3D modelling of a hydrological structure combining spatial data science and geophysics: Application to a coastal aquifer system in the island of Crete, Greece

Groundwater resources in Mediterranean coastal aquifers are under threat due to
overexploitation and climate change impacts, resulting in saltwater intrusion. This situation is
deteriorated by the absence of sustainable groundwater resources management plans. Efficient
management and monitoring of groundwater systems requires interpreting all sources of
available data. This work aims at the development of a set of plausible 3D geological models
combining 2D geophysical profiles, spatial data analytics and geostatistical simulation techniques.
The resulting set of models represents possible scenarios of the structure of the coastal aquifer
system under investigation. Inverted resistivity profiles, along with borehole data, are explored
using spatial data science techniques to identify regions associated with higher uncertainty.
Relevant parts of the profiles will be used to generate 3D models after detailed Anisotropy and
variogram analysis. Multidimensional statistical techniques are then used to select representative
models of the true subsurface while exploring the uncertainty space. The resulting models will
help to identify primary gaps in existing knowledge about the groundwater system and to optimize
the groundwater monitoring network. A comparison with a numerical groundwater flow model will
identify similarities and differences and it will be used to develop a typical hydrogeological model,
which will aid the management and monitoring of the area's groundwater resources. This work
will help the development of a reliable groundwater flow model to investigate future groundwater
level fluctuations at the study area under climate change scenarios.