Wave Attenuation by Artificial Seaweed

A series of wave tank tests was conducted at this Center CERC to determine the ability of a field of low specific gravity artificial seaweed to attenuate wave action. Wave gages were located on both sides of the seaweed field to measure wave attenuation. The field consisted of seven rows of seaweed with the rows spaced 3 meters apart. Ten distinct wave conditions were tested using periods ranging from 2.6 to 8.2 seconds and wave heights from 0.24 to 1.1 meters. Stillwater depth for all tests was 2.4 meters. There was a measureable level of wave attenuation for only the shortest period, 2.6 seconds. For the 2.6-second period, the reduction in wave height on passing through the seaweed field was about 12. This study shows that, for the width of field tested, the low specific gravity artificial seaweed is not effective in attenuating wave energy at wave periods commonly found in the ocean or other large bodies of water.