Hydrological analysis of Sooriyawewa area using remote sensing and GIS techniques

Abstract

Sri Lanka is traditionally divided into three main zones namely Wet Zone, Intermediate Zone and Dry Zone according to the average annual rainfall. The dry zone of Sri Lanka is very often faced with severe drought conditions and the situation is becoming worse as time moves on. On the basis of surface water availability, Hambantota area, which falls with in the dry zone, appears to be a heavily affected area. Proper water management systems as well as preservation of existing surface and ground water resources and recycling are essential measures to overcome this problem. Hydrological analysis of the area is needed for a proper water management system. Integration of Remote Sensing and Geographical Information System (GIS) techniques provides a reliable, accurate and updated database on land and water resources, which is a pre-requisite for a proper water management system. Sooriyawewa was selected as the project area considering the average rainfall variations in Hambantota District. The spatial data based hydrological conditions such as, flow direction, catchments, drainage lines, drainage points, etc. were interpreted in the area. The hydrological condition in Sooriyawewa area is adequately delineated using these techniques, as pre-requisite to a proper water management system.