Stability of a tidal marsh under extreme flow conditions: a flume experiment

Coasts and river mouths (estuaries) are increasingly exposed to flood risks due the global and local changes, resulting in sea level rise, increasing magnitude and frequency of storm surges. This increasing flood risk motivates a paradigm shift towards nature-based flood defense, where engineered flood defense structures (like dikes) are supplemented with conservation or creation of wetlands (like tidal marshes) in front of the dikes, which contribute to lower the flood risks. In this EU-INTERREG project, the combined protective function of dikes and natural wetland foreshores in front of dikes are tested under field and laboratory conditions. In the field, controlled dike breach experiments (in the Hedwige-Prosperpolder, Schelde estuary, Belgium & the Netherlands) are conducted to investigate the process of dike breach growth and the interaction with stability of the vegetated marsh foreshore. More specifically within this sub-project, the stability of the marsh soil and vegetation under extreme flow conditions that occur during dike breaches, is tested in a new tidal flume lab facility at the UAntwerp campus (the so-called Mesodrome). Marsh soil monoliths (0.8 m wide x 1.2 m long x 0.4 m deep) containing the marsh vegetation are excavated from the field and placed in the flume, and the responses of the vegetation and soil to extreme flow velocities (up to 2 m/s) are tested.

Keywords:HYDRODYNAMICS, EROSION, WETLANDS

Disciplines:Geomorphology and landscape evolution, Coastal and estuarine hydraulics

Project type:Service project