Limitations of GALDIT to map seawater intrusion vulnerability in a highly touristic coastal area

Abstract

Coastal aquifers are susceptible to seawater intrusion, especially touristic areas where the overexploitation combined with the agricultural use of groundwater represent a severe issue for water management. GALDIT methodology was applied as a management tool to identify and prevent salinization of the aquifer. GALDIT methodology needs six input parameters: groundwater occurrence (G), aquifer hydraulic conductivity (A), groundwater head above sea level (L), distance from the shore (D), impact of the existing status of seawater intrusion (I), and thickness of the aquifer (T). Then a contour map is created using three degree of vulnerability: high, medium and low. The higher vulnerability zone ranges from 40 to 550 m towards the mainland with the rest of the aquifer characterized by medium vulnerability. The main problem affecting the selected field site is the large water requirement during the summer period due to the touristic activities, but the correct use of surplus water collected in the winter can overcome this problem. This study demonstrates that further investigation on groundwater hydrochemistry and on water demand trends from the different activities impacting the field site should be implemented, in order to guarantee environmental and touristic development sustainability.