The Water Quality Monitor supports VMM in measuring and reporting surface water quality. View project case page on the VITO-website

Posted on - Ann Crabbé
Every 5 days the water quality of all Flemish waterbodies is automatically monitored by satellite images.

The Flanders Environment Agency (VMM) has a wide range of responsibilities in the domains of water, air and environment. The Water Monitor Department of VMM has, among other tasks, the task of measuring, modelling and reporting surface water quality. In support of the European Water Framework Directive, the quality element phytoplankton is reported by VMM on the basis of chlorophyll-a concentrations. Chlorophyll-a concentration is currently measured in 100 rivers and 16 lakes.

To support VMM with this task, remote sensing experts in water quality monitoring at the Flemish Institute for Technological Research (VITO) use free Copernicus Sentinel-2 satellite images and remote sensing technology to produce time series of chlorophyll-a maps. These chlorophyll-a products are provided to VMM via the online Water Monitor platform developed here at Nazka Mapps. The Water Monitor allows VMM to easily search, navigate and monitor chlorophyll-a temporally and spatially for Flemish water bodies.

Sentinel-2 satellites pass by every 5 days and chlorophyll-a is derived from their satellite images. Unless clouds obscure the satellite view, VMM can access chlorophyll-a maps of most of our inland water bodies every 5 days within 24 hours after Sentinel-2 image acquisition.

In addition, the Water Monitor includes for each water body of interest the OWL code, a classification of the Flemish surface water bodies according category, type and statute, the thresholds for chlorophyll-a Ecological classes (good, mediocre, inadequate and bad) and the chlorophyll-a maps with a colour code optimized for Water Framework Directive reporting. The VMM chlorophyll-a field measurements are also included for comparison.

The first beta version, a static Water Monitor, was developed together with VITO in the framework of the H2020 DCS4COP project. In the summer of 2020 we released a new version of the Water Monitor to offer near-real-time water quality monitoring. The new version also includes an additional product NDAVI, an aquatic vegetation index. The new version is a close collaboration with the EODaS programme (Earth Observation Data Science) of the Flanders Information Agency, VITO and VMM. This innovative project is hereby a contribution in taking new steps in introducing digital transformation and innovation in the Flemish Government.


With this product, Nazka Mapps proves its expertise in the integration of remote sensing-data and in building performant map applications with a user friendly interface. Moreover it is a nice example of how our maps can improve and innovate the daily workflow in the professional environment of the client. With this water quality monitor we hope to support VMM with a more efficient and prior selection for the time-consuming field measurements, a more global overview on the full waterbody both in space and time, and a more efficient reporting for Europe.

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