IADC (International Association of Dredging Companies) recently presented an article on the multiple benefits of the Hondsbossche and Pettemer sea dunes, valued by IISD through the SAVi methodology.
An assessment with the Sustainable Asset Valuation (SAVi) methodology by the International Institute for Sustainable Development (IISD) showed that the Hondsbossche and Pettemer (H&P) sea dunes outperformed conventional flood protection infrastructure.
In comparison to a grey infrastructure alternative of raising the sea dike, the nature-based infrastructure (NBI) was cheaper to build and brings greater benefits for tourism.
Based on IISD’s modelling, the sand dunes increase tourism revenue by almost EUR 203 million over 50 years, while the grey alternative would have increased it by only EUR 103 million.
Hondsbossche and Pettemer sea dunes
In 2004, the Directorate-General of Public Works and Water Management in the Netherlands (Rijkswaterstaat) declared that the dunes and sea dykes of H&P are not in line with the flood protection standards of the Netherlands.
Therefore, a EUR 250 million project was undertaken to improve flood safety and spatial quality. This project followed the Building with Nature (BwN) design to comply with the sustainability aspects.
The specifics of the design allow for a seabed erosion-free solution that also provides a shallow foreshore for leisure and an artificial dune landscape that can develop into a natural habitat (EcoShape, 2018).