A method is described to calculate the relationship (/3) between the eddy diffusivity of suspended particles and the eddy viscosity of the fluid. The data were obtained while making suspended sediment concentration measurements near the seabed on the British continental shelf./3 was calculated for 0.5~ size fractions and varies inversely with the suspended sediment concentration. The values were used successfully to calculate suspended sediment transport rates for separate sand fractions through a spring tidal cycle. Finally, specific values of/3 are suggested for varying concentrations of sand at a reference height of 100 cm above the seabed.

Sand transport measurements of bedload and suspended load in the Sizewell‐Dunwich Banks area, East Anglia have shown that the suspended mode is dominant. The depth‐integrated spring tidal residual is 5.66 g cm−1 sec−1, although the neap rate is only one‐fifth of this. The calculated bedload transport rates also vary, from 0.012 to 0.040 g cm−1 sec−1, correlating with changing meteorological conditions. In order to predict the bedload sediment circulation pattern from midwater current meter measurements, five sediment transport equations were calibrated, using fluorescent dyed sand. Yalin's relationship gave the best estimates. The bed shear stress was determined by extrapolating the velocity profile as a power law relationship, with an exponent equal to 0.1, from midwater down to 2 m and as a lognormal profile from 2 m to the sea‐bed. Roughness length values appropriate to the substrate were used. Although bedload transport residuals are mainly to the south, the banks trend northwards from the coast and have also elongated in this direction. This is thought to be in response to the dominance of the suspended sediment transport. It is suggested that a tidal residual eddy mechanism is responsible for the banks’maintenance, similar to the process operating in Start Bay, Devon. The well‐documented westward movement of the banks is likely to be related to wave processes.

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Two hundred and fifty two samples from 40 cores and 40 seafloor samples have been analysed using sedimentological and foraminiferid techniques. The results have been used to interpret the sedimentological history of Start Bay during the later phases of the Holocene marine transgression. They indicate the existence of a barrier–lagoon complex, with associated tidal marshes and rivers and an open sea environment c. 8000 years BP. With a continuing rise in sea level and accompanying barrier migration shoreward the Bay and coastline with enclosed freshwater lagoons were established. Geophysical evidence supports this hypothesis.