Lough Neagh sand mining likely harming lake’s ecosystem, Queen’s research warns

New research led by Queen’s University Belfast outlines how Lough Neagh, the UK and Ireland’s largest freshwater lake, is under threat from commercial sand dredging.

Sand dredging is the underwater excavation and removal of sand from seabed’s, rivers, or lakes using specialised vessels.

Published today 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.

Lough Neagh supplies over 40% of Northern Ireland’s drinking water, supports fisheries with its habitats and wildlife that is internationally, nationally and locally designated. In recent years, however, it has become a symbol of environmental decline, with toxic algal blooms, biodiversity loss with growing public concern.

Dr Neil Reid, Reader in Conservation Biology at the Co-Centre for Climate + Biodiversity + Water in the School of Biological Sciences at Queen’s, and lead author of the study, said the work represents a step change in understanding: “This is the first attempt to quantify the range of potential impacts from sand extraction throughout Lough Neagh and to infer potential ecological consequences. Our findings suggest disturbance is not localised, but widespread across much of the lake ecosystem.”

Sand is a vital resource that underpins modern infrastructure, used in concrete, construction, and land reclamation.

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Using high-resolution sonar mapping, the researchers examined the lakebed in part of the dredging zone with results revealing extensive physical alteration. 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, with plumes of silt spilling from dredging vessels, kicked up by vessel propulsion during transit, as well as runoff from landing sites. Sedimentation is a well-established cause of damage to aquatic ecosystems and a key factor in the decline of freshwater wildlife.

Dr Reid added: “The situation at Lough Neagh reflects a wider global challenge. 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 effecting water quality, habitats, and biodiversity.

“For Lough Neagh, the message is clear. If the lake is to recover, management cannot focus on nutrients alone while ignoring physical disturbance. That places a responsibility on government to ensure that regulation, monitoring, and enforcement reflect the true scale of sand extraction impacts.

"There are practical ways to reduce the environmental footprint of dredging. Adjusting suction settings could reduce sediment disturbance while limiting hopper overflow could reduce sediment discharge. Slower vessel speeds and fixed shipping lanes could confine disturbance. In shallow water, avoiding high-thrust manoeuvres or protecting the lakebed could reduce resuspension. On land, covering sand piles and using settlement ponds or vegetation buffers could intercept runoff."