| dc.description.abstract | Seaweed cultivation is a globally emerging sector and is expected to show large growth in
the coming decades as a sustainable marine resource. However, the influences of seaweed
cultivation on local hydrodynamics and with that nutrient dynamics remains relatively
understudied. Therefore, this thesis investigates how seaweed farms modify flow pat-
terns in both vertical and horizontal dimensions. The Delft3D-FM model was used to sim-
ulate scenarios in an idealised flume setup and in the real-world environment of Bantry
Bay, Ireland. A modelling approach which looks at the basic influences in an idealised
flume setting includes a baseline configuration of a seaweed farm represented by vege-
tation elements, followed by sensitivity studies with varying values for the stem height,
density, diameter, and drag coefficient.
Results show that seaweed presence reduces surface flow velocities by up to 70% in the
flume model, with the depth of maximum velocity shifting downward by approximately
10 metres in a water column of 20 metres in total. Wake lengths downstream of farms
range from 55 to 92 metres, corresponding to 22 to 36% of the seaweed patch, respectively,
depending on vegetation parameters and flow conditions. Sensitivity analyses indicate
that stem height has largest influence on hydrodynamic effects, followed by stem diame-
ter and stem density. In Bantry Bay, similar surface flow reductions are observed, though
wake structures are less uniform due to tidal forcing and bathymetric complexity.
This study offers insights into how seaweed farms interact with local hydrodynamics and
provides a foundation for future work on farm design optimisation and environmental
impact assessment. | |
