The artificial island of Peberholm under construction. Photo: Øresundsbron

The dredging and reclamation task on the Øresund Fixed Link were of large scale. More than 7.5 million cubic meters of sea materials were excavated. One of the main tasks was to dredge the 4 km trench for installation of the tunnel, but also the relocation and deepening of the navigational channels ”Drogden” and “Flinterenden” was a large task of a total of 25 km of dredging.

The surplus material was used to create an artificial peninsula on the Danish side and an artificial island, 130 hectares large, in the middle of Øresund.

The cutter suction dredger “Castor”, one of the world’s largest vessels of its kind, carried out some of the compensation dredging and the tunnel trench on the Øresund project. “Castor” was equipped with a large rotating cutter head which cut the bottom material. The material was then sucked up and pumped directly into the reclamation area via a pipeline. Here, the fine material was deposited in a sedimentation basin.

 
Cutter-suction dredger "Castor" was one of the world’s largest of its kind, able to dig out 20.000 square meters per day. Photo: Øresundsbron

On Øresund, the reclamation areas (the island and the peninsula) were constructed as basins surrounded by coarse pebble bunds lined with a geotextile membrane and then backfilled with the clay till to prevent the suspended sediment from escaping out to the sea.

 
Dipper dredger “Chicago” was able to dig 24 square meters of seabed in one mouthful. The larger quantity of material the machine grabs in one bite, the less the percentage spill. Photo: Øresundsbron