Seasonal changes and coastal erosion in the South Western part of Sri Lanka

Abstract

Sri Lanka is an Island, the economy of which relies very much on the developments of the coastal region, which supports tourism and fisheries. In addition, especially in the South-Western part of the country, the infrastructure lays in the proximity to the coast and the land is more precious and valuable. Further, the constructions around the coastal expanse, alter the sand dynamics of the coastal belt, increasing erosion and deposition at specific points. The erosion cannot be identified at a glance in one day, but when considering long-term sustainable developments, the loss of expanse due to erosion becomes vital. Hence, in this study we analysed the erosion pattern and gross land loss along South-Western part of Sri Lanka, considering duration of 6 months (Jun/07 till Jan/08). The variations of beach profile were determined from leveling perpendicular to the beach at 10 predetermined locations at one month interval. Grain size variations were also analysed from the samples collected from the mean sea level from each sampling locations. A strong correlation was observed at this location between the monsoon and erosion, while at Egodauyana, Panadura Moya, kani Lanka hotel and Payagala revealed rapid changes in erosion/deposition. Although the rainfall influences the beach variation, longshore currents, tides and coastal features (natural and artificial) are found to be dominating at these locations.