ASSESSMENT OF THE POTENTIAL ENVIRONMENTAL-IMPACT OF LARGE-SCALE SAND-DREDGING FOR THE BUILDING OF ARTIFICIAL ISLANDS IN THE NORTH-SEA

The building of artificial islands is contemplated in the coastal waters of the Netherlands. The potential environmental impact of a large-scale sand-dredging (1 · 109 m3) is evaluated. The most suitable mining methods, the effect on water quality-turbidity, the disturbance of the balance between bottom sediment and water column in relation to heavy metals, nutrients and PCB's are discussed, as well as the effect of dredging upon plankton, bottom fauna, fishes and on larvae and young stages of sea animals in general. The recovery time for the bottom fauna is estimated to be about three years. The consequences for the fisheries are mentioned, as the Netherlands coastal zone plays a very important role in the life of the North Sea species. This is related to the Dutch shrimp, plaice and sole fishery. An estimation of the yearly damage to the fisheries during the building phase is made (Dfl. 500,000 per year). The building time for the island would be about 8 years. The island would cause damage to fisheries, in respect of a permanent loss of catches of Dfl. 10,000,000. © 1979.