Evolution of the coast of north Lebanon from 1962 - 2007: mapping changes for the identifications of hotspots and for future management interventions

Abstract

The Lebanese coast, recognized as being sediment starved, has been experiencing increased anthropological pressures that have led to its beaches being eroded at relatively high rates. The current study aimed at detecting erosion, accretion, and sea-filling along the coast of North Lebanon between 1962 and 2007 in order to identify affected areas that require further investigation and management intervention, and to raise awareness at all levels for responsible coastal zone management. Aerial photographs for the year 1962 and satellite imagery for the years 1970, 1994 and 2007 were digitized and analysed. The shoreline was drawn according to the High Water Mark (HWM) seen on the imagery as the dry/wet limit. Then, a comparison between shorelines for the years 1970, 1994 and 2007 was made, respectively, using the year 1962 as the reference shoreline. The absence of basic geographic data in the form of topographic maps led to the purchase of geo-referenced spatial imagery. The evolution study was therefore conducted using simple photo-interpretation methods where the surfaces were measured as polygon areas and rounding made at the thousand level. Overall, the majority of erosion occurred between the years 1962 and 1994 and stabilized afterwards while sea-filling activities started in 1970 and continued until 2007. Erosion nevertheless may have caused irreversible damages as the amount of lost material may not be recovered on this sediment starved coastline. On the other hand, extensive sea-filling has caused the destruction of intertidal and littoral habitats and led to modifications in coastal dynamics. However, identifying the main causes of the damage and understanding the dynamics of the affected areas should be investigated in order to propose suitable measures to prevent further degradation and to sustainably conserve coastal areas and their resources for the benefit of coastal communities.