Hard engineering coastal structures; detrimental or beneficial: A case study of Agami−Sidi Kerair coast, Mediterranean Sea, Egypt

Abstract

This study was conducted to conjugate geospatial technology with Digital Shoreline Analysis System (DSAS) to monitor, analyze, and quantify the impacts of hard structures on the spatiotemporal shoreline dynamics along Agami−Sidi Kerair coastal” Pilot” area over the last 25 years (1995–2020). The results revealed that the study area lost about 63.78 % (erosion) of the beach area while gaining about 36.22 % of the beach area (accretion). During 1995–2020, Agami–Sidi Kerair shoreline experienced an accretion with an average rate of 0.56 m/year (End Point Rate, EPR) and 1.00 (Linear Regression Rate, LRR), reaching a maximum rate of 3.19 m/year (EPR) and 4.30 m/year (LRR). The shoreline analysis showed that applying hard defenses for the study area is detrimental since they convey the shoreline retreat and the beach erosion problem to the adjacent areas. In addition, they disturb sediments supply and accelerate the bottom erosion in front of them, causing downdrift scouring as a barrier to the longshore sediments transport. Furthermore, the grown level of negative consequences would cause hazardous rip current increasing the potential for drownings. Moreover, they are expensive and require costly ongoing maintenance.