Long term coastal erosion and shoreline positions of Sri Lanka

Coastal zone of Sri Lanka is a key to sustainable development of the country. The erosion of country’s coastal zone has been identified as a long standing problem. Therefore, coastal sediment dynamics around the country has to be identified to develop an appropriate coastal zone management plan. Remote sensing and GIS techniques can be used for quantitative and qualitative analyses of coastal processes including the coastal erosional and accretional trends. In this study, past and very recent Google Earth satellite images have been processed and analysed in an Arc Gis environment to investigate erosional and accretional trends in the coastal zone all around Sri Lanka. Using the results of the study, near shore sediment transportation directions and patterns along the coastline around the country were also predicted. Most of the south-western coastline of Sri Lanka shows considerable erosion during stormy conditions under south-western monsoon period, but most of them get recovered during fair weather north-eastern monsoon conditions. Therefore, no any severe long term erosion conditions prevail in the western, south-western and north-western coasts. However, some isolated locations in the north-eastern and eastern coastline show considerable erosion. Predicted nearshore sediment transportation directions proved that it is mainly governed by wind and waves of southwest and northeast monsoons.