusions etc. The results may be the basis for studies on processes.

Current Projects

  • KisNet
    DFG network for investigating freshwater discharge in the Königshafen bay (Sylt)
  • DynaDeep
    Dynamics of the deep subsurface of high-energy beaches
  • Drone-EM
    Application of drone-based EM for groundwater related tasks
    Observation of salt/freshwater interfaces with Saltwater-Monitoring Systems

Finished projects

  • go-CAM (2017-2020)
    Implementing strategic development goals in coastal aquifer management
  • TOPSOIL (2015-2021)
    Top soil and water –  The climate challenge in the near subsurface
  • NAWAK (2013-2016)
    Entwicklung nachhaltiger Anpassungsstrategien für die Infrastrukturen der Wasserwirtschaft unter den Bedingungen des klimatischen und demographischen Wandels
  • SaMoLEG (2011-2015)
    Salzwasser-Monitoring mit Langelektroden-Geoelektrik
  • CLIWAT (2009-2012)
    Climate & Water - Einfluss des Klimawandels auf Grundwassersysteme


Michael Grinat

Mathias Ronczka

Thomas Günther

Nico Skibbe

Jan Igel