In-Situ Benthic Annular Flume

The in situ annular Flume, Voyager II, was deployed at three sites in the North Sea in order to investigate resuspension events, to determine the physical characteristics of the seabed, to determine the threshold of resuspension of the bed and to quantify erosion rates and erosion depths. These are the "rst
controlled, in situ !ume experiments to study resuspension in the North Sea, and were combined with long-term measurements of waves and currents. resuspension experiments were undertaken at two muddy, and one sandy site: north of the Dogger Bank (DG: water depths w80 m, very "ne, poorly sorted,
very "ne-skewed sediment experiencing seasonal thermal strati"cation of the water column along with oxygen depletion); the Oyster Grounds (OG: w40 m, similar bed properties, year round water column thermal strati"cation, Atlantic forcing); and in the Sean Gas Field (SGF: w20 m, moderately sorted, very
coarse-skewed sand, and well mixed water column). The erosion thresholds of the bed were found to be 0.66e1.04 Pa (DG) and 0.91e1.27 Pa (OG), with corresponding erosion depths of 0.1e0.15 mm and 0.02 e0.06 mm throughout the experiments. Evaluation of a year of current velocities from 2007 indicated that at OG, resuspension of the consolidated bed was limited to on average w8% of the time as a result of tidal forcing alone for short (