Behaviour of sludge

 

Dredging

Groningen Seaports is undertaking a major capital dredging project in the Eemshaven. The harbour will be deepened and widened to give access to bigger ships, especially for liquid gas and coal, for the energy industry. A significant extra amount of sediment will be dredged from the harbour during the winter seasons and moved to 3 disposal sites, situated in the Oude Westereems and in front of the harbour entrance.

 

Monitoring

Studies were developed to monitor dredge material disposal on 3 dredge disposal sites in the Ems. Groningen Seaports has set up a major monitoring and measuring campaign. Studies include monitoring the changes in bathymetry, sea bed composition and mass balances.

 

Sediments

To obtain adequate information on the mass balance of the disposed dredging material, information about bed sediments and accurate height of the sea floor is necessary. After a baseline measurement, a high resolution multibeam echosounder is used on a regular basis for measuring the seafloor height. This has been surveyed in cooperation with Geoplus BV. The Medusa system is used to obtain information about the sediment composition of the sea bed, and the silt content.
This long term monitoring  of the silt content and morphology of the seafloor can help to quantify behaviour of dredging material in relation with natural dynamics due to resuspension and large-scale sediment transport patterns and the buffering capacity of the seafloor. The information will also be used as input parameters for the 3D model of Deltares developed for the Ems Estuary.