Identification of artificial groundwater recharge zones in Vavuniya district using remote sensing and GIS

Ground water is a major source for domestic and irrigation purposes in Sri Lanka and plays a crucial role to human life and economic activity. With rapid growth of population and urbanization water requirements for drinking and other purposes are dramatically increasing. The over extraction and unplanned development of ground water resources have led to considerable depletion of water resources. Artificial recharge is the practice of increasing the amount of water that enters groundwater reservoir by artificial means of planned human activity. The distribution and recharge of groundwater in the country varies significantly depending on geology, rainfall and geomorphology. The objective of this study was to identify artificial recharge potential. This study was conducted in Vavuniya district since the water shortage was observed over the years. Geomorphology, geology, soil, land use and stream data along with Landsat 7 ETM+ and DEM images were utilized to develop the relevant thematic layers such as geology, geomorphology, soil, slope, lineament density, land use and stream density by integrating GIS (Geographic Information System) and image processing techniques. The resultant thematic layers were utilized to prepare the groundwater recharge maps of the area through a weighted overlay method in a GIS platform. The results revealed that the artificial recharge was high in Southern part of the study area. Further the area has significant groundwater recharge zones which can be utilized for a sustainable ground water management system