The turbidity maximum in a mesotidal estuary, the Tamar Estuary, UK: I. Dynamics of suspended sediment
Dyer, K.R.; Bale, A.J.; Christie, M.C.; Feates, N.; Jones, S.; Manning, A.J. (2002). The turbidity maximum in a mesotidal estuary, the Tamar Estuary, UK: I. Dynamics of suspended sediment, in: Winterwerp, J.C. et al. (Ed.) Fine sediment dynamics in the marine environment. Proceedings in Marine Science, 5: pp. 203-218 In: Winterwerp, J.C.; Kranenburg, C. (Ed.) (2002). Fine sediment dynamics in the marine environment. Proceedings in Marine Science, 5. Elsevier: Amsterdam. ISBN 0-444-51136-9. XV, 713 pp., more In: Proceedings in Marine Science. Elsevier: New York. ISSN 1568-2692; e-ISSN 2352-2860, more |  |
| Keyword | | | Author keywords | Turbidity maximum; suspended sediment concentration; turbulence; flocculation; salinity intrusion; shear stress; water slopes |
| Authors | | Top | - Dyer, K.R.
- Bale, A.J.
- Christie, M.C.
| - Feates, N.
- Jones, S.
- Manning, A.J., more
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| Abstract | A series of detailed simultaneous measurements of current velocity, salinity, suspended sediment concentration and turbulence, at two stations in the upper Tamar Estuary, has revealed that the turbidity maximum is centred about 1 km upstream of the salt intrusion, and is created mostly from entrainment from the bed. Suspended sediment concentrations at about 0.5m above the bed reach about 6g.l-1on spring tides, but only about 0.3g l-1 on neaps. Based on measurements of turbulent energy, the threshold of sediment erosion is estimated as 0.17-0.2Nm-2 Drag reduction was experienced when the suspended sediment concentration gradients exceeded 4kgm-4 . Analysis of surface water slopes in conjunction with the currents suggests that there is a minimum in velocity between the salt intrusion and the turbidity maximum which coincides with a reduction in the water level, together forming a 'bow-wave' effect, upstream of the salt intrusion. These results form the background for detailed analysis of the distribution of floc properties, particularly settling velocity, within the turbidity maximum (discussed in Part II). |
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