General geology and delineation of aquifer zone in Kg. Asahan Hulu, Tanah Merah, Kelantan

Identifying potential zones for groundwater exploration in hard rock terrain is a challenging task. In such situations topographic, hydrogeological and geomorphological features provide useful clues for the selection of suitable sites. The study area lies between latitude 5° 47’ 2” N and 5' 49’ 32” N and longitude 101° 59’ 13” E and 102° 20’ 00” E. In hard rock terrains, groundwater is predominantly confined to secondary porosity developed due to weathering, fracturing, faulting, and all these controlling aspects are highly variable and change sharply even within very short distances, contributing to near-surface aquifer. Most of the hard rocks in the area can be classified as crystalline igneous and metamorphic rocks. These hard rocks are devoid of any significant primary porosity and primary permeability from groundwater exploration point of view. However, due to weathering and deformation of the consolidated rocks, fractures have developed on the outcrops which promote the seepage of water and mark the area very prospective for further groundwater investigations. Moreover, hydraulic properties of these rocks are mainly controlled by fractures, thus are also referred as fractured rocks. These fractures serve as conduits for seepage and lateral groundwater movement. The present research is focused on the surface investigations for delineation of groundwater potential zones using geological mapping and Geographical Information System (GIS) in and around Kg. Asahan Hulu, Tanah Merah, Kelantan. Initially based on the satellite imageries, topographical, geomorphological and hydrogeological inferences, promising zones were demarcated in hard rock areas of and around Kg. Asahan Hulu area. For this purpose, the essential thematic layers such as lineament density, lithology, drainage density, and slope density were generated using Geographic Information System (GIS) application to produce groundwater potential zonation map. The final map of groundwater potential shows the potential zones in the study area. Based on hydrogeomorphological, geological and lineament mapping, the study area has qualitatively been categorized into five conditions and it is found that the most promising groundwater zones having high potentiality are situated near to the lineament zones in study area.