The contract is the first of its kind awarded to Grontmij. The project completion time is six months. The clients are the La MER foundation (a consortium of commercial sand extraction companies) and the Directorate-General for Public Works and Water Management, North Holland Department.

Sand extraction
The contract involves the supervising and drawing up of two environmental impact reports on large-scale sand extraction in the North Sea. The first of these, for the Directorate-General for Public Works and Water Management, North Holland Department, will be entitled the “Extracting of Nourishment Sand 2008-2013” and deal with the dredging of approximately 130 million cubic metres of nourishment sand from 18 extraction areas. The second report, for the La MER foundation, will be entitled “Extracting of Sand for Fill 2008-2018” and cover the dredging of approximately 250 million cubic metres of fill sand from seven extraction areas.  
 
Cluster Midwest is the project’s main contractor, with Svasek Hydraulics, WL|Delft Hydraulics, AquaSense and the Netherlands Institute for Sea Research as subcontractors. An important component of the project is the selecting of prospective extraction areas in the North Sea that will be dredged for the next 10 years. Support for this will come from Grontmij’s geoinformation department. GIS software will show us where we can expect to encounter obstacles in the form of wind farms, cables and pipes, platforms, dredge spoil disposal areas and Natura 2000 sites. Extraction sites, from where sand can be dredged for the next five to 10 years, will be selected from the remaining areas during interactive workshops with the clients.
 
Impacts
One of the most serious effects of sand extraction is the dispersing of silt in the North Sea. Considerable amounts of silt can enter the water system during large-scale sand extraction. This fine material influences the levels of light – and hence the levels of phytoplankton (algae) – in the North Sea. Given that phytoplankton form the base of the food chain, this can have a damaging effect on animals, such as birds, fish and sea mammals, that are higher up the food chain.
 
To visualise the impact this will have, Svasek Hydraulics uses computer models to calculate sea currents and silt dispersal. WL|Delft Hydraulics subsequently calculates how silt dispersal impacts on phytoplankton, and these data are used by the Netherlands Institute for Sea Research and Grontmij to estimate the effects on the rest of the ecosystem.
 
Maasvlakte 2
Besides the dredging to obtain nourishment sand and sand for fill, large amounts of sand will also be extracted from the North Sea in the next few years for use in the construction of the Maasvlakte 2, the new industrial zone for the Port of Rotterdam. As a result of silt dispersion, the combined large-scale sand extractions can have a negative impact on the North Sea ecosystem. This is why considerable attention will be given to making sure the environmental impact reports on sand extraction dovetail with the recently published final draft version of the environmental impact report on the Maasvlakte 2.