Daphne van der Wal – physical geographer at NIOZ and professor at the University of Twente – observes deltas, coasts and estuaries from space and from the air. ‘That can be done via satellites but also with the help of drones. The use of these remote sensing techniques can teach us a lot about coastal defence, water quality and nature conservation.’
‘Satellites have the advantage that, in many cases, they allow us to look back over several decades. This is because we have a long history of satellite images which have continually observed a piece of the Earth’s surface in the same way. For example, from satellite images, we can see where coastal vegetation, such as saltmarshes and mangroves, has expanded and where plants have disappeared or where their growth was hampered. We analyse satellite images in relation to coastal protection for the Dutch coast, but also for the coast of Louisiana, for example. Together with modellers, we are examining how vegetation attenuate the waves and trap sediments and can reduce the chance of the land becoming flooded during heavy storms. That allows us to learn what the ingredients are for sufficiently strong coastal defences. Such information is becoming increasingly relevant in light of the changing climate and expected increase in extreme weather.
‘Satellite images are also well suited for studying the quality of the water and the seabed. For example, we examine the interaction between sediment and the algae and animals that live in the water and seabed. This knowledge is important with respect to, for example, the dredging of estuaries for shipping.’
‘We also use radar images; these can observe, for example, the roughness of tidal mudflats. This way, radar can even be used to map mussel and oyster reefs on tidal mudflats. Now we can also make use of techniques like drones. These provide very detailed spatial information.
With all these forms of remote sensing, we are finding out how our coastal systems work and how they adapt to changing conditions and interventions. We are also learning how coastal processes help us, and how we can protect our coasts.’Read more +
I am a physical geographer, specialized in coastal processes (PhD 1999, University of Amsterdam; postdoctoral research fellow 1999 up to 2002 at Royal Holloway, University of London).
In 2002, I joined NIOO/NIOZ in Yerseke, focusing on remote sensing of tidal (eco)systems.
Since Oct 2017, I am also part-time full professor at the University of Twente, Faculty of Geo-Information Science and Earth Observation (ITC).
I focus on remote sensing and geo-informatics of coastal and estuarine systems and processes. An overview of my research interests can be found in my inaugural lecture:
The central theme of my work is to assess interactions between organisms (such as saltmarshes, algae, shellfish) and their environment, shaping the estuarine, delta and coastal landscape, including both the bottom sediment and the water column.
Current research topics
Methods & techniques
I use remote sensing techniques and geo-informatics to investigate coastal and estuarine systems and processes:
Laengner, M.L.; Siteur, K.; van der Wal, D. (2019). Trends in the seaward extent of saltmarshes across Europe from long-term satellite data. Remote Sensing 11(14): 1653. https://dx.doi.org/10.3390/rs11141653
- NWO/NSO Ruimteonderzoek, “Saltmarshes under stress: thresholds for saltmarsh dynamics from global satellite data” (MARSH), PhD candidate at NIOZ: Marieke Laengner, started 2017.
- STW Perspective AllRisk – Implementing new flood safety norms. Project Foreshore Ecosystems Management. https://kbase.ncr-web.org/all-risk/projects/b1-foreshore-ecosystems-management/#overview. PhD candidate NIOZ: Beatriz Marin Diaz (joint supervision NIOZ/RUG: Tjeerd Bouma, Han Olff, Laura Govers, Daphne van der Wal)
- EU FP7 SPACE - FAST "Foreshore Assessment using Space Technology". Consortium Deltares, University of Cambridge, NIOZ Royal Netherlands Institute for Sea Research, University of Cadiz, GeoEcoMar. PhD candidate at NIOZ: Bas Oteman, started 2014.
- NWO/NSO Ruimteonderzoek: “Benthic diatoms as indicator for ecosystem structuring in shallow tidal waters. PhD candidate at NIOZ Tisja Daggers, started 2013.
- NWO/NSO Ruimteonderzoek: "Consequences of global change for ecosystem engineering of shellfish". PhD-candidate at NIOZ Sil Nieuwhof, started 2012. See Sil's PhD thesis.
FAST has developed services to help design nature-based flood risk strategies in foreshores, based on earth observation data and big data analysis capabilities.
Read more on EU FAST in the associated article on this Copernicus downstream service for coastal needs.
Have a tour around the Danube Delta in Romania, one of the field sites in the EU FAST project!
See also the synthesis of results of the EU FAST project.
MI SAFE tool to calculate wave attenuation over vegetated foreshores around the globe (tool currently not active):