Synthesis Report on the Effects of Dredged Material Disposal on the Marine Environment (Licensing Period 2006-'08)

Synthesis report on the effects of dredged material disposal on the marine environment (licensing period 2006-'08)

Brigitte Lauwaert1, Karen Bekaert2, Miguel Berteloot3, Dirk De Brauwer4, Michael Fettweis1, Hans Hillewaert2, Stefan Hoffman2, Kris Hostens2, Koen Mergaert4, Ine Moulaert2, Koen Parmentier2, Gert Vanhoey2, Johan Verstraeten3

Report by MUMM1, ILVO2, CD3 and aMT4, conform art. 10 of the royal decree of 12 March 2000 defining the procedure for licensing of disposal in the North Sea of certain substances and materials. BL/2008/01 Colofon Synthesis report on the effects of dregded material disposal on the marine environment (licensing period 2006-'08).

1 MUMM – Management Unit of the North Sea Mathematical Models, Gulledelle 100, 1200 Brussel. 2 ILVO – Unit Animal Sciences – Fisheries, Monitoring section, Ankerstraat 1, 8400 Oostende. 3 aMT – Department Mobility and Public Works, Maritime Access Division, Tavernierkaai 3, 2000 Antwerpen. 4 CD – Coast Division – Agency for Maritime Services and Coast, Vrijhavenstraat 3, 8400 Oostende.

Participated in this report: ILVO: Bossaer M., Demaerel B., Goutsmit H., Jacobs L., Van Hoey G., Van Ryckeghem M., Wittoeck J. MUMM: Roose P., Van den Eynde D., Francken F., Backers J., De Blauwe J.P. CODA: Guns M., Van Hoeyweghen P.

With thanks to the crew of the R.V. Belgica

Contacts: [email protected]; +32(0)2-7732120 [email protected]; +32(0)59-569848 [email protected]; +32(0)3-2220883

Report made according to article 10 of the royal decree of 12th of March 2000 defining the proce- dures for licensing the dumping of certain matters and materials in the North Sea.

BL/2008/01

1 1 Introduction ...... 3 2 Dredging and dumping activities ...... 4 2.1 Bathymetric measurements in dumping grounds for dredged materials ...... 4 2.2 Dredging Activities ...... 6 2.3 Dumping Activities ...... 7 3 Results from MUMM‟s research programme MOMO...... 14 3.1 Introduction ...... 14 3.2 Development of a 3D numerical model of the Zeebrugge area ...... 14 3.3 Influence of anthropogenic activities on the cohesive sediment distribution ...... 15 3.4 SPM transport in the southern North Sea...... 16 3.5 Floc dynamics in the Belgian coastal zone ...... 22 3.6 Modelling of dumping of dredged matter at Nieuwpoort and Blankenberge ...... 30 3.7 Conclusions ...... 32 4 Scientific programme ILVO-Fisheries ...... 33 4.1 General introduction ...... 33 4.2 Reports ...... 33 4.3 Study area ...... 35 4.4 Sediment ...... 36 4.5 Macrobenthos ...... 39 4.6 Epibenthos and demersal fish ...... 52 4.7 Fish diseases ...... 66 4.8 Biological effects of environmental pollutants on fish populations ...... 68 4.9 Chemical contaminants in sediment ...... 70 4.10 Chemical contaminants in epibenthic species ...... 81 5 Monitoring programme 2007 of the dredging areas ...... 89 5.1 Introduction ...... 89 5.2 Results of the monitoring programme 2007 – Physico-chemical analysis ...... 89 5.3 Summary of results ...... 91 5.4 Final results...... 100 6 References ...... 105 7 Abbreviations ...... 109

2 1 Introduction To conserve the maritime access channels to the Belgian coastal harbours and to maintain the depth of the Flemish coastal harbours dredging is needed (Flemish competence) in order to guarantee safe maritime transport. A distinction is being made between maintenance and capital dredging. Maintenance dredging is the periodical removal of material, typically sand and silt deposited by na- ture through river flow, tidal currents or wave action in areas previously dredged. Capital dredging is the initial deepening of an area such as a channel, harbour or berthing facility, but can also in- clude excavatio