Muddy waters and the Wadden Sea harbours

Several harbours along the Dutch Wadden Sea deal with large siltation rates and limited possibilities for developments. However, development of new harbour activities is needed for these harbours to be able to survive in the long run. As these harbours lie in or close to areas with a protected status, expansion is not straightforward. In this paper we illustrate that harbour development is possible when a Building with Nature approach is used. This approach facilitates a design in which the proactive utilization and/or provision of ecosystem services serves as part of the engineering solution. We introduce four Building with Nature concepts that can be used in harbour designs, i.e. 1) optimising dredging strategies, 2) enhancing saltmarsh development, 3) creating estuarine gradients, and 4) optimising flow patterns. Based on these concepts, three case studies have been identified and pilot projects initiated. In the Port of Harlingen a pilot has started in which an optimized dredging strategy is combined with saltmarsh development. Around the Port of Delfzijl an estuarine gradient is combined with a salt marsh. For the Port of Den Helder a new design was proposed in which the concepts of enhancing salt marsh development, creating estuarine gradients and optimizing flow patterns are combined. Our conclusion is that even in a UNESCO listed site such as the Wadden Sea, harbour development is possible when ecosystem services are used and provided for, and when a Building with Nature concept is put at the heart of an engineering design.