oa Can Electrical Geophysical Methods Detect The Salinity Transition Zone Beneath Ground-Water Lenses?

The most common type of aquifer found in oceanic islands is the<br>fresh-water lens floating on intruded salt water. The bottom of<br>these lenses is marked by a transition zone where the ground<br>water salinities are transitional between fresh and salt water.<br>Lens shapes can be generally defined using electrical geophysical<br>methods, but the transition zones are not commonly resolved as<br>well. The geophysical models either do not include a transition<br>zone, or approximate the transition zone as a simple, constant<br>resistivity layer. Efficient explotation of these lenses<br>requires accurate knowledge of the thickness of and depth to the<br>transition zone