Analysis of the abundance of abandoned tanks in Hambantota District, Sri Lanka using GIS techniques

Abstract

Around two thirds of the area in Sri Lanka is covered by the dry zone, which receives less than 1750 mm average annual rainfall, but not equally distributed over the land. Due to rainfall variations, dry zone of Sri Lanka faced periodic drought conditions in the past. On the basis of surface water availability, Hambantota District appears to be a highly affected area. Tanks have been constructed in order to harvest rainwater to overcome this problem. But, there are many abandoned tanks in Hambantota, which decrease the effectiveness and efficiency of water harvesting. In order to minimize the number of abandoned tanks, an analysis is carried out to find the cause for the abundance of abandoned tanks in the area. Integrating GIS techniques with the relevant data such as rainfall, topographic contours, spot heights, land use, temperature, geology, etc. gives an accurate and updated database, which helps to analyze the reason for the abundance of the abandoned tanks in the area, and hence facilitate the increase of efficiency and effectiveness of rainwater harvesting through a proper water management system.