Application of TEM sounding method on riverbank filtration site subsurface suitability

Transient electromagnetic (TEM) sounding technology is known for its capability in detecting resistive zones, especially those associated with fresh water. Nevertheless, to date, there have been no available studies that have employed TEM for riverbank filtration (RBF) application. Therefore, this study was conducted to investigate the capability of TEM technology in profiling the subsurface of RBF areas adjacent to Sungai Perak, Kota Lama Kiri, Kuala Kangsar. A total of 27 survey points of simple rectangular loop configuration with loop area of 100 m2 (10 m × 10 m) were executed in the study area. A suite of TerraTEM equipment was used for the data acquisition process. The inversion and interpretation processes were then conducted by using the modeling program of ‘TDEM Geomodel’ and Surfer 13. The results showed four 2-D resistivity cross-section (depth–distance) profiles with their corresponding geological units. The interpretation results indicated that the subsurfaces of the study area were identified as alluvial-type soils (with a range of 10 to 40 Ωm) up to 8 m due to the presence of silt, sand and gravel. Based on the good quality results produced as well as its convenience, it is recommended that the TEM method is used for RBF exploration in future work.