Study reveals how dredging is altering the lakebed and threatening biodiversity at Lough Neagh in Ireland
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The UK and Ireland’s largest freshwater lake, Lough Neagh, is under threat from commercial sand dredging, according to latest research led by Queen’s University Belfast.
Sand dredging involves excavating and removing sand from seabeds, rivers or lakes using specialised vessels. It can lead to a significant loss of biodiversity as sand is dredged up, as well as issues in flood management and air pollution.
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Published in the Journal of Environmental Management, the study led by Queen’s University Belfast in collaboration with Newcastle University is the first-of-its-kind and implies that sand dredging may be having broader and more persistent impacts on the lake than previously understood.
Using high-resolution sonar mapping, researchers examined the lakebed in part of the dredging zone, with results revealing extensive physical damage. Dredging had carved deep depressions into the sediment, lowering the lakebed by up to 17 metres.
Satellite imagery analysis revealed widespread sedimentation clearly visible from space, as well as runoff. Sedimentation is a well-established cause of damage to aquatic ecosystems and a key factor in the decline of freshwater wildlife.
‘The situation at Lough Neagh reflects a wider global challenge,’ said Reader in Conservation Biology at Queen’s University Belfast. ‘Demand for sand is increasing rapidly with extraction pressures growing in many aquatic environments, so understanding the full extent of the impacts is essential.’
‘This study suggests that the effects of sand dredging extend far beyond the point of extraction, influencing the entire ecosystem, likely negatively affecting water quality, habitats, and biodiversity.’
Solutions to help Lough Neagh include slower vessel speeds and fixed shipping lanes to help confine disturbance. On land, covering sand piles and using settlement ponds or vegetation buffers could help to prevent runoff.
Lough Neagh supplies more than 40 per cent of Northern Ireland’s drinking water, supports fisheries with its habitats and wildlife that is internationally, nationally and locally designated. However, in recent years, it has become a symbol of environmental decline due to the presence of toxic algal blooms and biodiversity loss.
A cause for concern
The impacts of sand dredging on the communities and regions in which it occurs are vast.
Removing larger quantities of sand has a vast impact on water flows, flood regulation and marine currents within environments. In particular, sand mining can lead to the removal of sediment from rivers, changing their composition and impairing both upstream and downstream flows. If excavating sand from deep underwater, noise pollution can impact certain marine creatures, and changes to the motion of the water can disturb species as well.
Ultimately, we are currently mining sand at a faster rate than the planet can replace it. If we are to protect biodiversity, future species and the security of many valuable ecosystems, it is vital that sand mining’s popularity is quashed.
Already, some measures are being devised to help lessen its extensive use. In Singapore, some construction companies are using recycled glass waste instead of sand to produce 3D-printed concrete. The same concept is being applied to restore Louisiana’s coastline, after two students founded one of the state’s only glass recycling centres.
Elsewhere, developed countries are also being encouraged to look at the untapped potential of recycling building rubble to produce concrete, rather than using sand to make it.
