Experimental investigation of wind-generated waves over a fringing reef with impermeable and porous surface conditions

Wind-generated waves over fringing reefs are affected simultaneously by sustained wind forcing and reef-induced transformation, with important implications for coastal flooding and protection. However, previous laboratory studies have mainly focused on remotely generated swells, while locally generated wind waves over porous reef surfaces remain insufficiently understood. Laboratory experiments were conducted using a 1:10-scale idealized fringing-reef model under four wind speeds, two reef-flat water depths, and impermeable and porous surface conditions. Wave spectra, wave-height statistics, total wave energy, waveform nonlinearity, wave setup, and runup were examined. Increasing wind speed increased wave height, total wave energy, maximum setup, and maximum runup, while shifting the spectral peak toward lower frequencies. At G1 under the impermeable-surface condition with a reef-flat water depth of 0.1 m, the measured spectral density near the peak exceeded the corresponding Texel–Marsen–Arsloe estimate for the parameterization adopted here, and the difference increased with wind speed. The porous surface layer enhanced the attenuation of wave height and total wave energy and reduced maximum runup, particularly at higher wind speeds and over the shallower reef flat, but generally increased maximum setup. Separate descriptive empirical relationships for dimensionless maximum runup were fitted to the tested model-scale cases under the two reef-surface conditions.