Coastlines and seabeds are dynamic regions with sediments undergoing periods of erosion, transport, sedimentation and consolidation. The driving forces for these processes are primarily tidal currents, and surface waves. Transportation of sediments, in particular fine-grained silts and clays which are often contaminated, creates a variety of environmental impacts, including silting of harbour areas and docks, reduction in water transparency, affecting marine life, and longshore drift. An understanding of the fundamental sediment transport processes is essential if we are to address these issues and provide genuine, scientifically sound solutions.

ETS have developed specialist expertise in sediment transport and have clients including port and harbour authorities, dredging contractors, local and regional councils and private construction firms from both the UK and abroad. At the heart of ETS' expertise lies our unique Sediment Particle Tracing Technology. ETS has developed a system of environmentally benign synthetic sediment tracers. These comprise fluorescently labeled particles that mimic the size and density of target species dependent upon the application. In addition, we have the capability to coat a fluorescent signal onto natural sediment (silt, sand) collected from a study site. Tracer technology complements more traditional methods (current metering, turbidity measurements and modelling) and is the only unequivocal method of direct assessment of sediment transport pathways.

Tracer technology is ideally suited to a range of sediment-based environmental problems. ETS has experience of a wide variety of studies including:

	Environmental assessment of dredging on adjacent beaches.
	Dispersal study of dredge sediment and wastewater sludge.
	Impact assessment of proposed dredging campaigns.
	Investigation of sediment bioturbation versus resuspension in shallow inlets.
	Offshore-onshore sediment exchange.
	Beach sediment transport study (beach nourishment).
	Dredge material disposal site characterization studies.
	Fisheries impact assessment of plough dredge bed-levelling.
	Silt dispersal study for inland waterways.
	Particle tracing study of sediment dispersal from dredge spillways.
	Particle tracing study for licence sediment extraction areas.
	Inter-tidal sediment recharge studies.
	Long term dredge spoil disposal strategies.
	Fine sediment behaviour in harbours.
	Infilling rates of confined disposal pits (Boston Harbour).
	Rate of return of dredge material to a mudflat-saltmarsh system.

ETS offers a full tracer service, from initial field site evaluation, through specific tracer manufacture, to ocean release and subsequent recapture. In addition, ETS also capture supplementary data to support the tracer study. These data include bottom and suspended particle size distribution, water turbidity, wave-current climate, and seabed bathymetry.

To view ETS' experience in the application of tracer technology click here.

For further information about Sediment Transport Services contact:
Dr Jon Marsh.