Multidisciplinary approach to assess the far-field effects of sand extraction in the Belgian part of the North Sea. 

• DOI: 10.5194/egusphere-egu24-7810
• Publication Date: 2024-03-08T16:44:50Z
• Authors: Benjamin Van Rooz...; Koen Degrendele; Florian Barette; Helga Vandenreyken; Anne-Sophie Piette; Vera Van Lancker; Lars Kint; Katrijn Baetens; Pauline Denis; Peter Urban; Nore Praet; Marc Roche

Sand extraction on the sand banks in Belgian part of North Sea has various impacts marine environment. The direct near-field effects areas where takes place, are regularly monitored for at least two decades and well understood. In contrast, several important questions remain regarding far-field impact associated with dispersion suspended particle matter (SPM) plumes. On longer term, these SPM plumes could significantly change integrity seafloor damage ecological valuable habitats bordering exploited banks. Therefore, Continental Shelf Service SPF Economy, responsible management extraction, instigated a project to define range significance far field this activity. close partnership RBINS, UGent VLIZ, number controlled measurements were devised validate models predicting dispersal and, if necessary, improve them. Based models, frequency magnitude disturbance nearby protected can then be determined all sectors.In order characterize estimate their distance, experimental setups developed, combining continuous point use quasi-real-time model. performed board RV Belgica during campaigns November 2022 March 2023 following dredging vessels performing operations.During experiments, model mapped estimated trajectory, extension, deposition real time, using combination hydrodynamic, waves wind data, sediment properties position activity vessels. This real-time information allowed us vessel ideal location presence plume its an set-up combined acoustic in-situ measurements. Continuous water column involving Kongsberg EM2040 dual RX multibeam echosounder (MBES), Simrad EK80 single beam (SBES) Teledyne Acoustic Doppler Current Profiler (ADCP) carried out jointly map actual position, extent density These completed situ through (Aquascat 1000R) optical (LISST-200X, OBS) sensors mounted carousel. Additionally, samples collected Niskin bottles that filtered further analyses (SPM, particulate organic carbon nitrogen, Chlorophyl a), analysed Hach turbidimeter.  Samples extracted sediments onboard granulometric analysis.The first analysis experiments indicate good performance used excellent concordance between detection MBES, SBES ADCP. our results show importance profound knowledge spatial configuration involved instruments research itself column.