Fine sediment resuspension dynamics in a large semi-enclosed bay

Abstract A field study was conducted to investigate fine sediment resuspension dynamics in Moreton Bay, a large semi-enclosed bay situated in South East Queensland, Australia. One S4ADW current meter and three OBS sensors were used to collect the field data on tides, mean currents, waves and suspended sediment concentrations in a mean water depth of 6.1 m for about 3 weeks. Two small cleaning units were specially designed to automatically clean the OBS sensors several times every hour to avoid biological growth on the OBS sensors. Based on the collected field data, the main driving force for fine sediment resuspension is found to be the storm wind-waves generated locally in the Bay, not the tidal current or penetrated ocean swell. The critical wind-wave orbital velocity for sediment resuspension was determined to be U rms =7 cm/s and the critical bed shear stress τ cr =0.083–0.095 Pa at this study site.

[1]  Zaijin You,et al.  Statistical Distribution of Nearbed Wave Orbital Velocity under Irregular Waves , 2001 .

[2]  Wim van Leussen,et al.  Physical Processes in Estuaries , 1988 .

[3]  L. Sanford.  Wave-forced resuspension of upper Chesapeake Bay muds , 1994 .

[4]  A. J. Mehta,et al.  Laboratory Studies on Cohesive Sediment Deposition and Erosion , 1988 .

[5]  C. Officer.  Physical dynamics of estuarine suspended sediments , 1981 .

[6]  You Zai-Jin,et al.  A simple model for current velocity profiles in combined wave-current flows , 1994 .

[7]  L. Wright,et al.  The bottom boundary layer of the bay stem plains environment of lower Chesapeake bay , 1992 .

[8]  M. Pejrup.  Parameters affecting fine-grained suspended sediment concentrations in a shallow micro-tidal estuary, Ho Bugt, Denmark , 1986 .

[9]  K. Tenore,et al.  Tidal resuspension in Buzzards Bay, Massachusetts: I. Seasonal changes in the resuspension of organic carbon and chlorophyll a , 1978 .

[10]  Walter R. Boynton,et al.  The influence of waves and seagrass communities on suspended particulates in an estuarine embayment , 1984 .

[11]  I. G. Jonsson.  A new approach to oscillatory rough turbulent boundary layers , 1980 .

[12]  E. Toorman,et al.  The characterisation of cohesive sediment properties , 1993 .

[13]  C. Amos,et al.  Sea Carousel--A Benthic, Annular Flume , 1992 .

[14]  E. Baker,et al.  An in situ erosion rate for a fine‐grained marine sediment , 1984 .

[15]  J. Maa,et al.  vims Sea Carousel: A field instrument for studying sediment transport , 1993 .