Beneficial use of muddy dredged material in the UK
Type:
Presented during:
CEDA Dredging Days 2007 - The Day After we Stop Dredging, Rotterdam
Authors:
Dearnaley M P, Fletcher C A, and Costaras M, HR Wallingford, United Kingdom
Abstract: In the UK between 30 and 40 million wet tonnes of material are typically dredged for navigation purposes each year. This material arises from both capital and maintenance operations. The majority of this material is muddy. The management of this muddy material has become under ever increasing scrutiny and benefits associated with the use of the material are important to identify.
In the UK the main benefit attributed to the use of muddy material is recycling or retaining of fine sediment within the same sediment system. This can be achieved through the selection of local disposal sites and the use of agitation dredging techniques. In the UK by far the majority of - beneficial use - can be attributed to this approach. However, a very small proportion of the total volume of muddy material dredged is placed directly in some manner to achieve a benefit. Recent examples include raising levels inside managed realignment sites to enhance the habitat function of the site and the direct placement of material on the foreshore of an estuary confined behind some sort of bund constructed from imported or in-situ materials.
The paper will consider the recent trends in - beneficial use - of material in the UK; the present and future role of muddy dredged material in meeting flood and coastal defence and nature conservation targets and the consequences of a scenario of not dredging.
Keywords: beneficial use, muddy dredged material, nature conservation targets