North East File Collection - NEFC

The Dutch process involves first making a preliminary investigation of an area which should be able to pull in temporal as well as spatial contamination information, this is defined the Dutch standard NEN5717.

The information from the NEN5717 preliminary investigation is then used to define a location specific research strategy according to NEN5720, where the area being investigated is divided into appropriate sub-locations. Each sub-location effectively has its own research strategy, determined by the type of contaminants present and the risks of them being present.

This is one area that UK licences do not make clear which is implicit in all the Dutch standards, but is made explicit in the “Rikswaterstaat|Guidelines for assessing waterbeds” is that correct compartmentalisation of a waterbed into sub-locations (deellocaties) is a prerequisite of achieving a contamination picture of an area which is truly representative of the true state of contamination, as expessed on page 115: “The objective of this guidance document is to assess whether the sediment is impeding the achievement of the quality objectives. This means that one has to gain a clear insight in the type, extent and spatial distribution of any sediment contamination. The NEN 5720 can be used to compartmentalize the area, provided that the compartments do not differ from each other with respect to the properties of the water system that – according to the methods in this guidance document - determine the effects of the sediment on the objectives and functions considered (see §1.6 of this guidance document).

As stated in §5.3.3 of the NEN 5720, the research strategy may be adjusted by changing the compartmentalization, the number of sediment cores, the thickness of the sampled layer or the number of analyses. Although the number of sediment cores may be limited, enough cores have to be taken in order to get a clear insight into the spatial distribution of the sediment contamination. Sampling of the top sediment layer suffices. This is the sediment layer that interacts with the water column. The thickness of this interactive layer depends on factors such as water type and water dynamics (flow rate, number of passing ships etc.). It is advisable to include a layer of 20-50 cm thickness in the survey.”

Practical aspects of sampling are covered in KIKB Protocol 2003 - Fieldwork in enivornmental quality waterbed research, NPR 5741:2015nl - guidance for selection and use of drilling techniques and sampling aparatus for soil, sediments, sludge and groundwater in environmental investigations, NEN 5742:2001nl - sampling of soil and sediments for the determination of metals, inorganic compounds and physico-chemical soil characteristics, NEN 5743:1995nl - sampling of soil and sediments for the determination of volatile compounds,

Compartmentalisation of materials from soil

Water and Soil Legislation Chapter G - Dredging and transport

FAQ Status of dredged material

Environmentally polluting activity involving the use of soil or dredged material (Paragraph 3.2.26 Bal)

Policy rule on the application and distribution of dredged material in the North Sea

Rikswaterstaat - Dredged material

Dredging for fairway maintenance

Toxicity tests for salt dredged material - RIKZ manual

Quality requirements for applying soil or dredged material in surface water

Soil Quality Regulation 2022

In the Netherlands, before dredging first you have to conduct a preliminary investigation following: NEN5717 Soil - Sediment - Strategy for the preliminary investigation of the environmental quality One of the outputs of the preliminary investigation is a stratification of the area to be dredged into sublocations which are internally relatively homogeneous and typically between 10 and 30 hectares in size. then you follow.

NEN5270 Soil - Sediments - Strategy for exploratory investigation or the environmental quality The Port of Rotterdam authority follow this procedure and take 6 samples from each of 300 different locations within the dredged area.

Netherlands standard - https://connect.nen.nl/ - full text freely visible on line after registration.

The Netherlands does not dump dredged material at sea, instead it relocates sediment for beneficial uses and takes contaminated sediment to land where it is treated. Rivers are dredged by a national authority with the maintenance dredging process being described here and a series of dredging depots are operated to store and treat contaminated dredged material.

Licensing of disposal to sea is not used, instead dredging is licensed under national water / soil standards and as these exceed OSPAR requirements, so the developer/port authority does not touch OSPAR.

Policy Rule on the Application and Distribution of Dredged Material in the North Sea

Using dredged material as a raw material

Dredge material from Rotterdam - where do you put it