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Expected outcome
Insights on the coastal ecosystem dynamics for their application on coastal protection in the face of climate change.
This is me collecting soil samples in a saltmarsh from Schiermonnikoog, an island in the Dutch Wadden Sea, to understand the erosion mechanisms of saltmarshes (Photo and scheme by Beatriz Marin).
Motivation and practical challenge
From the coastal areas near my home in Barcelona to the Dutch coast that I now study, I acknowledge that hard engineering measures such as dykes or levees are needed for flood protection. However, their implementation may negatively affect the foreshores areas near the coast. The changes to the coastal dynamics deteriorate many natural ecosystems, such as the saltmarshes, which are salt-tolerant plants growing in areas that are flooded by the high tides. These plants are important for coastal protection by reducing waves, but also provide other important ecosystem services like water quality improvement and carbon sequestration. As an environmental biologist, I am therefore motivated to protect our ecosystems by offering alternatives to hard engineering with more eco-friendly or ecosystem-based coastal defences. For example, by preserving along the Wadden Sea natural ecosystems like the saltmarshes but also the mudflats, about 100 km dikes may, in theory, convert their safety status from insufficient to safe. Nevertheless, the uncertainties about the actual effects also hamper the practical implementation of these ecosystem-based measures.
Research challenge
Therefore, in this project, I investigate how the foreshore ecosystems near the coast work, and what is the effect of their management on gaining both flood protection and ecological value?
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Innovative components
To address the above question, I follow four steps, each with the following unique aspects to understand:
- The soil erosion mechanisms of mudflats and saltmarshes across The Netherlands. On flow and wave flumes, I test the top and lateral soil erosion of soil samples, including bare mudflats, not grazed vegetated saltmarshes and grazed vegetated saltmarshes.
- The utilization of artificial reefs for coastal protection. The presence of mussel beds may help the saltmarshes expansion, therefore increasing the protection of the dykes. In 2017, together with colleagues at the institute, we recreated this process into an artificial reef experiment, and I am studying their effect on both wave attenuation and mudflat change of elevation.
- The role of saltmarshes on wave attenuation and reduction of wave run up on the dykes. We are monitoring these variables in five locations of the Dutch Wadden Sea.
- Influential factors for the saltmarshes development in the Wadden Sea. By using long term aerial images and maps I explore factors such as the soil elevation and the effects of different management styles that may influence the development of saltmarshes.
Relevant for whom and where?
Researchers, nature managers, organizations, and authorities involved in the design of ecosystem-based coastal defence.
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Progress and practical application
The research is still ongoing. Yet, progress results show that fine-grained saltmarshes may provide more protection to the dykes in case of failure than bare mudflats. [Explain here the fine grained saltmarshes]. Moreover, the grazing of hares, geese and cattle may reduce saltmarsh lateral erodibility. However, intensive cattle grazing may lower soil elevation, which could negatively impact the resilience to sea-level rise in the face of climate change. Last, we found that saltmarshes attenuate waves and reduce wave run-up on the dykes, but their effects vary accross the five monitored locations.
Status for day-to-day practice
Based on these preliminary results, we recommend the management of foreshores for coastal protection by preserving existent saltmarshes through the maintenance of brushwood groins [explain what it means]. We also recommend preserving small herbivores such as hares and geese in the low saltmarshes as they may limit erosion without reducing the soil elevation.
Next steps
We will continue analyzing results from the experiments and storms monitoring during 2020-2021. We are further looking for relationships between large scale factors and the variables that we are measuring along the different locations. These relationships in the Wadden Sea may be useful for designing a more eco-friendly coastal protection.
Last modified: 01/05/2020
Explore the contact details to get to know more about the researchers, the supervisory team and the organizations that contribute to this project.
Contributing researchers
Beatriz Marin Diaz
NIOZ
As soon as available, explore the storyline to get to know more about the main methods or prototype tools that were developed within this project.
Explore the output details for available publications to get a glance of the innovative components and implications to practice as well as the links to supporting datasets.
Research outputs are currently under preparation so we list the latest publication:
- Marin‐Diaz, B., Bouma, T. J., & Infantes, E. (2019). Role of eelgrass on bed‐load transport and sediment resuspension under oscillatory flow. Limnology and Oceanography. https://doi.org/10.1002/lno.11312.
Take a look to the dissemination efforts and application experiences which are available in the news items and blogs.
