Fort Steurgat – implementation of vegetated foreshores

Global change is altering the frequency and intensity of storms and related flood risks. This calls for an update of the flood protection systems in many countries. Dikes and levees have traditionally been designed as the main feature of this flood protection strategy. However, with the changing storm conditions many are in need of updating to increased levels of protection. Doing this with traditional methods (raising and widening the dikes) is often costly, and has a high impact on society and the landscape.

salix-alba-chermesina-kl-120225bAt Fort Steurgat (NL) a willow plantation was part of the landscape design to reduce wave height. As a result, the required dike height could be lowered with 65cm. Deltares plays a major role in many of these projects on the design and implementation of vegetated foreshores both in the Netherlands and abroad. We do so by making the scientific and applied knowledge from these projects generic and publicly available via tools and publications. Deltares also has an extensive role in the state-of-the-art monitoring of these processes in the field using Remote Sensing, Automated monitoring stations and new data storing, handling and sharing protocols.

Many pilot projects on vegetated foreshores in front of existing dikes are currently being Aangepaste_artist_impression_Grienddijktested in the field, such as the implementation of a vegetated foreshore in a large shallow lake in the Netherlands (Lake Markermeer), the use of existing vegetation in floodplains of the Rhine river and the restoration of saltmarshes in the ‘Waddensea’ Estuary by smart distribution of dredged materials in front of the marshes. Also willow trees can play a role in flood risk reduction.

Vegetated sandy foreshores can be implemented in front of existing dikes in order to strengthen these dikes and reduce the wave impact on the dikes. The foreshore becomes an integrated part of the safety design and at the same time provides other ecosystem services and habitats for species to settle, creating a win-win situation for both disaster risk reduction strategies and natural values.