A New Approach to Sustainable Canal Sediment Management in Scotland

Abstract

Abstract 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.