Dredging and pollution

Clean or contaminated dredged material

Before we start dredging, we first check the quality of the dredged material. We do this by conducting a waterbed investigation. This investigation determines whether we need to take samples. When we take samples, they are tested for contaminants. This allows us to know in advance whether the dredged material is clean or not.

Clean dredged material: We are permitted to distribute and remove this dredged material freely.
Spreadable dredged material: This dredged material is clean enough to be spread in the immediate vicinity of the watercourse. We are permitted to spread the dredged material over the adjacent plot of land.
Non-dispersible dredged material: the dredged material contains many contaminants. We transport the dredged material to a special landfill site.

The following steps are taken into account when assessing the quality of the dredged material.

There are three dredging streams: dispersal along the watercourse, reuse elsewhere, and special situations. In the case of dispersal along the watercourse, we assess whether the dredged material can be dispersed. Reuse on land depends on land use. The categories are clean, residential, industrial, and not applicable. In the case of reuse underwater, we distinguish between the categories clean, class A, class B, and not applicable. Specific situations include large-scale soil application and area-specific policy.

We transport dredged material that cannot be spread due to buildings to our transit depots. This situation often occurs in urban areas. We dry this dredged material and use it in our flood defenses, among other things.

Handling contaminated dredged material during inspection

Do you want or need to carry out dredging work as part of the inspection and do you suspect that the dredged material is contaminated? We have regulations in place for testing and processing the dredged material. Please contact us for more information.

This is how HHNK deals with PFAS and dredging

Since 2019, strict standards have been in place in the Netherlands for the distribution and use of soil and dredged material containing PFAS. It is understandable that landowners are concerned about receiving and processing dredged material, given all the media coverage. We share these concerns. That is why we investigated the presence of PFAS in waterbeds and dredged material in 2021.

Very little PFAS contamination

To determine the effect of the new regulations on dredging activities, we examined the waterbeds of 20 ditches and canals in our working area. These locations are representative of the rural area. Careful analysis shows that the concentration of PFAS in the dredged material remains well below (at least a factor of 10) the standard that applies to the spreading of dredged material on the shore. Prior to our dredging activities, we conduct research into the quality of the dredged material. This includes looking at the risk of PFAS occurrence.

As a landowner, can you process dredged material?

Based on the temporary PFAS action framework of the Ministry of Infrastructure and Water Management, we can continue dredging in the outlying area and depositing the dredged material on an adjacent plot. Landowners can also continue to clean up and spread the dredged material without endangering human health, animals, or the environment. We always investigate suspicious locations first. We will continue to closely monitor PFAS developments and adjust our dredging activities if necessary.