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Generic Studies |
NERC, Centre for Coastal and Marine Sciences, Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, UK
Surveys of subtidal and intertidal sediment distributions were undertaken in the upper Humber and Ouse during autumn (fall) and winter. Within the Ouse, the great majority of sediment samples comprised a mixture of predominantly silt and clay (<63 µm) and very fine sand (>63 and <125 µm). A pronounced seasonal transport was observed both in subtidal lag sediments and intertidal bank sediments. The strongest difference between autumn and winter distributions of subtidal bed sediments resulted from the down-estuary movement of very fine sand from the upper reaches of the Ouse during winter. This feature was also evident in the intertidal sediments. Intertidal banks in the upper reaches of the Ouse utilized very fine sand to grow during summer and autumn, and were eroded back to stronger silt and clay substrates over the winter period. The down-channel redistribution of sand-sized sediment was a response to increased freshwater inflows over winter. This movement is approximately balanced in summer and autumn, during low freshwater inflows, by an up-channel sediment transport due to tidal velocity asymmetry and its associated flood dominance.
