Ecologically sound sand extraction

Sand extraction is the process of extracting sand from natural sources, such as rivers, lakes, quarries or the sea, for various purposes. Sand is a valuable natural material used for coastal reinforcement and in construction, including the production of concrete, asphalt and building materials.

Extracting this sand requires the use of heavy machinery such as dredgers or excavators to remove sand from the source. The extracted sand is then transported to designated areas, where it is further processed, such as sieving, washing and grading, to meet specific requirements for different applications. Sand used for coastal reinforcement is sprayed directly from the sea via pipelines or from the ship onto the beach or deposited underwater off the coast.

Sand extraction is needed in the Netherlands for several reasons:

1. Building materials: Sand is an essential constituent of concrete and is used in the construction of buildings, roads, bridges and other infrastructure projects. It is also used as a filler material and in asphalt for road construction.
2. Land reclamation: The Netherlands is a country largely below sea level. To protect the country from floods and create new areas, sand extraction is used to spray sand and strengthen dykes and beaches.
3. Natural coastal defence: Sand extraction is also used as a form of coastal defence. By replenishing sand on beaches and dunes, natural protection against erosion and storms can be strengthened.

However, it is important to carry out sand extraction in a sustainable and responsible manner, taking into account environmental impacts and the preservation of ecological systems.

Sand extraction from the sea removes benthic fauna and potentially buries and smothers benthic life in the surrounding area. The properties of the sediment may change at the site itself, in its vicinity or in more distant areas. The shape of the seabed changes, leading to changes in sea currents, fine particle transport and silt fill. As a result, the habitat for benthic animals and benthic fish changes and the species composition, density and biomass may change.

Large-scale sand extraction will lead to changes in the three-dimensional mixing of seawater in the coastal zone, and this may affect the transport of fine sediments and fish larvae. Problems may arise for fish larvae and shrimp to reach their shallow nursery areas, which may affect the stock size and adult distribution of commercially important target species.

Indirect effects of sand mining arise from increased concentrations of sediment, potentially leading to changes in timing and extent of algal growth, and resulting changes in food availability for shellfish, fish and birds.

Recently, the Dutch government and commercial and civil society actors negotiated a North Sea agreement, aimed at balancing maritime activities and nature protection. However, the negotiations and the agreement paid little attention to the aspect of (future) sand extraction, which is expected to increase from 12 million m3 of sand for coastal protection and up to 15 million m3/year for construction purposes to 35-50 million m3/year from 2035 onwards. In view of coastal protection measures, sand dredging will not only have to increase in volume, but also be carried out deeper and with innovative techniques. Ecological restoration of deeply mined areas to their original, undisturbed state is unlikely to occur, potentially leading to tipping points in ecosystem functioning. Such ecological consequences and impacts, and how they affect other users especially the fishing industry, are currently unknown. In this project, we will focus on the effects of sand extraction and contribute to the fundamental knowledge base for predicting effects on marine ecology and marine fisheries.

OR ELSE will take on the challenge of not only improving understanding of the future impacts of sand extraction on the North Sea ecosystem and fisheries, but also improving cooperation and decision-making in the marine domain. The lack of understanding of the ecological effects associated with sand extraction hinders the identification of which sand extraction depths and designs lead to altered habitat conditions and how this changes (negatively or positively) diversity and productivity. The interdisciplinary OR ELSE consortium will contribute to promoting cooperation in marine policy across the North Sea by developing and playing a Serious Game for sand extraction. The impacts of sand extraction on the ecosystem and fisheries will be assessed and translated to policymakers and stakeholders for inclusion in future decision-making.