A study on the physical characteristics of currents and wave climate at Ramla Bay

Abstract

This baseline study investigates the nature of sea current circulation and wave climate of the wider Ramla Bay area, specifically the significant wave height and the wave direction, using numerical models. This study was undertaken because no existing studies or data on the physical hydrodynamics of the area are available. This information is unconditionally important for the input into management decisions. Through reviewed literature, it was expected that a cellular circulation arising from the formations of rip currents within the bay prevail. This was thought to be the case at Ramla because of the circular pattern of Posidonia oceanica seagrass beds in the centre of the bay. The results showed that rip currents were not prevalent during the studied period. The mapped sea currents were found to predominantly flow along the contours of the coastline around the embayment. It was, however, concluded that the occurrence of strong rip currents, should not be excluded as a possibility during the winter period when strong wave conditions occur. Data from the SWAN model for wave direction was found to approach the coast predominantly from the North East direction. Signifying possible accumulation of sediments on the west side of the embayed beach. Wave direction was also observed to have a positive relationship to the ensuing current direction but were found to be statistically insignificant. The significant wave height wave was also found to be significantly larger in the winter months compared to the summer months. Within the bay the temporal variation of SWH exhibited less fluctuation compared to deeper waters. The SWH was also found to be strongly associated with alterations in atmospheric pressure and showed that Ramla Bay is powerfully protected during storm events, by drastically attenuating the wave energy. This is an essential role when considering the dynamics of the beach morphology, as well as the dynamics of the backshore dunes.