Author(s): Sanchez Virginia; Lechuga Antonio; De La Pena Jose Manuel
Linked Author(s):
Keywords: Surfing; Beaches; Peel angle; Surf
Abstract: Many beaches along the Spanish coast are undergoing erosion processes, which makes it necessary for the administration to take measures to provide it with the adequate characteristics for its enjoyment and conservation. In the case of study, Barceloneta beach in Barcelona (Spain), the line of action proposed was received with some distrust by the local surfer group represented by the Asociacion Catalana de Surf. The members of the association were afraid the proposed coastal works may vanish the waves which they had been enjoying themselves with. The Directorate General of Coasts of the State Secretariat of Territory and Biodiversity of the Spanish Ministry of Environment commissioned to CEDEX the following study to verify the influence of the works planned on the surf conditions of the area. First, the wave peel angle and the height breaking wave were calculated for the main wave directions. These are the most important variables for the determination of the adequacy of a coastal area for the practice of surf, its difficulty level and the surfer profile, from several abacuses and tables. The information gathered on these tables came from the study of the physical processes of surf started in the early 70s (Walker and Palmer, 1972, 1974) and continued afterwards by some universities in New Zealand and Australia. The growing interest on surf is shown in Congresses such as the International Surfing Reef Symposium, which fifth edition was celebrated in California last 2005. The wave peel angle is the angle formed between the unbroken wave as it propagates shoreward and the whitewater which breaks gradually which would be the trajectory followed by the surfer. It is an angle related to the break angle and the wave obliquity at the broken depth. In the present study, the break zone and the wave fronts of the directions propagated were determined and the beach divided in three parts characterized by its peel angle. The propagation with and without the works planned was evaluated by means of a numerical model of refraction-diffraction. The results showed the influence of the proposal (Walker abacus, 1972) on the beach. It was observed that the detached breakwater would reduce the surfing area whereas the submerged groins, placed at the edges of the beach, would generate a greater diffraction improving surfing conditions. The proposed works are currently in process. Its monitoring when finished is important to verify the adjustment of the analysis developed and the suitability of the abacus used for the Spanish beaches. Since the number of surfers on our coasts as well as their concern towards any coastal work is growing, the research on this field is advisable. Besides, the experimentation in laboratory with scale models and the development of numerical models will be fundamental to boost knowledge about new coastal structures that not only do not reduce the beach surfability but also strengthen it.
Year: 2007