A preliminary investigation of Aeolian beach sediment transport At Ramla Bay, Gozo

Abstract

2.4% of the Maltese coastline is made up of small, fine-grained pocket beaches. Many studies have identified the onshore deposition of sediment and wave or human– induced erosion, yet none have quantified aeolian transport or deposition of sediment on pocket beaches in the Maltese Islands. This study aims at investigating the aeolian beach sediment transport at Ramla Bay in Gozo, where the predominant wind was found to be the north-westerly. On site collection of sediment for analysis was made possible via sand traps constructed inhouse. Wind direction and speed, precipitation, temperature and other climatic factors were recorded for the whole period of study, as well as other parameters such as the elevation of the sand traps and vegetation cover. These were required for the analysis of the data gathered in-situ and the results obtained in the laboratory for sand grain analysis. It was found that the fluid threshold velocity varied from 0.10 - 0.56 m/s depending on the grain size. It was also found that areas having a larger vegetation cover received less input of sediment and that different climatic phenomena also influenced the rate of transport and deposition. In conclusion it was found that the highest rate of transport for the year 2014 was 2.1217 x 10-5 m3 m-1 s-1 from the north-west, while that for the study period was 1.6126 x 10-5 m3 m-1 s-1 from the north-east, followed by the north-west at 1.6095 x 10-5 m3 m-1 s-1. It was estimated that the resultant annual rate of transport during the year 2014 was around 23.2099 m3 m-1 yr-1, of which 19.7827 m3 m-1 yr-1 was transported towards the south-east. The 5-month study period gave a resultant rate of 17.6055 m3 m-1 (5)m-1, 16.6040 m3 m-1 (5)m-1, of which were transported landwards, particularly towards the south-east.