Review of Impacts on Coastal Zone Due to Poor Riverine Flood Controlling Mechanism: A Case Study in Kalutara Coastal Zone, Sri Lanka

Abstract

Sri Lanka has attractive coastal zone that contributes to the economic value of the country by promoting tourism-related activities. In addition, due to the existence of natural coastal features, the coastal areas of the country have become the main obstacle to the natural coastal hazards as Tsunami. However, the coastal area of Kalutara is currently facing serious problems due to the anthropogenic activities. Kalutara is also highly vulnerable area for riverine flood of Kalu Ganga. In May 2017, a considerable portion of naturally formed sand barrier at Kalu Ganga River outfall was removed as a strategy to risk reduction process of flooding. The focus of this study is to review the negative impacts of this risk reduction process. To achieve this objective, the bathymetric profiles and the Google Earth satellite images from 2013 to 2019 were collected and analysed. The review data is shown a chronological variation of the sand barrier at the river outfall. Also erosion in the Kalutara coastal region is accelerating after May 2017. Moreover, from the questionnaire survey, salt water intrusion identified as a serious problem in the region. When applying risk reduction process for any disaster, first have to identify the best possible mechanism and it should be applied in proper manner for appropriate location. If not, other hazards may generate as side effects of the poor risk reduction strategies by developing harmful effects for the society and the environment.