Guisado, E., Malvárez, G. and Navas, F., 2013. Morphodynamic environments of the Costa del Sol, Spain.
The morphodynamic environments of the Costa del Sol, in southern Spain, have never been investigated at a littoral cell scale. In the last half of the 20th century the tourism industry have transformed the coastal landscapes and, importantly, the natural processes inducing irreversible damages and changes. For the most part, a project-based view on engineering works has focussed on individual beach behaviour, but no assessment on morphodynamics has been reported at physiographic scale. Using an integrated modelling approach, which combines wave energy propagation and digital terrain integration (land and sea), in this paper a new characterisation of coastal morphodynamics for western Costa del Sol is presented. Methodologically, the challenge of integrating land and sea has been overcome using existing methods, which takes high-resolution interoperable bathymetric models of the continental shelf of this section of the Mediterranean, and couples it with the Official Digital Terrain Model. This allows for propagation of waves from deep water to realistic nearshore environments. Wave input is represented by wave spectra from the recording network of the Spanish Port Authority, and the wave propagation model SWAN is used to propagate wave parameters onshore. Given the variability of wave climate in the region, characterised by long periods of calms (over 77% per year) followed by high energy events (dominated by high frequency storm waves with periods of less than 7 seconds and maximum wave heights exceeding 5 metres), a wave power index is used to identify and provide input data for extreme wave conditions of great significance for beach morphodynamics in the region. Results show that at littoral cell scale, even in the presence of the steep nearshore (i) the adaptation of the system tends towards generating dissipative environments, (ii) the presence of abrupt changes in local bathymetry affects significantly wave orbital velocities even at depths beyond wave base potentially inducing nearshore sediment transport, and (iii) high energy events affect the coastal stretch in complex ways, where highly active short-crested/high-frequency wave conditions induce transitional morphodynamic states.