Integrated Remote Sensing and GIS Approach for Demarcation of Groundwater Potential Zones in Ambalantota Divisional Secretariat

Abstract

Demand for water in Hambantota district is increasing rapidly due to agricultural activities, massive on-going development projects, industrialization and consequent population growth. Implementation of a proper water management system is essential in facing predicted water stress conditions where groundwater resources can play an important role. Delineation of groundwater potential zones, recharge zones and groundwater quality assessment can be identified as the three main segments of groundwater management. Geospatial technologies can be successfully utilized in such endeavours due to the cost and time effectiveness. Ambalantota Divisional Secretariat was selected as the study area in this research work. Rainfall, contour, geology, geomorphology, soil and drainage network data along with Landsat 7 ETM+ image were utilized to develop relevant thematic layers in delineating groundwater potential zones and recharging sites through a weighted overlay model on a GIS platform. Field studies were carried out to collect samples for water quality analysis and to verify the results. Groundwater quality map of the area was generated based on the results of laboratory analysis, depicting suitability level for drinking. The results indicate that Ambalantota DS has significant groundwater potential and recharge potential, hence can be effectively utilized as a hub for a water management system in Hambantota district.