Delineation of Seawater Intrusion Using Geo-Electrical Survey in a Coastal Aquifer of Kamala Beach, Phuket, Thailand

Abstract

The coastal areas of Phuket Island are facing the risk of seawater intrusion, because intense anthropic activity due to urbanization and the expansion of tourism influences coastal hydrologic systems. Indeed, the Kamala sub-district—on the western part of Phuket Island—is a well-known and attractive destination for tourists. Previous research indicates that there is likely to be a seawater intrusion in Kamala. The main purpose of this study was to delineate the seawater intrusion problem in a coastal aquifer in Kamala. Geo-electrical surveys of four lines were successfully conducted in the study area. Two-dimensional (2D) inversion models from the resistivity data show high-resolution subsurface resistivity anomalies of seawater intrusion. The concentration of the seawater intrusion decreases eastward toward the inland areas. Based on a sample measurement, the contaminated zone of seawater has a resistivity value smaller than 30 Ohm-m, and the empirical relationship between the formation conductivity and fluid conductivity of the study area was established. Finally, time-lapse Electrical Resistivity Imaging (time-lapse ERI) was conducted to prove that there was no presence of clay layers in study area; thus, the low resistivity plumes (smaller than 30 Ohm-m) were scientifically interpreted as being seawater intrusion.

Status of seawater intrusion in coastal aquifer of Gujarat, India: a review

“…Owing to excruciating anthropic exercise because of urbanization and proliferation of tourism with an approximate growth rate of 0.1 million guests/year that affects the coastal hydrologic systems the coastal regions of Phuket Island confront the jeopardy of SWI [10]. Geo-electrical surveys of four lines were prosperously operated in the field of study in this research.…”

“…Techniques related to hydrodynamic, and modeling are often integrated with multivariate geostatistical analysis, geospatial analysis, and tracer studies have been adopted for investigation [6,7]. The considerable difference in resistivity between the saturated formation of the saltwater and the freshwater has been applied by numerous researchers for investigating the SWI in coastal areas [10]. Groundwater salinity was estimated in the western part of the Netherlands using the resistivity method [11].…”

Assessment of groundwater resources potential using geoelectrical method and slug test in Tegal District, Central Java Province, Indonesia

“…Geoelectric is a geophysical method often used for the exploration of groundwater. It has been widely used to find porous aquifers [7][8][9][10], *corresponding author: wilopo_w@ugm.ac.id fractured aquifers [11], and to identify freshwater from saline water [12,13].…”

Geophysical Assessment of Seawater Intrusion into Coastal Aquifers of Bela Plain, Pakistan

“…Seawater intrusion occurs when, due to the over-extraction of groundwater resources, outflow exceeds the aquifer recharge which is dynamically connected to the sea [6,7]. Generally, problems arise, when the seawater enters the aquifer system due to excessive pumping beyond the natural recharge rate, or when the potentiometric surface lowered by the extreme pumping at local individual wells causes the upcoming of the natural boundary between saline water and freshwater [8,9]. In addition, coastal aquifers are sensitive to the sea level rise due to global warming, and the melting snowcaps add to the level of seawater encroachment and ease the accessibility of freshwater reserves [10].…”