Introduction
Dredging is of vital importance to many of the EU’s ports, harbours and waterways - providing and maintaining adequate water depths and hence safe navigational access.
Due account must be taken that dredging across the EU is subject to natural variations, which are particularly marked in coastal and estuarine areas where tidal influences can lead to massive changes in morphology and suspended sediment concentrations. In many estuaries the vast majority of sediment that has to be dredged comes from the sea and not the rivers. Further, the amount of sediment actually dredged from a turbid estuary may represent only a very small fraction of the quantities mobilised by the tides every day.
Dredging and sediment management is subject to a wide range of international and EU policies and legislation which sometimes causes unjustified restrictions or different interpretations. The problem is that different European pieces of legislation clearly affect dredging operatons but were originally not written specifically to regulate dredging. This leads to effects which were never foreseen and are unwanted.
ESPO believes that this situation requires rationalisation, harmonisation and clarification and supports therefore ongoing EU policy initiatives which envisage a better sediment management. The main instrument to realize this is the Water Framework Directive. For this reason ESPO is actively involved in the ongoing activities steering the implementation proces of the Water Framework Directive in the Member States. Nevertheless, ESPO fears that also in this process sediment management issues are under-represented and that more attention is required.
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Sediment management
ESPO believes that proposed measures against pollution of surface water under the Water Framework Directive will affect ports in a disproportional way. It could introduce potentially additional unnecessary controls on dredging and dredge disposal activities with potentially very significant cost implications.
Existing sediment contamination in European river basins causes problems for ports when these sediments have to be dredged. However, contamination may be sourced from elsewhere in the river basin and/or the problem may be widespread throughout the whole basin (historic contamination).
Therefore ESPO wants to raise more awareness of the implications of the Water Framework Directive may have for the wider navigation sector and specifically for sediment management.
Navigation Task Group workshop on Navigation and the WFD
On 31 January 2007 the Navigation Task Group organised a one-day workshop in Brussels specifically on the interrelationship between Navigation and the Water Framework Directive. Sediment management was one of the main topics discussed during the workshop.
Sediment management in River Basin Management Plans
Most participants of the workshop believed that sediment management could be effectively tackled in the River Basin Management Plans. Furthermore importance was placed on the need to consider the role of existing regulations and International conventions such as OSPAR and the Londen Convention. The WFD and the River Basin Management Plans must incorporate the experience and sediment management frameworks set out by these existing agreements. A seperate sediment strategy is not required as the preferred option is to have sediment included as an integral part of WFD River Basin Management Plans.
SEDNET report on sediment Management as an essential element of River Basin Management Plans
Marine Strategy Directive
The in 2008 adopted Marine Strategy Directive may potentially also have an impact on dredging and disposal activities in the marine environment. It foresees that good environmental status is reached in all EU marine waters by 2020. Therefore programmes of measures need to be developed by 2015. If dredging and/or disposal activities are being identified as an activity hampering good environmental status, than one of the measures in the programme of measures may have an impact on these activities.
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Dredging and the Birds and Habitats Directives
Given the link between dredging and nature conservation it is not surprise that the Habitats Directive applies within those estuaries and coastlines that are designated as SACs and SPAs (see also port development and nature protection). Detailed scrutiny of dredging proposals that have a possible impact on sites designated as SPAs or SACs is therefore necessary.
Different dredging works in the past required a full appropriate assesment under the Birds and Habitats Directives and required eventually some mitigation or compensation measures to off-set negative impacts on the designated area. These imposed mitigation and/or compensation measures related to dredging have led to an increasing better understanding of sediment especially in estuaries. Better modelling and monitoring identified key issues related to sediment streams within the water. Moreover, sediment was also effectively used for recreation of specific habitat such as mudflats and salt marshes.
Port authorities gain a lot of this research and scientific knowlegde and many port authorities decided to continue monitoring and modelling the characteristics of sediment in estuaries and coastal areas without a mandatory legal requirement. Ports can benefit of this directly when accurate information can show regulators that environmental impact of certain dredging operations is limited (e.g. in the Humber an experiment was carried out with depositing dredged material within the estuary and not offshore. Analysis of this approach suggests that sediment loss due to this maintenance dredging is minimal and currently not a matter of concern in the context of such a sediment-laden estuary. This research convinced Natural England and Defra that there would be no adverse affects arising. In that way a full assesment under the Birds and Habitats Directives was avoided.).
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Review of the Waste Directive
In December 2005 the Commission proposed a Thematic Strategy on the prevention and recycling of waste and an accompanying proposal for a Directive on Waste.
Although the Thematic Strategy and proposal for a Directive do not specificly address dredging activities it affects sediment management as relocation or replacement of dredged material is regarded as a substance which the holders discards, thus as waste.
ESPO believes that the waste definition results in a too stringent regime as regards the disposal of dredged material in sea.
Most dredged material consists of non contaminated dredged material: a natural, essentail and dynamic part of aquatic systems. Relocation or placement allows sediment to continue its important role within the dynamics of coastal and estuarial morpholigical systems, thus returning the sediments to where it belongs.
ESPO notices that several Member States are increasingly treating most dredged material as contaminated and thus as waste and in need of special treatment and/or disposal, even though only a minor part of the dredged material is contaminated. With this these Member States are increasingly restricting the use of direct sea relocation of the material being dredged. The result of this excessive caution is that ports are potentially facing huge costs related to disposal and treatment without a clear environmental benefit. It is also possible that such actions will lead to excessive depletion of sediment from the local system inducing changes which may cause longer term environmental harm.
ESPO believes that the Thematic Strategy on Waste and the accompanying Directive could create some possibilities to improve the system and make it more realistic as regards dredged material. For more information about the legislative developments of this proposal for a Directive.
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More information
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