This report, written for a broad audience, has been structured around a master chart (figure 1), a characterisation chart (figure 2), and five supplementary figures (3 to 7). Each figure is supported by text which provides procedural details concerning options for beneficial use and general guidance on the selection process involved.
Master Chart
The first consideration in the master chart is material contaminant status. If the material is unsuitable for beneficial use or cannot be made suitable by treatment, a decision must be made for disposal. If the material is suitable for beneficial use, the next step in the decision process is characterisation of materials to be dredged as illustrated in figure 2. The categorisation into different material types in the lower part of the figure will help guide the user to the better option. Although not discussed in this document, these considerations can be partially examined in the PIANC report, Classification of Soils and Rocks to be Dredged.
Identifying Beneficial Uses
When the material type has been determined, various beneficial uses according to material type are identified in figures 3 to 7. These figures and the supporting text form the heart of the report. They identify and describe potential beneficial uses for each different type of dredged material. When one or more potential beneficial uses are identified, the next steps are illustrated by the master chart (figure 1). For those beneficial uses which are identified, each use should be considered in relation to each suitable site. Following identification of the suitable sites, a detailed study of the technical feasibility should be initiated. If not technically feasible, the material should be disposed of in an environmentally acceptable manner.
Environmental Assessment
For each potential site the effect of policy, law, and regulation should be assessed. If the proposed uses are reasonably free of constraints, then the environmental impact, costs and benefits should be assessed. From this assessment the most desirable acceptable option for beneficial use at a particular site should emerge. Care should be taken to ensure that all of the potential benefits are taken into account. During and following implementation of the project, a program of site monitoring may be established to confirm or document the effects and success of the adopted beneficial use. The following chapters provide detailed information and illustrations on beneficial uses of dredged material.
