| Abstract Submission No. | ABS-2.3-0143 |
| Title of Abstract | Differentiating Saline Aquifers via Airborne EM and Hydrochemistry: Seawater intrusion vs. Mining effluents |
| Authors | Kattula Bhima Raju*, Sanchari Banerjee, Subash Chandra |
| Organisation | CSIR-NGRI; AcSIR, Ghaziabad- 201002, India |
| Address | Room no:118, groundwater building, CSIR-NGRI, Uppal road Hyderabad, Telangana, India Pincode: 500007 E-mail: bheemusonys@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | The coastal regions are increasingly susceptible to seawater intrusion (SWI), principally caused by excessive groundwater abstraction, placing significant stress on freshwater reserves. Surat, a rapidly developing urban centre on the Arabian Sea coast, is experiencing increasing reliance on groundwater and surface water from Tapi River for domestic and industrial requisites. Intensive withdrawals, compounded by the region�s semi-arid climate, have resulted in declining water levels and deteriorating water quality, accelerating risk of SWI. A dual moment airborne electromagnetic data provided high-resolution resistivity distribution of the near surface from upper a few meter to more than 300 m depth. The study area being located at the Arabian sea coast, it is prone for SWI especially due to heavy pumping. The industrial effluents coming out of the existing mine in the area also can influence the measured resistivity. This is also well-known fact the formation resistivity is cumulative effect of the physicochemical properties of the formation. However, neither there is clear understanding nor any established methodologies how the lithology, presence of water and water quality influence the formation resistivity, which is crucial for translation of resistivity data into lithological and hydrogeological models. The paper presents details analysis of AEM resistivity distribution and hydrochemical data from borewells measured during pre-monsoon and post monsoon period to differential zones influenced by SWI, industrial effluent and lithology. The study established that the resistivity falling below 3 m in the western sea coast is dominantly influenced by SWI . However, lowering of resistivity in the eastern part of the study area is caused by clay dominance. A small zone in the north east close to mine industry is caused by waste water coming out of mine where Mg+ is found exceptionally high, even during post monsoon season. |
| Keywords | Sea water intrusion, Dual moment, Resistivity, Seawater intrusion, Groundwater |