HYDROGEOPHYSICS AND REMOTE SENSING FOR THE DESIGN OF HYDROGEOLOGICAL CONCEPTUAL MODELS IN UPPER GADILAM RIVER BASIN TAMIL NADU, INDIA

R. Ayyandurai; S. Venkateswaran

Volume : VI, Issue : II, February - 2016

HYDROGEOPHYSICS AND REMOTE SENSING FOR THE DESIGN OF HYDROGEOLOGICAL CONCEPTUAL MODELS IN UPPER GADILAM RIVER BASIN TAMIL NADU, INDIA

R. Ayyandurai, S. Venkateswaran

Abstract :

A geoelectrical resistivity survey has been carried out in the Upper Gadilam river basin in Vizhupuram district of Tamil Nadu. With the purpose of delineating the geologic setting and its impact on the groundwater occurrence. The study involved measuring Vertical Electrical Sounding (VES) at twenty–Five locations using the Schlumberger Array. The results showed that the geoelectrical succession in the study area consists of four geoelectric layers which were grouped into three main zones. The first zone consists of four geoelectric layers corresponding to the dry upper surface layers. The second one is composed of four geoelectric layers that constitute the Eocene weathered zone of the study area. The third zone is consists of three and fourth geoelectric layers and corresponds to Pleistocene water beå zone the study area. In line with a general conceptual model of hard rock aquifers, we identified two main hydrostratigraphic layers: a saprolite layer and a fissured layer. Both layers were intersected and drained by fault zones that control the hydrogeology of the catchment. The spatial discontinuities of the saprolite layer were well defined by RS techniques while subsurface geometry and aquifer parameters. By using conventional GIS method, the spatial distribution maps for different layer thicknesses were prepared. The geoelectrical approach was successfully applied in the study area and can be therefore easily adopted for similar environments. The area was found to be affected by a group of normal faults. The results showed, also, that the lithological changes and thickness of the saturated zone have their effect on the groundwater potentiality in the study area. Moreover, the detected faults contribute to seepage of runoff water to recharge in to the water beå zone and control the flow.