Analysis of Causes and Effects of Coastal Erosion and Environmental Degradation in Southern Coastal Belt of Sri Lanka Special Reference to Unawatuna Coastal Area

摘要

Sri Lanka is an island with a coastline approximately 1600 km in length and it is the boundary between the land and the sea to protect the land mass of the country. Today coastal erosion and environmental degradation are accelerating along many coastal areas of the country due to the natural and anthropogenic activities. The prime objectives of this study are to identify the natural and anthropogenic activities to coastal erosion, problems associated with the instability of coastline, analysis of the intensity of erosion and identify possible management strategies against coastal erosion in southern coastal belt of Sri Lanka specially in the Unawatuna coastal area. Quick bird satellite images from Google Earth used to assess the behaviour of the coastline and to identify the land use patterns around the study area. Randomly selected 100 residents were subjected to collect primary data through questionnaire survey to assess the livelihood activities against coastal erosion. Chi square, used as statistical analysis tools while image processing, digitizing, geometrical calculations in GIS and Remote Sensing used as descriptive analysis tools to achieve the prime objectives of this study. The study found that both natural and anthropogenic factors are subjected to coastal erosion in the area. Natural sea waves became more destructive and its incentive increased due to the artificial rock dam (water break) constructed in the area. At present tourism and related human activities have been a stimulus for the coastal erosion. Erosion along the beach in 2007 was at natural level, and it represented 19408.87 m long. In 2011, erosion gradually increased and the length of beach represented as 10081.99 m, and in 2013, sand was pumped into the coast along the beach, thus expanding up to 13389.38 m. The sand pumped into the shore to stop the erosion deposited on coral reefs, and had made bad effects on the bottom dwellers of the sea. Also erosion has made a breakdown of tourist industry indirectly and the economy of the country. Removing the rock dam along the belt was a major suggestion, and several minor strategies are possible to be implemented to minimize this problem.