Published on: December 4, 2025, 09:39 AM
In 2019, Rijkswaterstaat elevated the Roggenplaat to preserve this area as a feeding ground for water birds. The results of five years of monitoring now show that this has succeeded. Bottom-dwelling animals and birds have returned to the elevated areas, and the plate has significantly increased in volume.
Important Feeding and Resting Area
The Roggenplaat is one of the most important feeding areas for birds in the Oosterschelde. At low tide, the plate is visited by nearly 20,000 birds enjoying the many crustaceans, worms, and shellfish that dwell in the sediment. The plate is also an important resting place for seals.
Since the construction of the Oosterschelde barrier, the tidal effect in the Oosterschelde has changed, and the Roggenplaat has gradually become deeper underwater. To preserve the plates as feeding grounds for birds, the sand plate was elevated five years ago with 1.1 million cubic meters of sand.
Sand supplements were distributed over seven locations to limit potential nature damage caused by the new sand deposits. A monitoring program was also initiated to assess the effects of the supplementation. This week, we published the final report.
After Five Years of Monitoring
The monitoring results show that the Roggenplaat has maintained its function as a feeding area for birds and is secured for the near future. The total number of feeding birds on the Roggenplaat has remained comparable to the situation before the elevation.
Birds have successfully adapted to changing conditions. In the first years after the elevation, birds used the non-elevated parts of the plate. Gradually, birds started using the elevated parts again as the bottom animal communities and sediments recovered.
Back on the Plate
Bottom-dwelling animals and birds have returned to all elevated parts after five years. Sheltered thinner supplements with finer sand showed comparable benthic life to the rest of the plate after two years. In places with much erosion and thicker supplements, this takes longer. But here too, bottom animals are returning.
Most birds (such as the ruddy turnstone, oystercatcher, red knot, curlew, and grey plover) now also use the supplemented parts of the plate. However, there are differences between species. The dunlin and red knot, which prefer finer sand and lower parts of the plate, use the elevated parts less intensively.
The ruddy turnstone appears to favor the new elevated parts of the plate.
No Longer Visible
The sand plate itself has developed according to plan and wishes. The seven individual supplements are no longer directly recognizable as supplements after five years. They seem to have merged into the Roggenplaat as a whole.
The area important for birds on the Roggenplaat (the area that is dry more than 50% of the time) has significantly increased due to the sand supplements, from 602 to 726 hectares. Erosion of the plate is also progressing as expected. After five years, 90% of the applied volume remains at the site or within 50 meters.
Lessons for the Galgenplaat
“We are very pleased with this result. It shows that we are getting better at supplementing in these sensitive areas,” said project leader Harry de Looff at Rijkswaterstaat. “By deliberately leaving zones on the plate untouched, we have enabled the bird community to adapt without loss of species and numbers.”
Next winter, the plan is to also elevate the Galgenplaat, the second important feeding area in the Oosterschelde. The lessons learned at the Roggenplaat will be applied to this project.
