Groundwater targeting using remote sensing, geographical information system and analytical hierarchy process method in hard rock aquifer system, Karur district, Tamil Nadu, India

Remote sensing (RS) and Geographic Information System (GIS) are potential tools for competent planning and administration of essential groundwater resources. In this study, a typical methodology is proposed to delineate groundwater target zones using integrated RS, GIS and Analytical Hierarchy Process (AHP) method. The developed methodology is confirmed by a case study in Karur district of Tamil Nadu, Southern India. Seven thematic layers, viz., Lithology, Lineament Density, Geomorphology, Slope, Post– Monsoon Water Level, Drainage Density and Landuse/Land cover were considered in this study. Selected seven thematic layers and their features were assigned suitable weights on the Saaty’s scale according to their virtual significance in groundwater incidence. The assigned weights of the thematic layers and their features were then normalized by using AHP. Finally, the selected seven thematic maps were incorporated by weighted linear combination method in a GIS environment to produce a groundwater targeting map. Thus, five groundwater targeting zones were identified and demarcated in the study area, viz., ‘very good’, ‘good’, ‘moderate’, ‘poor’ and ‘very poor’. The groundwater targeting map was finally verified using the well discharge data and the result was found acceptable. The ultimate result depicts the favorable groundwater targeting zones in the study area and can be helpful in better planning and managing of groundwater resources particularly in hard rock terrains.