Management, research and budgetting of aggregates in shelf seas related to end-users (Marebasse)

Sustainable management of the Belgian exclusive economic zone (EEZ) has become important increasingly. This is due mainly to higher exploitation demands of marine aggregates, but also the dredging industry imposes high stresses on the seafloor. To anticipate on future developments, including the implantation of windmill farms, efficient evaluation tools and strategies of seabed nature and dynamics are needed, based on the best available science.A three-tiered approach was followed, corresponding to three spatial scales: broad-based, regional and site-specific. On the scale of the Belgian part of the North Sea (BPNS), sediment transport models were further developed to evaluate large-scale sedimentary processes and to provide a baseline for any detailed investigation. On a regional scale, evaluation tools and strategies were developed within the view of the optimisation of environmental (impact) assessments. New site investigations integrated results from state-of-the-art geo-acoustical and terrain verification tools and from a multisensor benthic lander, equipped with hydrodynamic and sediment transport instrumentation. To assess the environmental impact of aggregate extraction, multidisciplinary research was carried through national and international cooperation. Knowledge was integrated on the physical, geomorphological, sedimentological and biological nature of the seafloor. Valorisation of the results comprised a series of thematic maps on the nature and dynamics of the BPNS and a suite of recommendations on sustainable management and exploitation of the EEZ. The latter include criteria to select most appropriate locations for aggregate extraction and dredging/dumping operations whilst minimising environmental effects. However, sustainability can be ensured only if good management/policy practices are in place and implemented in a structural way