Project

Capital and maintenance dredging in the river Scheldt. Reclamation of Industrial areas.

Location : Belgium, Antwerp

Client :
Ministerie van de Vlaamse Gemeenschap,
Departement Leefmilieu en Infrastructuur, Administratie Waterwegen en Zeewezen
Afdeling Maritieme Toegang

Contractor : T.V. Zeeschelde : DI – BDC - JDN

Period : since 1930

Scope of work

Capital dredging
Maintenance dredging
Reclamation
Silt treatment programs

General Information

Description of the works

Situation
The river Scheldt is the only maritime access to the Port of Antwerp.

The Flemish Government guarantees a minimum depth for sea going vessels along the trajectory towards the Port of Antwerp. As there is a constant process of sedimentation, maintenance dredging and capital dredging is required year round.

Nature of the dredged spoil
On the bars of the Dutch sector of the river Scheldt, the sediment consists mainly of sand with average grain sizes varying between 150 and 200 micron.
In the Belgian sector of the river Scheldt the dredged spoil consists of fine sand mixed with a varying volume of mud, depending on the season.
In the Western section of the Scheur (North Sea) mainly sand is dredged.

Reclamation
During the last 25 years the sand coming from the dredging works has been used for hydraulic reclamation of the polder areas in order to obtain additional industrial areas on the right and left bank of the river Scheldt and for the construction of the embankment and foundation of highways.

Within the framework of the Delta Works in the Netherlands and the Sigmaplan in Belgium, several million cum of sand from the dredging works were used to reinforce and raise the dikes.
However, the majority of the dredged sand stays in the tidal system, by preference in the flood channels, in order to guide the river through the main channel and avoid oblique currents over the bars.
Sand is also being dumped in the very deep areas or the deepest parts of the main channel and also along some banks to stop erosion and to increase the radius of the main channel in bends.
In order to maintain the dynamic equilibrium of the river system, the annual volume evacuated is limited to the estimated amounts of solids conveyed by the sea and deposited in the riverbed.

Main Equipment

Trailing Suction Hopper Dredgers, with a hopper capacity varying from 2.000 till 13.000m³, dredging an average quantity of 14 mio m³ per year.