The challenge

The island Griend is an overgrown sandbank with unique flora and fauna and is located in the Wadden Sea. The uninhabited area is a paradise for thousands of waterfowls and seals. Griend has been threatened with decaying, heavy erosion and geomorphological changes for decades. The island will disappear in the rough currents and waves without new coastal protection. Smart nature reservation and the excavation of overgrown areas are necessary to save many bird species, seals and insects. Sand nourishment was needed to construct a new sand engine. Clean dredged sand from waterway Blauwe Slenk has been distributed to construct a new sand engine. Next to the sand nourishment, shell banks were built for safe protection of small aquatic animals.


If we had done nothing, island Griend would have disappeared in the rough waves > Society for Preservation of Nature Monuments

Our contribution

Walhout Civil was contracted by Rijkswaterstaat, the Dutch Ministry of Infrastructure and Environment, for the contract preparation, tender guidance and technical advice during the execution. Walhout Civil worked in close cooperation with the society Natuurmonumenten, dredging contractor Boskalis and several stakeholders. The interests of the stakeholders and the client’s requirements are anchored in the contract and project bids during the process. The project has been delivered to Natuurmonumenten after a fast and accurate execution. Griend is again safe and protected in the coming years. A summary of our activities:

  • Stakeholder management and client interviews
  • Preparing and preparing client and system requirements (KES, SES)
  • Preparing of the contract demand specifications (E&C Contract)
  • Perparing of integral safety plan (IPV)
  • Verification of sand engine design
  • Expert and assesor in EMVI comission
  • Execution meetings on site
  • Technical consultancy
  • Technical validation of final results

Building with Nature

Griend is indispensable for achieving the Wadden Sea’s Natura 2000 goals. The know-how of the contract is based on practical insights and solutions according to the method ‘Building with Nature’. The aim is to optimize the flora and fauna, ecology and the morphology processes continuously. University of Groningen, Radboud University Nijmegen and the Royal Netherlands Institute of Sea Research will carry out research on the development of the nature and morphology processes of Griend in the coming years, to learn more about the nature of the Wadden Sea.