Field measurements of dune erosion and hydrodynamics during the Hybrid Dune experiment
2026-08-12
Hybrid flood defences combine sandy dunes with hard coastal structures such as dikes or dams. The Hybrid Dune experiment investigated hydro-morphodynamic interactions between dunes and hard structures during storm events in the collision regime. A 100-metre-long test dune was constructed just above the high-water line at the Sand Motor beach in the Netherlands, comprising four different cross-shore configurations: a sandy dune, dike-in-dune, seawall-in-dune, and dike. This paper presents a comprehensive dataset collected between 18 December 2024, and 8 January 2025, during which five consecutive storm events caused substantial dune erosion. Collected hydrodynamic data include offshore wave conditions, pressure sensor and velocimeter data at four cross-shore transects, and pressures at hard structural elements (wall, revetments) for wave impact and pore pressure analysis. Optical backscatter data were collected in the surf zone. Morphodynamic data include continuous measurements of the dune face during storms by multi-line LiDARs, complemented by bathymetric and topographic surveys. This dataset enables detailed analysis of hydro-morphodynamic processes at the beach-dune interface and especially the influence of hard structural elements on dune erosion, with direct relevance for improving and validating hybrid flood defences and dune erosion models.