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Nature-based coastal management is mainstream in the Netherlands. About 12 Mm3 of sand is added annually to the coast to compensate coastal erosion and maintain high safety levels against flooding. This amount will likely increase to compensate for accelerated sea level rise. (Mega-)Nourishments may also strengthen and support biodiversity and recreational values of the coastal zone and associated wetland areas. However, the ecological and societal impacts of mega-nourishments on open coasts are not well established, hampering comparison of pros and cons of different nourishment strategies. This knowledge gap is largely due to the lack of suitable methods to monitor and predict the spreading of nourishment sand along the coast and into tidal basins.
Ameland Inlet provides us with a unique opportunity to develop and test novel approaches to fill this knowledge gap in close collaboration with our consortium and stakeholders. In 2018 the first tidal inlet mega-nourishment (5 Mm3) was placed in the Ameland Inlet ebb-tidal delta, and geomorphic and biotic responses nearby are closely monitored in the Kustgenese 2.0 and SEAWAD programmes. Our research builds on the insights gained, will gather new data to investigate off-site effects (linked with SIBES/SIBUS sampling), and build a common knowledge-base with stakeholders. We will develop novel luminescence-based methods to monitor the temporal and spatial dispersal of nourishment sand. These insights will be combined with an inventory of off-site biotic responses to nourishment and the role biota play in the mixing of nourishment sand with natural sediments. Combined results will be used to develop and validate models to trace transport paths of individual grains and improve morphodynamic predictions. Throughout the project, we will collaborate and interact intensely with coastal managers and (local) stakeholders to address concerns and exchange insights, creating a platform for co-assessment and optimization of nourishment designs and strategies.