This is certainly the case at the Port of Rotterdam, which believes that the whole relationship between sediment, rivers and port basins needs to be closely examined. As an initial step in this direction, it was instrumental in setting up the European Sediment Network in 2001, having exhausted most of the easy solutions for dealing with contaminated sediment with its own port environs.

Indeed, Rotterdam’s success as a maritime port and industrial complex is due, in part, to its geographical position in the North Sea and to the fact that it is linked to the interior of the continent by the Rhine and Meuse rivers.However, its location comes at a price: each year millions of cubic metres of sand and silt (sediment) are carried into the port by the sea, of which the majority is deposited on the river beds and in the port basins.As a result, the port authority has to undertake a rolling programme of maintenance.

Around 20m cubic metres of sediment is removed annually as part of contracts awarded by the Port of Rotterdam and Ministry of Public Transport, Public Works and Waste Management. The vast majority of this is deposited out to sea. However, about 1.5m tonnes of contaminated sediment is dredged up each year,which has to then be stored at a special depot (“De Slufter”), located in the Massvlakte.

By 2015, all sediment must be sufficiently clean so that it can either be beneficially re-used or dumped out to sea. The Port of Rotterdam has been active in this area since the 1980s, when it introduced its “polluter pays” policy. Those companies located along the Rhine that were actually producing the majority of the contaminated dredged material were identified. These so-called “point discharges”were then forced to revise their disposal policies, while the Rhine Research Project (POR) was implemented with the remit of cleaning up the river. The result was cleaner water in the river and less contaminated silt in the port itself.

A second project, POR II, was launched in 2000, coinciding with a new EU directive.The European Water Framework Directive introduced by the European Union in 2000 should eventually have a major impact on the way ports deal with contaminated sediment.

The directive aims to harmonise policies for dealing with surface water, with a concomitant impact on how ports undertake management of contaminated sediment.The POR II project aimed to identify a variety of diffuse sources that were preventing the elimination of the remaining elements of contamination.However, pollution in the river was also entering via the atmosphere, rather than via direct discharge into the river itself by local industry. In addition, polluted groundwater was also finding its way into the Rhine from the surrounding urban environment.

POR II also studied the movement of historically contaminated sediment, which is slowly released into the river. This was found to be a significant source of river pollution, especially since ever higher tides (the suggested source of these being global warming) are moving the sediment in ways not previously seen. Around half of the Rhine’s sediment is deposited directly into the port itself, while the remaining 50% is swept out by the river water into the North Sea. In terms of sediment management, therefore, both the river and the sea have to be viewed as a single system.

The port authority has called for a united approach to solving river and port pollution involving the various political administrations in the region, which have united under the International Commission for the Protection of the Rhine.This body is now drawing up a plan to comprehensively management sediment generated by the Rhine.

In future, it is hoped that contaminated sediment that is a potential risk for the Port of Rotterdam, will be dealt with at a local level or risk posing unacceptable burdens on downstream sediment managers such as the port.

A Port of Rotterdam spokesperson tells Port Strategy: “Only clean ports have a future. For this reason, the sediment management programme has been implemented as part of the PoR’s overall Waste Plan.”