The groundwater vulnerability assessment to seawater intrusion
(SWI), applying the GIS-based overlay-index GALDIT method,
is provided for the Metaponto coastal aquifer (Basilicata region,
southern Italy). The method is based on six conditioning parameters:
groundwater occurrence (G), aquifer hydraulic conductivity (A),
groundwater level (L), distance from the shore (D), impact of the
existing status of SWI (I), and aquifer thickness (T).
Three vulnerability classes were detected: low, moderate,
and high, covering 70.40%, 22.65%, and 6.95% of the study
area, respectively. The highest class is located close to the coastal
sector due to the proximity to the sea, the greater thickness of the
aquifer, and the shallow freshwater-seawater interface.
To evaluate the sensitivity of the method on the predictive
analysis and the influence of the single parameter and weight on
the final vulnerability, the sensitivity analysis was carried out.
The single-parameter analysis indicated that the factors such
as groundwater table above sea level (a.s.l.), aquifer type, and
impact of SWI have the greatest influence on the vulnerability.
The application leads to the vulnerability mapping to SWI in
the coastal plain that results to be a promising tool for decisionmaking finalized to properly manage groundwater
