Minister responds to dredging questions

Holderness coast

Following an Adjournment Debate at the House of Commons on off-shore dredging, led by Beverley and Holderness MP Graham Stuart, a government minister has answered a series of questions.

Graham called for the debate after being contacted by constituents who believe off-shore dredging is causing coastal erosion to speed up.

The debate, on December 1, saw Graham calling on the Government to commission more detailed research into possible links between the removal of aggregates from the seabed and erosion along the Holderness coast.

While Huw Irranca-Davies, Minister for the Natural and Marine Environment, declined to launch further research he did promise to get back to Graham with more detail on what research has already been carried out.

His letter said: “During the adjournment debate on the ‘Effect on coastal erosion of off-shore dredging’ on 1st December I promised to write to you with further information on points that were raised about the research evidence base and the approach taken to the licensing, monitoring and enforcement of aggregates dredging. 

There is a substantial body of independent research. In particular, reports looking at sediment transport (and therefore addressing potential erosion from aggregates extraction) have been commissioned by local authorities, the Crown Estate and others.

 The Southern North Sea Sediment transport study (www.sns2.org) specifically looked at whether dredging was contributing to coastal erosion. In relation to Holderness it found that “Dredging areas adjacent to the Humber are to the east of the main sediment Pathway” and “Dredging activities are well outside this principal sediment stream” (see section 6.1.3 of the main report).

The South Coast Sediment Mobility Study (www.thecrownestate.co.uk/mrf aggregates) reported that “Dredging such material from the seafloor is thus unlikely to damage the coast by interrupting an onshore supply”.

Summarising the work, Sue Gubbay (2005) concluded that “Examples of research projects on this topic include the southern North Sea Sediment Transport Studies, the South Coast Seabed Mobility Study and the Inshore Seabed Characterisation Project. None of these studies have concluded that current marine aggregate extraction is influencing coastal erosion however, given concerns and the potential significance of any such effects, it is important that this type of investigation remains a key consideration in the consenting process”.

In addition, along each coastline, Shoreline Management Plans (see www.hecagsmp2.co.uk for the region from Flamborough Head to Gibraltar Point) will assess any impacts from aggregate extraction.

On the second point, about licensing, monitoring and enforcement, I can assure you that there are rigorous requirements to assess any impacts, from initial modelling and assessments of environmental impact to routine monitoring.

Current licensing regimes for the aggregate dredging industry exist to protect the marine environment from detrimental effects and must be adhered to in all cases. Any application must, therefore, contain sufficient data on which to base an informed decision, and a number of studies including an Environmental Impact Assessment and Coastal Impact Study are normally undertaken to support the dredging application.

The Coastal Impact Studies are carried out on a “worst case scenario”, and include information on wave modelling, sediment transport and an assessment of the possibility of adverse effects on the coastline. They are subject to scrutiny by the Marine and Fisheries Agency (MFA), its technical advisors and statutory consultees.

Until this information is provided, consent cannot be granted. Further work is also underway to bring the Coastal Impact Studies together in a more holistic way in Marine Aggregates Regional Environment Assessments for Norfolk/Suffolk and for the Humber area.

After a dredging permission has been granted, the operator must carry out surveys to characterise the seabed prior to commencement of dredging. This is often referred to as a “baseline” survey, as it provides a point of reference and comparison for the analysis of impacts once dredging is in operation.

Once the surveys are completed, a “Pre-Dredge Report” is submitted to the MFA, and is circulated to key consultant bodies (including Natural England, English Heritage, Maritime and Coastguard Agency) and the Government’s scientific advisor, Cefas, for comment.

Dredging cannot commence until approval has been given by the MFA on behalf of the Secretary of State.

All new permissions granted on the East Coast, require operators to follow the ‘Marine Aggregate Extraction and the Fishing Industry – East Coast Operational Code of Practice’.

This Code of Practice encourages liaison between the dredging companies and local fishermen, and requires that at least one week’s notice be given when dredging is due to commence.

A Schedule of Conditions is attached to dredging permissions. These may include restrictions on the zones within the area where dredging may be carried out, information on any seasonal restriction on dredging (such as to coincide with fish spawning seasons) and the maximum tonnage allowed. All operators are required to report the annual tonnage landed to both the MFA and the Crown Estate.

As part of the Schedule of Conditions attached to each dredging permission, operators are required to carry out environmental monitoring whilst dredging is in operation, and after it has ceased, to monitor seabed recovery. Bathymetric surveys, which assess the topography of the seabed using Multi-beam sonar systems, are generally carried out every two years, whereas others such as resource surveys (monitoring amount of aggregate left on the seabed) are required every four years. 

Coastal Processes monitoring and particularly sediment transport are a key part of the pre-dredge and operational licence conditions and use tracer studies and sidescan sonar techniques to analyse the movement of sediment on the seabed by wave and tidal forces. 

This is in addition to the wave modelling carried out in the Coastal Impact Study. These surveys are usually carried out bi-annually in the first five years of dredging, with the option to review the frequency after five years if necessary. 

A review of all monitoring data is carried out by the MFA and its scientific advisors at five and ten-year intervals and conditions can be added, removed or varied if necessary.

Dredging can be suspended at any time should the MFA believe that unpredicted significant environmental impacts have occurred. 

In addition to the monitoring requirements, the 2007 Marine Minerals Regulations also require dredgers to be fitted with an Environmental Monitoring System (EMS), which plots the course of the vessel whilst dredging is in operation. The MFA and Cefas monitor these data, and operators are liable to pay a fine or even face prosecution should their vessel dredge outside of the licensed area, or in an exclusion zone. 

For your information I have included a copy of the Schedule of Conditions for Area 480 (South East of the Humber Estuary), which was attached to the dredging permission issued to Hanson Aggregate Marine Ltd in May 2008. This sets out in detail the conditions imposed on this particular area, though many of them are general and are applied to all areas. All new dredging permissions and related documents are published on the MFA website and can be downloaded here.