Control and impacts at sea

 

The regulatory system takes account of the need to limit all adverse impacts of aggregates dredging and also cumulative impacts of all activities, not just aggregates dredging, on particular areas of the seabed with the aims of:

• minimising the areas that are concurrently affected and the impacts within sub-sections of the permitted areas affected;
• optimising the distance between dredging areas and to take account of potential cumulative effects of dredging with other activities in the vicinity;
• minimising impacts on other uses and users of the sea (e.g. fisheries, navigation, recreational diving and yachting, wind farms, cables and pipelines etc);
• protecting seabed heritage sites and war graves;
• controlling extraction levels to sustainable rates;
• protecting the water column and sea bed; and
• avoiding dredging during sensitive periods and near sensitive locations.

Conditions, based on the findings of the EIA, are attached to dredging permissions to ensure that adverse effects are minimised and that impacts are adequately monitored M0026, M0032. These, for example, identify:

• the date for commencement, duration and end date for dredging;
• boundaries of the dredging area and zones within it that will be worked at different times during the life of the permission and the need to give notice of movement between zones;
• the requirement for use of an electronic monitoring system and procedures for providing results to the regulator;
• maximum quantities of material that may be removed annually and in total;
• procedures for removal and treatment of overburden;
• the maximum thickness of sand and gravel that can be removed and condition of the seabed on cessation;
• necessary restrictions to the times when dredging may be undertaken (e.g. in certain seasonal or tidal conditions) or to delay implementation of dredging until nearby dredging has ceased;
• the type of dredger to be used;
• whether on not on-board screening of sand and gravel is allowed;
• exclusion areas around war graves, wrecks, other sites of archaeological interest, pipelines, aids to navigation and certain sensitive sites and habitats that must not be dredged;
• requirements for reporting archaeological discoveries;
• provisions to ensure navigational safety (e.g. notifying shipping of dredging locations and reporting any collisions or near-misses);
• provisions for liaison with fisheries organisations;
• organisations that should receive copies of monitoring reports;
• action to be taken if unacceptable impacts occur;
• circumstances under which review of the dredging permission will be required.

Monitoring and reviews of dredging permissions

Conditions are applied to secure baseline monitoring information on seabed composition, morphology and stability; bottom dwelling organisms and fisheries; water depth; fisheries; locations of wrecks and archaeological remains; any effects on nearby sensitive habitats; and to ensure that a suitable capping layer of sand and gravel to prevent exposure of underlying sediments is left after dredging to allow re-colonisation of the area by a biological assemblage similar to that which existed prior to dredging.

All minerals dredging vessels carry an Electronic Monitoring System (EMS) that automatically records the date, time and position of all dredging activity to ensure that conditions attached to the permission are properly observed 518. Recordings are sent regularly to the Crown Estate and the Regulator and are checked to ensure compliance with conditions attached to consents. Monitoring results are also compared with baseline surveys and threshold conditions included in the environmental impact assessment to identify significant changes. Results of monitoring are made available to the public for comment.

Monitoring helps to ensure that dredging conditions are complied with and that appropriate action is taken if any unexpected adverse environmental effects occur but also provides the information needed in reviews of the dredging permission. These normally take place at 5 year intervals but reviews can occur more frequently if defined in dredging conditions or if concerns about specific impacts arise to determine whether the dredging programme should be modified, continue, or be terminated.