The expected shoreline effect of a marine energy farm operating close to Sardinia Island

Abstract

Coastal areas are defined by numerous opportunities and threats. Among them we can mention emerging renewable projects and on the other hand coastal erosion. In the present work, the impact of a genericwind-wave farmon the nearshorewaves and currents in the vicinity of the Porto Ferro inlet (northwest Sardinia) was assessed. Using a reanalysis wave dataset that covers a 40-year interval (1979-2018), the most relevant wave characteristics in the target area were identified. These can reach during winter a maximum value of 7.35 m for the significant wave height. As a next step, considering a modeling system that combines a wave model (simulating waves nearshore (SWAN)) and a surf model, the coastal impact of some generic marine energy farms defined by a transmission coefficient of 25% was assessed. According to the results corresponding to the reference sites and lines defined close to the shore, it becomes obvious that there is a clear attenuation in terms of significant wave heights, and as regards current velocities, although the general tendency for them to decrease, there are, however, some situations when the values of the nearshore current velocities can also decrease. Finally, we can mention that the presence of a marine energy farm seems to be beneficial for the beach stability in this particular coastal environment, and in some cases the transformation of the breaking waves from plunging to spilling is noticed.