Beneficial use of dredged sediments, either in harbours or waterways, is based on their potential as alternative resources. Such sediments can be considered as bulk materials for industrial needs, which is predicated on their current waste status or meeting end-of-waste constraints. They also can be an integral part of beneficial use projects using sediments as a bulk component, including civil engineering and landscaping. This is particularly important for beneficial use projects focusing on climate change effects mitigation, such as flood protection works, coastline defence or littoral urban areas redevelopment. When dredged sediment is used as a bulk material, its acceptability is based on an assumed homogeneity of its properties. On-site analyses allow pre-dredging detailed mapping at a denser scale than laboratory ones; monitoring dredgings during operations and during processing; and continuous control of their properties at the implementation site. This is currently possible only for a selection of inorganic analytes. When dredgings are part of a larger beneficial use project, on-site analyses facilitate first the baseline survey and the sediment source characterisation. Continuous monitoring of the sediment load allows a fast detection of contamination hot spots and their adequate management. Site survey via on-site instruments allow end users and communities to check themselves the contamination level, hence acceptability is better. On-site dredged sediment analyses monitor both building properties and environmental compliance; soil and sediment analyses at receiving sites; surface and groundwater, either for impact assessment or for monitoring works. On-site instruments provide immediate results and allow dynamic or adaptive sampling strategies, as well as allowing operational decisions in real time. Confirmation by laboratory analyses is required for validation, but on-site sample screening for laboratory analyses improves their efficiency. The present paper was developed on the basis of an earlier presentation, which it developed and updated extensively.

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British Waterways is a public corporation which owns and manages 3220 km of canals and navigable rivers in Britain. Maintaining a safe navigation channel requires the regular removal of large quantities of accumulated sediment (150,000 tons per annum)Please note tons in this paper refers to metric tones, i.e., 1000 kg. which is often contaminated with a “cocktail” of organic and inorganic materials derived from both current and former industrial and agricultural activities. Over the past 15 years, British Waterways has developed and refined a sediment sampling and analysis protocol which takes account of the behavior of contaminated compounds in aqueous environments. This protocol has been developed in consultation with waste and soil chemistry experts and the statutory regulators to accommodate the changing legislative requirements over this period. The protocol facilitates the assessment of hazardous status and selection of appropriate uses for the sediment post removal. A menu of sediment reuse, including soil improvement and creation on agricultural land and recreational areas, production of soil alternatives, landfill capping material, and use as an engineering material is under development to reduce the dependency on landfill. Some of these options may require the sediment to undergo some form of treatment. Until recently, treatment options in the United Kingdom were limited. Now with the requirement for waste to be pretreated before being landfilled, treatment sites and mobile treatment plants are more common. Parallel to this process, British Waterways keeps a watching brief on proposed changes to relevant waste management legislation across the UK and lobbies, where appropriate, for changes which promote sustainable management of canal sediments. Review of, and involvement in, longer term catchment management policies and legislative controls through, inter alia, the European Water Framework Directive, aim to reduce the sediment management burden in the long term. A review of the European Waste Framework Directive is ongoing, which may bring legislative changes related to disposal and reuse of sediments, or both. A series of case studies in the Lowlands and Highlands of Scotland is presented to illustrate the practicalities of this process.

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The aim of the SURICATES (Sediment Uses as Resources in Circular And Territorial EconomieS) Project is to increase sediment reuse for erosion and flood protection. To investigate potential opportunities to reuse dredged sediments as topsoil following phyto-conditioning, a pilot scale operation was undertaken at Bowling, Scotland. As part of normal maintenance, 550 m3 of wet sediment was removed from the Forth and Clyde Canal at Old Kilpatrick by Scottish Canals using a hydraulic excavator during September 2020, transported by barge, then transferred to a dewatering cell constructed in an old canal basin by lining with a geotextile break-layer and installing engineered drainage. Following initial dewatering, the sediment was sown with three varieties of grass, which each germinated and survived the winter. By March 2021 composite soil samples already met the BS 3882:2015 criteria for topsoil, other than for Zn levels, which reflected the locally elevated baseline values. This allowed the conditioned sediment to be used immediately as topsoil as part of the nearby construction of a long-distance cycle track following an old railway embankment. Following reuse, replicated validations of six grass or wildflower seed mixtures were sown in April 2021 and monitored to verify longer-term suitability as a landscaping soil.