Dredging

We are the Statutory Harbour Authority (SHA) for most of our ports and, therefore, responsible for conservancy in the areas under our control, which includes the maintenance of safe navigation.  In addition, in many cases, we are the Competent Harbour Authority (CHA) for pilotage.  We are committed to maintaining high standards of navigational safety within our harbours. Competent pilotage and, where necessary, Vessel Traffic Services (VTS), are our primary safeguards against accidents.  We train and authorise pilots and issue exemption certificates to ships’ masters who use the ports regularly and demonstrate a suitable level of competence.  We regularly review, with our customers, the best practice for the use of escort tugs for oil tankers in our harbour areas and approaches.  The transport of hazardous goods is reported to the port before arrival so that the necessary handling arrangements can be made.

Maintenance dredging campaigns are periodically carried out to ensure sufficient depths of water exist for vessels to navigate and manoeuvre safely.  Without this work, the risk of marine accidents – and the potentially catastrophic consequences for the environment – would be increased. Almost all of our ports require dredging to maintain navigational channels.

Where dredging has taken place for many years, it has become an integral part of the dynamics and morphological development of an area.  If it were to cease, then the ecology of the area would change and not necessarily for the better.  In 2003, the volume of material we dredged at our UK ports was 17.9 million tonnes.  As part of the processes by which we obtain consents to undertake these operations, we consider the alternative uses to which the dredged material might be put.  These alternative uses are usually determined on the basis that they will have a significant benefit to the environment.  For example, they can be used for beach replenishment or intertidal recharge (creating mudflats or saltmarsh, both very important habitats), depending on the nature of the material involved and its suitability for the task.  Consequently, the recycling of dredged spoil, as undertaken at ABP Ipswich, for example, is being considered as an alternative to the traditional method of disposal at sea.

Dredging on the Humber is a major activity; to minimise environmental impact, dredging operations there are carefully monitored and planned with conservation bodies.  The resultant mathematical models allow us to identify deposit grounds, which means that little or no sediment is actually lost to the estuary as a result of dredging, and that much of the dredged material migrates to intertidal locations to form new habitats for plants and birds.  The issue of dredging is particularly sensitive in areas of high nature-conservation importance, such as EMS.  We are working with other relevant authorities in the development of dredging strategies for such areas, designed to consider how to mitigate the cumulative effect of different dredging campaigns over time.  We are also working with the same authorities (primarily DEFRA and EN) to identify ways of ensuring that the needs of the Birds and Habitats Directives are met when planning and seeking licences for maintenance dredging.

To see the legislation that governs our management of dredging in the ports and how we have translated this into environment policy objectives, refer to the Dredging page in the Legislation section.