Bart Schultz
On April 10, 2025, I attended one of the meetings about mobile barriers. The meeting was organized in cooperation with the Department of Hydraulic Engineering, Faculty of Civil Engineering, Delft University of Technology. It turned out that the Department had since twelve years a real test polder at the university campus, called Floodproof Holland, where various types of barriers can be tested.
Flood protection in the Netherlands is normally provided by dunes, dikes, and storm surge barriers. However, in the event of an emergency or the risk thereof, two other types of measures may be needed: temporary barriers and mobile barriers.
A clear example of temporary barriers are the rebates in gates and passages through dikes, into which stoplogs can be inserted to prevent flooding. During the 1995 flood, several colleagues and I examined such a facility in a river dike near the city of Tiel along the Waal River. There were even two rebates, one behind the other, into which stoplogs had been inserted, with horse manure poured between them, as it was very impermeable.
Sandbags were typically used for mobile barriers. However, filling and placing them is quite heavy and relatively time-consuming, so the search was for other types of mobile barriers, which have recently been tested in the test polder at the university campus.
The morning meeting consisted of introductions and a discussion, after which we were taken to the test polder for lunch, followed by an explanation, tour, and demonstration of the various test setups.
Mobile barriers have been used very little in the Netherlands. However, there are more applications abroad, some of which have also been studied in the test polder. During one of the presentations, it was revealed that the Ministry of Defence had a test area in the Marnewaard region of Groningen where soldiers can practice constructing mobile barriers, as they are often deployed in support in such situations.
During the 2021 floods in the province of Limburg, no fewer than 250,000 sandbags were filled and deployed using traditional methods. Following the floods, the Water Authority Limburg began researching alternatives to sandbags. Test sites were used near the city of Roermond as part of this research.
Based on the findings, the Water Authority Limburg has since purchased mobile barriers of the Geodesign Barrier type. These should be deployable within one hour. However, sandbags are still needed at some points, primarily to prevent leaking. The materials are currently stored in several containers at a suitable location. One container equals 60,000 sandbags. The Water Authority Limburg holds exercises every October to be ready in the event of a disaster.
A Mobile Barrier Handbook, published by Rijkswaterstaat in collaboration with international partners, was also presented. The book can be downloaded as a PDF.
As mentioned, after lunch in the test polder, various test setups were visited, demonstrated, and explained. Most were suitable for flood defences up to one metre high. However, the mobile dike type could withstand up to 3.5 metres, which is quite a considerable height for such a dike. All in all, a very interesting meeting, which showed that there are certainly new possibilities for deploying mobile barriers significantly faster and with less effort than the sandbags that were commonly used until recently.
