Does dredging have an impact on coastal erosion?
GREAT Yarmouth MP Brandon Lewis has objected to an aggregate firm’s bid to continue dredging off the Winterton coast because of fears that it could be affecting coastal erosion in the area.
Tarmac Marine has applied to the Marine Management Organisation to carry on extracting gravel and sand from the sea bed for another 15 years when its current licence expires in September.
If granted the licence will allow the company to take a maximum of 6,000,000 tonnes over that time.
High tides and gales over recent winters have swept away tonnes of sand from the beach at Winterton, exposing old defences and taking chunks out of the dune cliff and there are concerns that it could have been made worse by the dredging just 9kms off the shore.
In his letter to the MMO, Mr Lewis said: “Whilst I appreciate there is not a scientific consensus that dredging affects coastal erosion, there is considerable anecdotal evidence to suggest a relationship and I strongly believe that the continuing removal of material from sea, comparatively close to the coastline, could result in a disruption to the natural sediment flow, potentially creating further problems for coastal communities, either in Great Yarmouth or further along the coast.
“Considering the seriousness of this concern, I therefore cannot support the continuation of an activity which could potentially add to the difficulties faced by vulnerable communities within my constituency.”
Mr Lewis asked for his objection to be properly considered and to be given a written response. He also told the agency he wanted to be informed of any other aggregate dredging applications within the area.
Borough councillor for Winterton, James Bensly, is also concerned about the application to carry on dredging. “It is definitely not improving the situation,” he said. “You cannot judge the scale of the millions of tonnes of sand that we have lost.”
He grew up in the area and his father was a herring fisherman for 40 years. But now it was tourism that was vital to the area and it needed protection.
“Winterton is a special experience,” he said. “That escapism in this world of internet and mobile phones, that is priceless.”
Seeing the changes to both Winterton and Hemsby beaches in recent times was deeply concerning.
To make matters worse the villages only a short distance from the site saw nothing of the income from the operation because it all went to the Crown Estate.
It is believed dredging in UK waters nets at least £14m a year in royalties.
Cllr Bensly pointed to the Devon village of Hallsands that was lost to the sea just over 100 years ago after sand and gravel was dredged from the sea bed a short way up the coast so the naval dockyard at Plymouth could be expanded.
A report on the recent erosion that resulted in chalets falling over the dune cliff at Hemsby, is expected to be released soon and a meeting of all the agencies and authorities involved has been set for June 20.
It is not yet known whether any funding to recharge the beaches or provide sea defences is going to be on the table, but Mr Bensly said local people were determined and were prepared to make a noise about it. “ You are going to be a brave man to stop us from getting funding,” he said. “I am always a glass half full man. I would rather have a go than just sit at home on my keyboard."
But Winterton parish councillor John Allen is not convinced of the link between the dredging and the damage caused to the beach and dunes.
“As a member of the original Winterton-on-Sea coastal erosion group for over 10 years and now a member of the current one I can advise that we attended glossy presentations by the companies concerned and also met with various Government departments, the long and short of it was the licences were approved,” he said.
“The problem is there is no incontrovertible proof that dredging causes erosion. Until a genuine link can be made I regret to say that in my opinion little change is likely.
“However that does not preclude pressure being exerted on all aspects of causes of coastal erosion now and in the future.”
An environmental statement produced by MarineSpace for Tarmac Marine said the aggregates firm intended to relinquish part of its existing dredging area because the remaining material was insufficient to warrant renewal. As a result the application was for a smaller area covering 2.275kms sq.
Dredged material, used for building and beach replenishment, was likely to be delivered to ports on the east coast, the Thames Estuary, London and possibly to France, Holland and Belgium.
It explained the aggregate came from river channels and flood plains that were eroded by rivers around two million years ago, when sea levels were much lower. The sediment ended up on what was now the sea bed.
It pointed out government policy recognised the crucial contribution marine sand and gravel made towards feeding the country’s demand for construction material, much of it in the south east and London.
It also contributed to energy security and economic development through major coastal infrastructure projects like ports and power stations.
Citing the UK Marine Policy which stated extraction should continue as long as it was consistent with sustainable development and recognised that marine aggregates were a finite resource, the report said: “To meet construction and coastal defence demand, continuity of marine supply from the proven resources in the Anglian dredging region is vital, especially as there is increasing pressure on the constrained and declining land-based sources in the region. “
Dredgers had been operating off the East Anglian coast since the 1970s and the annual average extraction was 7.73m tonnes between 1998 and 2012. In 2015, said the report, more than 90 per cent of the aggregate went to London, seven per cent to the continent and the rest to the Humber and south coast.
It added: “ Alternatives to supply have also been considered, but it is concluded that these are either inappropriate in terms of quality, less economically viable, or produce a higher carbon footprint than the materials that can be extracted from Area 254. As a general rule, transporting aggregates by road more than 25 miles will result in the aggregates becoming economically unviable.”
Turning to the potential for changes in the waves and tides caused by dredging to affect rates of coastal erosion in the area, the report’s authors cited a 2011 study that included wave modelling.
“The HR Wallingford study (2011b) concluded that aggregate extraction at maximum levels (15 years) within the Yarmouth sub-region would have no impact on the surrounding coastlines. As this sub- region includes Area 254, the conclusion applies to the proposed application for a subsequent 15-year extraction period.” However they suggested monitoring would be needed to test the accuracy of the model and offered underwater surveys and sonar scans of the dredged area and a 500m buffer zone every two to three years. If the results showed significant changes a report would be submitted to the MMO.
The MarineSpace Area 254 environmental statement has been submitted with the Tarmac Marine bid REF MLA_2018_00174 and can be downloaded from the Marine Management Organisation’s public register of licence applications. The public consultation closes on June 29.
Objections to similar applications in 2013 by campaign group Marinet can be seen at http://www.marinet.org.uk/campaign-article/objections-to-dredging-licence-renewal-offshore-to-great-yarmouth
The British Marine Aggregate Producers Association and the Crown Estate have also produced a report which can be accessed via http://www.bmapa.org/documents/BMAPA_Norfolk_200115_FINAL.pdf