Offshore sediment studies

The movement of sediment offshore has been studied by HR Wallingford in the "Southern North Sea Sediment Transport Study, Phase 2". This work looked at the implications of offshore dredging for marine aggregates on the marine environment. However, although not part of the remit of the study it recognised the importance of considering in detail… "the possible physical effects of offshore dredging with particular regard to how such operations might alter waves, tidal currents, sediment transport and morphological changes of the seabed and along the coast. The results from such an assessment can be used to determine the likely effect on beaches and coastal defences." The report can be downloaded from HR Wallingford web site @ http://www.sns2.org/project-outputs.html. At a regional scale studies specific studies in the southern North Sea provide insights into the way sediment moves offshore (Brampton & Evans 1998) as does its companion volume (PR65), the Seabed sediment mobility study - west of the Isle of Wight. For information see the CIRIA web site http://www.ciria.org/index.html bookshop.

It seems clear that managing coastal shingle deposits whether for sea defence or nature conservation, must take into account the contemporary contribution of material to the coast. Since this will be derived from or affected by the action of tides, winds and waves it is not only important to know how much is coming from erosion of the land, but also from the sea. The studies mentioned above provide some indication of the way in which the systems operate. However the link between the land-based and marine sources has not been made.

References

Brampton, A.H. & Evans, C.D.R. 1998. Regional Seabed Sediments Studies and Assessment of Marine Aggregate Dredging. CIRIA. Abstract...