Pengukuran kemasinan air tanah di dataran pantai Pekan-Nenasi, Pahang dengan teknik geoelektrik dan geokimia

The lowering of groundwater levels and an increasing in salt content in the freshwater alluvial aquifer were detected during continuous monitoring works of the groundwater in Pekan-Nenasi coastal areas. Geophysical data are used in conjunction with the hydrogeological data for the monitoring processes. Geophysical surveys used in this monitoring study were both vertical electrical sounding and electrical imaging. They are specially employed in order to estimate boundaries of fresh-brackish-salt water in the alluvial aquifer. Results of the surveys show that areas influenced by salt-brackish water or the conductive zones are concentrated in areas around 1-5 kilometres from the beach. Preliminary results show that maximum depth of investigation through geoelectrical surveys are only between 20-30 metres. Therefore water salinity at depth greater than 30 metres could not be investigated by these surveys.