Effects of Wave-Dissipating Blocks on Reduction of Salinity in the Air Generated at a Vertical Breakwater Based on Field Observations

At Waku fishing port in Yamaguchi Prefecture, Japan, which has a vertical breakwater at the mouth of the port, wave-dissipating blocks were installed in front of the breakwater to reduce the sea water spray generated at the breakwater. To clarify the effect of wave-dissipating blocks on the reduction of the salinity in the air, a large number of field observations were conducted at the port in the winter seasons from 2005 to 2011; the run-ups of the splash (heights and frequency), the wind (velocity and direction) and the salinity concentrations in the air were measured at about 30 observation points. The data obtained before and after the construction showed that the violent run-up of splash was efficiently blocked by fully covering the vertical breakwater with the wave-dissipating blocks. Consequently, the salinity in the air was also drastically reduced.