The role of wave energy converter farms on coastal protection in eroding deltas, Guadalfeo, southern Spain

Many worldwide coasts are under erosion with climate projections indicating that damages will rise in future decades. Specifically, deltaic coasts are highly vulnerable systems due to their low-lying characteristics. This paper investigates the role of wave energy converter (WEC) farms on the protection of an eroding gravel-dominated deltaic coast (Guadalfeo, southern Spain). Eight scenarios with different alongshore locations of the wave farm were defined and results were compared with the present (no farm) configuration of the coast. Assuming that storm conditions drive the main destruction to the coast, we analysed the impact of the most energetic storm conditions and quantified the effects of the location of the farm. Significant wave heights in the lee of the farm were calculated by means of a calibrated wave propagation model (Delft3D-Wave); whereas wave run-up and morphological changes in eight beach profiles were quantified by means of a calibrated morphodynamic model (XBeach-G). The farm induces average reductions in significant wave heights at 10 m water depth and wave run-up on the coast down to 18.3% and 10.6%, respectively, in the stretch of beach most affected by erosion problems (Playa Granada). Furthermore, the erosion of the beach reduces by 44.5% in Playa Granada and 23.3% in the entire deltaic coast. Combining these results with previous works at the study site allowed selecting the best alternative of wave farm location based not only on coastal protection but also on energetic performance criteria. This work, whose methodology is feasibly extensible to other coasts worldwide, provides insights into the role of the alongshore location of WEC farms on wave propagation, run-up and morphological storm response of deltaic coasts.