Building flood resilience requires solutions that perform not only at installation, but over decades of exposure to changing environmental conditions. Large‑scale wave impact tests at the Vlassenbroek controlled floodplain show that dike covers reinforced with lime‑treated local soils maintain strong erosion resistance after six years of service, even under realistic storm conditions.
Flood protection infrastructure is a critical part of modern civil engineering, requiring solutions that withstand repeated stress, evolving climate conditions, and long service lifetimes. At the Vlassenbroek controlled floodplain in Belgium, large‑scale wave impact tests are used to help assess the erosion resistance of dike reinforcements - both at installation and after years of exposure, under realistic conditions.
A test plot designed for long‑term comparison
In 2019, De Vlaamse Waterweg nv, in collaboration with Lhoist, constructed a dedicated test plot along the ring dike of the Vlassenbroek floodplain. The plot includes three different types of dike cover:
- silt‑ and clay‑rich soil strengthened with 2% quicklime
- locally excavated sandy soil improved with 3% lime‑based binder
- an untreated reference layer for comparison
Using local soils allows performance differences to be assessed under identical environmental conditions.
Simulating realistic storm conditions
In April 2026, Infram Hydren carried out wave impact tests on six sections of the dike. The tests simulated storm conditions with wave heights of approximately 0.6 to 0.7 meters, focusing on the resistance of both vegetation and the underlying cover layers to repeated wave action.
These tests form part of a broader monitoring program and BONSAI – Boosting flood resilience in estuarine systems anticipating shifting climate zones were commissioned by the Departement Mobiliteit en Openbare Werken in the framework of the BONSAI – Boosting flood resilience in estuarine systems anticipating shifting climate zones project.
Early observations after six years
While the full results will be interpreted alongside other erosion resistance tests, initial observations already indicate the strong performance of vegetated, lime‑treated cover layers under wave impact.
Notably, this is the first time wave impact tests have been conducted on a dike reinforced with lime‑treated soils, confirming their long‑term erosion resistance under repeated hydraulic stress.
Supporting reliable flood protection solutions
At Lhoist, we work alongside infrastructure partners to apply technical expertise where it matters most. Lime‑based solutions, combined with practical know‑how, help support dike systems that must perform consistently - today and over decades of service. This long‑term perspective is essential when protecting critical infrastructure against increasingly variable environmental conditions.
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