Utilizing the Full Potential of Dredging Works

Marine extraction sites alter the morphology of the seabed and in doing so offer unique opportunities to create a new environment in these locations, stated the article “Utilizing the Full Potential of Dredging Works: Ecologically Enriched Extraction Sites”, published in the September issue of Terra et Aqua Journal.

A new physical lay-out means deeper waters and different currents and sediment characteristics, which offer conditions to develop a new ecosystem or a sanctuary for certain fish species. This potential has been tested in a full-scale pilot project in an extraction site in the North Sea within the Building with Nature research program.

The necessity for this pilot project on utilizing the potential of new extraction sites is evident. Rising sea levels and increasing pressure on available coastal lands lead to the need for new land reclamations for ports, cities, nature and recreation, but also sand nourishments for sustainable coastal safety.

These are only a few of the many projects that are expected to take place in the future, which will need significant amounts of sand from offshore sources, thus creating extensive extraction sites. These extraction operations should be seen as an opportunity to manage these sites and create an overall increase in natural value of the seabed.

The research done here derived from the premise: Instead of focussing on minimizing negative effects let’s create opportunities to maximise positive effects. This article describes efforts to do this during the design process, construction and monitoring program by creating a landscaped extraction site in the North Sea.

It provides an overview of the preliminary results, focussing on the added value of landscaped extraction sites. It also describes when they are most effective; it is important to realize that the choice for an ecological landscaping design should be based on both the potential for development of a new ecosystem and the economic workability of the extraction itself (main function of the site).

This article is based on a paper presented at the 33rd PIANC World Congress, San Francisco, California, in June 2014, which received first prize for the PIANC Young Professional Award for outstanding technical paper and presentation authored by a young professional.

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