Luis Aragonés Pomares

The effects of sediment used in beach nourishment: Study case El Portet de Moraira beach

Actions taken to prevent or reduce coastal erosion often do not have the desired effect, leading to major problems instead of solving the original one. This research focuses on why a nourished beach- with borrowed sand and 0.05% of particles <0.063 mm- causes the presence of suspended particles that are observed by beach users as turbidity. This means that the colour of the water was not its characteristic blue, even with calm wave conditions. This research involved a shoreline evolution analysis and a sedimentological study of the sand from 1977 to 2017. The results show that the turbidity episodes that occurred after the beach fill of May 2017 do not coincide with major storms that affected the beach. Furthermore, prior to this beach nourishment, even after the most important storms turbidity was not so pronounced. However, when the pre-nourishment and post-nourishment sediment are compared and analysed in detail, by studying the microstructure and morphology of the sand particles, their composition and morphology were observed to be completely different. These differences are also reflected in the accelerated particle weathering test, with the post-nourishment particles showing greater dissolution of carbonates. From its mineralogy, the post-nourishment material presents a smaller proportion of quartz in its composition and a significant amount of particles (9.6%) formed by clusters of Calcium and Silicon. The separation of this mineralogical composition produced by waves explains the formation of particles measuring <0.063 mm, a fact that has also been confirmed by the accelerated particle weathering test. This is, therefore, the cause of turbidity in the swash zone of the beach.

ALICANTE BEACH- CITY SUSTAINABLE DEVELOPMENT

Our research is focused on the city of Alicante (Spain). In concrete, the sunken area studied is placed at the south of Alicante Port, being the point of entry from the airport to the city. There are two important reasons that have generated that depressed area. Firstly, the development of the city has led to a change in the use of the soil, and secondly, the extension of Alicante Port. This area used to be a metallurgical industrial zone, but during the last 40 years, it has overcome an urban growth. The European Office for Harmonization in the Internal Market (OHIM), the most modern Film Studio in Europe ‘Ciudad de la luz’, a desalination plant and residential complexes and offices have settled down there. Unfortu nately, all this development has occurred without taking into account the coastal needs. Regarding to that, several elements that contribute to the deterioration of the area can be found along the coast, that is the mouth of a rift called ‘Barranco de las Ovejas’ at north, the ‘Agua Amarga’ rift at south and the desalination sewage pipe. Besides, there is a merchandise train line adjoining the Maritime-Terrestrial Public Domain that provides service to the port, but hinders the way for pedestrians going to the beach.