Pathways for Realising Climate Adaptation in the Wadden Sea (PaRCA)
- Authored by PaRCA -
The transdisciplinary project PaRCA is a joint initiative of Dutch, German, and Danish experts to analyse pathways for realising a sustainable climate adaptation of the Wadden Sea. This project focusses on the feasibility of the different sediment management measures (from direct and indirect nourishments to managed retreat) that can actively support the adaptation of tidal flats and barrier systems to sea level rise. The law and governance of sediment-based solutions in the Netherlands, Germany, and Denmark are analysed and management pathways are co-developed. The project is led by Christian Winter (CAU Kiel) and Zheng Bing Wang (Deltares / TU Delft). Experts from German (Federal Waterways and Shipping Institute (BAW) in Hamburg, Global Climate Forum (GCF) in Berlin, Kiel University (CAU), and Senckenberg am Meer Wilhelmshaven (SNG)) and Dutch (Royal Netherlands Institute for Sea Research (NIOZ) in Yerseke, DELTARES in Delft, Delft University of Technology (TUD)) institutions are forming the project consortium together with a group of stakeholders (here named cooperation partners) of environmental NGOs, Wadden Sea national parks, and coastal and waterways management.
The project began with a joint workshop of all project partners in Utrecht in November 2024. We officially kicked off with our cooperation partners in Groningen in January 2025. Within the project, different ways of communication were established: A cloud for file exchange and joint documents is available and a joint website were launched. In addition, we hold an online meeting every month. With our cooperation partners, we have agreed on the focus areas in Sylt (Germany) and Schiermonnikoog (the Netherlands), but are also open to other locations of interest. Project partners involved during co-design and co-development so far are LKN-SH, NPV, NLWKN, WSV in Germany. Joint measurement campaigns were carried out in Sylt and Schiermonnigkoog and first results were presented at the international conference RCEM 2025 (Barcelona). Later in 2025, a delegation will present numerous aspects of PaRCA at the 16th International Scientific Wadden Sea Symposium in Groningen.
The project is structured into three work packages (WP). The overall objective of WP1 “Governance” is to understand what kind of governance arrangements (i.e., formal and informal institutions, governmental and non-governmental organisations) can help to overcome social (i.e., administrative, legal, economic, financial, etc.) barriers associated to sediment management in the Wadden Sea. The objective of WP 2 “The physical system” is to quantify how interventions influence the physical state of the Wadden Sea in contrast to the natural dynamics, and how these changes translate into ecologically relevant parameters. The objective of WP3 “The ecosystem” is to predict the long-term resilience of Wadden Sea tidal flats communities to sea-level rise by investigating the effects of natural disturbances and human management on local community dynamics and biodiversity related to sediment dynamics. The single work packages are introduced in the following:
WP1a Law (CAU Kiel, Lead: Nele Matz-Lück)
The work package is assessing the legal implications of nourishment activities. Eva Sinemus started working in the project in July 2024, and Till Günther recently joined in September 2025. During the first year of the project, we have focused on the current legal framework regarding onshore and foreshore nourishments, specifically looking at permission procedures and environmental impact assessments. Further, we are researching legal implications of tidal flat nourishment as potential conservation or restoration measures, for example as habitat conservation in the sense of the Habitats Directive or as measures required under the MSFD or NRL.
WP1b: Social Conflict and Social Acceptability (GCF, Lead: Jochen Hinkel)
The work package investigates the governance of sediment management. Alexander Pechmann joined the project in June 2024. The first case study focuses on current decision-making around sand nourishments on Sylt. In collaboration with WP1a, we examine how laws and policies are translated into administrative practice, with a focus on informal institutions shaping financing, prioritisation, and permitting. A first round of interviews with LKN-SH and MEKUN staff has been completed. The case offers insights into decision-making in Schleswig-Holstein, enabling future comparisons with Lower Saxony and the Netherlands, and informs the potential of sand nourishment as a socially acceptable nature and coastal protection strategy.
