A review of the physical impacts of sediment dispersion from aggregate dredging

• Published in: Marine pollution bulletin Vol. 94; no. 1-2; pp. 260 - 277
• Main Author: Spearman, Jeremy
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.05.2015
• Subjects: Aggregate dredging; Dispersion; dispersions; dredging; ecology; Environmental Monitoring; Field data; Fine sediment; Geologic Sediments - analysis; Marine; Plume; Sand; Ships; suspended sediment; Water Pollutants - analysis; water pollution; Fine sediment; Sand; Plume; Field data; Aggregate dredging; Dispersion
• ISSN: 0025-326X; 1879-3363; 1879-3363
• DOI: 10.1016/j.marpolbul.2015.01.025

•Synthesis of modelling and field measurements based on a number of years of research in this subject.•Difference in perception and reality of dredging footprint discussed.•Plume footprint can extend from a few hundred metres to 3km from the point of dredging.•Footprints of change in substrate generally extend a few hundred metres from the point of dredging.•Larger footprints of substrate change can result from extensive screening and strong transport. The disturbance and subsequent dispersion of sediment arising from aggregate dredging results in increases in suspended sediment concentrations and, potentially, settlement of fine sediment or sand onto the bed, which may both cause adverse effects on local ecology. This subject is one area which has seen much research over many years and this paper sets out to synthesise some basic general conclusions for use when assessing the significance of planned operations. The literature detailing the dispersion of fine sediment plumes, and the longer term dispersion of sand released through the dredging process, is scrutinised, and in some cases re-evaluated, and used to identify an evidence-based footprint of potential impact.