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Ecological sand extraction

Ecological landscaping of seabed


The expected worldwide increase in the demand for marine sand due to economic growth and urbanisation as well as the long-term threats of climate change call for innovative approaches for sand extraction activities. Marine sand extraction traditionally focuses on minimizing environmental impact and quick recovery of seabed sediment composition and benthic assemblages. With large-scale extraction, this conservative approach can lead to constraining mitigation measures. Moreover, the potential of ecological development, cost reduction and a more efficient use of scarce space are not considered.


This Building Solution provides guidance for design, organisation and realisation of ecosystem-based landscaped sand extraction sites, based on research in the Maasvlakte 2 sand extraction site in the North Sea. Ecosystem-based design rules for future sand extraction sites are developed aimed at optimising the balance between impacted surface area, sand yield, costs and ecological effects.

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How to Use

This section describes and gives guidance to the steps to be taken to design landscaping of the seabed on basis of ecosystem approach. The steps are described following the BwN design steps:

1. Understand the system

  •  Effects of sand extraction 


2 . Identify realistic alternatives

  •  Assumptions in the approach of landscaping
  • Guidelines and boundary conditions
  • Determine the feasibility of an ecosystem-based sand extraction site


3. Valuate the qualities of alternatives and pre-select an integral solution

  • Determine a basic design for a landscaped ecological mining pit
  •  Ecosystem-based design rules for the minimum excavation depth ecological mining sites


4. Elaborate selected alternatives.

  • Optimize the design for an ecosystem-based landscaped sand extraction site
  •  Determine construction costs for seabed landscaping of sand extraction pit


Practical Applications

Examples are:

  • Gravel-seeding techniques to restore the seabed to pre-dredge conditions after gravel extraction in the English part of the North Sea (Cooper et al., 2011). Changes in bed shear stress values after sand extraction also the main drivers of ecological changes although not yet fully recognised. Optimisations in bed shear stress values, by fine-tuning extraction depths and orientations of the sand extraction sites with respect to the tidal current are possible (e.g. to prevent against sedimentation which may be harmful to hatching herring larvae on the gravelly seabed).
  • Seine estuary cooperation between dredging and fishing industries (Desprez, 2000; Marchal et al., 2014). Optimisations in bed shear stress values, by fine-tuning extraction depths and orientations of the sand extraction sites with respect to the tidal current are possible.
  • Maximum allowable changes in seabed level and bed shear stress values after sand extraction to maintain original macrozoobenthic characteristics (poster and oral sessions of Koen Degrendele and Dries van den Eynde at the ICES Annual Science Conference 2016)
  • Maintenance dredging in river and estuarine systems (Yuill et al., 2016).
  • Rijke riffen (van Duren et al., 2016), Building with North Sea Nature: eco-friendly scour protection (Lengkeek et al., 2017) and construction of artificial reefs in Japan (Thierry, 1988).
  • Rejuvenation dredging of tidal creeks in a mangrove systems (Bonaire and Curaçao). Habitat requirements for mangroves and Ecological rehabilitation Lac Bay Mangroves, Bonaire


Specifically, more information on the lessons-learned from the Maasvlakte 2 practical example are given below, discussing a range of factor around the project planning, execution and evaluation

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