Impact of oyster reefs on waves and erosion

Tidal flats in estuaries and tidal basins face the threat of drowning due to accelerated sea level rise in the (near) future. On top of this, human interventions further pressure tidal flats. Measures to reduce erosion of tidal flats are therefore needed. Oyster reefs can lead to wave attenuation and subsequent reduced erosion. Measurements were however very scarce. To explore the potential of oyster reefs on wave attenuation and erosion reduction, a field campaign was therefore conducted at an oyster reef in the Eastern Scheldt, the Netherlands. Results indicate that waves are only attenuated during a short period of the tidal cycle, namely for conditions with small water depths. These conditions are however the periods where bed shear stresses by waves are relatively high. We conclude that reefs reduce erosion rates during relatively mild conditions, but that they are not effective during severe storms.