Marine Aggregate Dredging – A sustainable activity?

Last Thursday (25^th October) member for Dept. of Agriculture, Fisheries & Forestry, David Quirk MHK introduced a presentation, based on a similar presentation given to the Department and other government bodies, to interested members of the public at the Erin Arts Centre.

The presentation was given by Gerry Sutton, BSc. (Hons), MSc., MIS of Coastal and Marine Resource Centre, an integral part of the Environmental Research Institute in University College Cork, Ireland.

The primary objective of the CMRC is described on their Website as: to make a significant contribution to the scientific understanding of coastal and marine environments and their management.

The presentation coincided with the recent granting, by the Dept. of Trade & Industry, of prospecting licences to Cemex Island Aggregates to research potential, recoverable sand and gravel deposits off the IOM coast.

Mr Sutton explained that although the data he was presenting had been gathered to assist the Irish and Welsh authorities, in making decisions about dredging in their waters, it was still relevant in an IOM context.

The driving force behind the research has been the growing demand for aggregates, in Ireland, on the back of an economic boom. Apparently there is an annual demand of 30 tonnes per person and it was claimed that supplies of onshore material is becoming exhausted. Added to the shortage of supply is the issue of the environmental cost of transporting material, by road, from quarries further and further away from the areas of development.

It is argued that transporting the material by sea, direct from the seabed to the nearest port to the development site, is 6 times less polluting than transporting by road.

So Mr Sutton posed the rhetorical question, “If it is such a good idea, why is this option not put into practice more often?”

The answer he said lay in the fact that there was no established policy on, what is widely regarded, such a ‘touchy’ subject. Combine this with the high set-up costs for any company wishing to exploit the possible reserves, and so many other uncertainties, it wasn’t surprising that investment was being stymied.

This is why CMRC, and other researchers, have become involved in the subject by providing data, collected from scientific studies, that is then made freely available to interested parties.

Mostly funded by the private sector, but with an element of government money, the Centre identified 5 areas in the Irish Sea to study. This was followed up with electronic mapping of the sea bed, and the sampling of deposits, to establish quantity and quality of potential resources.

Research of the sea bed ‘ecology’ was also conducted, to provide baseline figures on fish and other marine life in the areas. Sophisticated computer programmes were also employed to try and model any likely impacts, or interactions on adjacent areas, if material was removed.

Mr Sutton said that the findings of their research point to impacts being mostly localized and transient in nature. He did concede, during questioning, that damage to species numbers and diversity could result depending on the level of intensity of extraction; and whether the material was ‘processed’ on board the ship and the ‘waste’ returned to the sea.

He also conceded that, currently, there is little knowledge on the potential impacts of fisheries which is why he advocated a precautionary approach.

However, he stated that a French researcher, albeit based on anecdotal rather than scientific evidence, had suggested that some fisheries had improved post dredging; and therefore it was wrong to automatically assume that all the impacts would be negative.

The research had also found that emissions from marine extraction were 50% less than on land and that the process, from an engineering perspective, was much more efficient.

Overall, claimed Mr Sutton, the prognosis was favourable with an estimated 18 billion tonnes of reserves with the IMAGIN study area. He stated that he, and his colleagues, believed that these resources could be recovered in a sustainable manner as part of future sustainable development in Ireland and Wales.

The proposal now was to prepare a comprehensive map of the whole area and to formulate a spatial plan to deal with the planning aspects. They recommended that this plan be subjected to a Strategic Environmental Assessment.

Finally, Mr Sutton, was keen to emphasize that their findings were still, to a point, theoretical and that more research was still required; but that their work was not been driven by extraction licence applications.