Publication Abstract

The use of agitation dredging, water injection and sidecasting in the UK - Results of a survey of ports in England and Wales

N. Sullivan and L. Murray

The Centre for Environment, Fisheries and Aquaculture Science (CEFAS) carries out a diverse range of scientific research, advice and monitoring into aspects of the marine environment. The Regulatory Assessments Team work within CEFAS to provide expert scientific advice to the Ministry of Agriculture, Fisheries and Food on the impacts of the disposal of dredged material at sea. Disposal of material at sea in the UK, is regulated by the Food and Environment Protection Act (FEPA) Part II 1985. The day-to-day provision of advice is informed by research and monitoring programmes. Presently, dredging methods that involve relocation of sediment by means other than physical removal and deposition elsewhere are not regulated under FEPA. This paper presents the results of a recent review into the use of hydrodynamic dredging techniques in England and Wales.

A questionnaire was sent to 250 ports, harbours and marinas in the study area. The response was encouraging, with 42% of consultees submitting completed questionnaires. The responses were both geographically widespread, and representative of the study area. More than a quarter of respondents claimed to employ hydrodynamic dredging techniques. However, only 11 % of respondents use these techniques as their sole method of dredging. All but one of these ports are situated on the south coast of England. The Review also queried which conventional dredging methods were employed, what consultations were undertaken, and the environmental impacts of these activities. Several site visits provided a practical aspect to the review and allow the presentation of case studies.

In addition to the above, the paper draws on CEFAS's experience of marine construction operations and presents views on the impacts of sidecasting.

Reference:

N. Sullivan and L. Murray  (2000) The use of agitation dredging, water injection and sidecasting in the UK - Results of a survey of ports in England and Wales. Proceedings  of 'Dredging Challenged - CEDA Dredging Days' 18-19 November 1999