WP2a Availability (Deltares, Lead Zheng Bing Wang)
The work package is investigating limitations in sediment availability for the Wadden Sea to keep pace with rising sea levels, and measures to mitigate sediment shortages. We are currently developing a model using the ASMITA software that can be used to investigate the sediment balance on on the scale of tidal basins. Which such a model we can explore how trapping of fine sediments in one basin will influence the dynamics of downdrift basins. Developing this model requires modifications of the original software code and an extensive calibration procedure.
WP2b Turbidity (BAW, Lead Robert Lepper)
The work package is investigating what is normal, and what will the new normal be? Dr. Jannek Gundlach analyses available data to identify representative time frames and establishes a robust baseline for scenario development. Using long-term modelling data from the TrilaWatt database, we identify and distinguish key time scales that impact the spatial distribution of suspended sediments. We can now differentiate and quantify the impact of seasonal patterns, spring-neap variability, and storm in the Wadden Sea. Our current work focuses on deriving water column turbidity and light penetration information from these findings by combining modelled inorganic suspended sediments with organic modelling data from the Copernicus Marine Data Services.
WP2c Ecotopes (TUD, Lead Bas van Maren)
The work package explores methodologies for the intertidal areas to keep pace with SLR. In December 2024 Marthe Wassink started working on the project as a PhD student. So far, she has worked on comparing different bathymetry and sediment composition datasets from Germany and the Netherlands to calculate sediment budgets and intertidal area accretion for the trilateral Wadden Sea. The next step will be to relate bathymetry trends to sediment composition, to distinguish the contribution of sand versus mud. First steps have been taken with an idealised modelling of nourishments together with WP2b+e.
WP2d Variability (NIOZ, Lead Johan van De Koppel) Dr. Tim Grandjean
The work package will start in January 2026 to work on the project as postdoc. We have (even before the start of this project part) visited the field sites and investigated possible locations to study sediment dynamics in relation to biota presence. We are planning to measure sediment dynamics at Sylt in collaboration with the AWI research centre on Sylt, and on the island of Schiermonnikoog in 2026.
WP2e Substrate (CAU-IfG, Lead C. Winter)
The work package is exploring mechanisms of tidal flat growth at present and in the future. Dr. Amin Rahdarian has started in June 2024 working on the set-up of a numerical model for the simulation of morphodynamics for the investigation area of Sylt and the surrounding tidal flats of the North Frisian Wadden Sea. Boundary conditions will be generated by WP2b. Sampling campaigns have been carried out in cooperation with WP2d and WP3b in Sylt.
WP3a Interactions (NIOZ, Lead Johan van de Koppel)
The work package is exploring the effects of biota on sediment distribution in the Wadden Sea. PhD student Divya Varadharajan has started in January 2025 to work on simulation models of the interaction between biota and sediment. Divya will in part focus on the effects of biota (seagrass, lugworms, mussels as a first start) on mud accumulation, patchiness, and tidal flat resilience, and in part on the effect of biota on the islands (dune & salt marsh vegetation) on sand fluxes towards the Waddden Sea, for the most using model analysis. The NIOZ team has visited field locations on Sylt and Schiermonnikoog to investigate opportunities for field studies.
WP3b Impact (SNG, Lead G. Veit-Köhler)
The work package focuses on the impact of natural changes and sediment management strategies on the biodiversity of sediment-inhabiting organisms. In June 2024, PhD student Iryna Kapshyna was employed. In 2025, we conducted spring and summer fieldwork in Sylt and Jade Bay, where we sampled different intertidal habitats as a baseline for a large-scale meiofauna distribution model. In cooperation with WP2e, we initiated a time series to investigate the impact of sediment changes on community compositions before and after a foreshore nourishment implemented as a coastal protection measure at Sylt. We carried out a field campaign at Schiermonnikoog in cooperation with WP3a, and we are discussing further sampling sites with the Nationalparkverwaltung Niedersächsisches Wattenmeer.
For more information and impressions, visit the project website
