1 "Sediment management requires a solid mix of pragmatism and sound science" The actual discussion on the role of sediments in the European water legislation is a typical example, how the development of environmental policies mixes legal requirements with socio-economic aspects, issues of technical feasibility, and sci- 2 entific knowledge . In fact, the Sixth Environmental Action programme of 2001 has stipulated, namely, that "sound scientific knowledge and economic assessments, reliable and up-to-date environmental data and information, and the use of indi- tors will underpin the drawing...