Data-driven insights into coastal bathymetry for climate and coastal research
Expert(s) |
Etiënne Kras
|
Ruben White
Did you know that much of the ocean floor has never been mapped in detail? While we can zoom in to street level with Google Maps, the underwater world remains largely uncharted. Deltares, together with European partners, is changing that using satellites, smart algorithms, and deep domain expertise.
A European project with global impact
Deltares is a key partner in the ambitious CMEMS (Copernicus Marine Service) initiative, part of the broader Europese Copernicus-programma. The project aims to develop a global coastal bathymetry map with a resolution of 100 metres. Bathymetry—the science of measuring water depth—is essentially the creation of an underwater elevation map. This map will support researchers, governments, and businesses in modelling flood risks, coastal change, and climate impacts.
In collaboration with EOMAP and GGS Geo Consultancy (GGSGC), Deltares is working on a coastal dataset that will soon be freely available via the Copernicus platform.
From pixels to depth maps
Within the consortium, Deltares is responsible for intertidal bathymetry—the zone between the highest and lowest astronomical tides. This is one of the most dynamic parts of the coast, alternately exposed and submerged. It plays a crucial role in coastal safety and ecology.
Deltares uses satellite imagery from Sentinel-2 (ESA) and Landsat (NASA), combined with the Global Storm Surge Information System (based on Delft-FEWS platform and Delft3D FM simulation software), to determine how often a given pixel—essentially a 10x10 metre square—appears dry.
Etiënne Kras, researcher in Resilient Ports and Coasts and Product Owner of the project at Deltares, explains: “Each pixel contains information about how light reflects off that patch of land or water. By analysing how often a pixel appears dry—meaning it reflects no water—and linking that to tidal data, we can infer the elevation of the seabed at that location. This is done using advanced algorithms running on Google Cloud, enabling efficient analysis of millions of images.”
Ruben White, researcher in Resilient Ports & Coasts at Deltares, adds: “We’re also working on ‘Wave Kinematics’ bathymetry, where we analyse wave motion in satellite imagery to estimate seabed depth. This method is particularly useful in shallower coastal zones where waves begin to ‘feel’ the seabed.”
The power of combining methods
The project’s strength lies in combining three techniques: Intertidal bathymetry (Deltares), Subtidal bathymetry (EOMAP) and Wave Kinematics bathymetry (Deltares and EOMAP).
Etiënne explains: “Our third partner, GGSGC, merges these layers into a single, harmonised dataset. For each location (pixel), the most reliable method is selected. This avoids the ‘vertical jumps’ often seen when combining different data sources.”
From raw data to usable product
Although the final dataset will only be a few dozen gigabytes, it is distilled from terabytes of raw satellite imagery. Through smart compression and by excluding deep ocean areas, the result is a compact, globally applicable product.
The first version of the static dataset is hosted on the Copernicus platform. Anyone, from scientists to policymakers, can now freely use this data.
What I enjoy most is building something that’s reusable, scalable, and genuinely impactful. This project is technically demanding, but also socially relevant—and that’s what makes it so valuable.
Etiënne Kras, Deltares
From global to local: scalable and customisable
The static dataset provides a consistent global baseline of coastal seabed elevations. For local applications—such as around a specific port or vulnerable coastline—more detailed data may be needed. Thanks to a flexible data-processing pipeline, Deltares can quickly generate tailored local datasets by adjusting parameters and rerunning algorithms.
Ruben White notes: “Many users will start with the open dataset but may later need local refinements. That’s where Deltares excels: combining data analytics with domain expertise to deliver actionable insights.”
Open data as a catalyst for collaboration
The project aligns with the European Union’s “dare-to-share” principle: making data openly available to tackle societal challenges such as climate change, energy transition, and coastal safety.
Etiënne: “We believe open data drives innovation. At the same time, we retain intellectual property over the underlying routines and possess deep domain knowledge. This allows us to continue delivering tailored solutions. Our expertise is built on nearly a century of experience in water and subsurface research.”
What sets Deltares apart is its unique combination of:
- Deep-rooted domain knowledge in water and subsurface systems, spanning 9 different areas of expertise such as drought, flooding, sea-level rise, and energy transition
- Technical expertise in cloud computing, modelling, and data analytics
- Multidisciplinarity, enabling rapid collaboration across fields
Etiënne concludes: “This blend allows Deltares to offer integrated advice and solutions—from data to policy.”
Towards dynamic bathymetry?
In addition to the static map, the consortium is exploring dynamic bathymetry. Etiënne explains: “In some areas, like the tidal inlets of the Wadden Sea, the seabed changes monthly. We’re developing a roadmap to assess whether annual—or even more frequent—updates are feasible.”
The vision for dynamic bathymetry will be delivered by the end of 2025. If successful, the project will be extended.
Data: fuel for the future
Bathymetry underpins nearly every model involving water or the seabed—from flood risk to shoreline change and groundwater studies. By making this data openly available, we not only accelerate our own research but also contribute to a safer, more sustainable, and better-understood global coastal system.
Data is the fuel that powers our models. The better the data, the more accurate our predictions—and the more effectively we can contribute to solutions for today’s major societal challenges.
Ruben White, Deltares
International recognition and future potential
The project has been recognised as a UN Ocean Decade project, aligning with the Ocean Decade action framework. Ruben notes: “This opens the door to additional funding, enabling further innovation—such as using Artificial Intelligence (AI) to fill data gaps or enhance resolution in complex coastal zones.”
Added value of a multidisciplinary team
At Deltares, this project is carried out by a multidisciplinary team of experts in coastal engineering, data analysis, and modelling. A multidisciplinary approach brings together diverse perspectives and areas of expertise, leading to innovative solutions and more well-founded decisions. The team includes: Etiënne Kras, Ruben White, Matthijs Gawehn, Martin Verlaan, Mario Fuentes Monjaraz, Maarten Pronk, Marieke Eleveld, Arjen Luijendijk and Antonio Moreno Rodenas.
