Bart Schultz
It's now clear that beavers thrive so well in the Netherlands that it is needed to take measures to prevent them from developing their activities in the wrong places. Responsibility for water management and flood protection lies primarily with the Water Authorities (regional) and Rijkswaterstaat (national). Similar problems also arise with roads and railways.
Beavers prefer to live in family groups in watery environments. The polders and the floodplains of the rivers meet this need perfectly well. During the high river water levels in the Netherlands in December 2023 and January 2024, several Water Authorities were therefore actively searching for beavers. The Water Authorities wanted to prevent the beavers from taking advantage of the high water levels to dig their dens in risky locations in the dikes, with all the potentially harmful consequences that entailed.
In 2024, the Foundation for Applied Water Research (STOWA), the knowledge centre for the Water Authorities and Provinces, organized four field visits related to the activities of beavers in watercourse banks and dikes. Each visit had a different theme. The themes were: Restoring of activities of beavers in dikes and dams, water management systems, preventive measures in dike reinforcements, and high water. Only twenty people could participate in each theme, which meant that all four visits were quickly fully booked. I was able to participate in the field visit to the Water Authority Hollandse Delta, which focused on Restoring of activities of beavers in dikes and dams. I also tried to participate in the High water field visit, but it was already fully booked.
The visit to the Hollandse Delta was well-organized and very interesting. We started with three excellent introductions. The first focused on the beaver, its behaviour, and its role in the ecosystem; the second on the potential damage beavers can cause to dikes and watercourses; and the third on the situation at the Water Authority Hollandse Delta. The introductions were well-structured and provided an interesting overview of what was happening and what the potential consequences could be.
We then went on a field visit to several relevant locations. One was where the beavers had dug their den from the bank in the backyard and under a shed of a dike house. Restoration work had been carried out, and improved bank protection had been installed. A newly developed method was also demonstrated, involving inserting a chicken-wire-like grid into a bank up to two metres deep - one metre below the ditch bottom - so that the beavers could no longer pass under it. A steeply sloped bank at the edge of a nature reserve was also shown, allowing the beavers to dig their burrows. They enthusiastically obliged. The spread of the beaver across the Netherlands and within the Water Authority Hollandse Delta management area made a particularly strong impression on me, as it has happened so rapidly, posing all the associated risks to the dikes and banks of the watercourses.
All in all, a very interesting and insightful excursion. We can only hope that the risks we face will soon be sufficiently recognized, so that the Water Authorities and Rijkswaterstaat can take the necessary measures; on the one hand, to properly manage the advance of the beavers in the polders, and on the other hand, to guarantee the safety of our dikes and banks of the watercourses. This will give the beavers the opportunity to develop their activities in places where it is easily possible in the densely populated Netherlands, allowing them to fulfil their role in the ecosystem.
