2D ERT survey was carry out at 11 sites within an area of 10 km2 to delineate deeper potential groundwater zones in a complex geological terrain underlain by quartzite, shale, limestone formations with varied resistivity characteristics in medium rainfall zone at Tadipatri, Andhra Pradesh state, India. The data reveals potential zones at only three sites in Tummalapenta, Ayyavaripalle and Guruvanipalle villages within the depth zone of 24-124 m. A major fault zone oriented in EW direction is mapped at Tummalapenta site. Four boreholes were drilled in complex (viz., limestone, shale and quartzite) formations up to a maximum depth of 192 m in the area with the yield ranging from 300 to ~5000 liter per hour (lph). These four anomalous drilled borehole sites corroborate with the aquifer zone delineated through ERT technique. The aquifer parameters estimated from pumping tests show the transmissivity varies between ~0.3 to 179.5 m2/day while the storage coefficient ranges from 0.137 to 0.5 indicating large variation in aquifer characteristics of the system in a small area. Suitable water conservation measures were suggested for improving the groundwater condition and yield of the pumping wells.
Figure Caption: (a) 2D inverted resistivity model shows a large resistivity contrast, delineated a major fault (F-F) structure and the groundwater potential zone towards the southern side near the fault; (b) depicted the geological model, main fault structure, borehole and the thick massive quartzite rock towards the north of the fault plane
Kumar, Dewashish, Rajesh, K., Mondal, S., Warsi, T. and Rangarajan, R., 2020. Groundwater exploration in limestone-shale-quartzite terrain through 2D electrical resistivity tomography in Tadipatri, Anantapur district Andhra Pradesh, Journal of Earth System Science, Springer Publication, Vol.129, no.71, pg. 1-15, Published online on 15th February, 2020, https://doi.org/10.1007/s12040-020-1341-0