Baeye, M.

De Mesel, I.

Evangelinos, D.

Francken, F.

Kerckhof, F.

Naudts, L.

Van den Branden, R.

Van den Eynde, D.

Van Lancker, V.

Open Marine Archive

Working together on innovative m onitoring strategies: adapting to 
nature, huge demands and grand challenges
Van Lancker Verala, Matthias Baeyela, Frederic Franckenla, Dries Van den Eyndela, D im itris 
Evangelinos2, Ilse De Mesellb, Francis Kerckhoflb, Reinhilde Van den Brandenlb and Lieven Naudtslb
1 Royal Belgian Institute o f Natural Sciences
“Operational Directorate Natural Environment, Gulledelle 100, B-1200 Brussels, Belgium 
bOperational Directorate Natural Environment, Bde en 23ste Linieregimentsplein, B-8400 
Oostende, Belgium
E-mail: vera.vanlancker@mumm.ac.be
2 MSc Marine and Lacustrine Science and Management (Oceans & Lakes), Pleinlaan 2,
B-1050 Brussels, Belgium
Socio-economic demands fo r marine aggregate resources have increased at an unprecedented pace. 
For the A tlantic region, hundreds o f m illions m3 o f offshore sand and gravel have been extracted fo r 
coastal maintenance, harbour extensions and onshore industria l use. Still, we are facing grand 
challenges, fo r which aggregate demands w ill be even higher. First, increasing volumes o f 
nourishment sand are needed as accelerating sea-level rise w ill leave our coastlines ever more 
vulnerable. Secondly, vast quantities o f sand and gravel w ill have to  be extracted to  realize the large 
infrastructural works that are the key components o f many visions on coastal zone and offshore 
development. Meanwhile, nature protection is increasing as well, and appropriate assessments are 
needed o f the environmental impacts.
The far offshore Hinder Banks are targeted fo r explo ita tion o f huge quantities o f sand, mainly fo r 
coastal defence works. Here, up to to 2.9 m illion m3 can be taken over 3 months, w ith a maximum 
o f 35 m illion m3 over a period o f 10 years. Large vessels can be used extracting 12500m 3 per run. 
Present-day yearly extraction levels recently surpassed 3 m illion m3, the m ajority o f which was 
extracted with vessels o f 1500m3. South o f the Hinder Banks concession, a Habitat Directive area is 
present, hosting ecologically valuable gravel beds. For these, it is critical to  assess the effect of 
multiple and frequent depositions from  dredging-induced sediment plumes.
How will nature react?
We anticipated w ith a m onitoring strategy, ta ilored fo r assessing the importance and extent of 
perturbations that are created by the extraction activities. Our m onitoring design is focussed on 
hydrodynamics and sediment transport w ith feedback loops between both modelling and field 
studies. Main targets are assessing changes in seafloor in tegrity  and hydrographic conditions, two 
key descriptors o f marine environmental status w ithin Europe’s Marine Strategy Framework 
Directive.
State-of-the-art instrum entation (from RV Belgica) is used, to  measure the 3D current structure, 
tu rb id ity , depth, backscatter and particle size o f the material in the water column, both in-situ and 
whilst sailing transects over the sandbanks. In the Habitat Directive Area, gravel bed in tegrity (i.e., 
epifauna; sand/gravel ratio; patchiness) is measured as well. Most innovatively, an autonomous 
underwater vehicle was deployed (Wave Glider, Liquid Robotics), resulting in 24 days o f current and 
tu rb id ity  data.
From a firs t data-model integration, and analyses against hydro-meteorological databases, main 
results show: (1) high spatial and temporal variab ility  o f tu rb id ity , unexpected in the so-called 
‘clear’ waters o f the Hinder Banks; (2) im portant resuspension by waves, regardless the area being 
considered as ‘deep’; (3) spreading and deposition o f sediment plumes; and (4) competitiveness o f 
ebb and flood, meaning that the potential fo r sediment deposition to  the south is high. Plume 
dispersion mechanisms and pathways are now estimated and modelled.
Data w ill be integrated w ith results from  the morphological and biological m onitoring, respectively 
carried out by the Continental Shelf Service o f FPS Economy and the Institute fo r Agricu ltura l and 
Fisheries Research. Together, tem poral and spatial patterns, scale and processes can be resolved 
and interlinked w ith pressures and system vulnerability.
- 1 1 0 -


Working together on innovative monitoring strategies: adapting to nature, huge demands and grand challenges

Working together on innovative monitoring strategies: adapting to nature, huge demands and grand challenges

Abstract

Similar works

Full text

Available Versions

Open Marine Archive