Abstract:

GALDIT method was given by Chachadi and Lobo-ferreira in 2001 and modified in 2005. This method uses six (6) indicators related to the characteristics of the aquifer, Groundwater occurrence, Aquifer hydraulic conductivity, height of groundwater Level above the sea level; Distance from the shore (distance inland perpendicular from shoreline), Impact of existing status of seawater intrusion in the area; and the Thickness of the aquifer that is being mapped. Base on the GALDIT factors represent different points of lower Pliocen aquifer in Tien Giang province, the authors have established the map of aquifer vulnerability to seawater intrusion, with very high vulnerability area (0.1% of total area); highly vulnerability area (with 76.9) and moderately vulnerability area (with 23.0%). By using the computed GALDIT index, the aquifer vulnerability map and saltwater intrusion lines, a network of 38 monitoring wells has been proposed and divided into 2 groups: spatial monitoring network (17 wells) and crosssection monitoring network along salt-fresh water interface (with 21 wells).