Evaluating the Application of Electrical Resistivity Tomography for Investigating Seawater Intrusion

Abstract

Seawater intrusion is a major issue in coastal areas, and the traditional technology of investigation mainly makes use of drilling for water level observation and sample analysis of groundwater; as drilling data is an information of points, it will cost more if it is extended to be information on the surface. Non-destructive geophysical exploration technology has been used in the investigation of the underground environments at all kinds of contaminated sites in recent years. Seawater intrusion is also a groundwater pollution situation, and "Surface and Space" information can be obtained with a small amount of drilling data. This research will use Electric Resistivity Tomography as a geophysical exploration technology to assess the situation at the interface of seawater intrusion and to explore the dynamic changes of seawater intrusion through long-term monitoring. The test site of this research is situated in the seawater intrusion area along Kinmen Island. The research results showed that the front edge of the seawater intrusion could be detected with Electric Resistivity Tomography, and a delay effect existing between seawater intrusion and tidal action was observed by means of Time-lapse. If a long-term observation system is established in future, it could contribute to the confrontation of seawater intrusion and salinization phenomena.

A Review on Applications of Time-Lapse Electrical Resistivity Tomography Over the Last 30 Years : Perspectives for Mining Waste Monitoring

“…Such high contrasts make TL-ERT a suitable tool (i) to monitor seawater intrusion which could lead to groundwater salinization (Chen et al. 2018 ; Palacios et al. 2020 ) and (ii) to characterize submarine groundwater discharge when contaminants flow from land to sea (Henderson et al.…”

Impact of Seawater Intrusion on Freshwater Quality in Coastal Area of South Kalimantan

“…https://dx.doi.org/10.22161/ijeab.73. 4 26 means of time-lapse observed a delay effect existing between seawater intrusion and tidal action.…”

“…The gap of electrical resistivity using geophysical techniques between seawater (0.2Ωm) and freshwater (> 5Ωm) is able to map the subsurface groundwater salinity distribution (Werner et al, 2013). The research by (Chen et al, 2018) showed that Electric Resistivity Tomography could detect the front edge of the seawater intrusion and ISSN: 2456-1878 (Int. J. Environ.…”

Appraisal of the Spatial Resolution of 2D Electrical Resistivity Tomography for Geotechnical Investigation

“…In the past decade, 2D ERT exploration has been extensively used in geotechnical engineering and environment engineering investigations and monitoring, such as geologic surveys [8][9][10], fault surveys [11][12][13][14][15][16][17], slipping plane surveys and monitoring [18][19][20][21][22][23], groundwater investigations and pollution monitoring [24,25], seawater intrusion investigations [26][27][28][29], dam leakage investigations and monitoring [30][31][32][33], landfill leakage investigations and monitoring [34][35][36][37][38], and archaeological surveys [39,40]. The 3D DC resistance method has been used by scholars [41][42][43], but it is difficult to be implemented, and the site is often limited to the measurement space, so the 2D DC resistance method is still the main method in engineering.…”