Modelling Exclusion Zones for Marine Aggregate Dredging
Justin Dix, 2008. https://doi.org/10.5284/1000038. How to cite using this DOI
Data copyright © Dr Justin Dix unless otherwise stated
This work is licensed under the ADS Terms of Use and Access.
Primary contact
Dr
Justin
Dix
Lecturer
Ocean and Earth Science
University of Southampton
Avenue Campus
Highfield
Southampton
SO17 1BJ
England
Tel: 023 8059 3057
Resource identifiers
- ADS Collection: 865
- ALSF Project Number: 3365
- DOI:https://doi.org/10.5284/1000038
- How to cite using this DOI
Overview
Project Background and Methodology
The project was been prepared in response to the announcement of the Aggregates Levy Sustainability Fund by English Heritage in April 2004. The project investigates the potential impact of aggregate dredging on submerged archaeological sites (principally but not exclusively wreck) through an enhanced understanding of the physical processes of site formation.
There are four perceived threats of aggregate dredging on artefact based sites:
- Direct interaction with the dredge head.
- Changes in seabed site dynamics in response to upstream modification of the flow regime due to bed elevation changes through dredging.
- Changes in site dynamics of inter-tidal and sub-tidal archaeology of localities adjacent to the dredging area (including the coastal zone).
- Impacts of the dredge plume on wreck site formation.
At present exclusion zones are constructed around archaeological sites (principally wreck material), found within and immediately adjacent to (less than 200 m) aggregate licensing areas, on the basis of a rule of thumb that uses between 50 and 100 m radii from any point on the "wreck". In addition as part of, standard, pre-extraction, environmental assessments, studies of both plume dispersion and the coastal impacts of dredging are undertaken, although these are infrequently, if ever used to predict likely archaeological impacts.
It is acknowledged by both the dredging and the marine archaeological communities that neither the definition of these exclusion zones nor the potential direct or indirect impacts of dredging on marine or coastal archaeology are well understood. This indeed mirrors the academic communities' paucity of knowledge of the physical controls on underwater site formation in general.
This project therefore aims to bring together experience and expertise from a variety of different disciplines, including: archaeological site formation studies; sediment and fluid dynamics (both in the field and in the laboratory); numerical modelling of dredge plume and coastal zone impacts; and direct experiential knowledge from the dredging industry; to study these issues and provide accurate, appropriate and most importantly cost-effective recommendations for defining exclusion zones in the future. This will include the potential of modelling sites pre-dredge to quantitatively assess the impact of downstream effects of dredging.
By providing an outcome that will be directly relevant to both the aggregate industry and National and International heritage organizations it shall strictly comply with the ALSF rationale. However, the knowledge gleaned from this research should also provide invaluable information on the impact of a range of other seabed based industries on our submerged cultural heritage. In particular it may be able to answer recent concerns on the impact of offshore wind farms and maintenance dredging on marine archaeological sites.
The digital archive
The digital archive currently consists of the following resources:
- Dix,J.K., Lambkin,D.O., Thomas,M.D. and Cazenave,P.W. 2007: Modelling Exclusion Zones for Marine Aggregate Dredging. English Heritage ALSF project no. 3365. School of Ocean and Earth Science, University of Southampton.
Non-digital Archive and Publications
In addition to the reports contained within the digital archive the project also produced the following outputs:
| Literary Outputs |
|---|
| Dix, J., Lambkin, D.O., Thomas, M. and Cazenave, P. (2006) Modelling exclusion zones for marine aggregate dredging. In, Newell, R.C. and Garner, D.J. (eds.) Marine aggregate dredging: helping to determine good practice. Marine Aggregate Levy Sustainability Fund (ALSF) conference proceedings: September 2006. Bath, UK, Marine Ecological Surveys Ltd, 172-175. |
| Lambkin,D., Dix,J. and Turnock 2006: Flow patterning around submerged 3D obstacles - a proxy to scour. Proceeding sof the 3rd International Conference on Scour and Erosion 1-3 November,2006. Amsterdam |
| Lambkin,D. and Dix,J. 2006: Tidal Flow conditions and sediment transport in the vicinty of the Hastings Shingle bank, UK. Report to Hanson Aggregates Marine Ltd. |
| Lambkin,D. 2005: Reynolds Number Effects in the Modelling of Fluid Flow around objects. Internal project report. |
| Lectures / Presentations |
| Presentation to English Heritage, London |
| Presentation to SOAS, London 06/07/2005 |
| Presentation to NOCS, Southampton 09/2006 |
| Poets corner lecture series, NOCS 11/2005 |
| Produman Oceanographic Laboratories, Liverpool 11/2005 |
| CCPEM Lecture series 06/2006 |
| UK Young Coastal Scientists' and Engineers' Conference 04/2006 |
| CEFAS, Burnham-on-Crouch 10/2006 |
| Meetings/technical forums |
| Hanson Aggregates Marine Ltd 05/2006 |
| Hanson Aggregates Marine Ltd 07/2006 |
| Hydraulic Research, Wallingford 10/2006 |
