HYDRODYNAMICS AND SEDIMENT DYNAMICS OF THE WASH EMBAYMENT, EASTERN ENGLAND

Water and sediment movement in The Wash embayment has been determined from an extensive set of data, consisting of tidal current readings an d suspended sediment concentration measurements. Instantaneous and res idual currents in the embayment show a distinct lateral inhomogeneity, whereas vertically the water column is almost homogenous. The central deep water area (30-40 m) of the embayment is dominated by a residual landward water movement, whilst on the margins, the residual movement is seaward. Sediment is supplied predominantly in suspension from the north, through the northern extremity of Boston Deep. Suspended sedim ent pathways are coincident with the spring tide water movements and t he subtidal channels act as the main conduits. Approximately 6 . 8 x 1 0(6) tonnes yr(-1) of suspended sediments are supplied to the embaymen t from offshore areas. Bedload sediment supply is of lesser importance , approximate to 1 . 4 x 10(4) tonnes yr(-1). Whereas suspended sedime nt movement appears to be the dominant mode of transport throughout th e embayment, bedload transport is important in reforming the sea bed i nto a variety of bedforms which are particularly well developed on the margins of channels and shoals.