Investigating flow development and sediment deposition within artificial and real seagrass meadows

Abstract:

Analytical models were developed to predict flow development and sediment deposition within a submerged artificial seagrass meadow. We validated these models with laboratory experiments using meadows constructed from rigid cylinders and individual model seagrass shoots. To study more complicated and realistic flow conditions, we conducted field experiments in a tidal channel in summer 2020. First, a simple method was developed and tested to measure flow velocity in the field using artificial seagrass blades and GoPro cameras with underwater housing. Second, sediment deposition within artificial seagrass meadows was measured, and the heterogeneity in sedimentation was linked to the local hydrodynamics. The deposition pattern and the flow reduction within artificial seagrass meadows in the field agree with our laboratory-based models. Also, artificial plants were used to increase the protection of transplanted shoots against hydrodynamic energy, because they could reduce the flow velocity and stabilize the sediment. The impact of artificial plants on transplant survival of real seagrass is being investigated.