Coastal Erosion is defined as wearing away of land and the removal of beach or dune sediments by wave action, tidal currents, wave currents and drainage or high winds. Although Sri Lanka has a 1585 km of coastal line, more than fifty percent of the shoreline is affected by coastal erosion, according to the estimations. Strong waves and high wind play a most important role in coastal erosion. While the waves strike the beaches and break fragments of ground, the wind blows away the sand. It is also said that tidal waves eventually smash rocks. Also there is a certain amount of human interference in coastal erosion. People do take sand from the banks of the rivers and buildings are being built along the coast of sea.
Kalpitiya, Matara, the Maha Oya river mouth, Uswetakeyya and Moratuwa are most critically affected areas by Coastal Erosion in Sri Lanka. Also it is found that recently Mount Lavinia, Wadduwa, Beruwala and Unawatuna are also being affected by coastal erosion. Placing sand bags as a temporary measure, building a sea wall, building groynes and placing large boulder barriers are some of the Erosion Control Strategies implemented by The Coast Conservative Department in Sri Lanka. These strategies are used in other countries also. Those who live in coastal areas build fences to avoid sand being shifted, where the system is not much effective. Although in Sri Lanka hundreds of people were left without homes due to coastal erosion, Sri Lanka is not affected as highly as other foreign countries. Being an island we Sri Lankans have some natural resources which may safeguard us from threatens like this. Coral Reef plays a major role in preventing coastal erosion.
In Sri Lanka coastal regions are homes to a larger population and to another population it is a place where they make their way of living by fishing, tourism and maritime activities. Considering these facts Engineering and Management of Coastal Zone has set some objectives such as; improving the status coastal environment, developing and managing the shoreline, improving the living standards of coastal communities and promoting and facilitating economics development based on coastal resources. Although so many strategies have been taken or will be taken in future it is a duty of every human being to protest our nature and our valuable resources.
The coastal erosion hazard profile
During the recent years coastal erosion was accelerated due to upstream anthropogenic activities and poorly planned coastal infrastructure development adding stresses on the coastal ecosystems.
The complex coastal environment processes and shoreline stability or the dynamics of accretion or erosion are driven by coastal hydrodynamics, sediment balance and coastal geomorphology etc. influenced by wave climate and shoreline geometry.
The coastal erosion hazard profile uses a sediment cell approach that considers wave incident angle, sediment balance and length of the cell on the shoreline stability. The coastal erosion driver significances have been adjusted in the study using the coping capacities corresponding to each cell, based on the physical coast protection structures. The final rank of the degree of erosion in each cell was determined in a reference scale. The degree of hazard was displayed as a linear feature on 1:50,000 maps.
The coastal erosion profile is useful for designing setback systems in coastal management and strategic planning bearing in mind the uncertainties associated in modelling and data limitations.
View hazard report of coastal erosion in Sri Lanka