Site suitability analysis for groundwater recharging structures in Hambantota district by using remote sensing and GIS techniques

Abstract

The dry zone of Sri Lanka faces drought conditions periodically, due to the rainfall variations over the island. Hambantota District in Sri Lanka appears to be a highly affected area from these drought conditions on the basis of surface water availability. This situation can be worse in the future, with the climatic changes in the world and human interference with the nature. Hence, a proper water management system, including preservation of existing surface and groundwater resources as well as recycling, is a must to overcome this problem. Rainwater harvesting is practiced throughout the world, as a solution to this problem. Groundwater consists of 30.}% of the freshwater resources in the earth, while surface water consists of only 1.3%. Hence recharging the runoff to the groundwater table is an effective method in rainwater harvesting. Integrating remote sensing and GIS techniques with relevant data can provide an updated, reliable database which is a pre-requisite for designing a proper water management system with dramatic saving of time. In this work, Suriyawewa District Secretariat Division was selected as the project area, considering its location within Hambantota District and its average climatic conditions. The suitable locations to recharge the runoff into groundwater table were found out by integrating land use, climatic, soil, stream and slope data of Suriyawewa with Remote Sensing and GIS techniques. This methodology can be generalized to Hambantota District and can be applied to other areas in the dry zone of the island.