Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Abstract:
The study investigates the erosion envisaged to be caused by the hard protection works provided for Eko Atlantic City, the contributory factors and sediment variability along Lagos Coast. Alpha Beach along the Lagos coast was modelled with a distortion of 1: 21.36 using a horizontal scale of 1:1,068, a vertical scale of 1:50, model wave period of 1.7s and wave height of 0.02m. Cross-shore profiles were taken before and after the experiment. Laboratory analyses of beach sediments obtained from field investigations were also carried out. The experiment confirmed large-scale erosion on Lagos coast, with erosion greatest in places farthest from the protection works, followed by the site closest to the protection works. Cross-shore sediment transport observed in the model was driven largely by rip currents while longshore currents were responsible for longshore sediment transport. The physical and empirical measurements of longshore transported sediments during the experiment were 1,339kg and 2,097kg respectively. Laboratory analyses confirmed sediment variability in the run-up faces of beaches in Lagos coast as a result of continuous mixing by wave attacks. Measures should be put in place to mitigate the large-scale erosion and flooding envisaged in the eastward end of the vast project.

Keywords: cross-shore transport, erosion, protection, longshore transport, coast

Download full paper