Background
Aggregate is sand, gravel and crushed rock used as raw materials by the construction industry. The majority of aggregate comes from land-based sources but since the 1960s developers have been increasingly reliant on marine sources to supplement demand and meet the UK’s construction needs.
Today approximately 21 per cent of the sand and gravel used in England and Wales is supplied by the marine aggregate industry. In the south east of England, 33 per cent of sand and gravel for construction comes from the seabed and has been used in a number of major developments in the east London corridor. One of the main benefits of using marine sources is that ships can deliver aggregates directly to wharves in urban areas, which eliminates transport by road, reducing congestion and pollution. In 2004 it is estimated this saved 340,000 lorry trips in London alone.
Marine aggregates are also used in beach replenishment schemes. Large volumes of aggregates are pumped directly from dredgers onto beaches, providing coastal protection as well as enhancing the amenity value and therefore the economy of an area.
The Crown Estate have had produced, in association with BMAPA, a glossary of marine aggregate terms. To download, please follow the link:
Our Involvement
The Crown Estate owns the mineral rights to the seabed extending to the edge of the UK continental shelf and issues consents for non-exclusive sampling and licences for commercial aggregate extraction. Our interest is that of a landowner. The planning and consenting process is the responsibility of government, who through a consultation process determines whether an area can be used for aggregate extraction.
Licences
To obtain a licence, companies who have been successful in a tender round run by The Crown Estate must obtain a Dredging Permission (DP) from the government, a procedure which includes the submission of an Environmental Impact Assessment (EIA). If a favourable DP is granted, The Crown Estate will issue the applicant with a production licence.
There are currently 79 production licences producing approximately 21 million tonnes of material per annum. The licences only cover about 0.12 per cent of the UK continental shelf, and of this only about 11 per cent was actively dredged during 2008, equating to 138 sq km.
For details on the area of seabed licensed, dredged and surrendered each year, as well as charts showing the extent and intensity of dredging operations for each region, please follow the links below:
This is published in conjunction with the British Marine Aggregates Producers Association (BMAPA).
Further information is available on our statistics page, which includes additional data on current dredging areas.
Ten-Year Review of Annual Area of Seabed Dredged
This report is published in conjunction with BMAPA. The review details the extent of annual dredging activity between 1998 and 2007 and outlines the changes in distribution of both the area of seabed licensed and the area of seabed dredged. It highlights The Crown Estate’s and the industry’s commitment to sustainable management of marine aggregate resources and the changes brought about through voluntary good practice initiatives.
Regulation & Monitoring
The industry is closely regulated by the Marine and Fisheries Agency (MFA)as an interim arrangement prior to the handover to the Marine Management Organisation (MMO).
Each ship carries a sophisticated electronic monitoring system (EMS) to track and record its movements. It tracks the vessel every 30 seconds when it is actively dredging and this ensures that the vessel remains within its allocated licensed area.
Coastal Impacts
There are frequent media articles regarding changes to receding coastline and reduction in volume of sand on beaches. These changes can be large and can occur quite rapidly. Inevitably, these changes cause concern amongst local communities who fear (i) loss of land and property, (ii) coastal flooding, (iii) damage to local business that rely on tourism and (iv) general damage to the environment in an amenity sense. In parts of the country where marine aggregate dredging occurs close to (sometimes within sight of) areas experiencing coastal erosion, the media articles frequently quote dredging as the prime cause of the coastal changes.
The Crown Estate's position is that:
1) It understands the concerns of stakeholders with respect to coastal erosion.
2) It knows of no evidence whatsoever that links licensed marine aggregate dredging to enhanced coastal erosion or loss of material from beaches. There is good evidence for the lack of impact.
3) Approval of an application for dredging by the Regulator (Marine and Fisheries Agency (MFA) in England, Welsh Assembly Government (WAG) in Wales, the Scottish government in Scotland and the Environment & Heritage Service (EHS) in Northern Ireland) includes a detailed examination of the potential impacts on the coast.
4) Regulatory approval for a scheme of dredging is accompanied by strict conditions with regard to the area to be dredged and monitoring of changes to the marine environment. The results of the monitoring are submitted to the Regulator.
5) The Crown Estate only grants a licence for aggregate dredging after a positive government view or permission for a particular scheme has been received from the Regulator.
6) As seabed mineral owner, The Crown Estate periodically examines the available scientific evidence and funds studies to ensure that it is up to date with the latest available knowledge.
As part of this ongoing scrutiny of the scientific position, the report arising from a recent study focused on an area offshore of East Anglia. 'A Synthesis of Current Knowledge on the Genesis of the Great Yarmouth and Norfolk Bank Systems' is available as a pdf file for download from the marine aggregate research page (link below).
Research
Despite the small area of seabed affected The Crown Estate recognises the potential impacts on the marine environment and is committed to understanding and minimising the effects of marine aggregate dredging. We regularly devote funding to research projects and we collaborate closely with associated organisations.
Details of recent research projects and downloadable project reports may be accessed from the marine aggregate research page.
Other good sources of information relating to the marine aggregate industry, and listing other research projects, include the BMAPA and Aggregate Levy Sustainability Fund (under DEFRA) websites.
Further Information
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