New wave-modeling work is putting harder numbers on something coastal communities have long observed: dense kelp canopies can measurably calm the water behind them. Because measuring this directly in wild, storm-battered kelp forests is difficult, a 2023 study from the University of Melbourne’s Coastal and Estuarine Adaptation Laboratory instead built a physics-based model using kelp aquaculture canopies, whose structure behaves similarly to natural kelp beds under waves.
Researchers Roma Bodycomb, Andrew Pomeroy and Rebecca Morris adapted an existing wave-attenuation model, originally built around how individual kelp blades bend and flex like small cantilevered beams, to simulate how a full suspended kelp canopy dampens waves moving through Port Phillip Bay. They ran the model across different kelp growth stages, canopy densities and water depths, under wave conditions typical of the bay, half-meter waves on a six-second cycle.
Under those baseline conditions, a fully grown kelp canopy dissipated about 94% of wave energy in shallow water, but that effect fell sharply as conditions changed: down to 51% at only a quarter of full growth, under 7% once the canopy’s lateral blades had been harvested away, and down to 67% simply by moving into water two meters deeper. The pattern suggests kelp’s wave-buffering power depends heavily on exactly how much canopy is actually there and how close to the surface it sits, not just on kelp being present at all. The authors note their model doesn’t yet account for blades sheltering each other, and was built around calmer bay conditions rather than extreme storm swell; their next step is validating it in wave-flume tanks and extending it to a full 3D storm model.