Water is one of the most basic components of human existence and socio-economic development, but its availability is usually taken for granted. Groundwater is a key natural resource in many parts of the world. Equally groundwater is important in specific climate and hydrological contexts such as arid and semi-arid areas, where it is commonly the only safe source of water. Groundwater occurrence in crystalline rock terrains is highly influenced by geological structures. These geological structures, unless mapped with precision, groundwater exploration may end up with low yielding or dry boreholes. This study aims to evaluate geologic and structural influences on groundwater. The present research is important for understanding the factors influencing the distribution, flow, and yield of groundwater. The area of investigation confines to the crystalline rock terrain of Gudimangalam block of Udumalpet taluk in Tiruppur district, Tamilnadu, which being a drought prone area. The total areal extent is about 100sqkms and aquifer mapping project for both irrigational and drinking water needs has been carried out. Systematic geological, hydrogeological investigations followed by surface geoelectric exploration by 1D VES [vertical electrical sounding] were done to delineate the fracture/ joints/lineaments of the subsurface. Totally 51 bore wells have been drilled. Iso apparent resistivity maps and bore well yield contour maps / aquifer potential mapshave been generated to study lineament pattern of the area. The Iso apparent resistivity map, electric log of a deep borewell and the aquifer yield contour maps throw light on the tectonic history revealing that this zone is tectonically disturbed with faulting, shearing and shattering of the subsurface lithology. The high potential aquifers confine to the lineament-Poolavadi-V.Vallakondapuram lineament and from these research it may be concluded that the occurrence, distribution and movement of groundwater are influenced and impacted by geological structures which have a direct control. The study clearly shows that there are three sets of lineament, the main being the one with north east-south west trend.

Keywords : Aquifer mapping; 1D VES; Iso apparent resistivity map; electrolog; lineament.