Maintaining sufficient water depths is the responsibility of bremenports’ expert staff in the dredging department, at the disposal facility and the sounding and bearing/surveying department. It is a natural phenomenon that sediment gradually accumulates on the floors of the harbour basins and entrances to the locks. We use a sonic depth finder to check that the water depth is always sufficient and to calculate the quantities of sediment and sand that have to be dredged. This is done using heavy-duty equipment such as bucket and suction dredgers. Special injection dredgers are used to flush up the sediment and keep it suspended. The sand that is removed can be used for construction projects or dumped at sea. The contaminated silt, on the other hand, undergoes special treatment and is taken to our own dump in the Seehausen district of Bremen which ensures correct disposal. The silt relocation can take the form of a disposal solution in water or on land.