Sustainable coastal engineering techniques

1. Sustainable coastal engineering techniques for coastal protection Jaak Monbaliu Hydraulics Laboratory K.U.Leuven BeNCoRe Leuven 26 April 2007

2. YES: functional design morphological developments of coasts (erosion, accretion, ..) approach, methods, tools, structures ... for shore protection NO: structural design breakwaters offshore platforms, windmills, .. ‘ sustainable coastal engineering techniques ’

3. Coastal Erosion episodic events long term or structural erosion

4. Episodic Event • safety against storm attack(s) • cross-shore processes dominant • short term variability of cross-shore profile

6. structural erosion • long shore processes dominant (wave driven) • long term shift of ‘average’ cross shore profile • long term behaviour foreshore and nearshore • ...

9. Coastal Division of the Ministry of Mobility and Public Works plays a central role in coastal protection of our coast. Principles: • Integrated Coastal Zone Management • high protection level against flooding • resilient coast: keep, restore and where possible strengthen the natural character of the coast • let the coast “grow with the sea”: flexibility i.f.o. sea level rise • biodiversity One of the consequences is a preference for ‘soft’ techniques.

10. From ‘traditional’ techniques ..

11. to ‘sustainable’ ..

14. ...and innovative techniques De Haan

17. Jesolo Beach (Adriatic Coast)

18. Jesolo Beach (Adriatic Coast)

19. ARTIFICIAL HARD SURFACES Dikes Harbour walls Wooden constructions groins ... not forgetting bio-diversity and natural character

20. ARTIFICIAL HARD SURFACES richness in species Dykes Piers Harbour Walls Groins

21. ‘chaotic’ groin

22. Yzermonding

23. Westhoek

24. Towards better understanding, predictability and managemenent

25. Episodic events • extensive monitoring • modelling tools: • physical model tests + numerical model (M. Huygens): • An integrated research on sand supplies for coastal defense: application to the Belgian east coast • Optimisation of coastal defence works in front of the Flemish coast • numerical model DUROSTA: • extensive validation study De Haan 1990 • all coastal sections

28. Understanding long term behaviour through observation, monitoring and modelling • muddy & mangrove coast (K.U.Leuven, VUB) • effects of dredging, dumping, aggregate mining, beach fill, ..: • interpretation of hyperspectral images (VITO,..) • coastline modelling (IMDC / MOW) • antropogenic influence: Marebasse, QUEST4D,... • Nautical Bottom (MOW/FH/U.Gent/K.U.Leuven/consultants)

29. mud and mangroves

30. 2 1 2 2 4 6 3 2 5 5

33. old dumping site Oostende from Marebasse Scientific Report Year 2

35. data needs • bathymetry, beach profiles, .. (over time !) • anthropogenic interference: sediment volumes and characteristics (where and when borrowed and used, ...), .... • sediment characteristics (grain size, erosion parameters, layer thickness, ...) • driving forces (currents, waves, wind, ...) - extrapolation by wave, current, .. models ! • biological parameters: fauna and flora • .....

36. Some final thoughts • ‘simple’ view longshore / cross shore processes probably too simplistic • many factors involved: multidisciplinary • a single view, model will not do the job • coasts/sediments/expertise do not stop at national boundaries • same data often needed by different groups • “easier” access to the ‘complete’ dataset would be very beneficial

37. Acknowledgements Tina, Toon, Peter, Bart, Vera, Kristien, Bernard, Steven, Erik, Stefanie, Stefaan, .... Apologies to many not (explicitly) mentioned Action add to the incomplete