Groundwater Investigation by Combined Vertical Electrical Sounding and Magnetotelluric Sounding in Eastern Region of Mekong Delta, in the South of Vietnam

Abstract

In the Eastern Region of Mekong Delta (South Vietnam) may contain brackish
or saline water from land surface to great depth, both superficial Quaternary and deep
Tertiary Alluvium. The combination of two geophysical methods, the Vertical Electrical
Sounding (VES) for shallow investigation, and the Magnetotelluric Sounding (MTS) for
deep investigation, provides a complete electrical image of the sedimentary series from the
surface to the deep crystalline basement. It turns out very efficient to delineate the
groundwater contamination in both superficial and deep aquifers. The combined results
reveal a close correlation of the extent of the contamination with the paleogeomorphology
of laterites, and subsequently with the paleorelief during the Tertiary and Quaternary times.
Because this study area is very complicated hydrogeological structure, it is necessary to
survey the current status of deep-water storage floors with geophysical measurement
technologies to prevent groundwater pollution when exploiting groundwater here.