Experimental investigation on wave attenuation capacity of kelp farms

Kelp farms hold significant potential for carbon sequestration and sustainable aquaculture, requiring a thorough understanding of their wave interactions to optimize design. This study investigates wave attenuation by kelp farms through wave flume experiments using a physical model crafted from PVC sheets, replicating the mechanical properties of Saccharina japonica under geometric similarity. Six factors are analyzed: wave period, wave height, kelp blade height, row spacing, submergence depth, and farm length along the wave propagation direction. The wave transmission coefficient (k_t) is employed to quantify wave attenuation. Results indicate that k_t of the kelp farm increases with longer periods of regular waves but decreases with longer periods of irregular waves. For both wave types, k_t decreases with the increase of wave height, blade height, and farm length, but increases with the increase of row spacing. Submergence depth effects varied, suggesting adjustments based on kelp growth stages. An empirical formula incorporating the attenuation damping coefficient (α), derived through dimensional analysis, provides high accuracy (R² = 0.80 for regular waves, 0.85 for irregular waves) in predicting wave attenuation. This supports the design of kelp farms to enhance wave dissipation in coastal ecosystems.