2d-Electrical Resistivity Tomography for Assessment of Fresh Groundwater Potential in Sedimentary Aquifer in Part of Ottapidaram Taluk, Thoothukudi District, Tamil Nadu, India

Abstract

Electrical resistivity tomography (ERT) is one of the most widely used geophysical
methods in geological, hydro geological and geo-environmental investigations. The
study aims to assessment of fresh groundwater in sedimentary Aquifer part of
Ottapitaram Taluk, area about 743.62 km.
2
latitudes N 9°3'14" and 8°48'33", longitudes E
77°47'04" and 78°12'53" . The major source for groundwater in the study area is rainfall
during monsoon season. The study area is mainly underlined by fluviomarine sediment,
marine formation and followed by the fluviomarine sedimentary rock. Using SYSCAL
Junior SWITCH 48 Multi Electrodes, the electrodes were spread maximum of 144 m,
electrodes Spacing in 3m and the maximum depth investigated was 26.6 m (87.26928
feet) depth only. Using Winner-Schlumberger Configuration, Apparent resistivity data
were interpreted in the RES2DINV Software (Inverse model Resistivity section). The
ERT was carried out at six locations, Venkatasalapuram, Therkukalmedu, sundanpachari,
A.Kumarapuram, Vallinayagipuram and Kollamparambu in the Sedimentary region
overall resistivity range from 1.3 Ohm m to 1391 Ohm m with representation of four
layer ERT section. A favourable considers resistivity of 10 to 70 Ohm m and
considerable layer thickness were noticed in third and fourth layer. Considers favourable
resistivity range in second layer of the study area in 2 locations. First, five study
locations of the first layer resistivity value is very low <10m, this value indicates may be
Saline water or unconsolidated topsoil.